Plants used for treating respiratory infections in rural Maputaland, KwaZulu-Natal, South Africa

Extraction and Processing of Bioactive Phytoconstituents from Widely Used South African Medicinal Plants for the Preparation of Effective Traditional Herbal Medicine Products: A Narrative Review

Medicinal plants are sources of crude traditional herbal medicines that are utilized to reduce the risk of, treat, or manage diseases in most indigenous communities. This is due to their potent antioxidant and anti-inflammatory effects. It is estimated that about 80% of the population in developing countries rely on herbal traditional medicines for healthcare. This signifies the need for traditional herbal medicines, which are polyherbal formulations prepared by traditional health practitioners. This review examines preparatory steps to extract bioactive phytoconstituents and post-extraction processes to increase the potency of the extracted bioactive phytoconstituents. Achieving this will allow for the reduced use of plant materials and promote the sustainable use of the limited resource of medicinal plants, especially in our South African context. Electronic ethnobotanical books and online databases were used to find studies that focus on phytoconstituent extraction and post-extraction processing to enhance the potency of the extracted bioactive phytoconstituents. Modification of the extracted bioactive phytoconstituents to synthesize daughter compounds facilitates an enhancement in their potency and bioavailability. Based on the data collected through this review, the importance of understanding the properties of the targeted phytoconstituents is essential in selecting the required extraction method. This determines the quality and yield of extracted bioactive phytoconstituents.

Indigenous Knowledge and Quantitative Analysis of Medicinal Plants Used to Remedy Respiratory Tract Disorders in Mid-Western Tanzania

This study is aimed at documenting the indigenous knowledge and quantitative analysis of medicinal plants (MPs) used by traditional health practitioners (THPs) of Urambo District in mid-western Tanzania to manage respiratory tract disorders (RTDs). The ethnomedicinal data were collected using semistructured interviews with 55 THPs using a snowballing technique in the district. The data were analysed for indigenous knowledge among gender, age groups, education status, and experience. Family importance value (FIV), use value (UV), relative frequency of citation (RFC), informant consensus factor (ICF), and Jaccard index (JI) were computed. A total of 42 MPs representing 28 families were recorded being used against RTDs in the district. Fabaceae was the dominant family in terms of species (16.7%) and FIV (84%). Decoction (51.0%) was the preferred technique for preparing remedies, while trees (61.9%) and leaves (38.1%) were the most utilised life form and plant parts, respectively. The RFC in the current study varied from 0.055 (Musa paradisiaca L.) to 0.655 (Zingiber officinale Roscoe) and 0.073 (Dichrostachys cinerea (L.) Wight & Arn.) to 0.673 (Entada abyssinica Steud. ex A.Rich.), respectively. The highest ICF was recorded for cough (0.922). The JI ranged from 2.7 to 7.9. Among the documented MPs, 55% had least concern, 2% were endangered, 7% had data deficiency conservation status, and 36% had no record in the IUCN Red List. The study revealed that the district's population depends on MPs for healthcare. Thus, conservation strategies are needed for the sustainable utilisation of the MPs. Importantly, the documented MPs hold immense potential in future pharmacological and phytochemical studies, offering hope for the development of new drugs for RTDs. Also, the study suggests the need for scientific validation of the MP's efficacy and safety.

Targeting chemokine-receptor mediated molecular signaling by ethnopharmacological approaches

ETHNOPHARMACOLOGICAL RELEVANCE

Infection and inflammation are critical to global human health status and the goal of current pharmacological interventions intends formulating medications/preventives as a measure to deal with this situation. Chemokines and their cognate receptors are major regulatory molecules in many of these ailments. Natural products have been a keen source to the drug development industry, every year contributing significantly to the growing list of FDA approved drugs. A multiverse of natural resource is employed as a part of curative regimen in folk/traditional/ethnomedicine which can be employed to discover, repurpose, and design potent medications for the diseases of clinical concern.

AIM OF THE STUDY

This review aims to systematically document the ethnopharmacologically active agents targeting the infectious-inflammatory diseases through the chemokine-receptor nexus.

MATERIALS AND METHODS

Articles related to chemokine/receptor modulating ethnopharmacological anti-inflammatory, anti-infectious natural sources, bioactive compounds, and formulations have been examined with special emphasis on women related diseases. The available literature has been thoroughly scrutinized for the application of traditional medicines in chemokine associated experimental methods, their regulatory outcomes, and pertinence to women's health wherever applicable. Moreover, the potential traditional regimens under clinical trials have been critically assessed.

RESULTS

A systematic and comprehensive review on the chemokine-receptor targeting ethnopharmaceutics from the available literature has been provided. The article discusses the implication of traditional medicine in the chemokine system dynamics in diverse infectious-inflammatory disorders such as cardiovascular diseases, allergic diseases, inflammatory diseases, neuroinflammation, and cancer. On this note, critical evaluation of the available data surfaced multiple diseases prevalent in women such as osteoporosis, rheumatoid arthritis, breast cancer, cervical cancer and urinary tract infection. Currently there is no available literature highlighting chemokine-receptor targeting using traditional medicinal approach from women's health perspective. Moreover, despite being potent in vitro and in vivo setups there remains a gap in clinical translation of these formulations, which needs to be strategically and scientifically addressed to pave the way for their successful industrial translation.

CONCLUSIONS

The review provides an optimistic global perspective towards the applicability of ethnopharmacology in chemokine-receptor regulated infectious and inflammatory diseases with special emphasis on ailments prevalent in women, consecutively addressing their current status of clinical translation and future directions.

Blood purification practices: Some ethnopharmacological insight from a rural community in KwaZulu-Natal, South Africa

ETHNOPHARMACOLOGICAL RELEVANCE

Blood purification practices, also referred to as blood cleansing or detoxification, is an ancient concept which is widespread within African traditional medicine. There is, however, limited consolidated information about the selection of plant species, the purpose of use and how the preparation is made. An in-depth examination of how regional communities use medicinal plants for blood purification is needed to better understand this ethnopharmacological practice.

AIM OF THE STUDY

To gather knowledge on the traditional use of medicinal plants used for the purpose of blood purification by laypersons in northern Maputaland, KwaZulu-Natal, South Africa.

METHODS

An ethnobotanical survey was conducted on medicinal plants used in the rural areas of northern Maputaland for blood purification. Interviews were conducted in 55 homesteads, where the most knowledgeable participant per household was interviewed using structured questionnaires. Information collected included knowledge of the concept of blood purification, purpose for medicating, plant selection, and mode of preparation. The most important species and families were identified through indices.

RESULTS

Sixty-four plant species from 35 families were recorded as blood purifiers for the treatment of ailments linked to the need for blood purification. Terminalia sericea Burch. ex DC. was the most used plant species (mentioned by 39% of the people interviewed). The conditions that were mostly associated with blood purification were skin complaints, gastro-intestinal disorders, and overall improvement of general health. Blood purification is also commonly used for non-medical purposes such as granting good luck or as a love charm. Six new plant species and five new Zulu vernacular names had not previously been documented for blood purification.

CONCLUSION

The frequently mentioned use of medicinal plants for blood purification by the rural community of northern Maputaland clearly emphasises the importance of this cultural practice. There is no doubt that when examining African traditional medicine, holistic terms such as "blood cleansing" cannot be ignored. Future studies may provide a better understanding of this often misunderstood and undocumented practice.

An imprecise probability approach-based determination of over-represented southern African plant genera and families used in ethnopharmacology

ETHNOPHARMACOLOGICAL RELEVANCE

The analyses of patterns of over-representation of southern African traditional medicinal plants at the genus and family level provide information about the differences in plant use among southern African countries and disease categories. 'Over-representation' refers to the phenomenon whereby the proportion of plants belonging to a taxonomic group is higher in ethnobotanical pharmacopoeia than in the total flora.

AIM OF THE STUDY

This study aimed to use the Imprecise Dirichlet Model (IDM) to analyse data from ten southern African countries to establish how over-represented medicinal plant families compare with over-represented genera, how over-represented medicinal taxa differ among countries in this region of Africa, and how over-represented taxa differ among six major disease categories.

MATERIALS AND METHODS

Floral data for the total species composition of each country were obtained from online databases. Medicinal plant species lists were generated from published surveys, inventories, and books. IDM calculations were executed using the inverse of the cumulative beta probability density function in Microsoft Excel™. Python programming language source code was used to calculate Pearson correlation (r) values and Jaccard coefficients (J).

RESULTS

Nine of forty-two over-represented medicinal plant families in southern Africa (group 1) do not have over-represented genera. Seven of the forty genera with the highest margins of over-representation belong to under-represented families. Nineteen of the forty-two over-represented families have margins of over-representation smaller than the cumulative margins of their over-represented genera. Groups of countries with similar overall flora (J ≥ 0.333) are Botswana and Namibia (group 2), Malawi, Mozambique, Zambia and Zimbabwe (group 3). The families and genera with the highest margins of over-representation are Loganiaceae and Albizia in group 1, Combretaceae and Vachellia in group 2, Dioscoreaceae and Senna in group 3, and Sapotaceae and Solanum in group 4 (South Africa). The families and genera with the highest margins of over-representation across disease categories are Ebenaceae and Albizia, Canellaceae and Dicoma, Combretaceae and Pterocelastrus, Ebenaceae and Bersama, Francoaceae and Erythrina, and Aristolochiaceae and Strychnos for plants used in the treatment of STIs, febrile and mosquito-vector diseases, microbial infections, pain, skin conditions, and female sexual/reproductive problems, respectively.

