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

ETHNOPHARMACOLOGICAL RELEVANCE: Blood purification practices, also referred to as blood cleansing or detoxification, is an ancient concept which is widespread within African traditional medicine. There is, however, limited consolidated information about the selection of plant species, the purpose of use and how the preparation is made. An in-depth examination of how regional communities use medicinal plants for blood purification is needed to better understand this ethnopharmacological practice. AIM OF THE STUDY: To gather knowledge on the traditional use of medicinal plants used for the purpose of blood purification by laypersons in northern Maputaland, KwaZulu-Natal, South Africa. METHODS: An ethnobotanical survey was conducted on medicinal plants used in the rural areas of northern Maputaland for blood purification. Interviews were conducted in 55 homesteads, where the most knowledgeable participant per household was interviewed using structured questionnaires. Information collected included knowledge of the concept of blood purification, purpose for medicating, plant selection, and mode of preparation. The most important species and families were identified through indices. RESULTS: Sixty-four plant species from 35 families were recorded as blood purifiers for the treatment of ailments linked to the need for blood purification. Terminalia sericea Burch. ex DC. was the most used plant species (mentioned by 39% of the people interviewed). The conditions that were mostly associated with blood purification were skin complaints, gastro-intestinal disorders, and overall improvement of general health. Blood purification is also commonly used for non-medical purposes such as granting good luck or as a love charm. Six new plant species and five new Zulu vernacular names had not previously been documented for blood purification. CONCLUSION: The frequently mentioned use of medicinal plants for blood purification by the rural community of northern Maputaland clearly emphasises the importance of this cultural practice. There is no doubt that when examining African traditional medicine, holistic terms such as "blood cleansing" cannot be ignored. Future studies may provide a better understanding of this often misunderstood and undocumented practice.

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

ETHNOPHARMACOLOGICAL RELEVANCE: Multiple plant species are used traditionally in southern Africa to treat fever. This review summarises the traditional use, highlights promising plant species and focuses on validation studies to highlight future areas of research. AIM OF THE STUDY: This study aimed to critically review the use of southern African plants to alleviate fever. Additionally, an examination of research into those plants was undertaken to highlight gaps in the literature with the aim of stimulating further research in this field. MATERIALS AND METHODS: Ethnobotanical books, reviews and primary research studies were searched to identify plant species traditionally used to treat fever in southern Africa and to summarise the current knowledge and identify areas requiring further research. This study was non-biased and did not have any taxonomic preferences, nor did it favour any southern African healing systems over the others. RESULTS: The traditional therapeutic uses of 203 southern African plant species to alleviate fever were recorded. Leaves and roots/bulbs/rhizomes were the most commonly used plant part, and they were most commonly prepared as decoctions or infusions and consumed orally. Notably, only twenty-two species (∼11% of the identified species) have been scientifically evaluated for antipyretic properties, with substantially fewer mechanistic studies evident. CONCLUSIONS: Despite the availability of ethnobotanical records, the antipyretic properties of southern African medicinal plants are poorly reported. Indeed, the efficacy of most plants is yet to be verified and very few mechanistic studies are available.

Traditionally used polyherbals in a southern African therapeutic context.

