Antifungal activity of some Tanzanian plants used traditionally for the treatment of fungal infections

A Review on the Phytochemistry and Pharmacology of the Genus Sterculia

The Sterculia genus is comprised of approximately 300 species, which have been widely used as traditional medicines to treat inflammation, snake bites, gastrointestinal diseases, skin diseases, microbial infections and many other diseases. To gain a comprehensive understanding of the therapeutic potential of Sterculia plants, an extensive literature search was conducted in CNKI, Bing, Wanfang Database, Springer Database, Elsevier Database, Google Scholar, Baidu Scholar, PubMed, and other similar websites from January 1971 to March 2024. The research indicated that Sterculia species predominantly contain flavonoids, terpenoids, phenylpropanoids, fatty acids, alkaloids and other chemical components. A wide range of pharmacologic activities such as anti-inflammatory, antioxidant, antibacterial and other biological activities have been reported. Nevertheless, there isn't much scholarly research on the therapeutic material basis of the genus Sterculia. This review reports the ethnobotany, phytochemicals, and biological activities of the plants in the Sterculia genus as herbal remedies.

Preserving Ethnoveterinary Medicine (EVM) along the Transhumance Routes in Southwestern Angola: Synergies between International Cooperation and Academic Research

This study delves into the ethnoveterinary medicine (EVM) practiced by pastoralists along the transhumance routes in southwestern Angola. Within the framework of three cooperation projects, we conducted 434 interviews, collecting information on 89 taxa used for treating 16 livestock diseases. The most cited species was Ptaeroxylon obliquum (132 citations), followed by Salvadora persica (59) and Elaeodendron transvaalense (49). Contagious bovine pleuropneumonia (CBPP) was the disease most cited (223 citations; 44 species), followed by wounds (95; 20) and Newcastle (86; 14). We found that 30 species and 48 uses have not been previously reported in the ethnoveterinary literature. Jaccard index (mean value = 0.13) showed a greatly diversified knowledge among the ethnic groups: Kuvale and Nyaneka were the most knowledgeable and should be included in the various strategies for disseminating EVM in the area. Most informants recognized that abundance of some species decreased in the last years as a result of human activities and climatic changes. Finally, we discuss challenges in preserving the EVM in the area. Our findings suggest that preservation of the EVM in southwestern Angola is widely impacted by the access to biomedicine. Future studies should investigate the opportunity to integrate traditional medicine into mainstream development projects, which is crucial for decolonizing the veterinary sector in Angola.

The Genus Diospyros: A Review of Novel Insights into the Biological Activity and Species of Mozambican Flora

Species of the Diospyros L. genus (Ebenaceae family) have been largely used in traditional medicine for the treatment of several diseases, especially infectious ones. To date, active major compounds such as naphthoquinones, triterpenoids, and tannins have been isolated and pharmacologically validated from Diospyros species. The present study summarizes the information available in the literature on the species described in the Flora of Mozambique. To do so, scientific databases (e.g., PubMed, Scopus, Web of Science, and Google Scholar) were searched using various keywords and Boolean connectors to gather and summarize the information. Of the 31 native and naturalized species in the Flora of Mozambique, 17 are used in different regions of Africa and were described for their traditional uses. They were reported to treat more than 20 diseases, mostly infectious, in the gastrointestinal and oral cavity compartments. This work provides an overview of the therapeutical potential of Diospyros species and explores novel insights on the antimicrobial potential of extracts and/or isolated compounds of these Mozambican species.

Ethnobotanical study of medicinal plants utilized in the management of candidiasis in Northern Uganda

Background

The emergence of resistant Candida species to antifungal drugs has led to resurgence in herbal usage globally. However, little is known about anti-candida plants. This study explored ethnomedicinal plants as treatment option for candidiasis in Pader, Northern Uganda.

Methods

A cross-sectional survey of potential anti-candida plants was conducted using questionnaires, focus group discussions and field observations in March 2022. Sixty-three respondents were selected by snowball technique. The frequencies of respondents/responses were analyzed, associations of respondents’ socio-demographics with indigenous knowledge of herbal usage established by Chi-square (χ²) test using SPSS 27. Informant Consensus Factor was computed to establish level of agreement on herbal usage, and thematic analysis done for focus group discussions.

Results

Candidiasis is still common and troublesome in Pader. All herbalist had equal chances of receiving and treating candidiasis patients irrespective of herbalist’s gender, age, education level, occupation, marital status and religion (p > 0.05). About 39.7% of herbalists received candidiasis patients weekly (p < 0.01). All herbalists had knowledge on candidiasis. Death (56.8%) and discomfort (36.8%) were the major health risks of oropharyngeal candidiasis (OPC) and vulvovaginal candidiasis (VVC), respectively. A total of 32 potential anti-candida plant species in 18 families were identified. Families of Fabaceae (9 species) and Asteraceae (5 species) had most plant species. Trees (50.0%) and herbs (43.8%) were the dominant life forms. The commonest plants by frequency of mention were: Momordica foetida (26), Sansevieria dawei (20), Khaya anthotheca (15), Piliostigma thonningii (10), Clerodendrum umbellatum (7), Hallea rubrostipulata (5) and unidentified plant, ‘Agaba/daa layata’ in Acholi dialect (5). Plant parts mainly used were roots (56.3%) and stem barks (15.6%) harvested majorly by cutting (46.9%) and uprooting (12.5%). Most respondents (females, 95%) preferred herbal to western medication (p < 0.01) due to its perceived effectiveness. There was high consensus among herbalists on herbal remedies for OPC and VVC (FIC = 0.9).

Conclusions

 Pader communities have diverse indigenous knowledge on candidiasis and prefer herbal medicines to orthodox treatment for candidiasis. However, the herbalists use unsustainable harvesting techniques like uprooting whole plants and cutting main roots. Hence, the need to document such indigenous knowledge before being lost for community usage and scientific validation.

Peelu (Salvadora oleoides Decne.): An Unexplored Medicinal Fruit with Minerals, Antioxidants, and Phytochemicals

The Peelu (Salvadora oleoides Decne.) fruit is well known for its nutritional and medicinal values. The current study analyzed the chemical composition of Salvadora oleoides fruit. Fresh Peelu fruits were harvested, and physicochemical properties, proximate composition, macro- and micronutrients, and phytochemical properties were determined. Moreover, ethanol and methanol fruit extract was analyzed for physicochemical properties. The Peelu fruit seemed to be a potential source of essential macro- ((nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), and magnesium (Mg)) and micronutrients (zinc (Zn), manganese (Mn), iron (Fe), and copper (Cu)). The fruit had significant biochemical properties (total soluble solids (TSS), total acidity (TA), and TSS : TA ratio) with appreciable moisture, crude fiber, and ash contents. The fruit extracts demonstrated significantly higher antioxidants and phenolics, ascorbic acid contents, and carotenoids. Phytochemical screening of fruit revealed the presence of coumarins, flavonoids, phlobatannins, tannins, and terpenoids. Physicochemical and sensory evaluation of extracts indicated its potential for further in vivo study trials. The Peelu fruit was found to be a good source of mineral nutrients, proximate contents, vitamins (ascorbic acid and carotenoid), phytochemicals (total phenolic sand antioxidant contents), and pharmaceutically important metabolites that can be used as functional drink.

Antimicrobial activities of the extracts and secondary metabolites from Clausena genus – A review

Antimicrobial drug resistance has become a global challenge and one of utmost concern due to the global epidemiological infections. Medicinal plants have long performed an essential role in medicine and can be an essential source of recent antimicrobials and techniques for treating resistance. Clausena is a genus in the Rutaceae family which are widely recognized and utilized in traditional medicines. Many members of this genus have been a primary source of medications and drug history. The antimicrobial effectiveness of the secondary metabolites from the roots, stems, leaves, rhizomes, twigs, seeds, fruits, and flowers of several Clausena species has been widely examined and was found to be more effective against bacteria with Clausena anisata being the most promising specie. A total of 16 active compounds including 12 alkaloids, 2 coumarins, and 2 terpenoids were reported to be isolated from different parts of the plant species with mukonal being the only compound that shows dual potency both against fungi and protozoa. This review aims to sum up research advances made from 2000 to date, on the antibacterial, antifungal, and antiprotozoal activities of Clausena species, and highlight the potential use of Clausena plants in the prevention and treatment of infectious diseases.

