Unraveling the medicinal potential of South African Aloe species

Phytochemical Composition and Antibacterial Activity of Barleria albostellata C.B. Clarke Leaf and Stem Extracts

Barleria albostellata (Acanthaceae) is a shrub located in South Africa and is relatively understudied. However, plants within this genus are well known for their medicinal and ethnopharmacological properties. This study aimed to characterise the phytochemical compounds and antibacterial efficacies of B. albostellata. Phytochemical analysis, fluorescence microscopy and gas chromatography-mass spectrometry (GC-MS) analysis were performed to determine the composition of compounds that may be of medicinal importance. Crude leaf and stem extracts (hexane, chloroform and methanol) were subjected to an antibacterial analysis against several pathogenic microorganisms. The qualitative phytochemical screening of leaf and stem extracts revealed the presence various compounds. Fluorescence microscopy qualitatively assessed the leaf and stem powdered material, which displayed various colours under bright and UV light. GC-MS chromatograms represents 10-108 peaks of various compounds detected in the leaf and stem crude extracts. Major pharmacologically active compounds found in the extracts were alpha-amyrin, flavone, phenol, phytol, phytol acetate, squalene and stigmasterol. Crude extracts positively inhibited Gram-positive and Gram-negative bacteria. Significance was established at p < 0.05 for all concentrations and treatments. These results indicate that the leaves and stems of B. albostellata are rich in bioactive compounds, which could be a potential source of antibacterial agents for treating various diseases linked to the pathogenic bacteria studied. Future discoveries from this plant could advance the use of indigenous traditional medicine and provide novel drug leads.

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.

In vitro dual activity of Aloe marlothii roots and its chemical constituents against Plasmodium falciparum asexual and sexual stage parasites

ETHNOPHARMACOLOGICAL RELEVANCE

Aloe marlothii A.Berger (Xanthorrhoeaceae) is indigenous to southern African countries where its aqueous preparations are used in traditional medicine to treat several ailments including hypertension, respiratory infections, venereal diseases, chest pain, sore throat and malaria.

AIM OF THE STUDY

The aims of this study were as follows: (i) isolate and identify the antiplasmodial active compounds in A. marlothii roots. As the water extract was previously inactive, the dichloromethane:methanol (DCM:MeOH) (1:1) was used, (ii) examine the activity of the isolated compounds against Plasmodium falciparum asexual blood stage (ABS) parasites as well as for transmission-blocking activity against gametocytes and gametes, and (iii) to use in silico tools to predict the target(s) of the active molecules.

MATERIALS AND METHODS

The crude DCM:MeOH (1:1) extract of A. marlothii roots was fractionated on a reverse phase C8 column, using a positive pressure solid-phase extraction (ppSPE) workstation to produce seven fractions. The resulting fractions and the crude DCM:MeOH extract were tested in vitro against P. falciparum (NF54) ABS parasites using the malaria SYBR Green I based-fluorescence assay. Flash silica chromatography and mass-directed preparative high-performance liquid chromatography were utilised to isolate the active compounds. The isolated compounds were evaluated in vitro against P. falciparum asexual (NF54 and K1 strains) and sexual (gametocytes and gametes) stage parasites. Molecular docking was then used for the in silico prediction of targets for the isolated active compounds in P. falciparum.

RESULTS

The crude extract and two SPE fractions displayed good antiplasmodial activity with >97% and 100% inhibition of ABS parasites proliferation at 10 and 20 μg/mL, respectively. Following UPLC-MS analysis of these active fractions, a targeted purification resulted in the isolation of six compounds identified as aloesaponol I (1), aloesaponarin I (2), aloesaponol IV (3), β-sorigenin-1-O-methylether (4), emodin (5), and chrysophanol (6). Aloesaponarin I (2) was the most bioactive, compared to other isolated constituents, against P. falciparum ABS parasites exhibiting equipotency against the drug-sensitive (NF54) (IC₅₀ = 1.54 μg/mL (5 μM)) and multidrug-resistant (K1) (IC₅₀ = 1.58 μg/mL (5 μM)) strains. Aloesaponol IV (3) showed pronounced activity against late-stage (>90% stage IV/V) gametocytes (IC₅₀ = 6.53 μg/mL (22.6 μM)) demonstrating a 3-fold selective potency towards these sexual stages compared to asexual forms of the parasite (IC₅₀ = 19.77 ± 6.835 μg/mL (68 μM)). Transmission-blocking potential of aloesaponol IV (3) was validated by in vitro inhibition of exflagellation of male gametes (94% inhibition at 20 μg/mL). In silico studies identified β-hematin and DNA topoisomerase II as potential biological targets of compounds 2 and 3, respectively.

CONCLUSION

The findings from our study substantiate the traditional use of A. marlothii to treat malaria. To our knowledge, this study has provided the first report on the isolation and identification of antiplasmodial compounds from A. marlothii roots. Furthermore, our study has provided the first report on the transmission-blocking potential of one of the compounds from the genus Aloe, motivating for the investigation of other species within this genus for their potential P. falciparum transmission-blocking activity.