CONCLUSIONS

Genus-level calculations are more efficient in generating taxonomic lists that can be used for ethnopharmacological investigations due to the exclusion of under-represented genera. Limiting the size of geographical areas from which medicinal plant lists are sampled and targeting plants used to treat specific types of disease prevents the underestimation of niche over-represented taxa.

An inventory and analysis of the medicinal plants of Mozambique

ETHNOPHARMACOLOGICAL RELEVANCE

A comprehensive checklist and analysis of medicinal plant species and their uses in Mozambique, and a comparison with South Africa provided a more profound understanding of the broad concept of Traditional African Medicine as a healing culture and the need for a more informative classification system.

AIMS OF THE STUDY

This study was aimed at recording all medicinal plants reported in Mozambique according to literature and answer four main questions. 1. How many medicinal plant species have been recorded for Mozambique? Of those, how many are indigenous to Mozambique, and how many are introduced or cultivated exotics? 2. What are the main medicinal uses in Mozambique and which species are used for which ailments? 3. What are the similarities and differences between the medicinal floras of Mozambique and South Africa - are the same species used for the same ailments and is there evidence of cultural exchange? 4. Do the data provide new insights into Traditional African Medicine as one of the oldest medicine systems in the world?

MATERIALS AND METHODS

A literature survey was done to compile the medicinal checklist of Mozambique using 29 available literature sources, which were found from published books, journal articles, reports, unpublished theses, dissertations, and online databases.

RESULTS

A total of 731 medicinal plant species and infraspecific taxa from 447 genera and 120 families was recorded for Mozambique. Of these, 590 (81%) are indigenous, and 87 are non-indigenous (50 naturalised and 37 cultivated exotics). Of the 731 medicinal plant species, 494 (68%) are also used medicinally in South Africa and 148 (30%) are used for the same or similar ailments. Many of the shared taxa and uses have been recorded in the adjoining KwaZulu-Natal Province of South Africa, which has similar vegetation types.

CONCLUSION

The similarity between Mozambique and South Africa (and especially the KwaZulu-Natal Province) not only suggest an exchange of traditional knowledge but also indicates the existence of a hitherto unnamed medicinal system of the southern and eastern African Bantu-speaking cultures that is in need of detailed comparative studies.

Antiviral Effects of the Plant Family Amaryllidaceae

Background

In spite of the significant progress in modern medicine, viruses continue to be a formidable challenge to human health. The use of plants for the remediation of viral-borne diseases stretches back to the very dawn of mankind. Among bulbous plants, the Amaryllidaceae is one of the most popular families exploited in the traditional remediation of infectious diseases.

Methods

This account details the findings from a literature search carried out on the antiviral properties of the Amaryllidaceae. The keyword engaged in the search was “antiviral” in combination with the words “Amaryllidaceae,” “Amaryllidaceae specie,” and “Amaryllidaceae alkaloid.”

Results

Thirty-six taxa from 13 countries, notably in Africa and parts of Asia, have been cited as traditional remedies for viral diseases. Alcoholic bulb extracts of 18 species were evaluated against 23 different pathogens from 13 viral families. A wide range of activities was observed, with the whole-plant methanol extract of Zephyranthes candida seen to be the most striking (IC50 0.0019 µg/mL against poliovirus). The active principles in the main were isoquinoline alkaloids, of which lycorine impressed against the Avian influenza virus (strain H5N1). The mechanisms underlying the antiviral effects were seen to be related to the inhibition of DNA, RNA, and protein synthesis as well as inhibitory effects toward reverse transcriptase and protease enzymes.

Conclusion

Amaryllidaceae provides a richly diverse platform for antiviral drug research. Such endeavors have been fortified by the significant amounts of information emerging from indigenous knowledge systems. Ongoing studies will continue to target the active entities, particularly from taxa with verifiable ethnomedicinal backgrounds.

The traditional use of Southern African medicinal plants to alleviate fever and their antipyretic activities

ETHNOPHARMACOLOGICAL RELEVANCE

Multiple plant species are used traditionally in southern Africa to treat fever. This review summarises the traditional use, highlights promising plant species and focuses on validation studies to highlight future areas of research.

AIM OF THE STUDY

This study aimed to critically review the use of southern African plants to alleviate fever. Additionally, an examination of research into those plants was undertaken to highlight gaps in the literature with the aim of stimulating further research in this field.

MATERIALS AND METHODS

Ethnobotanical books, reviews and primary research studies were searched to identify plant species traditionally used to treat fever in southern Africa and to summarise the current knowledge and identify areas requiring further research. This study was non-biased and did not have any taxonomic preferences, nor did it favour any southern African healing systems over the others.

RESULTS

The traditional therapeutic uses of 203 southern African plant species to alleviate fever were recorded. Leaves and roots/bulbs/rhizomes were the most commonly used plant part, and they were most commonly prepared as decoctions or infusions and consumed orally. Notably, only twenty-two species (∼11% of the identified species) have been scientifically evaluated for antipyretic properties, with substantially fewer mechanistic studies evident.

CONCLUSIONS

Despite the availability of ethnobotanical records, the antipyretic properties of southern African medicinal plants are poorly reported. Indeed, the efficacy of most plants is yet to be verified and very few mechanistic studies are available.

Traditionally used polyherbals in a southern African therapeutic context

ETHNOPHARMACOLOGICAL RELEVANCE

In African traditional medicine, there are several plant species that are used in combination with either other plant species or non-plant derived combinations such as sugar and honey, salt and vinegar, milk, fat etc. This review examines the role of these combinations and postulates the scientific and therapeutic validation of such combinations.

AIM OF THE STUDY

This study reviewed the ethnopharmacological literature and documented the use of southern African plant combinations to find a scientific rationale for such combinations, and provide recommendations for future studies.

MATERIALS AND METHODS

Ethnobotanical books and online databases such as Scopus, ScienceDirect, PubMed and Google Scholar were used to find ethnobotanical studies within the southern African context that focus on the combinations of plants with other plants or various additional ingredients. The scientific literature was examined to determine if evidence was available to substantiate such combinations.

RESULTS

One hundred and eighty-seven medicinal plant (plant-to-plant) combinations that are used in the southern African traditional healing system were recorded. These plant combinations were used against infections of the gastrointestinal tract, respiratory tract, and skin as well other non-infectious diseases such as reproductive and psychiatric disorders. Respiratory infections were the most documented infections to be treated using plant combinations. The plant that was documented to be most commonly used in combination with other plants was Artemisia afra Jacq. ex Willd. While plant-plant combinations have drawn a marked interest, comparatively, plant-adjuvant (e.g. milk, sugar, honey, salt, vinegar, fats) combinations have attracted less research interest. Milk was reported as the most used additional ingredient in combination with medicinal plants. The combination of animal urine and dung with medicinal plants has been reported as a treatment for treat prostate infections, the human immunodeficiency virus (HIV). Other ingredients such as clay and flour were also documented, and these are often mixed with medicinal plants to treat fever, stomach ailments, sexually transmitted infections (STI) and skin conditions. Although combination therapy has been frequently reported in ethnobotanical records, over 90% of the combinations reviewed still need to be scientifically validated.

CONCLUSION

Scientific reports on the antimicrobial, anti-oxidant, anti-inflammatory and other pharmacological effects of these combinations may offer an understanding of traditional combination therapy. In addition, investigation into the mechanisms of action of these combinations are also recommended to supplement the findings. Nonetheless, the use of plant combinations is still an untapped research area in southern Africa and there is a need to validate the use of those documented combinations to obtain a better understanding of combined traditional medicinal plant use.

Neuroprotective effects of Lippia javanica (Burm.F.) Spreng. Herbal tea infusion on Lead-induced oxidative brain damage in Wistar rats

Background

Though Lippia javanica (Burm.f.) Spreng antioxidant activity has been demonstrated, its effect in protecting the brain from lead (Pb)-induced oxidative damage is unknown. This study investigated the effect of L. javanica against Pb-induced oxidative stress, inflammation, apoptosis and acetylcholinesterase activity in rat’s brain.

Methods

L. javanica herbal tea infusion was prepared, its phytochemical constituent was revealed by liquid chromatography-Mass spectrometer (LC-MS) and was administered simultaneously with Pb. Four groups of male Wistar rats (n = 5/group) were used: control received distilled water; Pb-acetate group received 50 mg Pb/ Kg bodyweight (bw), treatment group received 50 mg Pb/ Kg Pb-acetate + 5 ml/kg bw L. javanica and L. javanica group received 5 ml/Kg bw of L. javanica tea infusion only. After 6 weeks of treatment, oxidative status, acetylcholinesterase activity, inflammation and apoptosis was assessed in brain tissue which was also histologically examined.

Results

Mean brain and heart weight was reduced (p < 0.05) while liver and spleen weights were increased (p < 0.05) in Pb exposed animals but were prevented by L. juvanica treatment. Treatment with L. javanica increased (p < 0.05) overall brain antioxidant status (glutathione and superoxide dismutase activities) and reduced lipid peroxidation (p < 0.05) compared to the Pb exposed animals. Pro-inflammatory cytokine tumour necrotic factor-alpha, pro-apoptosis Bax protein and anticholinesterase activity were reduced (p < 0.05) in Pb-L. javanica treated animals compared to the Pb exposed group. Histological examination confirmed neuroprotective effects of L. javanica as evidenced by reduced apoptosis/necrosis and inflammation-induced vacuolization and oedema in the hippocampus. The L. javanica treatment alone had no detrimental effects to the rats. LC-MS analysis revealed L. javanica to be rich in phenolics.

Conclusions

This study demonstrated that L. javanica, rich in phenolics was effective in reducing Pb-induced brain oxidative stress, inflammation, apoptosis, acetylcholinesterase activity and neuronal damage.