Antifungal Activities of Phytochemically Characterized Hydroethanolic Extracts of Sclerocarya birrea Leaves and Stem Bark against Fluconazole-Resistant Candida albicans Strains

The study evaluated the antifungal activities of the 70% ethanol extracts of Sclerocarya birrea leaves (SBL) and stem bark (SBB) against C. albicans strains and fluconazole-resistant isolates, their antifungal effects in combination with conventional antifungals as well as their effects on the biofilms of the C. albicans strains and isolates. UPLC-QTOF-MS/MS analysis was then carried out to investigate the metabolite profile of the extracts and UPLC fingerprints developed for their routine identification as part of quality control measures. The extracts exhibited considerable antifungal activity with MIC ranging from 12.21 to 97.66 μg/mL and MFC from 12.21 to 390.63 μg/mL against the C. albicans strains and isolates. The antifungal activity of the stem bark extract was higher than the leaf extract. SBL and SBB also significantly inhibited biofilm formation (IC50 = 12.49 to 164.42 μg/mL) and the mature biofilms (IC50 = 91.50 to 685.20 μg/mL) of the strains and isolates of the C. albicans and demonstrated potential for their use in combination therapies with currently used antifungals especially the stem bark extract with nystatin. Metabolite profiling identified the presence of polyphenolic compounds in both leaves and stem bark mostly flavonoids, their derivatives, and proanthocyanidins, which contribute in part to the bioactivity of the plant. Whereas flavonoids like quercetin, myricetin, and their derivatives were abundant in the leaves, epicatechin monomers with their condensed tannins, including procyanidin B2 and procyanidin C, were abundant in the stem bark. Fingerprints of SBL and SBB were developed and validated and could be used as qualitative tools to authenticate the plant. The outcomes of the study show the promise of the leaf and stem bark extracts of S. birrea to be studied further and developed as antifungal agents.

Identification of Secondary Metabolites from Mexican Plants with Antifungal Activity against Pathogenic Candida Species

In the last three decades, invasive fungal infections caused by Candida species have become an important public health problem, because they are associated with high rates of morbidity and mortality in immunocompromised and hospitalized patients. The diagnosis and treatment of candidiasis are difficult and usually inefficient. Accordingly, a diversity of available drugs, currently employed to attack candidiasis, frequently induce resistance in patients promoting toxicity due to long-term treatments. Therefore, development of accurate diagnoses and novel antifungals is of high priority to improve life’s quality and expectancy of individuals infected with this pathogen. Plants are invaluable sources of new biologically active compounds. Among the plants used in Mexico in traditional herbolary medicine which have empirically been demonstrated to have antifungal activity are Pedilanthus tithymaloides, Thymus vulgaris, and Ocimum basilicum. In the present study, we analyzed whether these plants contain metabolites with antifungal activity against five Candida species. The extracts from the different plant organs were obtained by macerating them in ethyl alcohol or hexane and filtering. The obtained extracts were preserved in amber flasks at 4°C until used. The minimum inhibitory concentrations (MICs) of the active compound were determined by a microdilution assay. In addition, the following secondary metabolites were identified: linalool (3,7-dimethylocta-1,6-dien-3-ol), eugenol (4-allyl-2-methoxyphenol), limonene (1-methyl-4-(1-methylethenyl)-cyclohexene), and borneol ([(2R)-1,7,7-trimethyl-2-bicyclo[2.2.1]heptanyl] formate). All these compounds were found in the three plants, traditionally used in everyday life, and proved to be effective against Candida species and therefore a viable alternative to conventional antifungals.

Studies on the chemical composition of plants used in traditional medicine in Congo

The knowledge of the chemical composition of herbs used medicinally in Africa is relatively low, and at the same time, the growing interest in alternative medicine prompts scientists to search for justification for the use of various plants. Due to these, the aim of the study was to analyze ten botanical species of medicinal plants originating from Congo to determine the contents of non-metals (P, Se), metallic elements (Cu, Zn, Fe, Mn, Ca, Mg, Na, K, Cd, Pb, Cr, Co, Al), phenolic compounds, and L(+) ascorbic acid and antioxidant activities. To prepare plant samples for quantitative analysis by flame atomic absorption spectrometry (FAAS) and inductively coupled plasma-optical emission spectroscopy, the microwave digestion was applied. The contents of phenolic acids, flavonoids, polyphenolic compounds, and vitamin C were assayed in extracts of medicinal plants spectrophotometrically, while the antioxidant activity was determined by ferric reducing antioxidant power (FRAP), 2,2-Diphenyl-1-picryl-hydrazyl-hydrate (DPPH), and 2,2 -Azino-bis-3-ethylbanzothiazoline-6-sulfonic acid (ABTS) techniques. The studies showed that the medicinal plants from Congo differed to a high degree. Principal component analysis demonstrated that the concentrations of Cu, Fe, Mn, and also phenolic compounds and antioxidant activity had the highest impact on sample’s differentiation. The relationship between the type of plant material (bark, root, or leaf) and its chemical composition was noticed, too.

Antibacterial and Antibiofilm Activity of Selected Medicinal Plant Leaf Extracts Against Pathogens Implicated in Poultry Diseases

Antimicrobial resistant poultry pathogens are responsible for treatment failure and economic losses, and can also be a source of resistant zoonotic infections representing a risk to human health. In 2006 the European Union banned the use of antibiotics as growth promoters in farm animals and other regions are likely to follow suit. Alternative products and strategies are sought to help maintain animal gut health to reduce the prevalence of pathogens in the food chain. The minimum inhibitory concentration (MIC) of organic and aqueous leaf extracts of Alchornea laxiflora, Ficus exasperata, Morinda lucida, Jatropha gossypiifolia, Ocimum gratissimum, and Acalypha wilkesiana were tested against bacterial poultry pathogens including Staphylococcus aureus, Enterococcus faecalis, Salmonella spp., Escherichia coli, Campylobacter spp., and fungal species (Aspergillus fumigatus, Aspergillus flavus, and Candida albicans) using a 2-fold serial microdilution method. Activity of extracts against biofilms of the pathogens was done using a modified crystal violet staining in vitro assay. The safety of extracts was determined against Vero and Caco-2 cells using a tetrazolium-based in vitro assay. Acetone and cold water extracts of M. lucida had the best activity against three bacteria (MIC = 0.05-0.07 mg/ml) and two fungal (MIC = 0.03-0.15 mg/ml) organisms, respectively. The E. coli isolate and A. flavus were the most susceptible bacteria and fungi, respectively. Caco-2 cells generally displayed higher selectivity index (SI) values compared to Vero cells and average SI values against Vero and Caco-2 cells for both bacteria and fungi ranged from 0.01 to 4.48 and 0.005 to 16.41, respectively. All plant extracts had good anti-biofilm activity (>50%) against at least one organism. The disruption of established biofilm growth by the plant samples proved to be more difficult to achieve than efficacy against planktonic forms of bacteria. This study shows that some of the plant species are potential candidates as alternative feed additives in poultry production. In the future, a poultry feed trial to evaluate their in vivo efficacy as herbal feed additives will be conducted.

Phytochemicals and Biological Activities of Barleria (Acanthaceae)

Plant species belonging to the family Acanthaceae are globally known to possess various medicinal properties and have cultural and economic importance in both traditional medicine and horticulture. They are important to both animals and humans and are used as food or for ornamental purposes worldwide. Barleria is the third largest genus in the family Acanthaceae. A few of the highly important and reported species of Barleria include B. prionitis, B. cristata, B. grandiflora, and B. lupulina. The flowers, leaves, stems, roots, and seed extracts of plants belonging to this genus are rich in bioactive compounds and have exhibited significant medicinal potential for the treatment of various ailments and infections. Evidence derived from several studies has demonstrated the antioxidant, antibacterial, antifungal, anti-inflammatory, anticancer, antidiabetic, antiulcer, hepatoprotective, analgesic, antiamoebic, antihelminthic, antiarthritic, antihypertensive, antiviral properties and toxicity of extracts, in addition inhibition of acetylcholinesterase activity and biosynthesis of nanoparticles, of the plant and seed extracts of species belonging to Barleria. Studies have reported that bioactive compounds such as flavonoids, quinones, iridoids, phenylethanoid glycosides, the immunostimulant protein “Sankaranin”, and antibiotics isolated from Barleria species are resposnsible for the above biological activities. Traditionally, the genus Barleria has significant medicinal potential; however, there is a scarcity of information on various species that are yet to be evaluated. This review provides a comprehensive report on existing literature, concerning the phytochemistry and biological activities of the genus Barleria.