ETHNOPHARMACOLOGICAL RELEVANCE: In African traditional medicine, there are several plant species that are used in combination with either other plant species or non-plant derived combinations such as sugar and honey, salt and vinegar, milk, fat etc. This review examines the role of these combinations and postulates the scientific and therapeutic validation of such combinations. AIM OF THE STUDY: This study reviewed the ethnopharmacological literature and documented the use of southern African plant combinations to find a scientific rationale for such combinations, and provide recommendations for future studies. MATERIALS AND METHODS: Ethnobotanical books and online databases such as Scopus, ScienceDirect, PubMed and Google Scholar were used to find ethnobotanical studies within the southern African context that focus on the combinations of plants with other plants or various additional ingredients. The scientific literature was examined to determine if evidence was available to substantiate such combinations. RESULTS: One hundred and eighty-seven medicinal plant (plant-to-plant) combinations that are used in the southern African traditional healing system were recorded. These plant combinations were used against infections of the gastrointestinal tract, respiratory tract, and skin as well other non-infectious diseases such as reproductive and psychiatric disorders. Respiratory infections were the most documented infections to be treated using plant combinations. The plant that was documented to be most commonly used in combination with other plants was Artemisia afra Jacq. ex Willd. While plant-plant combinations have drawn a marked interest, comparatively, plant-adjuvant (e.g. milk, sugar, honey, salt, vinegar, fats) combinations have attracted less research interest. Milk was reported as the most used additional ingredient in combination with medicinal plants. The combination of animal urine and dung with medicinal plants has been reported as a treatment for treat prostate infections, the human immunodeficiency virus (HIV). Other ingredients such as clay and flour were also documented, and these are often mixed with medicinal plants to treat fever, stomach ailments, sexually transmitted infections (STI) and skin conditions. Although combination therapy has been frequently reported in ethnobotanical records, over 90% of the combinations reviewed still need to be scientifically validated. CONCLUSION: Scientific reports on the antimicrobial, anti-oxidant, anti-inflammatory and other pharmacological effects of these combinations may offer an understanding of traditional combination therapy. In addition, investigation into the mechanisms of action of these combinations are also recommended to supplement the findings. Nonetheless, the use of plant combinations is still an untapped research area in southern Africa and there is a need to validate the use of those documented combinations to obtain a better understanding of combined traditional medicinal plant use.

Essential oil combinations against Clostridium perfringens and Clostridium septicum - the causative agents of gas gangrene.

AIMS: The inhibitory and bactericidal effect of a wide range of essential oils, and their selected combinations against two pathogens (Clostridium perfringens and Clostridium septicum), the causative pathogens of gas gangrenous infections were investigated. Fractional inhibitory indices were also calculated to determine the interactions. METHODS AND RESULTS: The Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) assays were used to determine the efficacy of the essential oils. Santalum austrocaledonicum demonstrated the highest activity inhibiting both Clostridial pathogens at the lowest concentration of 0·02 mg ml-1 . Santalum austrocaledonicum combined with Cymbopogon martinii had the strongest inhibition against C. perfringens (MIC 0·02 mg ml-1 ) and C. septicum (MIC 0·01 mg ml-1 ). Selected combinations demonstrated synergy (ΣFIC ≤ 0·50) in combination against both pathogens tested. Antagonism was also observed in many combinations. CONCLUSIONS: Selected essential oils, when studied either individually or in combination, have high inhibitory and bactericidal effects against both Clostridial strains. Nine combinations have proven to be synergistic with 23 combinations additive; 96 indifferent and 77 having an antagonistic effect against the pathogenic strains. Some combinations demonstrated extreme antagonism and as such, careful consideration needs to be given to essential oil selection against these pathogens. SIGNIFICANT IMPACT OF THE STUDY: Very few essential oils have been antimicrobially screened (MIC and MBC) against Clostridial strains and furthermore, the efficacies in combination are not known.

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.

Laboratory-based study of novel antimicrobial cold spray coatings to combat surface microbial contamination.

OBJECTIVE: To investigate the touch-contact antimicrobial efficacy of novel cold spray surface coatings composed of copper and silver metals, regard to their rate of microbial elimination. DESIGN: Antimicrobial time-kill assay. SETTING: Laboratory-based study. METHODS: An adapted time-kill assay was conducted to characterize the antimicrobial efficacy of the developed coatings. A simulated touch-contact pathogenic exposure to Gram-positive Staphylococcus aureus (ATCC 25923), Gram-negative Pseudomonas aeruginosa (ATCC 27853), and the yeast Candida albicans (ATCC 10231), as well as corresponding resistant strains of gentamicin-methicillin-resistant S. aureus (ATCC 33592), azlocillin-carbenicillin-resistant P. aeruginosa (DSM 46316), and a fluconazole-resistant C. albicans strain was undertaken. Linear regression modeling was used to deduce microbial reduction rates. RESULTS: A >7 log reduction in microbial colony forming units was achieved within minutes on surfaces with cold spray coatings compared to a single log bacterial reduction on copper metal sheets within a 3 hour contact period. Copper-coated 3-dimensional (3D) printed acrylonitrile butadiene styrene (ABS) achieved complete microbial elimination against all tested pathogens within a 15 minute exposure period. Similarly, a copper-on-copper coating achieved microbial elimination within 10 minutes and within 5 minutes with the addition of silver powder as a 5 wt% coating constituent. CONCLUSIONS: In response to the global need for alternative solutions for infection control and prevention, these effective antimicrobial surface coatings were proposed. A longitudinal study is the next step toward technology integration.