LC-MS Characterization and Biological Activities of Cuban Cultivars of Plectranthus neochilus Schltr

Plectranthus neochilus Schltr. (Lamiaceae) is a plant recently introduced in Cuba. Worldwide, it is an ethnomedicinal alternative for its use against microbial infections, but the Cuban population use the extracts to treat sleep disorders. To address this apparent incongruity, four collections (from different seasonal conditions in the year) of Cuban P. neochilus cultivars were analyzed in terms of their pharmacognostic characteristics. Three extracts using fresh and dried leaves were chemically and biologically characterized. UPLC-DAD-MS/MS analysis was performed to determine their chemical composition, while a panel of nine microorganisms was used to evaluate their antimicrobial activity. Finally, cytotoxic effects of different fractions were measured in three cell lines by the resazurin viability assay. In contrast to previously reported micro and macromorphological properties of P. neochilus, the leaves from the Cuban cultivars did not present glandular trichomes, nor did they produce quantifiable levels of essential oils. Moreover, aqueous extracts used by the population revealed no significant antimicrobial activity and were not cytotoxic. The three extracts showed a similar phytochemical composition, i.e., eight flavonoids, seven abietane diterpenes, and rosmarinic acid as the major constituent, most of them reported for the first time in this species. The low yield of essential oil, the absence of glandular trichomes, compounds with a high level of oxidation, and a moderate antimicrobial activity detected were the most distinctive pharmacognostic and biological characteristics of P. neochilus grown in Cuba. These aspects could explain its non-use as an antimicrobial.

Lippia javanica (Zumbani) herbal tea infusion attenuates allergic airway inflammation via inhibition of Th2 cell activation and suppression of oxidative stress

BACKGROUND

Lippia javanica (lemon bush) is commonly used in the treatment of respiratory ailments, including asthma in southern African countries but there is no scientific evidence to support this claim. This study investigated the anti-inflammatory, antioxidant and anti-asthmatic effects of L. javanica using a rat model of asthma.

METHODS

A 5% w/v L. javanica tea infusion was prepared and characterised by liquid chromatography-mass spectrometer (LC-MS). Animals were intraperitoneally sensitized with ovalbumin (OVA) and subsequently challenged intranasal with OVA on day 15 except the control group. Animals were grouped (n = 5/group) for treatment: unsensitised control, sensitised control, sensitised + prednisolone and sensitised + L. javanica at 50 mg/kg/day and 100 mg/kg/day - equivalent to 1 and 2 cups of tea per day, respectively. After 2 weeks of treatment, bronchoalveolar lavage fluid (BALF) was collected for total and differential white blood cell (WBC) count. Nitric oxide (NO), lipid peroxidation and antioxidants were also assessed in BALF. Ovalbumin specific IgE antibody and inflammatory cytokines: IL-4, IL-5, IL-13 and TNF-alpha were measured in serum. Lung and muscle tissues were histological examined.

RESULTS

L. javanica was rich in phenolic compounds. OVA sensitisation resulted in development of allergic asthma in rats. L. javanica treatment resulted in a reduction in total WBC count as well as eosinophils, lymphocytes and neutrophils in BALF. L. javanica inhibited Th2-mediated immune response, which was evident by a decrease in serum IgE and inflammatory cytokines: IL-4, IL-5, IL-13 and TNF-α. L. javanica treatment also reduced malondialdehyde (MDA) and NO, and increased superoxide dismutase, glutathione and total antioxidant capacity. Histology showed significant attenuation of lung infiltration of inflammatory cells, alveolar thickening, and bronchiole smooth muscle thickening.

CONCLUSION

L. javanica suppressed allergic airway inflammation by reducing Th2-mediated immune response and oxidative stress in OVA-sensitized rats which may be attributed to the presence of phenolic compound in the plant. This finding validates the traditional use of L. javanica in the treatment of respiratory disorders.

South Africa's Best BARK Medicines Prescribed at the Johannesburg Muthi Markets for Skin, Gut, and Lung Infections: MIC's and Brine Shrimp Lethality

Indigenous trade of medicinal plants in South Africa is a multi-million-rand industry and is still highly relevant in terms of primary health care. The purpose of this study was to identify today's most traded medicinal barks, traditionally and contemporaneously used for dermatological, gastrointestinal, and respiratory tract infections; then, to investigate the antimicrobial activity and toxicity of the respective extracts and interpret outcomes in light of pharmacokinetics. Thirty-one popularly traded medicinal barks were purchased from the Faraday and Kwa Mai-Mai markets in Johannesburg, South Africa. Information on the medicinal uses of bark-based medicines in modern commerce was recorded from randomly selected traders. The minimum inhibitory concentration (MIC) method was used for antimicrobial screening, and brine shrimp lethality was used to determine toxicity. New medicinal uses were recorded for 14 bark species. Plants demonstrating some broad-spectrum activities against tested bacteria include Elaeodendron transvaalense, Erythrina lysistemon, Garcinia livingstonei, Pterocelastrus rostratus, Rapanea melanophloeos, Schotia brachypetala, Sclerocarya birrea, and Ziziphus mucronata. The lowest MIC value of 0.004 mg/mL was observed against Staphylococcus epidermidis for a dichloromethane bark extract of E. lysistemon. The tested medicinal barks were shown to be non-toxic against the Artemia nauplii (brine shrimp) bioassay, except for a methanol extract from Trichilia emetica (69.52% mortality). Bacterial inhibition of bark extracts with minimal associated toxicity is consistent with the safety and valuable use of medicinal barks for local muthi market customers. Antimicrobial outcomes against skin and gastrointestinal pathogens are feasible because mere contact-inhibition is required in vivo; however, MIC values against respiratory pathogens require further explaining from a pharmacokinetics or pharmacodynamics perspective, particularly for ingested rather than smoked therapies.

Evidence on collaboration of traditional and biomedical practitioners in the management of antimicrobial resistance in sub-Saharan Africa over 15 years: a systematic review protocol

BACKGROUND

The overuse of prescribed antimicrobials, concurrent use of traditional medicine, and prescribed antimicrobials have led to antimicrobial resistance. The absence of collaboration between traditional health practitioners and biomedically trained healthcare professionals can contribute to antimicrobial resistance, treatment failure, overdose, toxicity, and misadministration. This scoping review explores the evidence on collaboration between traditional health practitioners and biomedically trained healthcare professionals to reduce antimicrobial resistance and treatment failure in bacterial and viral diseases.

METHODS

We will search for electronic databases such as Science Direct, Google Scholar, PubMed, and MEDLINE via EBSCOhost. We will also search reference lists of included studies. A two-stage mapping procedure will be carried out. Stage one (1) will consist of the title, abstracts, and full article screening, respectively. A pilot screening form guided by the defined eligibility criteria will be used. In stage two (2), data will be extracted from the included studies. Two reviewers will conduct parallel screening and data extraction. Mixed methods appraisal tool (MMAT) will be used to assess the quality of the included studies. NVIVO version 11 will be employed to aid pertinent thematic analysis. The outcomes of interest will be as follows: Primary outcome will be preventing and reducing antimicrobial resistance. The secondary effect is the effective collaboration between traditional healthcare practitioners and biomedically healthcare professionals.

DISCUSSION

This review anticipates uncovering pertinent publications reporting the evidence of collaboration between traditional health practitioners and biomedically trained healthcare professionals to reduce antimicrobial resistance in sub-Saharan Africa. The sum-up of evidence acquired from the included studies will help guide future research. The result of the study will be print and electronically exposed.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO, CRD42017072952.

[Cultivation and use of medicinal plants and association with reporting of childhood asthma: A case-control study in the Bogotá savanna]

Introduction

The prevalence of childhood asthma has increased in recent years. The World Health Organization has called for conducting research exploring the role of traditional medicine and medicinal plants in respiratory disease control.

Objective

To identify the relationship between the prevalence of childhood asthma and traditional care of the respiratory system, including cultivation and use of medicinal plants.

Methods

We conducted an observational, analytic, case-control study that included children 2 to 14 years old who used official health services in eight municipalities near Bogota between 2014 and 2015. Cases were children diagnosed with asthma. We randomly selected the controls among the remaining patients of the same healthcare facilities. We applied an 18-question survey. The Mantel-Haenszel procedure identified significant associations using 95% confidence intervals.

Results

We surveyed the caretakers of 97 cases and 279 controls in eight municipalities. Some 23.4% (88/376) and 37.9% (142/375) reported using traditional remedies for fever control and common cold management, respectively. 8.8% (33/376) reported following traditional care during a common cold, 30.4% (114/375) reported growing medicinal plants at home, and 45% (166/369) reported using medicinal plants for health purposes in their household. Multivariate analysis showed that having and using medicinal plants at home is associated with a lower reporting of asthma (odds ratio 0.49; 95% confidence interval: 0.25 to 0.99).

Conclusions

Cultivating and using medicinal plants at home is associated with a lower reporting of childhood asthma. Researchers should consider the therapeutic, environmental, and cultural properties of medicinal plants to prevent respiratory diseases.

Ethnobotanical biocultural diversity by rural communities in the Cuatrociénegas Valley, Coahuila; Mexico

BACKGROUND

Cuatrociénegas, part of the Chihuahuan Desert, is a region of unique biological, geological, geographical, and evolutionary importance. Its current population is mestizo; nevertheless, it has high national historical, cultural, and touristic relevance in Mexico. It has been cataloged as nationally significant for its flora and fauna by Mexican law, as well as being designated a High Protection site by the World Wildlife Fund and UNESCO. Because of its diverse and complex biological and sociocultural characteristics, we considered it important to determine, identify, and analyze various aspects of the traditional ethnobotanical knowledge and practices in this region.