A formulation of Clausena anisata (Willd.) Hook. f. Ex Benth and Cassia sieberiana DC. alleviates the symptoms associated with osteoarthritis: a single-blind, randomised controlled trial of a traditional Ghanaian remedy

Background

Clinical validation of herbal medicinal products is important for their widespread acceptance and application. In this single-blind, randomised controlled trial, a traditional Ghanaian herbal medicine formulation with Clausena anisata (Willd.) Hook. f. ex Benth and Cassia sieberiana DC. as ingredients was evaluated for its safety and effectiveness in the management of patients with osteoarthritis. The formulation for the purposes of this study was labelled with the code GC-500.

Methods

A total of 57 participants were randomly assigned to receive either this herbal remedy, GC-500, or the control treatment of diclofenac. Subjects were then followed up for a period of 8 weeks using a modified Graded Chronic Pain Scale (GCPS) for their efficacy assessments. The control treatment comprised 13 subjects and the GC-500 group 44 subjects.

Results

Upon completion of the study, 28 (63.63%) subjects in the GC-500 group attained the primary outcome, (GCPS of Grade 0) compared to 5 (38.46%) subjects in the control group. Improvement in disease indicators such as characteristic pain intensity, disability score and disability days was comparable between the GC-500 and diclofenac. Intensity of pain reduced after 8 weeks of treatment; disability score and disability days also declined indicating an improvement in the quality of life of subjects. GC-500 was also shown to be safe for human use.

Conclusion

The herbal medicine formulation GC-500, provides a credible treatment option for managing the pain associated with osteoarthritis.

Trial registration

This study was retrospectively registered with the Pan-African Trial registry with a Trial ID: PACTR201909643671755 on 25th September, 2019 at https://pactr.samrc.ac.za/Search.aspx

ALS3 Expression as an Indicator for Candida albicans Biofilm Formation and Drug Resistance

Resistance caused by the formation of the Candida albicans (C. albicans) biofilm is one of the main reasons for antifungal therapy failure. Thus, it is important to find indicators that predict C. albicans biofilm formation to provide evidence for the early prevention and treatment of the C. albicans biofilms. In this study, C. albicans samples were selected from C. albicans septicemia that were sensitive to common antifungal agents. It was found that the agglutinin-like sequence 3 (ALS3) gene was differentially expressed in free, antifungal, drug-sensitive C. albicans. The average ALS3 gene expression was higher in the C. albicans strains with biofilm formation than that in the C. albicans strains without biofilm formation. Then, it was further confirmed that the rate of biofilm formation was higher in the high ALS3 gene expression group than that in the low ALS3 gene expression group. It was found that C. albicans with biofilm formation was more resistant to fluconazole, voriconazole, and itraconazole. However, it maintained its sensitivity to caspofungin and micafungin in vitro and in mice. Further experiments regarding the prevention of C. albicans biofilm formation were performed in mice, in which only caspofungin and micafungin prevented C. albicans biofilm formation. These results suggest that the expression level of ALS3 in C. albicans may be used as an indicator to determine whether C. albicans will form biofilms. The results also show that the biofilm formation of C. albicans remained sensitive to caspofungin and micafungin, which may help to guide the selection of clinical antifungal agents for prevention and therapy.

Medicinal plants used in managing diseases of the respiratory system among the Luo community: an appraisal of Kisumu East Sub-County, Kenya

BACKGROUND

Poor access to healthcare in rural communities causes many people to seek herbalists who use medicinal plants for the treatment of various disease conditions. Most knowledge of traditional herbal medicine makes use of indigenous remedies which are often undocumented and are at risk of being lost. The preservation of this knowledge may facilitate scientific inquiry into promising new therapeutic molecules.

METHODS

Semi-structured questionnaires were used to collect the sociodemographic information of 30 herbalists in Kisumu East Sub County. The local names of medicinal plants used in managing illnesses of the respiratory system, their habit, active parts, indications, methods of preparation, routes of administration, scientific identity, and conservation status were also recorded. Other reported traditional uses, pharmacological activities, and toxicological data were identified via a literature search.

RESULTS

Most herbalists were female (86.7%), aged between 61 and 70 years (43.3%) with no formal education (56.7%), and had 21-30 years of practice (30%). 44 plant species, belonging to 43 genera and 28 families were identified. Leguminosae and Rutaceae plant families were predominant, leaves were frequently used (33%), and trees were the most common habit (44.4%). Most plants were collected in the wild (79.2%), preparation was mainly by decoction (68.8%), and the administration was mainly orally. The main indication was cough and 79.5% of all documented plant species had previously been reported to have a pharmacological activity relevant to the mitigation of respiratory illnesses. Toxicological data was available for 84.1% of the plant species identified.

CONCLUSIONS

The predominant use of roots, root barks, and root tubers by herbalists in Kisumu East Sub County threatens to negatively impact the ecological survival of some plant species. The preservation of herbalists' knowledge of medicinal plants in the study area is a pressing concern considering their advanced age and little formal education. There is a need to conserve some of the medicinal plants documented in this study. The medicinal claims made by herbalists also warrant scientific scrutiny.

Nkadimeng S, Lall N, Kabasa JD, J. McGaw L. Ethnobotany, Phytochemistry and Pharmacological Activity of Kigelia africana (Lam.) Benth. (Bignoniaceae)

Kigelia africana has been used in the management of human ailments since time immemorial. Ethnobotanists have documented the traditional uses of K. africana, which include treatment of skin disorders, cancer and gynecological complaints, among others. This has interested scientists, who have examined K. africana plant parts for their bioactivity. This review provides an insightful understanding on the ethnobotany, phytochemistry and pharmacology of K. africana. Web search engines Google and Google Scholar, as well as the databases of PubMed, Scopus, JSTOR, HINARI, SID, AJOL and Springer Link, were exhaustively searched using key words and phrases. Institutional reports and conference papers were also consulted. A total of 125 relevant international literature sources meeting the inclusion criteria were included. Kigelia africana has biologically active phytochemicals, many of which have been isolated. Whilst the fruits are most often cited in pharmacological studies, other plant parts are also used in herbal preparations. Commercially available products have been formulated from K. africana, though many have not been fully standardized. Despite many efforts by researchers to scientifically validate traditional uses of K. africana, many remain merely claims, thus the need to conduct more research, scientifically validate other traditional uses, isolate new bioactive phytochemicals and standardize K. africana products.

A review of traditional uses, phytochemistry and pharmacology of the genus Indigofera

ETHNOPHARMACOLOGICAL RELEVANCE

Indigofera is the third-largest genus in the family of Fabaceae, with approximately 750 species. It is distributed across all tropical regions. Indigofera species are widely employed in traditional medicine all around the world, against many ailments. Thus, based on these medicinal properties, various investigations have been undertaken in order to appraise the pharmacological activities and the chemical composition of these species. A recent paper provides a summary of the phytochemistry and pharmacology of the genus Indigofera. Consequently, this review is a continuation of this previous study by updating some data and adding information about the phylogeny and traditional uses of the genus.

AIM OF THE STUDY

To provide an overview of the phylogeny, traditional uses, phytochemistry, pharmacology and toxicity of the genus Indigofera, and to identify the remaining gaps and thus supply a basis for further investigations.

MATERIALS AND METHODS

A review of the literature was performed by consulting scientific databases such as 'ScienceDirect', 'PubMed', 'Google Scholar' and 'SpringerLink' and using the keyword Indigofera.

RESULTS

Over 60 Indigofera species are reported in traditional medicine. The uses depend on the country and the species, but similarities have been noticed. Indeed, treatments of gastrointestinal disorders, inflammatory conditions and pain, skin ailments, and respiratory and infectious diseases are recurring. Phytochemical studies have led to the identification of more than 200 compounds, notably flavonoids and terpenoids. Many pharmacological activities have been demonstrated, particularly antimicrobial, cytotoxic and anti-inflammatory activities, and thus allowed to assert most of the traditional uses of the genus. Some active compounds have been isolated and have shown remarkable therapeutic potential, like the alkaloid indirubin, which is currently being clinically trialed.