Bioprospecting of endophytic actinobacterium associated with Aloe ferox mill for antibacterial activity

BACKGROUND

The emergence of drug resistance among pathogens has resulted in renewed interest in bioprospecting for natural microbial products.

METHODS

This study aimed to bioprospecting endophytic actinobacterium associated with Aloe ferox Mill for its antibacterial activity. Endophytic actinomycetes were isolated from the gel of A. ferox Mill by surface sterilization technique using actinomycete isolation agar. The isolate with a promising antibacterial activity was identified using 16S rRNA sequence analysis. The minimum inhibitory concentration (MIC) of the extract was assessed by the micro-dilution method and its effect on the respiratory chain dehydrogenase (RCD) activity was ascertained by the iodonitrotetrazolium chloride (INT) assay. Fourier transform-infrared spectrophotometer (FTIR) and gas chromatography-mass spectrophotometry (GC-MS) were employed to identify functional groups and the chemical constituents, respectively.

RESULTS

The actinobacterium was found to be Streptomyces olivaceus CP016795.1. Its extract displayed noteworthy antibacterial activity (MIC ≤1 mg/mL) against Staphylococcus aureus (ATCC 25925), Bacillus cereus (ATCC 10102), and Escherichia coli (ATCC 25922); and showed an inhibitory effect on the RCD activity. FTIR spectrum displayed hydroxyl, amine, and aromatic groups, and the GC-MS revealed 5-Hydroxymethylfurfural as the main constituent (19.47%).

CONCLUSIONS

S. olivaceus CP016795.1 can serve as a potential source of effective antibacterial compounds.

Design of polysaccharidicAloe veragel incorporated PVA/tetracycline electrospun cell culture scaffolds for biomedical applications

In this study, hybrid nanofibrous 3D scaffolds containingAloe vera(AV), polyvinyl alcohol (PVA) and tetracycline hydrochloride (TCH) are fabricated by electrospinning for cell culture applications. The role of polysaccharides present in AV gel is found to enhance the biocompatibility of the nanofibrous scaffolds. Different combinations of the polymers were selected to produce homogenous nanofibers with favorable mean fiber diameter and tensile strength. The surface morphology of the products was studied by SEM and it is found that the mean fiber diameter is decreased to about 188 nm upon addition of the AV component. The electrospun scaffolds were investigated by FT-IR spectroscopy to reveal the chemical structure of the samples and their crystallinity was studied by XRD. The hydrophilicity of the scaffolds was tested by optical contact angle measurements and their mechanical strength was examined by tensile strength tests. It is found that PVA is the main component contributing the mechanical stability of the scaffold structure. The fabricated scaffolds presented a more pronounced inhibitory effect against Gram-positive bacterial strains ofS. aureusandB. cereus. Cell culture experiments using fibroblast L929 murine cells reveals that the AV/PVA/TCH scaffolds are promising for cell growth and the cells are capable of achieving a proper cell adhesion and proliferation. The cell viability experiment by MTT assay exhibits the contributing role of AV gel to L929 cell viability on the AV/PVA/TCH scaffolds.

Antibacterial Activity of Some Medicinal Plants in Al Baha Region, Saudi Arabia, Against Carcinogenic Bacteria Related to Gastrointestinal Cancers

BACKGROUND

Gastrointestinal cancers are the most dangerous cancers all over the world. The gut microbiota dysbiosis increases the risk of GI cancers and induces the host's susceptibility to carcinogenic bacteria. Antibiotic resistance is rising in these bacteria. Thus, discovering new safe and effective antibacterial agents is a worldwide concern. This study evaluates the antibacterial activity of six wild medicinal plants from the Al Bahah region in Saudi Arabia.

METHODS

Arial parts of Cissus quadrangularis, Aloe castellorum, Psiadia punctulata, Aloe pseudorubroviolacea, Barbeya oleoides, Teucrium yemense were collected and dried for extraction with ethanol. The minimum inhibitory concentrations (MIC) of these ethanolic extracts against carcinogenic bacteria Bacteroides fragilis, Clostridium ssp., Cutibacterium acnes, Escherichia coli, Fusobacterium nucleatum, Helicobacter pylori, Mycoplasma spp., Neisseria gonorrhoeae, Porphyromonas gingivalis, Salmonella enterica, and Treponema pallidum were evaluated to determine its antibacterial activity.

RESULTS

All extracts showed antibacterial activity with MIC lower than 1 mg/ml. Psiadia punctulata showed higher antibacterial activity, while the Aloe species showed the lowest antibacterial activity.

CONCLUSION

The studied plants' extracts showed high effectiveness as antibacterial activity against the carcinogenic bacteria related to gastrointestinal cancers due to their high content of pharmaceutical components. These plants could be explored further for the development of new antibacterial products against these carcinogenic bacteria.