METHODS

Between 2016 and 2019, seven field trips were made to document the knowledge and use of flora. Cuatrociénegas is a protected area, collecting botanical material is regulated, so specimens were photographed and collected in neighboring communities, and in public and private gardens. Later permission was obtained to complete the collection of specimens (2019-2020). The plants were identified and entered into the flora database of the state of Coahuila, and deposited in the Herbarium of the Faculty of Forest Sciences, Autonomous University of Nuevo León, Mexico. One hundred ten local residents (50 men and 60 women), aged between 27 and 91 years, were interviewed (semi-structured interviews). The cultural importance of ethnobotanical resources (cultural significance index) and its significance with respect to ethnobotanical richness in other Biosphere Reserves in Mexico (Mann-Whitney test), and similarities in the diversity of exotic species (Sørensen index) were studied.

RESULTS AND DISCUSSION

The ethnobotanical information registers 158 species and 132 genera in 57 vascular and non-vascular families, documenting a greater knowledge and use of cultivated species (84) with respect to wild species (74). The diversity of plants reported is compared to other ethnobotanical studies carried out in Mexican Biosphere Reserves. These results are highly relevant, in spite of unique exotic species. The people local pay special attention to medicinal and ornamental plants. The species that presented the highest use values are Larrea tridentata, Jatropha dioica, and Machaeranthera pinnatifida, three species characteristic of the desert region.

CONCLUSIONS

The particular diversity of wild flora in Cuatrociénegas Valley, combined with the varied introduced flora, is an important multifunctional resource. Special attention to introduced species is associated with harvesting use restrictions in the protected area as well as the high value of ornamental species that are difficult to maintain in desert areas. The extensive use of ethnobotanical knowledge is an example that biocultural diversity (at the conceptual level) is also strongly associated with socio-ecological systems incorporating mestizo groups and semi-urban rural landscapes, thus ceasing to be an exclusive focus of indigenous communities and regions.

Phytochemical composition and in vitro safety evaluation of Ziziphora clinopodioides Lam. ethanolic extract: Cytotoxicity, genotoxicity and mutagenicity assessment

ETHNOPHARMACOLOGICAL RELEVANCE

The application of the herb Ziziphora clinopodioides Lam. in folk medicine and as a food additive has been recommended due to its many claimed bioactivities. Regardless of the plant benefits, its safety considerations are largely unknown.

AIM OF THE STUDY

The aim of the present research was to determine the chemical compositions and cytotoxicity, genotoxicity, and mutagenicity potentials of the ethanolic extract of Ziziphora clinopdioides Lam. (EEZC).

MATERIALS AND METHODS

GC-MS and LC-MS analysis were used for chemical composition determination. The MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) and trypan blue exclusion dye assays were used for cytotoxicity and the Comet assay was employed for genotoxicity assessment on human blood lymphocytes. Also, the Ames Salmonella/microsome test was carried out for the evaluation of mutagenicity.

RESULTS

Pulegone was the main component of the n-hexane fraction. Different phenolic acids and flavonoids were detected by LC-MS. The cytotoxicity study indicated a conspicuous decline in human lymphocyte viability ranging from 52% to 100% as showed by the MTT assay and 67% up to 100% by the trypan blue assay, at 1 and 10 mg/mL, respectively. The Comet assay results revealed a dose dependent genotoxicity, in so much as 90% and 98% of the cells were screened as damaged at concentrations of 5 and 10 mg/mL, respectively. An incidence rate of 8% and 13% of grade 4 damage was observed at 5 and 10 mg/mL, respectively. Additionally, the DNA damage index (DI) was elevated dose-dependently by a rising concentration of the extract, wherein the DI at 10 mg/mL concentration was 2.22, which was 22 times greater than that of negative control, and even more than positive control. The Ames test exhibited no signs of mutagenicity for neither Salmonella typhimurium TA98 nor TA100 strains, accompanied or unaccompanied by S9 metabolic activation.

CONCLUSION

Results indicated a dose-dependent cytotoxicity and genotoxicity potential of the EEZC on human lymphocytes, suggesting that this plant should be used with caution by consumers, even in the food and pharmaceutical industries. Since the plant usage in daily life continues to increase due to its ever growing phytotherapical and phytonutritional properties, it may pose a health risk by its high concentration's uptake. Although no mutagenicity of this extract was observed in this study, further research is recommended to clarify the mutagenic risks of this herb.

The traditional use of southern African medicinal plants for the treatment of bacterial respiratory diseases: A review of the ethnobotany and scientific evaluations

ETHNOPHARMACOLOGICAL RELEVANCE

Multiple plant species were used traditionally in southern Africa to treat bacterial respiratory diseases. This review summarises this usage and highlights plant species that are yet to be verified for these activities.

AIM OF THE STUDY

This manuscript reviews the traditional usage of southern African plant species to treat bacterial respiratory diseases with the aim of highlighting gaps in the literature and focusing future studies.

MATERIALS AND METHODS

An extensive review of ethnobotanical books, reviews and primary scientific studies was undertaken to identify southern African plants which are used in traditional southern African medicine to treat bacterial respiratory diseases. We also searched for southern African plants whose inhibitory activity against bacterial respiratory pathogens has been conmfirmed, to highlight gaps in the literature and focus future studies.

RESULTS

One hundred and eighty-seven southern African plant species are recorded as traditional therapies for bacterial respiratory infections. Scientific evaluations of 178 plant species were recorded, although only 42 of these were selected for screening on the basis of their ethnobotanical uses. Therefore, the potential of 146 species used teraditionally to treat bacterial respiratory diseases are yet to be verified.

CONCLUSIONS

The inhibitory properties of southern African medicinal plants against bacterial respiratory pathogens is relatively poorly explored and the antibacterial activity of most plant species remains to be verified.

Combinatory therapeutic approaches for common cold and SARS-CoV-2

Many countries in the world face the new challenge of having human coronavirus infection to manage commendably - the large affliction of human health. Together, each country has modern drugs and a variety of medicinal products developed from their traditional medical practitioners to treat a common cold. In this review, we describe potentially synergistic therapeutics of traditional and complementary medicine available for common cold which might be useful for prevention or for the adjuvant treatment of the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). Further, we provide a phylogenetic overview of SARSCoV-2 based on a complete genome sequence of common cold viruses. We suggest modern and traditional medicine and preventive strategies which might control the disease to offer more suitable and acceptable common cold management including coronavirus. A substantial proportion of medicinal products developed by traditional medicine against common cold as well as modern medicine mainly focus on symptoms suppression. The recombinant interferon alpha-2b and lactoferrin derived from modern medicine in combination with herbal based products from traditional medicine may support the prevention of novel coronavirus infections. An integrated approach against common cold viruses to establish efficacy and safety through modern and traditional medicine and regular physical exercise along with preventive dietary sources is proposed.

The traditional use of southern African medicinal plants in the treatment of viral respiratory diseases: A review of the ethnobotany and scientific evaluations

ETHNOPHARMACOLOGICAL RELEVANCE

Viral respiratory infections are amongst the most common infections globally, with most of the world's population contracting at least one infection annually. Numerous plant species are used in traditional southern African healing systems to treat these diseases and to alleviate the symptoms. Despite this, the therapeutic potential of these plants against viral respiratory diseases remains poorly explored.

AIM OF THE STUDY

The aim of this study was to document the southern African plant species used in traditional medicine to treat viral respiratory infections. We also examined the extent of scientific evaluations of southern African plant species against the respiratory-infective viruses, with the aim of stimulating interest in this area and focusing on future studies.

MATERIALS AND METHODS

We undertook an extensive review of ethnobotanical books, reviews and primary scientific studies to identify southern African plants which are used in traditional southern African medicine to treat viral respiratory diseases. This information was used to identify gaps in the current research that require further study.

RESULTS

Two hundred and fifty-seven southern African plant species were identified as traditional therapies for viral respiratory diseases. Surprisingly, only one of those species (as well as twenty-one other species not recorded for these purposes) has been evaluated for the ability to block respiratory virus production. Furthermore, most of these studies screened against a single viral strain and none of those studies examined the mechanism of action of the plant preparations.

CONCLUSIONS

Despite well documented records of the use of southern African plants to treat respiratory viral diseases, the field is poorly explored. Nearly all of the plant species used in traditional healing systems to treat these diseases are yet to be tested. Substantial further work is required to verify the efficacy of these traditional medicines.

Extraction of Essential Oils from Medicinal Plants and their Utilization as Food Antioxidants

BACKGROUND

The use of essential oils is receiving increasing attention worldwide, as these oils are good sources of several bioactive compounds. Nowadays essential oils are preferred over synthetic preservatives thanks to their antioxidant and antimicrobial properties. Several studies highlight the beneficial effect of essential oils extracted from medicinal plants to cure human diseases such as hypertension, diabetes, or obesity. However, to preserve their bioactivity, the use of appropriate extraction technologies is required.

METHODS

The present review aims to describe the studies published so far on the essential oils focusing on their sources and chemical composition, the technologies used for their recovery and their application as antioxidants in food products.

RESULTS

The review has been structured in three parts. In the first part, the main compounds present in essential oils extracted from medicinal plants have been listed and described. In the second part, the most important technologies used for extraction and distillation, have been presented. In detail, conventional methods have been described and compared with innovative and green technologies. Finally, in the last part, the studies related to the application of essential oils as antioxidants in food products have been reviewed and the main findings discussed in detail.

CONCLUSION

In summary, an overview of the aforementioned subjects is presented by discussing the results of the most recent published studies.