CONCLUSIONS

The data on the genus Indigofera are extensive, but gaps still remain. Indeed, some promising species have not been assessed for their phytochemistry and/or pharmacology and thus remain unexplored. Moreover, relatively few active compounds have been isolated and tested for their biological activity, and studies to explain their mechanism of action are nearly inexistent. Furthermore, some pharmacological studies have inappropriate methodologies that make the results difficult to interpret. Consequently, further in-depth and relevant research is required to supplement the knowledge on this wide-ranging genus and to confirm its reported therapeutic potential.

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.

The role of bracken fern illudanes in bracken fern-induced toxicities

Bracken fern is carcinogenic when fed to domestic and laboratory animals inducing bladder and ileal tumours and is currently classified as a possible human carcinogen by IARC. The carcinogenic illudane, ptaquiloside (PTQ) was isolated from bracken fern and is widely assumed to be the major bracken carcinogen. However, several other structurally similar illudanes are found in bracken fern, in some cases at higher levels than PTQ and so may contribute to the overall toxicity and carcinogenicity of bracken fern. In this review, we critically evaluate the role of illudanes in bracken fern induced toxicity and carcinogenicity, the mechanistic basis of these effects including the role of DNA damage, and the potential for human exposure in order to highlight deficiencies in the current literature. Critical gaps remain in our understanding of bracken fern induced carcinogenesis, a better understanding of these processes is essential to establish whether bracken fern is also a human carcinogen.

Antibacterial Activity of Coumarins and Carbazole Alkaloid from Roots of Clausena anisata

Clausena anisata is one of the medicinal plants used traditionally for treatment of parasitic infections, irritation (boils, ringworm, and eczema), flatworm infestations, influenza, abdominal cramps, and constipation. Phytochemical screening test of dichloromethane/methanol (1 : 1) roots extract revealed the presence of flavonoids, phytosterols, coumarins, phenols, alkaloids, tannins, terpenoids, and free reducing sugars and the absence of saponins. Silica gel column chromatographic separation of the dichloromethane/methanol (1 : 1) extract afforded a carbazole alkaloid derivative of heptazoline (1) and three coumarins (2-4), including the known coumarins imperatorin (3) and chalepin (4). Structures of the compounds were elucidated by spectroscopic techniques (IR, ¹H NMR, ¹³C NMR, and DEPT-135). Antibacterial activity of the crude extracts and isolated compounds was screened using agar diffusion method against strains of Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, and Bacillus substilis. The results of antibacterial test revealed derivative of heptaphylline (1) and imperatorin (3) exhibited comparable antibacterial activity against S. aureus and B. substilis (14 and 13 mm zone of inhibition, respectively) to that of ciprofloxacin (15 mm zone of inhibition) at a concentration of 20 µg/mL. Chalepin (4) revealed more antibacterial activity against B. substilis (16 mm zone of inhibition) compared to ciprofloxacin (15 mm).

New compounds with antimicrobial activities from Elaeodendron buchananii stem bark

The plant species Elaeodendron buchananii Loes is widely used in folklore medicine to manage microbial infections in Kenya. Previous studies on the plant fruits and root bark revealed the presence of steroids and terpenoids. The present phytochemical analysis of the plant stem bark has led to the isolation of four new triterpenes characterized as methyl 3β-acetoxy-11α, 19α, 28-trihydroxyurs-12-en-23-oic acid (1), 3β, 11α, 19α-trihydroxyurs-12-en-23, 28-dioic acid (2), 3β-acetoxy-19α, 23, 28-trihydroxyurs-12-ene (3) and 3-oxo-19α, 28-dihydroxyurs-12-en-24-oic acid (4), together with ten known ones (5-14), whose structures were elucidated using spectroscopic techniques. The isolate canophyllol (8) showed promising antibacterial activity against N. meningitides with MIC value of 31.25 μg/ml.

Medicinal foods and beverages among Maasai agro-pastoralists in northern Tanzania

ETHNOPHARMACOLOGICAL RELEVANCE

Pastoralist Maasai populations of east Africa use several different wild plants as dietary and medicinal additives in beverages (soups and teas), yet little is known about how the plants used and the rationales for use compare and contrast across different Maasai beverages, including how gender specific dietary and health concerns structure patterns of intake.

AIM OF THE STUDY

We investigated three Maasai beverages: almajani (tea or herbal infusion); motorí (traditional soup); and okiti (psychoactive herbal tea). In order to build knowledge about the cultural functions of these Maasai food-medicines and their incidence of use we also investigated use rationales and self-reported frequencies of use. We conclude by examining gender differences and the possible pharmacological antimicrobial activity of the most frequently used plants.

MATERIALS AND METHODS

Research was conducted in 2015, with a population of semi-nomadic agropastoralist Maasai residing in northern Tanzania. Data were collected using key informant interviews, plant collections, n = 32 structured surveys, and n = 40 freelist interviews followed by a literature review to determine the known antimicrobial activity of the most used plants.

RESULTS

We identified 20 plants that Maasai add to soup, 11 in tea, and 11 in the psychoactive tea, for a total of 24 herbal additives. Seven plant species were used in all three Maasai beverages, and these clustered with 10 common ailments. Based on self-reports, women use the beverages less frequently and in smaller amounts than men. There were also several gender differences in the plants that Maasai add to motorí and their associated use rationales.

CONCLUSIONS

There are several intersections concerning the plant species used and their associated rationales for use in almajani, motori, and okiti. Moving outward, Maasai beverages and their additives increasingly involve gender specific concerns. Female use of food-medicines, relative to men, is structured by concerns over pregnancy, birth, and lactation. The frequent consumption of herbal additives, many of which contain antimicrobial compounds, potentially helps modulate infections, but could have other unintentional effects as well.

Mosquito control with green nanopesticides: towards the One Health approach? A review of non-target effects

The rapid spread of highly aggressive arboviruses, parasites, and bacteria along with the development of resistance in the pathogens and parasites, as well as in their arthropod vectors, represents a huge challenge in modern parasitology and tropical medicine. Eco-friendly vector control programs are crucial to fight, besides malaria, the spread of dengue, West Nile, chikungunya, and Zika virus, as well as other arboviruses such as St. Louis encephalitis and Japanese encephalitis. However, research efforts on the control of mosquito vectors are experiencing a serious lack of eco-friendly and highly effective pesticides, as well as the limited success of most biocontrol tools currently applied. Most importantly, a cooperative interface between the two disciplines is still lacking. To face this challenge, we have reviewed a wide number of promising results in the field of green-fabricated pesticides tested against mosquito vectors, outlining several examples of synergy with classic biological control tools. The non-target effects of green-fabricated nanopesticides, including acute toxicity, genotoxicity, and impact on behavioral traits of mosquito predators, have been critically discussed. In the final section, we have identified several key challenges at the interface between "green" nanotechnology and classic biological control, which deserve further research attention.

Clausena anisata and Dysphania ambrosioides essential oils: from ethno-medicine to modern uses as effective insecticides

Dysphania ambrosioides (L.) Mosyakin & Clemants (Amaranthaceae) and Clausena anisata (Willd.) Hook. f. ex Benth. (Rutaceae) are two aromatic species traditionally used in Cameroon to repel and kill insects. The present work was carried out to substantiate this traditional use and to evaluate the possible incorporation in commercial botanical insecticides of their essential oils (EOs). The EOs were distilled from leaves of C. anisata and aerial parts of D. ambrosioides and analyzed by gas chromatography-mass spectrometry (GC-MS). The insecticidal activity of both EOs was investigated against the filariasis vector, Culex quinquefasciatus, and the housefly, Musca domestica. As possible mode of action, the inhibition of acetylcholinesterase (AChE) by the two EOs was investigated as well. The D. ambrosioides EO was characterized by the monoterpene peroxide ascaridole (61.4%) and the aromatic p-cymene (29.0%), whereas the C. anisata EO was dominated by the phenylpropanoids (E)-anethole (64.6%) and (E)-methyl isoeugenol (16.1%). The C. anisata EO proved to be very toxic to third instar larvae of C. quinquefasciatus showing LC₅₀ of 29.3 μl/l, whereas D. ambrosioides EO was more toxic to adults of M. domestica showing a LD₅₀ of 51.7 μg/adult. The mixture of both EOs showed a significant synergistic effect against mosquito larvae with LC₅₀ estimated as 19.3 μl/l, whereas this phenomenon was not observed upon application to M. domestica adults (LD₅₀ = 75.9 μg/adult). Of the two EOs, the D. ambrosioides one provided a good inhibition of AChE (IC₅₀ = 77 μg/ml), whereas C. anisata oil was not effective. These findings provide new evidences supporting the ethno-botanical use of these two Cameroonian plants, and their possible application even in synergistic binary blends, to develop new eco-friendly, safe and effective herbal insecticides.