Enzymatic and Antimicrobial Activity of Biologically Active Samples from Aloe arborescens and Aloe barbadensis

Simple Summary

Antimicrobial resistance is one of the major threats to public health, and additional concerns are reduced efficacy and increased toxicity of synthetically derived drugs. Hence, it is all the more important to research new antimicrobials derived from natural sources. Aloe spp. have long been acknowledged in traditional medicine, as their ability of treating skin and digestive problems, wound healing, anti-inflammatory, antimicrobial and other promising properties are known. This study presents the content of various bioactive substances in samples of two Aloe spp., Aloe arborescens and Aloe barbadensis, and their enzymatic, antioxidant and antimicrobial activity. Obtained bioactive compounds with antimicrobial effect have a huge potential to inhibit the growth of microorganisms that are extremely susceptible to gaining resistance and could be used in versatile applications in the cosmetics, food, medical and pharmaceutical industries.

Abstract

Recently, the use of Aloe species has become very widespread. These are extensively used as a nutraceutical in a variety of health care products and food supplements. In addition, the occurrence of the quickly adaptable microorganisms, particularly bacteria, which can develop resistance to antibiotics, is a major problem for public health, and therefore, it is necessary to search for new antimicrobials. In our study, the content of total phenols, proanthocyanidins, and proteins in fresh and lyophilized samples of A. arborescens and A. barbadensis and their ethanol extracts was investigated. Furthermore, enzymatic and antioxidant activity of samples were studied. Since antimicrobial activity of fresh samples was determined in our latest research, a more detailed study of antimicrobial effectiveness of A. arborescens and A. barbadensis (lyophilized, extracts) was performed. Ethanol extracts in particular contain higher concentrations of bioactive substances and show the topmost antioxidant activity. The novelty of the study refers to the observation of industrially important enzyme activities such as α-amylase, cellulase, lipase, peroxidase, protease, and transglutaminase in the samples as well as the microbial growth inhibition rates determination (MGIR) at different concentrations of added aloe samples. All samples inhibited the growth of all tested microbial cells. MIC₉₀ for A. arborescens and A. barbadensis were also determined in case of B. cereus, P. aeruginosa, P. fluorescens, and S. aureus. The results of our study tend to give credence to the popular use of both aloes in medicine and in the cosmetic, food, and pharmaceutical industries.

The use of South African botanical species for the control of blood sugar

ETHNOPHARMACOLOGICAL RELEVANCE

Diabetes mellitus (DM) is one of the most prevalent diseases globally and is of considerable concern to global health. Approximately 425 million people are estimated to have DM globally and this is predicted to increase to >642 million by 2040. Whilst the prevalence of DM in South Africa is slightly lower than the global average, it is expected to rise rapidly in future years as more South Africans adopt a high calorie "westernised" diet. Traditional medicines offer an alternative for the development of new medicines to treat DM and the usage of South African plants is relatively well documented.

AIM OF THE STUDY

To critically review the literature on the anti-diabetic properties of South African plants and to document plant species used for the treatment of DM. Thereafter, a thorough examination of the related research will highlight where research is lacking in the field.

MATERIALS AND METHODS

A review of published ethnobotanical books, reviews and primary scientific studies was undertaken to identify plants used to treat DM in traditional South African healing systems and to identify gaps in the published research. The study was non-biased, without taxonomic preference and included both native and introduced species. To be included, species must be recorded in the pharmacopeia of at least one South African ethnic group for the treatment of DM.

RESULTS

One hundred and thirty-seven species are recorded as therapies for DM, with leaves and roots most commonly used. The activity of only 43 of these species have been verified by rigorous testing, and relatively few studies have examined the mechanism of action.

CONCLUSION

Despite relatively extensive ethnobotanical records and a diverse flora, the anti-diabetic properties of South African medicinal plants is relatively poorly explored. The efficacy of most plants used traditionally to treat DM are yet to be verified and few mechanistic studies are available. Further research is required in this field.

Differential inhibition of gelatinase activity in human colon adenocarcinoma cells by Aloe vera and Aloe arborescens extracts

BACKGROUND

Aloe's reported bioactivities (anticancer, anti-inflammatory and wound healing) suggest they might inhibit a subgroup of matrix metalloproteinases (MMPs) called gelatinases (MMP-2 and MMP-9). The goal of the present study was to compare the MMP inhibitory potential of two Aloe species, A. vera and A. arborescens.

METHODS

Different types of extraction were tested and specific bioactive compounds were quantified. Cancer cell invasion inhibitory activities were measured in vitro using the wound healing assay in human colon cancer cells (HT29). Effects on gelatinase activities were further assessed by dye-quenched gelatin and gelatin zymography.