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.

A review of the traditional use of southern African medicinal plants for the treatment of malaria.

ETHNOPHARMALOGICAL RELEVANCE: Malaria is one of the most prevalent and deadly parasitic diseases globally, with over 200 million new cases and nearly 500,000 deaths reported annually. It is estimated that approximately half of the world's population lives in malaria endemic areas. Malaria is substantially less prevalent in South Africa than in other African regions and the disease is limited to some regions of the Limpopo, Mpumalanga and KwaZulu-Natal provinces. However, it still has a significant impact on the health of the populations living in those regions. Traditional medicines have long been used in South Africa by multiple ethic groups and many people continue to rely on these natural therapies for their healthcare. The usage of South African medicinal plants in several traditional healing systems to treat malaria have been documented (particularly for Zulu and Venda traditional medicine), although ethnobotanical investigations of other ethnic groups living in endemic malaria areas remains relatively neglected. AIM OF THE STUDY: To document the use of South African medicinal plants known to be used traditionally to treat Plasmodium spp. infections. We also critically reviewed the literature on the therapeutic properties of these and other South African plants screened against Plasmodium spp. parasites with the aim of highlighting neglected studies and fostering future research in this area. MATERIALS AND METHODS: Books and ethnobotanical reviews were examined for medicinal plants used specifically for fever. Exclusion criteria were studies not involving southern African medicinal plants. Furthermore, while fever is a common symptom of malaria, if not accompanied by the term "malaria" it was not considered. Databases including PubMed, ScienceDirect, Scopus and Google Scholar were used to source research relevant to southern African plants and malaria. Exclusion criteria were those publications where full articles could not be accessed. RESULTS: Eighty South African plant species were identified as traditional therapies for malaria. The majority of these species were documented in Zulu ethnobotanical records, despite malaria occurring in only a relatively small portion of the Zulu's traditional territory. Surprisingly, far fewer species were reported to be used by Venda, Ndebele, northern Sotho, Tsonga, Tswana, and Pedi people, despite them living in endemic malaria areas. Interestingly many of the identified species have not been investigated further. This review summarises the available ethnobotanical and laboratory research in this field, with the aim of promoting and focusing research on priority areas. CONCLUSION: Although malaria remains a serious disease affecting millions of people, medicinal plants while used extensively, have not been given the attention warranted for further investigation.

Antimicrobial activity of Elytropappus rhinocerotis (Asteraceae) against micro-organisms associated with foot odour and skin ailments.