A Comparative Study on Phytochemical Profiles and Biological Activities of Sclerocarya birrea (A.Rich.) Hochst Leaf and Bark Extracts

Sclerocarya birrea (A.Rich.) Hochst (Anacardiaceae) is a savannah tree that has long been used in sub-Saharan Africa as a medicinal remedy for numerous ailments. The purpose of this study was to increase the scientific knowledge about this plant by evaluating the total content of polyphenols, flavonoids, and tannins in the methanol extracts of the leaves and bark (MLE and MBE, respectively), as well as the in vitro antioxidant activity and biological activities of these extracts. Reported results show that MLE is rich in flavonoids (132.7 ± 10.4 mg of quercetin equivalents/g), whereas MBE has the highest content of tannins (949.5 ± 29.7 mg of tannic acid equivalents/g). The antioxidant activity was measured using four different in vitro tests: β-carotene bleaching (BCB), 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), O₂-•, and nitric oxide (NO•) assays. In all cases, MBE was the most active compared to MLE and the standards used (Trolox and ascorbic acid). Furthermore, MBE and MLE were tested to evaluate their activity in HepG2 and fibroblast cell lines. A higher cytotoxic activity of MBE was evidenced and confirmed by more pronounced alterations in cell morphology. MBE induced cell death, triggering the intrinsic apoptotic pathway by reactive oxygen species (ROS) generation, which led to a loss of mitochondrial membrane potential with subsequent cytochrome c release from the mitochondria into the cytosol. Moreover, MBE showed lower cytotoxicity in normal human dermal fibroblasts, suggesting its potential as a selective anticancer agent.

Bioactive compounds in Diospyros mafiensis roots inhibit growth, sporulation and aflatoxin production by Aspergillus flavus and Aspergillus parasiticus

Diospyros mafiensis F. White is a medicinal shrub or small tree (6 m tall) widely distributed in the Zanzibar-Inhambane regional mosaic and traditionally used to treat leprosy, diarrhoea, and skin fungal infections in Tanzania and Mozambique. Our objective was to determine the anti-aflatoxigenic properties of compounds from D. mafiensis root bark against vegetative growth, sporulation and aflatoxin production by Aspergillus flavus and Aspergillus parasiticus. Bioassay-guided extraction, fractionation, and isolation of bioactive compounds using A. parasiticus B62 were employed. The bioactive compounds were elucidated using 1H and 13CNMR and LC-MS. Growth inhibition was determined by measuring the colony diameter of A. flavus AF3357 and A. parasiticus SU-1 ATCC56775. Inhibitory effects on sporulation were estimated using a haemocytometer. Total aflatoxin was quantified by direct competitive enzyme-linked immunosorbent assay (ELISA). Bioactive compounds diosquinone (DQ) and 3-hydroxydiosquinone (3HDQ) were identified. DQ weakly inhibited A. flavus and A. parasiticus vegetative growth (MIC50 > 100 µg/ml) and 3HDQ strongly inhibited A. flavus (MIC50 = 14.9 µg/ml) and A. parasiticus (MIC50 = 39.1 µg/ml). DQ strongly reduced total aflatoxin production by A. flavus from 157 to 36 ng/plate, and by A. parasiticus from 1,145 ng/plate to 45 ng/plate at 100 µg/ml. 3HDQ reduced total aflatoxin production by A. parasiticus from 1,145 to 32 ng/plate; stimulated production by A. flavus from 157 to 872 ng/plate at 12.5 µg/ml but reduced to 45 ng/plate at 100 µg/ml. In summary, DQ and 3HDQ could be used as natural antifungal compounds to prevent mould growth and aflatoxin accumulation in food and feed.

Systematic review and technological overview of the antimicrobial activity of Tagetes minuta and future perspectives

ETHNOPHARMACOLOGICAL RELEVANCE

The antimicrobial potential of Tagetes minuta was correlated with its traditional use as antibacterial, insecticidal, biocide, disinfectant, anthelminthic, antifungal, and antiseptic agent as well as its use in urinary tract infections.

AIM OF THE STUDY

This study aimed to systematically review articles and patents regarding the antimicrobial activity of T. minuta and give rise to perspectives on this plant as a potential antimicrobial agent.

MATERIALS AND METHODS

A literature search of studies published between 1997 and 2015 was conducted over five databases: MedLine (PubMed), Web of Science, Scopus, Google Scholar, Portal de Periódicos Capes and SciFinder, grey literature was explored using the System for Information on Dissertations database, and theses were searched using the ProQuest Dissertations and Theses Full text database and the Periódicos Capes Theses database. Additionally, the following databases for patents were analysed: United States Patent and Trademark Office (USPTO), Google Patents, National Institute of Industrial Property (INPI) and Espacenet patent search (EPO). The data were tabulated and analysed using Microsoft Office Excel 2010.

RESULTS

After title screening, 51 studies remained and this number decreased to 26 after careful examinations of the abstracts. The full texts of these 26 studies were assessed to check if they were eligible. Among them, 3 were excluded for not having full text access, and 11 were excluded because they did not fit the inclusion criteria, which left 10 articles for this systematic review. The same process was conducted for the patent search, resulting in 4 patents being included in this study.

CONCLUSION

Recent advances highlighted by this review may shed light on future directions of studies concerning T. minuta as a novel antimicrobial agent, which should be repeatedly proven in future animal and clinical studies. Although more evidence on its specificity and clinical efficacy are necessary to support its clinical use, T. minuta is expected to be a highly effective, safe and affordable treatment for infectious diseases.

In vitro and in vivo effects of suloctidil on growth and biofilm formation of the opportunistic fungus Candida albicans

As the most frequent fungal pathogen in humans, Candida albicans can develop serious drug resistance because its biofilms are resistant to most antifungal agents; this leads to an urgent need to develop novel antifungals. Here, we evaluated the efficacy of an antithrombotic drug, suloctidil, against C. albicans biofilms in vitro and in vivo. We found that suloctidil is effective to inhibit C. albicans biofilm, with a minimum inhibitory concentration (MIC₈₀) of 4 μg/mL, a biofilm inhibiting concentration (BIC₈₀) of 16 μg/mL and a biofilm eradicating concentration (BEC₈₀) of 64 μg/mL. Furthermore, the concentration-dependent characteristics of suloctidil were shown by its time-kill curves. Scanning electron microscopy images clearly revealed the morphological effects of suloctidil on biofilm. Yeast-to-hyphal form switching is a key virulence factor of C. albicans; therefore, we performed hyphal growth tests and observed that suloctidil inhibited yeast-to-hyphal form switching. This result was consistent with the down-regulation of hypha-specific gene (HWP1, ALS3, and ECE1) expression levels after suloctidil treatment. In vivo, 256 μg/mL of suloctidil significantly reduced fungal counts (P<0.01) compared to that in groups without treatment; the treatment group induced a slight histological reaction, especially when the treatment lasted for 5 days (P<0.01). Taken together, our data suggest that suloctidil is a potential antifungal agent.

IN VITRO EFFICACY OF EXTRACTS FROM PLANTS USED BY SMALL-HOLDER FARMERS IN THE TREATMENT OF DERMATOPHILOSIS IN CATTLE

Background:

Bovine dermatophilosis, an important skin disease of cattle caused by Dermatophilus congolensis, negatively impacts the livelihoods of small-holder farmers in Zimbabwe. This impact is through, morbidity, loss of draught animal power, costs incurred to manage the disease, losses associated with devalued damaged hides and the resultant culling of some of the affected cattle. Due to the inaccessibility of conventional drugs to manage bovine dermatophilosis, farmers have been reported to use local medicinal plants to manage the disease. The aim of the study was to evaluate the in vitro antimicrobial activities of three plants that small-holder farmers in Zimbabwe used to manage bovine dermatophilosis.