RESULTS

Different types of extraction yielded significantly different levels of bioactivities and of bioactive compounds, which might be due to a greater amount of extractable bioactive compounds such as anthraquinones. Both A. arborescens and A. vera have potential as inhibitory agents in cancer cell proliferation via MMP-9 and MMP-2 enzymatic activity inhibition, being able to reduce colon cancer cell proliferation and migration but A. arborescens showed to be a more effective inhibitor of cancer cell migration than A. vera.

CONCLUSION

This work opens novel perspectives on the mode of action of Aloe species in cancer cell migration and may provide clues as to why there are so many conflicting results on Aloe's activities.

Comparative analysis of some bioactive compounds in leaves of different Aloe species

Although a vast number of Aloe species are known, only the Aloe vera and Aloe arborescens species are currently used by cosmetic and pharmaceutical industries. Therefore, the current study aims to complete the existent literature data with new information on the phytochemical composition of some lesser-known Aloe species, with the main focus on carotenoids and fatty acids. Among the analyzed species, Aloe aculeata and Aloe ferox had the highest content in carotenoids, the major pigments being lutein and β-carotene (according to HPLC analysis). The fatty acid profile of each Aloe species was analysed by GC–MS. Linolenic and linoleic acids were the major polyunsaturated fatty acids found in higher percent in Aloe ferox, Aloe spectabilis and Aloe marlothii. Instead, Aloe aculeata proved to have a distinct fatty acid profile, rich in monounsaturated fatty acids. Species such as Aloe arborescens and Aloe marlothii proved to have the highest antioxidant potential according to data of DPPH, ORAC, HPS assays, even if the richest one in vitamin C was found to be Aloe spectabilis. Though the scientific research is mainly focused on the common species Aloe barbadensis, the current data suggests that other Aloe species could receive more attention from industry part, being great sources of bioactive compounds.

Treatment of Skin Disorders with Aloe Materials

The skin is the largest organ and functions as a barrier to protect the underlying tissues against the elements and pathogens, while also fulfilling many physiological roles and biochemical functions such as preventing excessive water loss. Skin disorders vary greatly in terms of origin, severity, symptoms and affect persons of all ages. Many plants have been used for medicinal purposes since ancient times including the treatment of skin disorders and diseases. Aloe represents one of the earliest medicinal plant species mentioned in antique scriptures and even in rock art dating back thousands of years. Different Aloe species and materials have been used in the prevention and treatment of skin related disorders. Aloe vera is the most commonly used Aloe species for medicinal purposes. Some of the most prominent skin related applications and disorders that Aloe materials have been investigated for are discussed in this paper, which include cosmetic, radiation, cancer, wound and antimicrobial applications. Both in vitro and in vivo studies are included in the discussions of this paper and comprehensive summaries of all these studies are given in tables in each section. Although some contradictory results were obtained among studies, certain Aloe materials have shown excellent efficacy and exhibited potential for the treatment of skin related disorders and cosmetic applications.

Efficient Micropropagation Protocol for the Conservation of the Endangered Aloe peglerae, an Ornamental and Medicinal Species

A number of Aloe species are facing an extremely high risk of extinction due to habitat loss and over-exploitation for medicinal and ornamental trade. The last global assessment of Aloe peglerae Schönland (in 2003) ranked its global conservation status as ‘endangered’ with a decreasing population trend. In the National Red List of South African Plants, the extremely rapid decline of this species has resulted in its conservation status being elevated from ‘endangered’ to ‘critically endangered’ based on recent or new field information. This dramatic decline necessitates the development of a simple, rapid and efficient micropropagation protocol as a conservation measure. An in vitro propagation protocol was therefore established with the regeneration of 12 shoots per shoot-tip explant within 8 weeks using Murashige and Skoog (MS) medium supplemented with 2.5 µM meta-topolin riboside (an aromatic cytokinin). The rooting of the shoots with a 100% frequency on half-strength MS medium without any plant growth resulted in additional six shoots produced per cultured shoot. The resultant plantlets were successfully acclimatized with a 100% survival frequency after 6 weeks. Overall, the developed protocol can result in the production of 3906 transplantable shoots that are ready for rooting per annum from a single shoot-tip explant. It is simple and efficient for seedling production in the ex situ cultivation and conservation of the endangered A. peglerae.

A review of the traditional use of southern African medicinal plants for the treatment of fungal skin infections

ETHNOPHARMACOLOGICAL RELEVANCE

Human dermatophyte infections are one of the most common classes of infection globally, with an estimated 1.7 billion people contracting at least one infection annually. Southern African ethnic groups used multiple plants to treat dermatophytosis and to alleviate the symptoms, yet the anti-dermatophyte properties of most species remain poorly explored.

AIM OF THE STUDY

Our study aimed to critically review the literature to document southern African plant species used to treat one or more dermatophytic infections, and to summarise scientific evaluations of these and other plant species. Our study aims to stimulate and focus future studies in this field.