ETHNOPHARMACOLOGICAL RELEVANCE: The twigs of Elytropappus rhinocerotis are widely used in the Cape region of South Africa to treat foot odour, perspiration and also itchy, chilblained and burning feet. However, no antimicrobial studies have hitherto been published on this popular Cape herbal medicine, which is also used for a wide range of ailments. AIMS OF THE STUDY: To determine the antimicrobial activity of the extracts, essential oil and two major labdane diterpenes isolated from E. rhinocerotis against micro-organisms associated with foot odour and other conditions associated with skin infections. MATERIALS AND METHODS: Leafy stems were harvested from three individual plants at three separate geographical localities, giving a total of nine plant samples. The samples were air-dried, powdered and extracted with a 1:1 mixture of methanol and dichloromethane, and also with sterile distilled water. A portion of each sample was also hydrodistilled to obtain nine samples of essential oil. Isolation of the major labdane diterpenes was performed using silica and ethyl acetate in hexane (3:7 v/v) as the mobile phase. Minimum inhibitory concentrations (MIC) were determined for nine crude extracts, as well as three essential oil samples and two labdane diterpenes obtained from a bulk sample. The test organisms used in this study were from Deutsche Sammlung von Mikrooganismen (DSM) and American type culture collection (ATCC) strains and included five bacterial species (Brevibacterium agri ATCC 51663, B. epidermidis DSM 20660, B. linens DSM 20425, Staphylococcus aureus ATCC 25923, S. epidermidis ATCC 12228) and one fungal species (Trichophyton mentagrophytes ATCC 9533) associated with the skin. RESULTS: The presence of essential oil is reported for the first time. Organic extracts and essential oil samples showed moderate to noteworthy activity against selected test organisms. For the Brevibacteria, the lowest MIC values for phenolic extracts were several times lower than the corresponding values for the positive control zinc (shown in brackets): 0.0031 mg/mL against Brevibacterium agri (0.33 mg/mL), 0.17 mg/mL against B. epidermidis (3.91 mg/mL) - both for sample 2 of Vanwyksdorp; 0.13 mg/mL against B. linens (2.28 mg/mL) - for sample 3 of Vanwyksdorp. Two isolated labdane diterpenoids (one of which is here first reported) were also antimicrobially tested and showed moderate activity but had high abundance in the extracts. Two major monoterpenes and four sesquiterpenes in the essential oil were identified as 1,8-cineole (4.6-12.3%), terpinen-4-ol (9.2-24.3%), germacrene A (3.9-15.6%), (-)-spathulenol (1.7-37.8%), viridiflorol (0.3-100%), and silphiperfol-6-en-5-one (4.5-26.8%). CONCLUSION: The antimicrobial results particularly for the essential oils and against the Brevibacteria support the traditional topical use of Elytropappus rhinocerotis twigs to treat foot perspiration, foot odour and other related skin conditions.

A review of the traditional use of southern African medicinal plants for the treatment of selected parasite infections affecting humans.

ETHNOPHARMACOLOGICAL RELEVANCE: Worldwide, more than three billion cases of parasitic disease are reported yearly and it is likely that this figure is substantially under-estimated. Approximately one in six people globally are estimated to be infected with at least one parasite species annually. In South Africa, the prevalence of Schistosoma haematobium (bilharzia) and intestinal worms and helminths are particularly high, especially in children and in crowded or poorer rural communities with inadequate sanitation and nutrition. Despite alarmingly high estimates, medical research into parasitic diseases remains neglected and only malaria receives significant attention and funding. Traditional medicines have been used for centuries in Africa by multiple ethnic groups and many people rely on these healing systems as their primary healthcare modality. The traditional use of South African medicinal plants to treat parasite infestations is relatively well documented, and it is important to link these traditional uses to scientific evidence validating efficacy. AIM OF THE STUDY: To document the medicinal plants used for parasitic infections and critically review the literature on the anti-parasitic properties of South African plants against some neglected parasitic diseases. MATERIALS AND METHODS: A review of the literature (ethnobotanical books and publications documenting traditional plant use) was undertaken related to specific medicinal use for parasitic infections in Southern Africa. Inclusion criteria focused on human use. Exclusion criteria included veterinary use and malaria due to the extensive nature of these subject matters. An in-depth analysis of previous studies was undertaken and future prospectives are considered. RESULTS: In particular, bilharzia, gastrointestinal worms and helminths, ectoparasites, trichomoniasis, leishmaniasis and trypanosomiasis are reviewed with special emphasis on the gaps in research. CONCLUSIONS: Despite the availability of relatively extensive ethnobotanical records on the anti-parasitic properties of southern African medicinal plants, the antiparasitic properties of many plants have been poorly examined. There was in many instances a lack of evidence to support traditional use of many species towards some parasites and research is urgently needed in this area.