Medicinal plants used by 'root doctors', local traditional healers in Bié province, Angola

ETHNOPHARMACOLOGICAL RELEVANCE

This study is one of the first post-civil war efforts to document traditional botanical knowledge in Bié province, central Angola, in a first step to bring more studies on the use of medicinal plant resources in this area so as to bring new insights into Angolan bio-cultural diversity.

AIM OF THE STUDY

Examine the variety of plant species used for medical purposes, as well as characterize their social and cultural values. Also, it is aimed to compare their uses in the studied region with those in Sub-Saharan Africa and report new ethnomedicinal uses.

MATERIALS AND METHODS

We documented traditional medicinal plant knowledge among professional herbalists in two areas in Bié province through participatory observation, semi-structured interviews and transect walks. Ethnobotanical information was quantified based on Use Reports to (1) rate traditional knowledge; and (2) determine most useful taxa.

RESULTS

In total, 10 traditional healers shared information on their knowledge. A total of 87 plant species distributed among 57 genera and 36 botanical families were documented with Fabaceae being the best-represented family with 18 species, followed by Phyllanthaceae (6), Apocynaceae (5), Asteraceae (5), Rubiaceae (5), Lamiaceae (4), and Ochnaceae (3). Most medicinal plants are usually gathered at a distance from human settlements because of the belief in the higher efficacy of 'wild' plants shared by all herbalists. Roots are the most common plant part used (79%), explaining why the consulted herbalists call themselves 'root doctors'.

CONCLUSIONS

The culturally most important medicinal species identified in this study, i.e. Securidaca longepedunculata, Garcinia huillensis, Annona stenophylla, Afzelia quanzensis and Strychnos cocculoides, were previously reported for the same use in neighbouring countries and elsewhere in Africa. Our study also indicates that there are several locally valuable species that have not yet been studied for their medical potential, to name a few: Alvesia rosmarinifolia, Diplorhynchus condylocarpon, Eriosema affine, Paropsia brazzaeana, Rhus squalida, Sclerocroton cornutus or Xylopia tomentosa. Moreover, the ethnomedicinal use of 26 species was reported for the first time to sub-Saharan Africa.

CLASSIFICATION

Ethnopharmacological field studies.

Ethnobotanical Survey of Plants Used for Treating Cough Associated with Respiratory Conditions in Ede South Local Government Area of Osun State, Nigeria

In many developing countries, community members depend on their local flora for treating diverse ailments including those affecting the respiratory system. This is often attributed to the high cost and limited access to health care facilities. This present study focused on the documentation of plant species used against cough associated with the respiratory diseases in Ede South Local Government Area of Osun State. The survey was conducted using semi-structured interviews among 100 participants. Information obtained was analyzed using different ethno-botanical indices including relative frequency of citation (RFC) and fidelity level (FL). A total of 87 plant species from 39 families, which was mostly represented by Fabaceae, were reported in the study area. Crinum jagus was the most popular plant used against cough and approximately 32% of the plants have been reported as cough remedies for the first time. However, some of the documented plants have been reported for the treatment of cough and related respiratory diseases in several countries. In terms of the life-form, trees constituted the highest proportion of the medicinal plants (37%), while leaves (36%) were the predominant plant part prescribed for cough. Decoction was the main method of preparing the plants, which were all administered orally. Approximately 63% of the plants were exclusively sourced from the wild. The current study revealed the richness and widespread use of plant species for managing cough associated with respiratory diseases in the study area. The generated inventory contributes to the expanding database of valuable plant resources with medicinal potential in Nigeria and Africa.

Comparison Study of Different Extracts of Plectranthus madagascariensis, P. neochilus and the Rare P. porcatus (Lamiaceae): Chemical Characterization, Antioxidant, Antimicrobial and Cytotoxic Activities

Medicinal plants of the Plectranthus genus (Lamiaceae) are known for their ethnopharmacological relevance, mainly against infectious, dermatologic and gastrointestinal pathologies. Three Plectranthus species originated from South Africa, namely P. madagascariensis, P. neochilus and the rare P. porcatus were hereby screened for their antimicrobial and cytotoxic activities related with their known and/or potential ethnomedicinal uses. Twenty-six extracts were prepared by the combination of extraction methods (infusion, decoction, microwave-assisted, ultrasound-assisted, maceration and supercritical fluid extraction) with different polarity solvents (water, methanol, acetone and supercritical CO₂). The comparison study of these extracts was elucidated through the corresponding chemical characterization and cytotoxic activity data. Therefore, the acetone extract from P. madagascariensis prepared by ultrasound extraction method revealed potent antibacterial activity against Gram-positive bacteria (1.95 < minimum inhibitory concentration (MIC) < 7.81 μg/mL), including a methicillin-resistant Staphylococcus aureus (MRSA) strain. Additionally, acetone extracts from both P. madagascariensis and P. neochilus exhibited relevant antibacterial activity against Gram-negative Klebsiella pneumonia (0.48 < MIC < 3.91 μg/mL), validating the traditional uses of such plants as anti-infectious agents. All methanolic extracts showed potent antioxidant effects at 100 μg/mL measured as their radical scavenging activity (60.8–89.0%) in the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay. The P. madagascariensis extract obtained by maceration in acetone showed moderate cytotoxic effects in the MDA-MB-231 cell line (triple negative human breast carcinoma). The extract concentration that caused a 50% inhibition in cell viability (IC₅₀) was 64.52 μg/mL. All extracts in this comparative study were profiled by high-performance liquid chromatography-HPLC with a diode-array detector-DAD (HPLC-DAD) and the main known bioactive components were identified in each extract, which included polyphenols (caffeic 1, chlorogenic 2 and rosmarinic 3 acids), abietane diterpenes (7α-acetoxy-6β-hydroxyroyleanone 4 and coleon U 5) and flavone glycosides (rutin 6 and naringin 7).

Antihypertensive effects of the hydro-ethanol extract of Senecio serratuloides DC in rats

BACKGROUND

Senecio serratuloides DC is used in folk medicine for treating hypertension, skin disorders, internal and external sores, rashes, burns and wounds. This study aimed at investigating the antihypertensive effects of the hydroethanol extract of S. serratuloides (HESS) in N-Nitro-L-arginine methyl ester (L-NAME) induced hypertension in rats.

METHODS

Acute toxicity of HESS was first determined to provide guidance on doses to be used in this study. Lorke's method was used to determine safety of the extract in mice. Female Wistar rats were treated orally once daily with L-NAME (40 mg/kg) for 4 weeks and then concomitantly with L-NAME (20 mg/kg) and plant extract (150 and 300 mg/kg), captopril (20 mg/kg) or saline as per assigned group for 2 weeks followed by a 2-week period of assigned treatments only. Blood pressure was monitored weekly. Lipid profile, nitric oxide, renin and angiotensin II concentrations were determined in serum while mineralocorticoid receptor concentration was quantified in the kidney homogenate. Nitric oxide (NO) concentration was determined in serum and cardiac histology performed.

RESULTS

HESS was found to be non-toxic, having a LD50 greater than 5000 mg/kg. Blood pressure increased progressively in all animals from the second week of L-NAME treatment. HESS treatment significantly and dose-dependently lowered systolic blood pressure (p < 0.001), diastolic blood pressure (p < 0.01), low density lipoprotein cholesterol (p < 0.01) and triglycerides (p < 0.01). It significantly prevented L-NAME induced decrease in serum angiotensin II (p < 0.01), high density lipoprotein cholesterol (p < 0.001) and serum nitric oxide concentrations (p < 0.001). HESS also significantly (p < 0.01) prevented collagen deposition in cardiac tissue.

CONCLUSION

The hydro-ethanol extract of Senecio serratuloides showed antihypertensive, antihyperlipidemic and cardioprotective effects in rats thus confirming its usefulness in traditional antihypertensive therapy and potential for antihypertensive drug development.

Data on medicinal plants used to treat respiratory infections and related symptoms in South Africa

We provide details of 306 plant species used to treat and manage respiratory infections and related symptoms in South Africa. About a third of the documented species belong to four plant families, namely the Asteraceae (15.7%), Fabaceae (6.1%), Lamiaceae (5.6%) and Amaryllidaceae (4.6%). An overwhelming majority of documented species are used as medicine to treat tuberculosis (40.2%), cough (36.6%), fever (29.1%), chest complaints (28.8%) and cold (23.2%). The potentially bioactive phytochemical compounds and associated pharmacological properties of the documented plant species are also provided. This data demonstrated strong correlation between phytochemistry, pharmacological properties and medicinal uses of more than three quarters (80.1%) of the documented species used against respiratory infections and related symptoms. Data of this nature can be used to identify research gaps on ethnomedicinal uses, phytochemistry and pharmacological properties of plant species used as herbal medicines.

Plants Used by Bapedi Traditional Healers to Treat Asthma and Related Symptoms in Limpopo Province, South Africa

To the best of our knowledge there are presently no ethnobotanical surveys focusing on the utilisation of herbal remedies for asthma in South Africa. The present study is therefore an attempt to fill this gap in knowledge. A total of 140 Bapedi traditional healers (THs) practicing in the Capricorn, Sekhukhune, and Waterberg districts of the Limpopo Province (South Africa) were queried using semistructured questionnaires, supplemented by field observations during face-to-face interview. A total of 104 medicinal plant species (92 indigenous and 12 exotics) belonging to 92 genera, distributed across 54 botanical families, mostly the Asteraceae and Fabaceae (18.5%, for each) as well as Malvaceae (12.9%), were used as antiasthmatics and related symptoms by these THs. Most of the plants were trees and herbs (37.5%, for each), with root (57%), leaf (15.8%), and bark (7.5%), respectively, being the saliently used parts for preparation of remedies. Clerodendrum ternatum, Cryptocarya transvaalensis, Lasiosiphon caffer, Enicostema axillare, Mimusops obovata, Sclerocarya birrea, and Stylochaeton natalensis were widely used and valued by all THs across the surveyed districts. Furthermore, these taxa also scored both the highest use value and fidelity level indexes as asthma therapies. Overall, the larger number of species documented in the present study is recorded for the first time in literature as asthma and/or related symptoms remedies. Our study finding generally contributes towards an establishment of South African database of herbal therapies used traditionally against these conditions.