MATERIALS AND METHODS

A thorough review of the ethnobotanical books, reviews and primary scientific studies were undertaken to identify southern African plants used traditionally to treat dermatophytosis, thereby identifying gaps in the research requiring further study.

RESULTS

Eighty-nine southern African plant species are recorded as traditional therapies for dermatophytosis. Scientific evaluations of 140 plant species were identified, although most of the species in those studies were selected for reasons apart from their traditional uses. None of those studies examined the mechanism of action of the plant species, and only a single study screened the extracts for toxicity.

CONCLUSIONS

Despite southern Africa having some of the longest continuous human civilisations globally, as well as unique and diverse flora, and good ethnobotanical records, the anti-dermatophyte properties of southern African medicinal plants remains relatively poorly explored. The efficacy of the majority of plants used traditionally to treat fungal skin disease are yet to be verified and substantial further research is required in this field.

Molecular perspective and anticancer activity of medicinal plants

To evaluate phytochemical constituents from the methanolic extracts of medicinal plants Aloe castellorum and Aloe pseudorubroviolacea. The cytotoxic activity of Aloe castellorum and Aloe pseudorubroviolacea leaf extracts against Human colon cancer cell line (HCT-116) was also assessed. The two medicinal plant extracts having significant cytotoxic activity, meanwhile the methanolic extract of Aloe castellorum shows higher cytotoxic activity than Aloe pseudorubroviolacea extract. The Aloe castellorum shows remarkable activity against respective cell line than control. The characteristic chemical constituents of Aloe castellorum and Aloe pseudorubroviolacea leaf extracts were recognized from Gas chromatography and Mass spectrometry (GC–MS) technique. The molecular docking studies also support the cytotoxic activity.

Natural resources used as folk cosmeceuticals among rural communities in Vhembe district municipality, Limpopo province, South Africa

BACKGROUND

Skin-related diseases affect every individual irrespective of age, gender or social status. Since time immemorial, humans have explored natural resources from their environment for the maintenance of the skin. This explorative survey was conducted to document the natural resources (plant and non-plant materials) used for folk cosmeceuticals by rural communities in Vhembe district municipality, Limpopo province, South Africa.

METHODS

The research was conducted in six communities namely: Tshakuma, Shigalo, Tshamutilikwa, Luvhimbi (Masikhwa), Khakhanwa, and Folovhodwe in Vhembe district. Random and convenient sampling was used to access the target population. Semi-structured questionnaires were used to interview 71 participants that comprised traditional practitioners, herbalists and laypeople from the study area. Collected data were analysed using both quantitative (for e.g. frequency, use-value and relative frequency of citation) and qualitative (thematic) analytical methods.

RESULTS

A total of 52 plants from 27 families and 22 non-plant materials were used as folk cosmeceuticals in the study area. The most cited plants included Dicerocaryum zanguebarium (Pedaliaceae), Ricinus communis (Euphorbiaceae) and Helinus integrifolius (Rhamnaceae). Trees and shrubs were the most common plant-life form while leaves were the most popular plant part. Pig fats, red ochre (Luvhundi soil) and ashes were the most cited non-plant materials. These documented natural resources are frequently prepared by crushing and mostly used to heal wounds.

CONCLUSION

Traditional knowledge concerning folk cosmeceuticals is mostly held by elders. The high number of natural resources documented is an indication that Vhembe district is rich in ethnopharmacological knowledge. Scientific investigation of the efficacies and safety of these natural resources is highly recommended as a drive aimed at innovations with benefits to the rural communities who are the custodians of this valuable knowledge.

Review: Southern African medicinal plants used as blood purifiers

ETHNOPHARMALOGICAL RELEVANCE

Blood purification practices, also referred to as blood cleansing or detoxification, is an ancient concept which is widespread amongst African traditional medicine, but for which no modern scientific basis exists. There prevails considerable ambiguity in defining what a blood purifier is.

AIM OF THE STUDY

The purpose of this review is to firstly define what a blood purifier is in the context of African traditional medicine and compare to other cultural and westernized interpretations. Thereafter, this study identifies traditionally used medicinal plants used as blood purifiers in southern Africa and correlates these species to scientific studies, which may support evidence for these "blood purifying plant species".

MATERIALS AND METHODS

Ethnobotanical books and review articles were used to identify medicinal plants used for blood purification. Databases such as Scopus, ScienceDirect, PubMed and Google Scholar were used to source scientific articles. An evaluation was made to try correlate traditional use to scientific value of the plant species.

RESULTS

One hundred and fifty nine plant species have been documented as traditional remedies for blood purification. Most of the plant species have some pharmacological activity, however, very little link to the traditional use for blood purification. There has been some justification of the link between blood purification and the use as an antimicrobial and this has been explored in many of the plant species identified as blood purifiers. Other pharmacological studies specifically pertaining to the blood require further attention.

CONCLUSION

Irrespective of the ambiguity of interpretation, medicinal plants used to "cleanse the blood", play an important holistic role in traditional medicine and this review with recommendations for further study provides some value of exploring this theme in the future.