Methods:

Dried plant materials were ground into powder and extracted individually using, water, 80 % acetone and 80 % methanol. The antimicrobial properties of the plants were evaluated against two Gram-negative (Escherichia coli and Pseudomonas aeruginosa) and one Gram-positive (Staphylococcus aureus) reference bacterial strains. They were further evaluated against a field isolate of Dermatophilus congolensis. The assays used were the disc diffusion, minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC).

Results:

Acetone and methanol extracts had superior inhibitory activities than did those of water. Pterocarpus angolensis DC extracts had better inhibitory properties with absolute MIC values of 0.156 – 5 mg/ml, Cissus Quadrangularis L had MIC values in the range 0.156 – 5 mg/ml while that of Catunaregam spinosa Thunb, Terveng was 0.156 – 10 mg/ml. Dermatophilus congolensis was more sensitive to Pterocarpus angolensis DC average MIC = 0.63 mg/ml than to Cissus quadrangularis L average MIC = 1.25 mg/ml and Catunaregam. spinosa Thunb, Terveng average MIC = 2.08 mg/ml.

Conclusion:

These results suggest the potential antibacterial activities of extracts of the three plants and hence farmers are, in a way, justified in using the plants. Better results (lower MIC) could be obtained by extracting and evaluating pure active compounds of the plants.

Anti-inflammatory and Analgesic Effects in Rodent Models of Ethanol Extract of Clausena anisata Roots and their Chemical Constituents

The in vivo anti-inflammatory and analgesic activities of the crude ethanol extract and chemical constituents of Clausena anisata roots were investigated. The crude extract, which was devoid of any visible acute toxicity, displayed significant anti-inflammatory effect at the dose of 1000 mg/kg (p.o.) when assessed using the carrageenan-induced oedema model. In the acetic acid-induced writhing and hot plate tests, it produced a very significant ( p < 0.001), dose-dependent analgesic effect, with maximum analgesic activity of 72.1% at 1000 mg/kg (p.o.). Phytochemical analysis of the crude extract resulted in the isolation of four coumarins (anisocoumarin B, osthol, imperatorin and xanthotoxol) and a carbazole alkaloid, heptaphylline. Among the isolated compounds, osthol and anisocoumarin B produced the highest anti-inflammatory activity at 9 mg/kg (p.o.): slightly better than the positive control, indomethacin. Except for xanthotoxol, all the isolated compounds administered at 6 mg/kg (p.o.) produced significant analgesic activity and higher than diclofenac; with heptaphylline being the most potent (48.7%). The analgesic activity of anisocoumarin B (50.4%) was the highest among the isolates tested and the standard, tramadol, in the hot plate test. The nonselective opioid receptor antagonist, naloxone, abolished the analgesic effect of the crude extract and the tested isolates (anisocoumarin B and xanthotoxol) in the hot plate test suggesting an effect via the central opioidergic system. These findings provide the scientific basis for the use of C. anisata roots in traditional medicine as anti-inflammatory and analgesic agents.

Ethnobotanical survey and toxicity evaluation of medicinal plants used for fungal remedy in the Southern Highlands of Tanzania

Background/Aim:

Some of the antifungal drugs used in the current treatments regime are responding to antimicrobial resistance. In rural areas of Southern Tanzania, indigenous people use antifungal drugs alone or together with medicinal plants to curb the effects of antibiotic resistance. This study documented ethnobotanical information of medicinal plants used for managing fungal infections in the Southern Highlands of Tanzania and further assess their safety.

Materials and Methods:

Ethnobotanical survey was conducted in Makete and Mufindi districts between July 2014 and December 2015 using semi-structured questionnaires followed by two focus group discussions to verify respondents’ information. Cytotoxicity study was conducted on extracts of collected plants using brine shrimp lethality test and analyzed by MS Excel 2013 program.

Results:

During this survey about 46 plant species belonging to 28 families of angiosperms were reported to be traditionally useful in managing fungal and other health conditions. Among these, Terminalia sericea, Aloe nutii, Aloe lateritia, Zanthoxylum chalybeum, Zanthoxylum deremense, and Kigelia africana were frequently mentioned to be used for managing fungal infections. The preparation of these herbals was mostly by boiling plant parts especially the leaves and roots. Cytotoxicity study revealed that most of the plants tested were nontoxic with LC₅₀ > 100 which implies that most compounds from these plants are safe for therapeutic use. The dichloromethane extract of Croton macrostachyus recorded the highest with LC₅₀ value 12.94 µg/ml. The ethnobotanical survey correlated well with documented literature from elsewhere about the bioactivity of most plants.

Conclusions:

The ethnobotanical survey has revealed that traditional healers are rich of knowledge to build on for therapeutic studies. Most of the plants are safe for use; and thus can be considered for further studies on drug discovery.

The use of Clausena anisata in insect pest control in Africa: A review

ETHNOPHARMACOLOGICAL RELEVANCE

Clausena anisata is used traditionally by various communities across Africa against pests such as mosquitoes, flies and weevils among others. Pests are a major cause of disease and production losses in various crop and livestock production systems in Africa. This review discusses the available information on the occurrence, chemistry, biological activity and possible commercialization of Clausena anisata with a view to see the plant species being integrated in pest management.

MATERIALS AND METHODS

Information on the ethnomedical use, chemistry and biological activity of C. anisata published between 1980 and 2016 was accessed from various databases namely Science Direct, Springer Link and Wiley Online Library. In addition various relevant books were also consulted.

RESULTS

The crude extracts as well as different fractions of C. anisata have been evaluated for activity against various insect pests and have been shown to be active. Furthermore, close to 50 compounds have been isolated and identified from C. anisata, which include coumarins, carbazole alkaloids, limonoids and essential oils (monoterpenes). Some of these compounds have been proven to exhibit pesticidal properties in both laboratory and field studies against various pests including mosquitoes, flies and weevils. The possible mechanisms of action of these compounds have been explored in this review.

CONCLUSION

The results of pesticidal and phytochemical screening of C. anisata strongly indicate that the species is endowed with pesticidal properties that can be harnessed into commercial products. However, one glaring challenge in the evaluation of this plant species for pesticidal activity has been the non-availability of standard testing systems. Researchers have used various methods which they developed based on their own circumstances and resources. Formulation, standard appropriate testing systems and agronomic research are key in unlocking the potential of this important African species.

Kigelia africana (Lam.) Benth. (Sausage tree): Phytochemistry and pharmacological review of a quintessential African traditional medicinal plant

ETHNOPHARMACOLOGICAL RELEVANCE

Kigelia africana is a quintessential African herbal medicinal plant with a pan-African distribution and immense indigenous medicinal and non-medicinal applications. The plant is use traditionally as a remedy for numerous disease such as use wounds healing, rheumatism, psoriasis, diarrhea and stomach ailments. It is also use as an aphrodisiac and for skin care.

AIM OF THE REVIEW

The present review aims to compile an up-to-date review of the progress made in the continuous pharmacological and phytochemistry investigation of K. africana and the corresponding commercial and pharmaceutical application of these findings with the ultimate objective of providing a guide for future research on this plant.

METHOD

The scholarly information needed for this paper were predominantly sourced from the electronic search engines such as Google, Google scholar; publishing sites such as Elsevier, scienceDirect, BMC, PubMed; other scientific database sites for chemicals such as ChemSpider, PubChem, and also from online books.

RESULTS

Pharmacological investigations conducted confirm the anti-inflammatory, analgesic, antioxidant and anticancer activity of the extract of different parts of the plant. Bioactive constituents are found to be present in all parts of the plant. So far, approximately 150 compounds have been characterized from different part of the plant. Iridoids, naphthoquinones, flavonoids, terpenes and phenylethanoglycosides are the major class of compounds isolated. Novel compounds with potent antioxidant, antimicrobial and anticancer effect such as verbascoside, verminoside and pinnatal among others, have been identified. Commercial trade of K. africana has boosted in the las few decades. Its effect in the maintenance of skin has been recognized resulting in a handful of skin formulations in the market.