The in vitro antimicrobial evaluation of commercially essential oils and their combinations against acne.

OBJECTIVE: The study investigated the efficacy of commercial essential oil combinations against the two pathogens responsible for acne with the aim to identify synergy and favourable oils to possibly use in a blend. MATERIALS AND METHODS: Antimicrobial activity was assessed using the minimum inhibitory concentration (MIC) assay against Staphylococcus epidermidis (ATCC 2223) and Propionibacterium acnes (ATCC 11827), and the fractional inhibitory concentration index (ΣFIC) was calculated. Combinations displaying synergistic interactions were further investigated at varied ratios and the results plotted on isobolograms. RESULTS: From the 408 combinations investigated, 167 combinations were identified as displaying noteworthy antimicrobial activity (MIC value ≤1.00 mg mL-1 ). Thirteen synergistic interactions were observed against S. epidermidis, and three synergistic combinations were observed against P. acnes. It was found that not one of the synergistic interactions identified were based on the combinations recommended in the layman's aroma-therapeutic literature. Synergy was evident rather from leads based on antimicrobial activity from previous studies, thus emphasizing the importance of scientific validation. Leptospermum scoparium J.R.Forst. and G.Forst (manuka) was the essential oil mostly involved in synergistic interactions (four) against S. epidermidis. Cananga odorata (Lam.) Hook.f. and Thomson (ylang ylang) essential oil was also frequently involved in synergy where synergistic interactions could be observed against both pathogens. The combination with the lowest MIC value against both acne pathogens was Vetiveria zizanioides Stapf (vetiver) with Cinnamomum verum J.Presl (cinnamon bark) (MIC values 0.19-0.25 mg mL-1 ). Pogostemon patchouli Benth. (patchouli), V. zizanioides, C. verum and Santalum spp. (sandalwood) could be identified as the oils that contributed the most noteworthy antimicrobial activity towards the combinations. The different chemotypes of the essential oils used in the combinations predominantly resulted in similar antimicrobial activity. CONCLUSIONS: The investigated essential oil combinations resulted in at least 50% of the combinations displaying noteworthy antimicrobial activity. Most of the synergistic interactions do not necessarily correspond to the recommended layman's aroma-therapeutic literature, which highlights a need for scientific validation of essential oil antimicrobial activity. No antagonism was observed.

Antibacterial effects of Alchornea cordifolia (Schumach. and Thonn.) Müll. Arg extracts and compounds on gastrointestinal, skin, respiratory and urinary tract pathogens.