Cytotoxic and cytostatic effects of four Annonaceae plants on human cancer cell lines

Several species of the Annonaceae plants have been used as complementary medicine for cancer-associated illnesses in some ethnic groups of northern Thailand. This study investigated the cytotoxic and cytostatic activity of methanolic extracts derived from the stems of these plants, including Uvaria longipes (Craib) L.L.Zhou, Y.C.F.Su & R.M.K.Saunders, Artabotrys burmanicus A.DC, Marsypopetalum modestum (Pierre) B.Xue & R.M.K.Saunders, and Dasymaschalon sp. Cell death induction of seven human cancer cell lines and cell cycle analyses were assessed by Annexin V and/or propidium iodide (PI) staining and analyzed by flow cytometry. Treatment of cancer cell lines with the extract of four Annonaceae plants resulted in various cytotoxic activities depending on cell type. The extract of U. longipes exhibited the highest cytotoxic activity capable of inducing cell death of several cancer cell lines, particularly against hepatocellular carcinoma cell lines (HepG2 and Hep3B). This extract was capable of inducing cell cycle arrest at the SubG1 phase. Phytochemical screening of all the extracts revealed the presence of alkaloids, sterols, tannins, anthraquinone glycoside, coumarin, and flavonoids. Determination of active compounds by high-performance liquid chromatography standards revealed bullatacin and asiminecin in all the extracts. The extract of Annonaceae stem or its compounds may provide an opportunity for the development of new therapies against cancer.

Evaluation of the in vitro effects of commercial herbal preparations significant in African traditional medicine on platelets

BACKGROUND

Commercial herbal medicines (CHMs) marketed as immune boosters are gaining wide popularity in South Africa, in the absence of control and regulatory guidelines. These commercially packaged and labelled herbal preparations, acquired in various retail outlets, are used without consulting either a conventional health provider or a traditional health practitioner. Although they are indicated for immune-boosting purposes, they might exert many other beneficial and unwanted effects on physiological systems. Platelets are crucial in haemostasis and important for the immunological system. The aim was to investigate the effect of the CHMs used to strengthen the immune system on the activity of human platelets.

METHODS

Six CHMs commonly used as African traditional medicines in Pretoria, South Africa, were tested for their effects on healthy, isolated human platelets, using a bioluminescence method. The tested herbal medicines were Intlamba Zifo™, Maphilisa™ Herbal medicine, Matla™ African medicine for all diseases, Ngoma™ Herbal Tonic Immune Booster, Stametta™ Body Healing Liquid, and Vuka Uphile™ Immune Booster and serial-diluted standards of each from 10 to 10,000 times. The luminol-enhanced luminescence activity of the platelets was measured after incubation with the herbal medicines and activation with phorbol myristate acetate (PMA) or N-formyl-methionyl-leucyl-phenylalanine (fMLP).

RESULTS

Five herbal medicines, namely Intlamba Zifo™, Maphilisa™ Herbal medicine, Matla™ African medicine for all diseases, Stametta™ Body Healing Liquid, and Vuka Uphile™ Immune Booster exerted comparable weak inhibitory effects on both PMA and fMLP-induced platelets, which were concentration dependent at high doses, and inversely related to concentration at low doses. Intlamba Zifo™, Matla™ African medicine for all diseases, Stametta™ Body Healing Liquid, and Vuka Uphile™ exhibited weak, but non-systematic stimulatory effects at low doses, which were not statistically significant. Ngoma™ Herbal Tonic Immune Booster had weak, inhibitory effects at high doses and weak stimulatory effects that were inversely related to concentration at low doses.

CONCLUSION

The findings suggest a potential beneficial role of the CHMs in the suppression of platelets' reactivity and in enhancing the immune system. Caution, however, should be exercised as platelet inhibition and stimulation predispose to the risk of bleeding and thrombosis, respectively.

Antiglycation Activity and HT-29 Cellular Uptake of Aloe-Emodin, Aloin, and Aloe arborescens Leaf Extracts

Aloe arborescens is a relevant species largely used in traditional medicine of several countries. In particular, the decoction of leaves is prepared for various medicinal purposes including antidiabetic care. The aim of this research was the study of the antiglycation activity of two A. arborescens leaf extracts and isolated compounds: aloin and aloe-emodin. These phytoconstituents were quantitatively assessed in methanolic and hydroalcoholic extracts using high performance liquid chromatography (HPLC) analysis. In addition, the total phenolic and flavonoid contents were detected. In order to study their potential use in diabetic conditions, the antiglycation and antiradical properties of the two extracts and aloin and aloe-emodin were investigated by means of bovine serum albumin (BSA) and 1,1-diphenyl-2-picryl-hydrazil (DPPH) assays; further, their cytotoxicity in HT-29 human colon adenocarcinoma cells was evaluated by 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide (MTT) assay. Furthermore, the ability of aloin and aloe-emodin to permeate the cellular membranes of HT-29 cells was determined in order to estimate their potential in vivo absorption. This assessment indicated that aloe-emodin can substantially pass through cell membranes (~20%), whereas aloin did not permeate into HT-29 cells. Overall, the data show that both the methanolic and the hydroalcoholic A. arborescens extracts determine significant inhibition of glycation and free-radical persistence, without any cytotoxic activity. The data also show that the antiglycation and the antiradical activities of aloin and aloe-emodin are lower than those of the two extracts. In relation to the permeability study, only aloe-emodin is able to cross HT-29 cellular membranes, showing the attitude to pass through the intestinal layer. Overall, the present data surely support the traditional use of A. arborescens leaf extracts against hyperglycemic conditions, while aloin and aloe-emodin as potential drugs need further study.