CONCLUSIONS

The pharmaceutical potentials of K. africana has been recognized and have witness a surge in research interest. However, till date, many of its traditional medicinal uses has not been investigated scientifically. Further probing of the existential researches on its pharmacological activity is recommended with the end-goal of unravelling the pharmacodynamics, pharmacokinetics, clinical relevance and possible toxicity and side effects of both the extract and the active ingredients isolated.

Mutation of G234 amino acid residue in candida albicans drug-resistance-related protein Rta2p is associated with fluconazole resistance and dihydrosphingosine transport

Widespread and repeated use of azoles has led to the rapid development of drug resistance in Candida albicans. Our previous study found Rta2p, a membrane protein with 7 transmembrane domains, was involved in calcineurin-mediated azole resistance and sphingoid long-chain base release in C. albicans. Conserved amino acids in the transmembrane domain of Rta2p were subjected to site-directed mutagenesis. The sensitivity of C. albicans to fluconazole in vitro was examined by minimum inhibitory concentration and killing assay, and the therapeutic efficacy of fluconazole in vivo was performed by systemic mice candidiasis model. Furthermore, dihydrosphingosine transport activity was detected by NBD labeled D-erythro-dihydrosphingosine uptake and release assay, and the sensitivity to sphingolipid biosynthesis inhibitors. We successfully constructed 14 mutant strains of Rta2p, screened them by minimum inhibitory concentration and found Ca(2+) did not completely induce fluconazole resistance with G158E and G234S mutations. Furthermore, we confirmed that G234S mutant enhanced the therapeutic efficacy of fluconazole against systemic candidiasis and significantly increased the accumulation of dihydrosphingosine by decreasing its release. However, G158E mutant didn't affect drug therapeutic efficacy in vivo and dihydrosphingosine transport in C. albicans. G234 of Rta2p in C. albicans is crucial in calcineurin-mediated fluconazole resistance and dihydrosphingosine transport.

Cytotoxicity of 91 Kenyan indigenous medicinal plants towards human CCRF-CEM leukemia cells

ETHNOPHARMACOLOGICAL RELEVANCE

Plants from Kenyan flora are traditionally used against many ailments, including cancer and related diseases. Cancer is characterized as a condition with complex signs and symptoms. Recently there are recommendations that ethnopharmacological usages such as immune and skin disorders, inflammatory, infectious, parasitic and viral diseases should be taken into account when selecting plants that treat cancer.

AIM

The present study was aimed at investigating the cytotoxicity of a plethora of 145 plant parts from 91 medicinal plants, most of which are used in the management of cancer and related diseases by different communities in Kenya, against CCRF-CEM leukemia cell line.

MATERIALS AND METHODS

Extracts from different plant parts (leaves, stems, stem bark, roots, root barks, aerial parts and whole herb) were obtained by cold percolation using different solvent systems, such as (1:1v/v) dichloromethane (CH2Cl2) and n-hexane (1), methanol (MeOH) and CH2Cl2 (2); neat MeOH (3), 5% H2O in MeOH (4) and with ethanol (EtOH, 5); their cytotoxicities were determined using the resazurin reduction assay against CCRF-CEM cells.

RESULTS

At a single concentration of 10μg/mL, 12 out of 145 extracts exhibited more than 50% cell inhibition. These include samples from the root bark of Erythrina sacleuxii (extracted with 50% n-hexane-CH2Cl2), the leaves of Albizia gummifera, and Strychnos usambarensis, the stem bark of Zanthoxylum gilletii, Bridelia micrantha, Croton sylvaticus, and Albizia schimperiana; the root bark of Erythrina burttii and E. sacleuxii (extracted with 50% CH2Cl2-MeOH), the stem bark of B. micrantha and Z. gilletii (extracted using 5% MeOH-H2O) and from the berries of Solanum aculeastrum (extracted with neat EtOH). The EtOH extract of the berries of S. aculeastrum and A. schimperiana stem bark extract displayed the highest cytotoxicity towards leukemia CCRF-CEM cells, with IC50 values of 1.36 and 2.97µg/mL, respectively. Other extracts having good activities included the extracts of the stem barks of Z. gilletii and B. micrantha and leaves of S. usambarensis with IC50 values of 9.04, 9.43 and 11.09µg/mL, respectively.

CONCLUSIONS

The results of this study provided information related to the possible use of some Kenyam medicinal plants, and mostly S. aculeastrum, A. schimperiana, C. sylvaticus, Z. gilletii, B. micrantha and S. usambarensis in the treatment of leukemia. The reported data helped to authenticate the claimed traditional use of these plants. However, most plants are used in combination as traditional herbal concoctions. Hence, the cytotoxicity of corresponding plant combinations should be tested in vitro to authenticate the traditional medical practitioners actual practices.

An ethnobotanical survey of medicinal plants used by communities of Northern Kordofan region, Sudan

ETHNOPHARMACOLOGICAL RELEVANCE

The present study provides significant ethnopharmacological information on plant species used in North Kordofan region, western Sudan. The study was undertaken with an aim to document the medicinal uses of the species known to some Northern Kordofan communities.

MATERIAL AND METHODS

The study was conducted between 2012 and 2013. The plants were identified and voucher specimens prepared. Information was collected by means of semi-structured interviews with 258 informants (195 men and 63 women). In addition, the use value (UV) of the species was determined and the informant consensus factor (ICF) was calculated for the medicinal plants researched in the study. Further analysis was carried out to compare results with previous studies from the study area and other regions of Sudan.

RESULTS

A total of 44 plant species representing 24 families were found to be commonly used in the treatment of 73 different human health problems. The families most represented were Leguminosae (18%), Caesalpiniaceae (9%), Malvaceae (9%), Asclepiadaceae (6.8%) and Combretaceae (6.8%). The highest number of plant species are used against digestive system disorders (23 species) followed by microbial infections (21 species) and dermatology (19 species). Among all the plant parts leaves (20%), roots (19%), fruits and bark (14% each) were the most preferred plant parts used by the informants. There was strong agreement among the informants as to the usages of the plants (informant consensus factor 0.63-0.93). The most important plants on the basis of use-value were Acacia nilotica, Acacia seyal, Balanites aegyptiaca, Cassia occidentalis, Cassia senna, Guiera senegalensis and Tamarindus indica.

CONCLUSION

This study has helped to document information that may otherwise be lost to future generations. This is the first ethnobotanical study in which statistical calculations about plants are carried out by means of the ICF and UV methods in the study area. Plants with high ICF and UV values should be subjected for further phytochemical and pharmacological investigation for scientific validation.

Ethnobotanical survey of food and medicinal plants of the Ilkisonko Maasai community in Kenya

AIM OF THE STUDY

Pastoralist communities such as the Maasai are heavily reliant on traditional foods and medicines. This survey sought to identify traditional foods and/or medicinal plants of the Ilkisonko Maasai community living in Kenya.

MATERIALS AND METHODS

Ethnobotanical knowledge of traditional plants used as food and human/veterinary medicine was obtained using structured and semi-structured questionnaires administered through face to face interviews of key informants.

RESULTS

A total of 30 species from 21 families and 25 genera were reportedly used as food and/or medicine by 48 respondents. The most commonly encountered genus was the Fabaceae. The growth forms encountered were tree (47%), shrub (33%) and herb (20%). Plants that were commonly mentioned by respondents were Salvadora persica (85%), Grewia villosa (52%), Ximenia americana (52%), Albizia anthelmintica (50%), Acacia robusta (46%) and Acacia nilotica (42%). The root/root bark was the most commonly used plant part (35%), followed by the stem/stem bark (30%), fruit (15%), leaves (11%) and whole plant (9%). Common ailments treated were stomach aches, constipation, back aches, joint aches, body pains and sexually transmitted infections. The plants were also used as tonics, digestives, and restoratives.

CONCLUSION

It was evident that traditional medicine was the preferred health care system for the Ilkisonko Maasai community. It is important to document and use this knowledge in producing novel products that could improve nutrition and healthcare in rural communities.

The traditional use of plants to manage candidiasis and related infections in Venda, South Africa

ETHNOPHARMACOLOGICAL RELEVANCE

This paper presents results of an ethnobotanical survey of medicinal plants used for the management of candidiasis and related fungal infections in the Venda area, South Africa.