ETHNOPHARMACOLOGICAL RELEVANCE: The leaves, stems and roots of Alchornea cordifolia (Schumach. and Thonn.) Müll. Arg. are used as traditional medicine in many African countries for the management of gastrointestinal, respiratory and urinary tract infections as well as for the treatment of wounds. AIM OF THE STUDY: To determine the in vitro antibacterial activity of the crude extracts of leaves and stems of A. cordifolia on gastrointestinal, skin, respiratory and urinary tract pathogens and to identify the compounds in the extracts that may be responsible for this activity. MATERIALS AND METHODS: The antibacterial activities of crude extracts [hexane, chloroform (CHCl3), ethyl acetate (EtOAc), ethanol (EtOH), methanol (MeOH) and water (H2O)] as well as pure compounds isolated from these extracts were evaluated by means of the micro-dilution assay against four Gram-positive bacteria, i.e. Bacillus cereus ATCC 11778, Enterococcus faecalis ATCC 29212, Staphylococcus aureus ATCC 25923 and S. saprophyticus ATCC 15305, as well as four Gram-negative bacterial strains, i.e. Escherichia coli ATCC 25922, Klebsiella pneumoniae ATCC 13883, Moraxella catarrhalis ATCC 23246 and Proteus mirabilis ATCC 43071. The isolation of the active constituents was undertaken by bio-autographic assays in conjunction with chromatographic techniques. The identification and characterisation of the isolated compounds were done using mass spectrometry (MS) and Fourier transformed infrared spectrometry (FTIR) as well as 1D- and 2D- nuclear magnetic resonance (NMR) analyses. RESULTS: The leaves and stems of A. cordifolia exhibited varied antibacterial activity against all eight pathogens. Most of the MIC values ranged between 63 and 2000µg/ml. The highest activities for the crude extracts (63µg/ml) were observed against S. saprophyticus [stem (EtOAc, CHCl3 and hexane), leaves (MeOH, EtOH, EtOAc and CHCl3)], E. coli [stem (MeOH and EtOH), leaves (MeOH, EtOH, EtOAc and CHCl3)], M. catarrhalis [leaves (EtOAc and CHCl3)], K. pneumoniae [stem (CHCl3), leaves (CHCl3)] and S. aureus [leaves (CHCl3)]. Seven constituents [stigmasterol (1), stigmasta-4,22-dien-3-one (2), friedelin (3), friedelane-3-one-28-al (4), 3-O-acetyl-aleuritolic acid (5), 3-O-acetyl-erythrodiol (6) and methyl-3,4,5-trihydroxybenzoate (methyl gallate) (7)] were isolated from the stem MeOH extract. All these compounds displayed some antibacterial activity against the eight pathogens with highest activity against S. saprophyticus (2µg/ml). Furthermore, this is the first report of compounds 1, 2, 3, 4, 6 and 7 isolated from A. cordifolia and where a complete set of 2D-NMR data for fridelane-3-one-28-al (4) is presented. CONCLUSION: The study demonstrated that the antibacterial activities of A. cordifolia extracts may be due to the presence of the seven isolated compounds, where compounds 3-6 showed the best activity. The observed activity against gastrointestinal, skin, respiratory and urinary tract pathogens supports the traditional use for the treatment of such ailments.

Annickia affinis and A. chlorantha (Enantia chlorantha)--A review of two closely related medicinal plants from tropical Africa.

ETHNOPHARMACOLOGICAL RELEVANCE: Annickia affinis (Exell) Versteegh & Sosef, closely related to A. chlorantha Setten & P.J.Maas (both species also referred to as Enantia chlorantha Oliv.), from the Annonaceae family, are multi-purpose medicinal plants used widely across tropical Africa. The two Annickia species are morphologically distinct from each other and have different distribution patterns, but are frequently confused. Furthermore, the name Enantia chlorantha is an illegitimate name, but is still used today. MATERIALS AND METHODS: A review of the literature was undertaken and an in-depth analysis of previous research and future prospectives are considered. While a myriad of publications cite the species "Enantia chlorantha", this is not the case for A. affinis and A. chlorantha, and no reviews are available for any of the species to date. Consequently, a summary of their ethnobotany, phytochemistry and biological properties is presented here (for the period 1933 - November 2014) in order to substantiate their traditional importance as medicines for rural people in Africa. RESULTS: To this effect, these species seem to be the preferred traditional treatments for malaria in tropical Africa, an area suffering heavily under the malaria pandemic. Their chemical composition is dominated particularly by various isoquinoline alkaloids, as well as by acetogenins and sesquiterpenes, which have been isolated from the bark and leaves. All three of these classes of compounds have been reported to exhibit noteworthy biological activity. CONCLUSIONS: Due to their widespread use, especially of the bark, these species have already been categorized as threatened with extinction. Consequently this study further aims to identify areas where more research needs to be conducted involving these important species, and also to suggest possible means of increasing the biological activities of their extracts as a way to conserve the species.

A comparison of the antimicrobial activity and toxicity of six combretum and two terminalia species from southern Africa.