African Herbal Remedies with Antioxidant Activity: A Potential Resource Base for Wound Treatment

The use of traditional herbal remedies as alternative medicine plays an important role in Africa since it forms part of primary health care for treatment of various medical conditions, including wounds. Although physiological levels of free radicals are essential to the healing process, they are known to partly contribute to wound chronicity when in excess. Consequently, antioxidant therapy has been shown to facilitate healing of such wounds. Also, a growing body of evidence suggests that, at least, part of the therapeutic value of herbals may be explained by their antioxidant activity. This paper reviews African herbal remedies with antioxidant activity with the aim of indicating potential resources for wound treatment. Firstly, herbals with identified antioxidant compounds and, secondly, herbals with proven antioxidant activity, but where the compound(s) responsible for the activity has not yet been identified, are listed. In the latter case it has been attempted to ascribe the activity to a compound known to be present in the plant family and/or species, where related activity has previously been documented for another genus of the species. Also, the tests employed to assess antioxidant activity and the potential caveats thereof during assessment are briefly commented on.

Aloe Genus Plants: From Farm to Food Applications and Phytopharmacotherapy

Aloe genus plants, distributed in Old World, are widely known and have been used for centuries as topical and oral therapeutic agents due to their health, beauty, medicinal, and skin care properties. Among the well-investigated Aloe species are A. arborescens, A. barbadensis, A. ferox, and A. vera. Today, they account among the most economically important medicinal plants and are commonly used in primary health treatment, where they play a pivotal role in the treatment of various types of diseases via the modulation of biochemical and molecular pathways, besides being a rich source of valuable phytochemicals. In the present review, we summarized the recent advances in botany, phytochemical composition, ethnobotanical uses, food preservation, and the preclinical and clinical efficacy of Aloe plants. These data will be helpful to provide future directions for the industrial and medicinal use of Aloe plants.

Traditional and ethnobotanical dermatology practices in Africa

More than 80% of the global population depends on traditional medicine for their basic primary health care needs. Africa has a well-established history of botanicals use. These include a vast array of compounds that can be used to treat various skin-related conditions. The rationale for the use of traditional medicine in skincare stems from the physical effects these compounds have on skin, such as the ability to control bleeding and speed up wound healing, as well as the potential to treat burns and other disorders of pigmentation. Most African traditional healers employ decoctions and infusion methods in medicinal plant preparations; the former entails boiling of the whole or parts of the plant in water or other solvents to extract the active ingredients. Infusions involve immersion of the plant in hot or cold water for some time, followed by topically application to the affected skin area. The cosmetic skincare products are formulated to protect, enhance, and preserve the skin in its healthiest state to maintain its barrier function, thus protecting the human body. This review examines a number of botanicals that are used across Africa and the phytochemical actives that are responsible for skincare.

IN VITRO EFFECTS OF A COMMERCIAL HERBAL MEDICINE USED AS AFRICAN TRADITIONAL MEDICINE ON HUMAN NEUTROPHILS

Background:

Commercial herbal medicines (CHMs) being marketed as immune boosters or tonics, have gained widespread popularity. The many herbal mixtures sold have not been tested for efficacy and safety, despite their modern packaging and presentations. It is imperative that these herbal mixtures be investigated for their effects on human neutrophils.

Methods:

The selected herbal mixture (HM), Stametta™ Body healing liquid, is common in retail outlets in Pretoria, South Africa (SA) and is used as an immune booster or intended to strengthen the body. Isolated neutrophils as well as those in whole blood phagocytes were obtained from blood samples collected from consenting healthy adult volunteers. The neutrophils were incubated with the HM at different strengths, and taken through a luminol-enhanced luminescence assay, using activators- phorbol myristate acetate and N-formyl-methionyl-leucyl-phenylalanine.

Results:

The HM had variable stimulatory and inhibitory effects on the luminescence activity of healthy isolated and non-isolated human neutrophils. The effects, ranging from weak to potent were either directly or inversely related to the concentration of the HM and were mediated through a direct protein kinase C activating mechanism and an indirect formyl peptide receptor-linked mechanism.