Ethnobotanical knowledge of the lay people of Blouberg area (Pedi tribe), Limpopo Province, South Africa

BACKGROUND

Limpopo province, South Africa, has a rich plant diversity and is referred to as one of the hotspots areas within the country. The aim of the current work was to identify and document medicinal plant species used by the indigenous Pedi people of Blouberg area, Limpopo Province, South Africa.

METHODS

A total of 40 informants which includes both traditional healers and medicinal plant sellers were randomly selected and asked about the plant species used in treatment of variety of infections using a structured questionnaire. Follow-up visits and various field walks were also used to identify and document various plant species used in Traditional medicine (TM). The interviews were carried out from April 2008 to June 2016 using indigenous language (Sehananwa).

RESULTS

A total of 82 medicinal plants species belonging to 42 families have been collected, identified and documented. About 46.34% of the plant species were herbs, followed by trees (25.61%), shrubs (20.73%) and climbers (7.32%). The most used plant parts are roots and rhizomes (58.58%). Peltophorum africanum Sond revealed frequency index of greater than 70 and is used in combination with other plants species to treat various pathogenic infections. Most of the plant species reported are used in the treatment of sexually transmitted infections (24), management of HIV-AIDS (15) and stomach ache (14). Our informants indicated that the use of plant medicines in combinations is also applied to cure pathogenic infections.

CONCLUSION

The current study demonstrate that the indigenous people of Blouberg area, Limpopo Province harbours an important information about the vegetation around them. The plant species are used in the treatment of various pathogenic infections, offers fruits as additional source of food and form integral part of other medicinal products that may in turn produce income.

Antimicrobial natural product research: A review from a South African perspective for the years 2009-2016

ETHNOPHARMACOLOGICAL RELEVANCE

This review provides information on the antimicrobial research which has taken place on South African natural products for the last eight years (2009-2016). This important field is the backbone of all studies involving the use of medicinal plants against infectious diseases and hence can form the mainstay for future studies.

MATERIALS AND METHODS

All publications within the years 2009-2016 were considered. Exclusion criteria were studies not involving South African medicinal natural products and those publications where full articles could not be accessed. An overview of the most common experimental methods used and new advances in terms of antimicrobial investigations are provided. Disease categories selected for further investigation were skin and wounds, respiratory, gastrointestinal, sexually transmitted and ophthalmic infections amongst others. Alternate natural products and combinations studies were also included.

RESULTS

The minimum inhibitory concentration (MIC) was the most commonly used experimental method to determine antimicrobial activity. Staphylococcus aureus was the most commonly tested skin pathogen and Klebsiella pneumoniae was the most common pathogen implicated in respiratory disorders. Only 20% of gastrointestinal studies included commonly implicated pathogens such as Shigella flexneri and Campylobacter species.

CONCLUSION

Multidisciplinary studies have emerged as a strong support for antimicrobial investigations and show the importance of including toxicity when studying antimicrobial efficacy. Alternate approaches (for example biofilms and quorum sensing) at examining antimicrobial effects are encouraged. Studies on resistant strains require more insight and future recommendations should look at consistent dosing and investigations on compound interactions amongst others.

Distribution and Diversity of Usage of the Amaryllidaceae in the Traditional Remediation of Infectious Diseases

Globalization and multidrug resistance are amongst the factors implicated in the resurgence of infectious diseases in recent years. This has fostered a compelling need in drug discovery to replace (or supplement) existing schedules. The floral biodiversity has been identified as a viable resource platform due to its inimitable chemical characteristics as well as the presence of numerous of its members in traditional medicinal approaches towards these diseases. Whilst the plant family Amaryllidaceae is conventionally associated with cancer and motor-neuron disease therapies, this survey shows that it has a significant presence in the remediation of infections and infection-related ailments. This verifiable indigenous knowledge could amplify efforts towards the identification of the active chemical constituents.

Psidium guajava L., from ethnobiology to scientific evaluation: Elucidating bioactivity against pathogenic microorganisms

ETHNOPHARMACOLOGICAL RELEVANCE

The use of popular plants has guided pharmaceutical research aimed at combating pathogenic microorganisms. Psidium guajava L. is a plant of great versatility and it has been used both as food and as a therapeutic agent. Root, bark, leaves, fruits, flowers and seeds are used for medicinal purposes, especially in infusions and decoctions for oral and topical use. P. guajava is utilized in symptomatology treatment related to organ malfunction and of diseases caused by the action of pathogenic and/or opportunistic microorganisms. Many pharmacological studies have been conducted to scientifically assess its therapeutic potential.

AIMS OF STUDY

The aim of the current study is to relate the popular use of this plant and its bioscientific assessment as a therapeutic agent in the treatment of diseases and symptoms caused by the action of protozoa, fungi, bacteria and viruses, and also evaluate the safety for the usage and the interaction with drugs.

MATERIALS AND METHODS

A bibliographic database the ethnobiology of Psidium guajava (2005-2015) and the pharmacological infections and parasitic diseases (2010-2015). Searches were done in scientific disclosure databases such as PubMed, Web of Science, and Scopus.

RESULTS

P. guajava leaf extracts were scientifically investigated for the treatment of diseases caused by protozoa (leishmaniasis, malaria, giardiasis, amoebiasis and trichomoniasis), fungi (dermatosis, systemic and mucocutaneous diseases), bacteria (respiratory, mucocutaneous and gastrointestinal infections, cholera, gastritis and stomach ulcers, oral and periodontal infections, venereal diseases and urinary infections) and viruses (herpes, influenza, rotavirus disease and AIDS). The toxicity assays indicates the safet for usage.

CONCLUSIONS

Highlight and elucidate the therapeutic potential and versatility of P. guajava. They also justify using ethnobiology efficiency to guide pharmacological studies. Some limitations can be observed in this kind of study, as the lack for ethnobiological informations and the absence of some controls in the assays.

Ethnobotany, phytochemistry, toxicology and pharmacological properties of Terminalia sericea Burch. ex DC. (Combretaceae) - A review

ETHNOPHARMACOLOGICAL REFERENCE

The use of medicinal plants in the treatment of infections is ancient. A wide variety of ethnotherapeutic properties and pharmacological actions has been attributed to Terminalia sericea. Studies by various groups of investigators reveal that it is a multipurpose medicinal plant used mostly in the treatment of diarrhoea, sexually transmitted infections, skin rashes, tuberculosis and other infections. The current paper is aimed at providing an overview of the ethnomedicinal uses, toxicology, pharmacology and the phytochemistry of Terminalia sericea.

MATERIALS AND METHODS

Information was retrieved using various search engines, including Pubmed, Science Direct, Google Scholar, Scielo, SciFinder and Scopus. The key words used included Terminalia sericea, secondary metabolites, phytochemistry, biological activity, pharmacology, ethnobotanical survey, medicinal uses, safety, toxicology and other related words.

RESULTS

Terminalia sericea is an important medicinal plant which possesses anti-HIV, anti-fungal, anti-bacterial, anticancer, lipolytic, wound healing, antiparasitic, anti-inflammatory and anti-oxidant activity, as the most valuable biological activities, thus lending pharmacological support to the plant's folkloric uses in indigenous medicine. Toxicologically, the extracts and isolated compounds from the plant species may have mild toxic effects. Phytochemically, the plant species possesses valuable compounds including triterpenes, alkaloids and flavonoids which may well contribute to its biological activity.

CONCLUSIONS

Terminalia sericea contains secondary metabolites which are valuable in the treatment of a variety of human infections, including community acquired infections which may be prevalent in developing countries. The degree of toxicity reported in various extracts warrants further exploration of the cytotoxicity of the plant species, both against normal human cell lines and in vivo. Moreover, the acetylcholinesterase inhibitory and anti-inflammatory effects also need to be further investigated as there are only a few reports from the literature on these aspects. There is also a need to further understand the mode of action of the extracts against various enzymes relating to inflammation. Antioxidant activity of the plant extracts against various forms of free radicals needs to be investigated. Although T. sericea is reported to be used for ethnoveterinary infections, there are no scientific reports on the anti-parasitic activity of the plant species against common animal parasites.

Plants used to treat skin diseases in northern Maputaland, South Africa: antimicrobial activity and in vitro permeability studies

CONTEXT

Ethnobotanical claims of medicinal plants used in northern Maputaland are limited. Objectives To establish scientific validity for a selection of the plants used in Maputaland to treat skin diseases.

MATERIALS AND METHODS

Aqueous and dichloromethane-methanol extracts were prepared from 37 plant species which were collected from four rural communities in Maputaland. Antimicrobial screening was performed on extracts against 12 dermatological relevant pathogens using the micro-titre plate dilution assay. Their combined effect was evaluated by determining the sum of the fractional inhibitory concentrations (ΣFICs). Chemical analysis was undertaken using reverse-phase high-performance liquid chromatography (RP-HPLC) and investigated in vitro across excised intact porcine skin using the ILC07 automated system.