BACKGROUND: Plants of the family Combretaceae are amongst the most widely used plants for traditional medicinal purposes in southern Africa. In particular, many species of Combretum and Terminalia are used for their antibacterial, antifungal, antiprotozoal, antiviral, antidiarrhoeal, analgesic, antimalarial, antioxidant, anti-inflammatory and anticancer activities, yet their antimicrobial potential has not been rigorously studied and compared. MATERIALS AND METHODS: A survey of antimicrobial activity was undertaken on selected South African Combretum and Terminalia species. Sixteen extracts from 6 Combretum and 2 Terminalia plant species with a history of medicinal usage were investigated by disc diffusion assay against a panel of bacteria and fungi and their MIC values were determined. Toxicity was determined using the Artemia franciscana nauplii bioassay. RESULTS: All extracts tested displayed broad spectrum antibacterial activity, inhibiting the growth of 12-16 (75-100%) of the bacteria tested, with Gram-positive and Gram-negative bacteria being approximately equally susceptible. Potent antibacterial activities (generally in the range 200-5000 µg/ml) were evident for all Combretaceae extracts against both Gram-positive and Gram-negative bacteria. Similarly, the extracts also displayed good antifungal activity, inhibiting the growth of 2-3 (66.7-100%) of the fungal species tested, with fungal growth inhibition activities generally in the range 200-4000 µg/ml. In general, the Terminalia extracts had better efficacies than the Combretum extracts. Furthermore, the methanol extracts were generally better antimicrobial agents than the water extracts. All extracts were also shown to be non-toxic in the Artemia nauplii bioassay. CONCLUSION: The lack of toxicity of these extracts and their inhibitory bioactivity against a panel of bacteria and fungi indicate their potential as medicinal agents and partially validate their usage in multiple South African traditional medicinal systems.

The potential of selected South African plants with anti-Klebsiella activity for the treatment and prevention of ankylosing spondylitis.

A wide variety of herbal remedies are used in traditional African medicine to treat inflammatory disorders, including some autoimmune diseases. Thirty-four extracts from 13 South African plant species traditionally used for the treatment of inflammation were investigated for their ability to control a microbial trigger for ankylosing spondylitis (Klebsiella pneumoniae). Twenty-six of the extracts (76.5%) inhibited the growth of K. pneumoniae. Methanol and water extracts of Ballota africana, Carpobrotus edulis leaves, Kigellia africana, Lippia javanica, Pelargonium fasiculata, Syzygium cordatum (including bark), Terminalia pruinoides and Terminalia sericea were effective K. pneumoniae inhibitors, with MIC values <1000 µg/ml. The roots of Tulbaghia violaceae and bark from Warburgia salutaris also demonstrated efficacy. The most potent extracts were examined by RP-HPLC and UV-Vis spectroscopy for the presence of resveratrol. Methanolic extracts of B. africana, C. edulis leaves, L. javanica, T. pruinoides and T. sericea, as well as aqueous B. africana, T. pruinoides and T. sericea extracts, displayed peaks with retention times and UV-Vis spectra consistent with the presence of resveratrol. Resveratrol was generally a minor component, indicating that resveratrol was not solely responsible for the anti-Klebsiella growth inhibitory properties. Plant extracts with K. pneumoniae inhibitory activity were either non-toxic, or of low toxicity in the Artemia (brine shrimp) nauplii bioassay. Their low toxicity and antibiotic bioactivity against K. pneumoniae indicate their potential for both preventing the onset of ankylosing spondylitis and minimising its symptoms once the disease is established.

Antibacterial activity of the roots, stems and leaves of Alchornea floribunda.