Conclusion:

The findings have shown the immunomodulatory potential of Stametta™. The in vitro inhibitory and stimulatory effects on neutrophils which are furthermore time-based, suggest variable effects on the immune system, which may be beneficial as well as risky. The effects at different concentrations highlight the importance of appropriate dosing. It would therefore be prudent to caution users of this commercial herbal medicine accordingly.

Therapeutic effects of Aloe spp. in traditional and modern medicine: A review

Traditional medicine is a useful guide in medical sciences. In the Islamic Iranian traditional medicine, the medicinal properties of many plants have been mentioned that could be exploited in drug discovery. We aimed to explore the nature and properties of Aloe spp. As described in some major Islamic traditional texts including Ferdows al-Hekmah fi'l-Tibbe (The Paradise of Wisdom in Medicine), Al-Hawi fi'l-Tibb (Comprehensive Book of Medicine), Kamel al-Sanaat al-Tibbyyah (Complete Book of the Medical Art), Al-Qanun fi'l-Tibb (Canon of Medicine), Zakhireh Kharazmshahi (Treasure of Kharazmshah), and Makhzan al-Adwiah (Drug Treasure), and assess the conformity of traditional medicine instructions with the findings of modern pharmacological studies. Gastrointestinal activities, hepato-protective properties, beneficial effects against skin problems such as wounds, injuries, and infective diseases are among the most frequently mentioned properties of Aloe spp. Several activities of Aloe spp. described in traditional medicine have been the subject of recent in vitro and in vivo studies as well as clinical trials. Owing to the positive findings, different preparations of Aloe spp. are now present in pharmaceutical markets such as Aloe cosmetic products. On the other hand, there are many traditional therapeutic effects of Aloe spp. which have not been studied and require confirmatory experimental or clinical investigations. It is hoped that the present study could stimulate further research on the unexplored aspects of the medicinal properties of Aloe spp.

Propagation Techniques and Agronomic Requirements for the Cultivation of Barbados Aloe (Aloe vera (L.) Burm. F.)-A Review

Barbados aloe (Aloe vera (L.) Burm. F.) has traditionally been used for healing in natural medicine. However, aloe is now attracting great interest in the global market due to its bioactive chemicals which are extracted from the leaves and used in industrial preparations for pharmaceutical, cosmetic, and food products. Aloe originated from tropical and sub-tropical Africa, but it is also now cultivated in warm climatic areas of Asia, Europe, and America. In this review, the most important factors affecting aloe production are described. We focus on propagation techniques, sustainable agronomic practices and efficient post harvesting and processing systems.

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.

Ethnopharmacological analysis of medicinal plants and animals used in the treatment and management of pain in Mauritius

ETHNOPHARMACOLOGICAL RELEVANCE

Pain is a multi-faceted and multi-factorial condition which is challenging to manage and treat. Conventional therapies such as analgesics, Non-steroidal anti-inflammatory drugs (NSAIDs), and corticosteroids amongst others have been successful to some extent in its management and treatment. Nonetheless, such therapies tend to be accompanied by undesirable effects and have a limited therapeutic range. Consequently, there is a pressing need to probe for novel analgesic and anti-nociceptive drugs from traditional medicines (TM). This study was designed to record, document and analyze herbal and animal-based therapies used for the management and treatment of pain in the tropical of Mauritius.

MATERIALS AND METHODS

Data was collected via face-to-face interviews with TM users (n=332) and practitioners (n=20). Seven quantitative ethnopharmacological indexes, namely family use value (FUV), use value (UV), informant agreement ratio (IAR), relative frequency of citation (RFC), fidelity level (FL), relative importance (RI) and ethnobotanicity index (EI) were calculated.

RESULTS

A total of 79 plant species distributed within 40 families and 20 polyherbal preparations was recorded. Interestingly, 6 indigenous/endemic plants have been reported for the first time to be in common use for pain management and treatment in Mauritius. The most significant biologically important plant family was Xanthorrhoeaceae with highest FUV. The species which ranked highest according to its UV was Morinda citrifolia L. Morinda citrifolia L. and Ricinus communis L. also scored the highest RFC. The IAR values for the disease categories were high (0.95-0.97). Based on EI, plants species which are known to be useful in TM accounted for 11.5% of the total flora in Mauritius. Coix lacryma-jobi L. (FL=100%) had highest FL for lower back ache. Morinda citrifolia L. scored highest on most of the quantitative indices calculated including RI, which is endorsed by extensive documentation on its versatility and particularly its anti-nociceptive properties. Seven animal species were recorded to be in common use.

CONCLUSION

The present ethnopharmacological study revealed a panoply of TM to be in common use for pain management and treatment in Mauritius. This study has documented for the first time medicinal plants and animal species with potential analgesic and/or anti-nociceptive properties. This study has therefore provided important baseline primary data for the discovery of new lead molecules for drug development geared towards pain management and treatment.