RESULTS

The organic extract of Garcinia livingstonei T. Anderson (Clusiaceae) was found to be the most antimicrobially active displaying an average broad-spectrum MIC value of 270 μg/mL. The combination of Sclerocarya birrea (A. Rich.) Hotsch. (Anacardaceae) with Syzygium cordatum Hochst. ex C. Krauss (Myrtaceae) displayed synergistic effects. The four antimicrobially active organic extracts were found to possess mainly anthraquinones, flavonoids, tannins and saponins. The organic extracts of Kigelia africana (Lam.) Benth. (Bignoniaceae) and S. cordatum were found to have more compounds capable of permeating intact skin after 10 min of exposure.

CONCLUSION

More than 80% of the organic extracts tested displayed a correlation between the antimicrobial efficacy and the reported traditional uses of the plants. Furthermore, the traditional use of topically applied plant preparations is validated as some compounds from the active plants are capable of permeating the skin in vitro.

Antileishmanial and immunomodulatory effects of the essential oil from Tetradenia riparia (Hochstetter) Codd

Cutaneous leishmaniasis usually presents therapeutic resistance to antimonials, and the existing therapies for leishmaniasis have many adverse effects and toxicity. Natural products may be regarded as possible candidates for alternative leishmaniasis treatment. The plant Tetradenia riparia has shown promise for the treatment of infectious diseases in folk medicine. We evaluated the antileishmanial activity of an essential oil from T. riparia (TrEO) and the modulatory effects of TrEO on cytokine modulation by peritoneal fluid cells that were infected with L. (L.) amazonensis. Peritoneal fluid cells were infected with Leishmania and incubated with TrEO (30 ng/mL) for 3, 6, and 24 h. Cytokines were screened using semi-quantitative reverse-transcription polymerase chain reaction (RT-PCR) and flow cytometry. Antileishmanial activity was evaluated at 24 h by microscopic counting and quantitative PCR (qPCR). TrEO treatment induced the death of 50% of Leishmania amastigotes (indicated by microscopic counting) and 91% of the parasite load (indicated by qPCR). TrEO inhibited some of the most critical cytokines for parasite growth and the establishment of infection, including granulocyte-macrophage colony-stimulating factor, interleukin-4 (IL-4), IL-10, and tumour necrosis factor. The parasite inhibited interferon-γ and IL-12, and TrEO blocked this inhibition, indicating that these cytokines are critical for activating mechanisms associated with the death and elimination of the parasite. These results suggest that TrEO may be an alternative leishmaniasis therapy when considering its antileishmanial and immunomodulatory activity.

A comparative ethnopharmacological analysis of traditional medicine used against respiratory tract diseases in Mauritius

ETHNOPHARMACOLOGICAL RELEVANCE

Despite laudable advances in conventional medicine, respiratory tract diseases (RTD) induced morbidity and mortality continue to inflict a substantial burden on healthcare systems worldwide. Similarly, in the tropical island of Mauritius, 13,320 hospital admissions and 8.2% mortality rates were attributed to RTD solely in the year 2013. Consequently, the therapeutic benefits and relief experienced with traditional medicine (TM) against RTD by the local inhabitants cannot be underestimated. The present study aims to report and quantitatively determine the extent of utilization of plant based therapies and other miscellaneous TM preparations concocted against RTD over the island. Additionally, a similarity index was generated which is indicative of the extent of harmonisation of individual plant species against RTD when the uses mentioned in the study are compared to previous ethnobotanical studies.

MATERIALS AND METHODS

Data was compiled using a semi-structured questionnaire via face-to-face interviews with TM users and practitioners (n=384). Three quantitative ethnopharmacological indices (the use value (UV), informant consensus factor (ICF), and ethnobotanicity index (EI)) were calculated. We also calculated the similarity ratio, similarity percentage, new uses for each plant species and percentage of new use against RTD to compare primary data collected in the present study.

RESULTS

Fifty five plants were documented to be in use against 18 RTD. The most used plant species belonged to the following taxa; Lamiaceae (9%), Fabaceae (7%) and Rutaceae (7%). Thirty two plants recorded in this study have been reported to be used against RTD in previous ethnobotanical studies, of which 22 of these plants have been attributed new uses against RTD based on the results of the present study. The remaining 23 plants species have been recorded for the first time to be used traditionally against RTD. Altogether, 81 different recipes were concocted from the medicinal plants and the most common route of administration was oral intake. Common methods of obtaining medicinal plants were from the wild, cultivation and as imported herbal products. Cough was the most common RTD managed by plant species. The largest proportion of plants were employed against cold. The preference ranking both for UV placed Curcuma longa L., Zingiber officinale Roscoe, Citrus×limonia Osbeck and Cymbopogon citratus (DC.) Stapf as the most useful plant species. Only a small proportion of the indigenous plants (7.73%) proved to be useful in TM.

CONCLUSION

This study provides empirical primary ethnopharmacological data on the use of TM to manage and/or treat RTD and can contribute in preserving indigenous knowledge in Mauritius. It is anticipated that these primary data will open new avenues to identify novel drugs that can help to alleviate sufferings.

Tuberculosis and nature's pharmacy of putative anti-tuberculosis agents

Due to the growing problem of drug resistant Mycobacterium tuberculosis strains, coupled with the twinning of tuberculosis (TB) to human immunodeficiency virus/acquired immunodeficiency syndrome (HIV/AIDS), the burden of TB is now difficult to manage. Therefore, new antimycobacterial agents are being sought from natural sources. This review focuses on natural antimycobacterial agents from endophytes and medicinal plants of Africa, Europe, Asia, South America and Canada. In the countries mentioned in this review, numerous plant species display putative anti-TB activity. Several antimycobacterial chemical compounds have also been isolated, including: ellagitannin punicalagin, allicin, anthraquinone glycosides, iridoids, phenylpropanoids, beta-sitosterol, galanthimine, crinine, friedelin, gallic acid, ellagic acids, anthocyanidin, taraxerol, termilignan B, arjunic acid, glucopyranosides, 1-epicatechol, leucopelargonidol, hydroxybenzoic acids, benzophenanthridine alkaloids, neolignans, and decarine. These compounds may provide leads to novel and more efficacious drugs to lessen the global burden of TB and drug-resistant M. tuberculosis strains. If there is a long-term remedy for TB, it must lie in nature's pharmacy of putative antimycobacterial agents.

Medicinal plants: An invaluable, dwindling resource in sub-Saharan Africa

ETHNOPHARMACOLOGICAL RELEVANCE

The use of plant species for different therapeutic/medicinal purposes is well-entrenched in sub-Saharan Africa.

AIM OF THE REVIEW

To provide a critical and updated review of the enormous medicinal plant heritage in sub-Saharan Africa with regards to the abundance, importance, conservation status and potential means to help sustain their availability for future generations.

METHODS

A comprehensive literature search involving different online databases, books and theses were conducted in order to obtain, collate and synthesize available information on various fundamental aspects pertaining to African medicinal plants.

RESULTS

African biodiversity hotspots are endowed with a high level of endemic species with a significant portion possessing medicinal value. Apart from the extensive ethnobotanical uses of medicinal plants found in Africa, scientific validation of their biological potential such as antimicrobial, antioxidant, anti-inflammatory and anti-diabetic properties have been recognized. Together with the demand arising from their biological efficacies, other anthropogenic factors are exerting conservation strains of the wild population of these medicinal plants. Even though researchers have acknowledged the importance and value of conserving these medicinal plants, several challenges have hampered these efforts on the Continent as a whole.

CONCLUSIONS

The rich flora occurring in sub-Saharan Africa suggests enormous potential for discovery of new chemical entity with therapeutic value. However, concerted efforts focused on documenting the conservation status of African medicinal plants are pertinent. Application of different biotechnological techniques is needed to sustain these valuable botanical entities, especially to meet increasing pharmaceutical demand. Most importantly, increased public enlightenment and awareness may help eradicate the prejudice against cultivation of medicinal plants.

Antileishmanial activity of essential oil and 6,7-dehydroroyleanone isolated from Tetradenia riparia

Tetradenia riparia plant is used as a traditional medicine in Africa for the treatment of inflammatory and infectious diseases as like parasitic. Therapy for leishmaniasis caused by Leishmania (Leishmania) amazonensis specie often fails, and the conventional drugs are toxic, expensive, require a long period of treatment, and adverse effects are common. The alternative therapies using natural products are inexpensive and have few or any adverse reaction. These reasons are sufficient to investigate the new natural therapeutic for leishmaniasis. We evaluated the potential of the essential oil (TrEO) and 6,7-dehydroroyleanone (TrROY) isolated from T. riparia on L. (L.) amazonensis promastigote and amastigote forms, cytotoxicity on human erythrocytes and murine macrophages, nitric production and inducible nitric oxide synthase (iNOS) mRNA expression. TrEO was the most effective to promote the Leishmania promastigote death. After 72 h incubation, the lethal dose of TrEO and TrROY that promoted 50% Leishmania death (LD50) were 0.8 μg/mL and 3 μg/mL, respectively. TrEO and TrROY were not cytotoxic to human erythrocytes, but TrROY was toxic to murine macrophages resulting in a low selectivity index. The transmission electronic microscopy showed that TrEO (0.03 μg/mL) was able to modify the promastigote ultrastructures suggesting autophagy as chromatin condensation, blebbing, membranous profiles and nuclear fragmentation. Infected-macrophages treated with TrEO (0.03 μg/mL) or TrROY (10 μg/mL) had an infection index decreased in 65 and 48%. TrEO did not induce iNOS mRNA expression or nitrite production in macrophages infected with Leishmania. TrROY and mainly TrEO promoted the Leishmania death, and TrROY showed loss toxicity to erythrocytes cells. Other compounds derived from T. riparia and the essential oil could be explored to develop a new alternative treatment for leishmaniasis.