MATERIALS AND METHODS

Ethnobotanical data about the uses of plants were gathered from eleven rural traditional healers using semi-structured interviews.

RESULTS

A total of 45 species belonging to 24 different families were identified, of which the dominant family was the Fabaceae with 13 species (28.9%) followed by the Asteraceae and Solanaceae with 3 species each (6.7 %). A total of 28 of these plant species (62.2%) have been shown to have anticandidal activity and 14 species (31%) have been recorded for antifungal uses in the literature. Amongst the 45 species recorded, 51% were trees, 33% were shrubs, and 16% were herbs. The most widely used plant species were Acacia caffra, Clerodendrum glabrum, Croton gratissimus, Elaeodendron transvaalense, Faurea saligna, Hippocratea longipetiolata, Osyris lanceolata, Richardia brasiliensis, Schkuhria pinnata, Schotia brachypetala, Spilanthes acmella, Strychnos potatorum, Vangueria infausta subsp. infausta and Withania somnifera. The plant parts mostly used in the therapeutic preparations were roots (27.7%), bark (23.2%), and a combination of roots, bark (18.7%) and leaves (14.3%). Decoctions (44.4%), infusions (20%), macerations (17.7%), burning (11.4%) and paste (6.5%) were used. Most of the herbal remedies were administered orally. The main factors threatening the conservation status of these plants are unsustainable methods of harvesting, logging for firewood, building materials and crafts.

CONCLUSION

The Venda area is rich in plant diversity and local indigenous knowledge of medicinal plants can play an important role as a model for low cost primary health care. Further studies are in progress to validate the indigenous plants recorded as traditional remedies in this area.

Antimicrobial Activities of a Plethora of Medicinal Plant Extracts and Hydrolates against Human Pathogens and Their Potential to Reverse Antibiotic Resistance

Microbial infections till date remain a scourge of humanity due to lack of vaccine against some infections, emergence of drug resistant phenotypes, and the resurgence of infections amongst others. Continuous quest for novel therapeutic approaches remains imperative. Here we (i) assessed the effects of extracts/hydrolates of some medicinal plants on pathogenic microorganisms and (ii) evaluated the inhibitory potential of the most active ones in combination with antibiotics. Extract E03 had the highest DZI (25 mm). Extracts E05 and E06 were active against all microorganisms tested. The MICs and MBCs of the methanol extracts ranged from 16.667 × 10³  μg/mL to 2 μg/mL and hydrolates from 0.028 to 333333 ppm. Extract E30 had the highest activity especially against S. saprophyticus (MIC of 6 ppm) and E. coli (MIC of 17 ppm). Combination with conventional antibiotics was shown to overcome resistance especially with E30. Analyses of the extracts revealed the presence of alkaloids, flavonoids, triterpenes, steroids, phenols, and saponins. These results justify the use of these plants in traditional medicine and the practice of supplementing decoctions/concoctions with conventional antibiotics. Nauclea pobeguinii (E30), the most active and synergistic of all these extracts, and some hydrolates with antimicrobial activity need further exploration for the development of novel antimicrobials.

Antioxidant and proapoptotic activities of Sclerocarya birrea [(A. Rich.) Hochst.] methanolic root extract on the hepatocellular carcinoma cell line HepG2

The main goal of this study was to characterize the in vitro antioxidant activity and the apoptotic potential of S. birrea methanolic root extract (MRE). Among four tested extracts, obtained with different solvents, MRE showed the highest content of polyphenols, flavonoids, and tannins together with antioxidant activities tested with superoxide, nitric oxide, ABTS, and beta-carotene bleaching assays. Moreover, the cytotoxic effect of MRE was evaluated on the hepatocarcinoma cell line HepG2. In these cells, MRE treatment induced apoptosis and generated reactive oxygen species (ROS) in dose-dependent manner. The cytotoxic effect promoted by MRE was prevented by pretreatment of HepG2 cells with N-acetyl-L-cysteine (NAC), suggesting that oxidative stress was pivotal in MRE-mediated cell death. Moreover, we showed that the MRE treatment induced the mitochondrial membrane depolarization and the cytochrome c release from mitochondria into the cytosol. It suggests that the apoptosis occurred in a mitochondrial-dependent pathway. Interestingly, MRE showed a sensibly lower cytotoxicity, associated with a low increase of ROS, in normal human dermal fibroblasts compared to HepG2 cells. It is suggested that the methanolic root extract of S. Birrea is able to selectively increase intracellular ROS levels in cancer cells, promoting cell death.

Antifungal activity of 40 TCMs used individually and in combination for treatment of superficial fungal infections

ETHNOPHARMACOLOGICAL RELEVANCE

A series of 40 important Traditional Chinese Medicines (TCMs), which were reported effective in treating superficial fungal infections of the skin in Chinese clinical trial publications and Chinese Herbal Classics, were chosen for the investigation of the individual and combination antifungal properties against 8 superficial fungal strains in vitro.

MATERIALS AND METHODS

Plant preparations were followed the theory of TCM by using sterile water boiled with plant material at 100°C to produce water decoction of the tested sample. The minimum inhibitory concentration (MIC) of each plant for each fungus was determined. For the compatibility investigation, both invariable (same amounts of each tested TCM) and variable (different amounts of each tested TCM) combinations were evaluated.

RESULTS

All the tested TCMs demonstrated varying degrees of antifungal activities against one or more of the tested superficial fungi, and 16 of which were effective on all of the fungi. Strong antifungal activities were exhibited by water decoction of 7 TCMs with MIC at about 100μg/ml, and among these effective antifungal extracts, 4 TCMs including Melaphis chinensis, Polygonum cuspidatum, Punica granatum and Schisandra chinensis showed the significantly inhibitory activities against all of the fungi with MICs among 50μg/ml. Most of the invariable combinations of the above-mentioned 4 TCMs showed synergic effects against 4 of the least susceptible fungi strains, especially the invariable combination of Punica granatum, Melaphis chinensis and Schisandra chinensis, with the MIC at 23.4μg/ml. However, their further variable combinations investigation demonstrated that only the combination of 7.5g Punica granatum with 10g Melaphis chinensis and 7.5g Schisandra chinensis showed synergic effect with the MIC at19.5μg/ml.

CONCLUSIONS

The present study aimed the discovery of therapeutically useful agents for treatment of superficial fungal infections. Findings suggested that the combination of 3 TCMs including Punica granatum, Melaphis chinensis and Schisandra chinensis showed potential antifungal activity and thus appeared to be promising agents in preventing superficial fungal skin infectious in a natural way through herbal resources. The synergic effects of invariable and variable combinations of the tested TCMs threw a light on our further animal model and clinical practice as well as the bio-guided isolation and identification of the antifungal compounds.

Antimicrobial, antioxidant and cytotoxicity potential of Manihot multifida (L.) Crantz (Euphorbiaceae)

Manihot multifida (L.) Crantz (Euphorbiaceae) is widely used in popular medicine for the treatment of infected wounds. This study evaluated the in vitro antioxidant and antimicrobial potential of this species against strains of Gram-positive and Gram-negative bacteria and fungi, known to cause infections in humans. The extracts showed minimal inhibitory concentration (MIC) varying from 39 to 2500 µg/mL for antimicrobial activity. The methanolic extract of fruits, aqueous and hexane extracts of leaves showed a very strong activity against Candida albicans (ATCC 18804) with MIC of 39 µg/mL. Furthermore, the methanolic extract of M. multifida leaves exhibited DPPH (1,1-diphenyl-2-picrylhydrazyl) scavenging potential with inhibitory concentration (IC50) values of 46.9 μg/mL, followed by hexane extract of leaves with IC50 values of 59.2 μg/mL. The cytotoxic activity against brine shrimp was stronger for the methanolic extract of leaves (lethal concentration - LC50 of 15.6 µg/mL). These results suggest that M. multifida has interesting antimicrobial and antioxidant activities. Moreover, these results corroborate the popular use of this specie in treating fungal infections since it demonstrates significant activity against C. albicans.

The chemistry and bioactivity of Southern African flora II: flavonoids, quinones and minor compound classes

This review is intended to highlight the relevance of natural products in drug discovery paying particular attention to those derived from Southern African medicinal plants with diverse biological activities.