Ethnobotanical survey of medicinally important shrubs and trees of Himalayan region of Azad Jammu and Kashmir, Pakistan

ETHNOPHARMACOLOGICAL RELEVANCE

Present study was commenced with an aim to document the indigenous knowledge of medicinally important shrubs and trees of Himalayan region of Azad Jammu and Kashmir, Pakistan. This is the first contribution to the quantitative ethnobotany of this region, as no reported data focusing on shrubs and trees from the area have been published. Study reported the ethnobotanical significance of medicinal plants for the treatment of various diseases.

METHOD

Study was conducted during 2012-2014 following standard ethnobotanical methods. The ethnomedicinal data was collected through informed consent semi- structured interviews of 160 key informants. Documented data was analyzed by using quantitative indices of informant consensus factor (ICF), fidelity level (FL), use value (UV) and relative frequency citation (RFC).

RESULTS

A total of 73 shrub and tree species belonging to 56 genera and 37 families were reported to be used ethnomedicinally for the treatment of various ailments. Medicinal plant diversity showed that Rosaceae was dominating family with (9 spp.) followed by Moraceae (7 spp.), Euphorbiaceae, Mimosaceae, Pinaceae, Rhamnaceae (4 spp. each), Oleaceae (3 spp.), Apocynaceae, Caesalpinaceae, Ebenaceae, Fagaceae, Lythraceae, Papilionaceae, Acanthaceae, Verbenaceae (2 spp. each) while remaining 22 families were represented by one species each. Leaves (23%) were highly utilized plant parts, followed by fruits (22%), bark (18%), seeds (10%), roots (9%), flowers (8%), whole plant and aerial parts (4% each) and stem (2%). Modes of preparation fall into 14 categories including powder (33 reports) followed by decoction (29 reports), paste (22 reports), juice (18 reports), infusion (12 reports), raw (8 reports), extract and latex (5 reports each), gum and oil (4 reports each), fresh part and pulp (2 reports each), chewed and cooked (1 report each). The highest FIC was recorded for Gastro-intestinal disorders (0.58) followed by nail, skin and hair disorders (0.44). Maximum fidelity level (FL=100%) was expressed by Abies pindrow, Adhatoda vasica, Bauhinia variegata and Cedrela serrata. Based on use value Juglans regia (0.88) was found most significant species followed by Acacia nilotica (0.83), Phyllanthus emblica (0.81), Pinus roxburghii (0.75) and Punica granatum (0.71).

CONCLUSION

The area has a rich diversity of medicinally important shrub and tree species. The tradition of using plants for medicinal purposes is still alive in the local community but recently this tradition is gradually declining in new generation. Therefore awareness is needed to be raised among the local people on sustainable use and conservation of local flora.

Medicinal plants used to treat TB in Ghana

AIMS

The current study was designed to document medicinal plant species that are traditionally used to treat tuberculosis (TB) by Ghanaian communities.

METHODS

The medicinal plants used against TB or its signs and symptoms were selected using library and online published data searches. A guided questionnaire interview was also conducted with a botanist involved in plant collection at the Centre for Scientific Research into Plant Medicine (CSRPM) at Mampong. Data obtained were entered in Excel and summarized into means and frequencies using SPSS 12.0.1 for windows, and expressed as tables and bar graphs.

RESULTS

A total of 15 medicinal plant species distributed between 13 genera and 13 families were documented. The following medicinal plant species were found to be used against TB in Greater Accra and Eastern parts of Ghana: Azadirachta indica A. Juss. Stem bark (Meliaceae), Hygrophila auriculata Heine, whole plant (Acanthaceae), Chenopodium ambrosioides L. leaves (Amaranthaceae), Coix lacryma-jobi L. glumes (Poaceae), Solanum torvum Sw. unripe fruits (Solanaceae), Solanum torvum Sw. leaves (Solanaceae), Bidens pilosa L. whole plant (Asteraceae), Phyllanthus fraternus G.L. Webster leaves (Phyllanthaceae), Dissotis rotundifolia (Sm.) Triana, leaves (Melastomataceae), Cymbopogon giganteus Chiov. Leaves (Poaceae), Cyperus articulatus L. roots (Cyperaceae), Allium sativum L. bulb (Amaryllidaceae), Zingiber officinale Roscoe, rhizomes (Zingiberaceae), Allium cepa L. bulbs (Amaryllidaceae), Allium cepa L. leaves (Amaryllidaceae), Aloe vera var. barbadensis aqueous extract from leaves (Xanthorrhoeaceae), Aloe vera var. barbadensis organic extract from leaves (Xanthorrhoeaceae), Cocos nucifera Linn, water (Arecaceae) and Cocos nucifera Linn. Husk (Arecaceae).

CONCLUSIONS

The collected plant species could be a source of a new class of drugs against TB. Bioactivity guided fractionation is recommended to identify lead compounds for antimycobacterial activity. The current paper documents for the first time medicinal plant species used by Ghanaian communities to treat TB. These results are a basis for selection of plants for further pharmacological, toxicological and phytochemical studies in developing new plant-based antimycobacterial drugs.

Volatile-oils composition, and bioactivity of the essential oils of Plectranthus barbatus, P. neochilus, and P. ornatus grown in Portugal

Volatile-oils chemical composition and bioactivity of the essentail oils from Plectranthus barbatus, P. neochilus, and P. ornatus (Lamiaceae) were assessed. Aerial parts from these three related Plectranthus species were collected from cultivated plants grown in Portugal, during vegetative and flowering phases. Volatiles, isolated by distillation-extraction, were analyzed by GC and GC/MS. Monoterpene hydrocarbons (12-74%) and sesquiterpene hydrocarbons (4-45%) constituted the main fractions in all volatiles. α-Pinene (3; 12-67%), oct-1-en-3-ol (6; traces-28%), β-pinene (7; 0.1-22%), and β-caryophyllene (50; 7-12%) dominated P. barbatus volatiles. P. neochilus major volatile components were α-terpenyl acetate (41; traces-48%), α-thujone (2; 2-28%), β-caryophyllene (50; 2-28%), β-pinene (7; 1-25%), and α-pinene (3; 1-19%). Oct-1-en-3-ol (6; 13-31%), β-pinene (7; 11-24%), α-pinene (3; 11-19%), and β-caryophyllene (50; traces-11%) were the main constituents from P. ornatus volatiles. These chemical compositions were rather different from those previously found for specimens harvested in Africa and Brazil. Moreover, the volatiles from the flowers are herewith reported for the first time. Essential oils, isolated by hydrodistillation from leaves and stems, showed a yellowish color and unpleasant odor, with yields ranging from 0.08% to 0.84% (v/dry weight). Antioxidant and antimicrobial activities of the essential oils were evaluated by DPPH· and TBARS assays, and agar disc-diffusion method, respectively. Results showed low or moderate antioxidant capacity and significant antimicrobial activity against Gram-positive bacteria.

Ethnobotanical uses of medicinal plants for respiratory disorders among the inhabitants of Gallies - Abbottabad, Northern Pakistan

ETHNOPHARMACOLOGICAL RELEVANCE

Rich accessibility of medicinal plants in the study area provides low cost health care for respiratory disorders to local communities. This first report survey was commenced with an aim to document ethnic knowledge regarding the use of folk herbal medicine for respiratory diseases among the local communities of Gallies Abbottabad, Northern Pakistan using quantitative ethnobotanical approaches.

METHOD

Field survey was carried out over the period of 2 years i.e., March 2012-March 2014 in study area. The ethnomedicinal data was collected through interviews among the local communities. Documented data was evaluated using use value (UV) and Relative Frequency Citation (RFC).

RESULTS

A total of 120 species of plants belonging to 90 genera of 51 families were reported to be used ethnomedicinally for the treatment of 25 different respiratory disorders. Leaves were the most commonly used plant parts and most of the herbal medicines were prepared in the form of decoctions and administered orally. The most significant species according to their use value were Solanum virginianum (5.00), Althea officinalis (3.00), Inula obtusifolia (3.00), Saxifraga hirculus (3.00) and Sisymbrium erysimoides (3.00).

CONCLUSION

This study reported traditional herbal medicines for the first time to be used against respiratory disorders in the Gallies, Northern Pakistan are still in common practice by the local communities. Some of the new ethnobotanical claims documented in this investigation should need to be further explore clinically. The medicinal plants with highest use values recorded in this study may signpost the probable existence of valuable phytochemical compounds that requires a search for prospective new drugs to cure many respiratory disorders.

Unraveling the medicinal potential of South African Aloe species

ETHNOPHARMACOLOGICAL RELEVANCE

Aloe species (family: Xanthorrhoeaceae) are widely used in ethnomedicine for treating various ailments. Approximately 125 Aloe taxa are documented as indigenous to South Africa. This review was aimed at critically evaluating the available data on the ethnomedicinal uses, pharmacological activities, safety and conservation status of the documented South African Aloe species.

MATERIALS AND METHODS

A detailed search using major electronic search engines (such as Google Scholar, Scopus and Scirus) and ethnobotanical literature was undertaken. Search terms used included 'medicinal properties of Aloe species', 'biological activity of South African Aloe species' and 'safety and toxicological evaluation of aloes'.

RESULTS

Although Aloe species are widely used as laxatives and for treating wound and skin-related ailments, only about 20% of South African Aloe species have been clearly documented for their medicinal uses. The pharmacological potential including the antimicrobial, antiinflammatory, antiplasmodial and anthelmintic activities of some of the species has been established, providing a rationale for their use in traditional medicine. Successful micropropagation protocols have been developed as a conservation strategy, but only for a few species.

CONCLUSIONS

The highlighted medicinal activities of some Aloe species indicate their therapeutic potential. Nonetheless, further research especially on the understudied species is required to properly document their ethnomedicinal uses and fully explore their pharmacological value.