ETHNOPHARMACOLOGICAL RELEVANCE: Alchornea floribunda Müll. Arg. is used in traditional medicine across Africa for the treatment of bacterial, fungal, parasitic and inflammatory disorders. AIM OF THE STUDY: To evaluate the antibacterial activity of the crude extracts of different plant parts in order to provide a scientific rationale for the proposed broad efficacy of Alchornea floribunda in the treatment of bacterial infections. MATERIALS AND METHODS: Extracts of roots, stems and leaves were prepared using solvents of various polarities in order to extract a wide range of phytochemicals. The antibacterial activity of these crude extracts was evaluated by micro-dilution assay, against Gram-positive (i.e. Bacillus cereus, Enterococcus faecalis, Staphylococcus aureus and Staphylococcus saprophyticus) as well as Gram-negative (i.e. Escherichia coli, Klebsiella pneumoniae, Moraxella catarrhalis and Proteus mirabilis) bacteria. RESULTS: Generally, the ethanol (EtOH), methanol (MeOH), ethyl acetate (EtOAc) and chloroform (CHCl3) extracts demonstrated the best activities, with the leaves exhibiting the highest average activity for six of the eight pathogens. Of these, the ethanolic leaf extract was the most active against Staphylococcus aureus with an MIC value of 50µg/mL. Some other notable activity was observed for the ethyl acetate and chloroform root extracts against Staphylococcus aureus (50µg/mL), and for selected stem extracts against Staphylococcus aureus (50µg/mL), Klebsiella pneumoniae (63µg/mL) and Staphylococcus saprophyticus (63µg/mL). CONCLUSION: This study demonstrates the promising antibacterial activity of Alchornea floribunda against both Gram-positive and Gram-negative bacteria responsible for gastrointestinal, skin, respiratory and urinary ailments, and validates its use in the ethnopharmacology of the region.

Anti-Proteus activity of some South African medicinal plants: their potential for the prevention of rheumatoid arthritis.

A wide variety of herbal remedies are used in traditional African medicine to treat rheumatoid arthritis (RA) and inflammation. Thirty-four extracts from 13 South African plant species with a history of ethnobotanical usage in the treatment of inflammation were investigated for their ability to control two microbial triggers for RA (Proteus mirabilis and Proteus vulgaris). Twenty-nine of the extracts (85.3 %) inhibited the growth of P. mirabilis and 23 of them tested (67.7 %) inhibited the growth of P. vulgaris. Methanol and water extracts of Carpobrotus edulis, Lippia javanica, Pelargonium viridflorum, Ptaeroxylon obliquum, Syzygium cordatum leaf and bark, Terminalia pruinoides, Terminalia sericea, Warburgia salutaris bark and an aqueous extract of W. salutaris leaf were effective Proteus inhibitors, with MIC values <2,000 µg/ml. The most potent extracts were examined by Reverse phase high performance liquid chromatography and UV-Vis spectroscopy for the presence of resveratrol. Only extracts from T. pruinoides and T. sericea contained resveratrol, indicating that it was not responsible for the anti-Proteus properties reported here. All extracts with Proteus inhibitory activity were also either non-toxic, or of low toxicity in the Artemia nauplii bioassay. The low toxicity of these extracts and their inhibitory bioactivity against Proteus spp. indicate their potential for blocking the onset of rheumatoid arthritis.

Plants traditionally used individually and in combination to treat sexually transmitted infections in northern Maputaland, South Africa: antimicrobial activity and cytotoxicity.

ETHNOPHARMACOLOGICAL RELEVANCE: Although medicinal plants are used extensively to treat sexually transmitted infections (STIs) in rural northern Maputaland, KwaZulu-Natal, the efficacy and safety of these plants have not previously been evaluated. AIM OF STUDY: A study was designed to investigate the in vitro antimicrobial activity and cytotoxicity profiles of a selection (individual plants and selected combinations) of traditionally used plants in this study area. MATERIALS AND METHODS: Aqueous and organic (dichloromethane: methanol, 1:1) extracts were prepared. Antimicrobial activity was assessed using the minimum inhibitory concentration (MIC) assay against the STI associated pathogens; Candida albicans ATCC 10231, Ureaplasma urealyticum clinical strain, Oligella ureolytica ATCC 43534, Trichomonas vaginalis clinical strain, Gardnerella vaginalis ATCC 14018 and Neisseria gonorrhoeae ATCC 19424. For the combination study, interactions were assessed using the fractional inhibitory concentration (ΣFIC). The plant species were assessed for safety using the 3-[4,5-dimethyl-2-thiazol-yl]-2,5-diphenyl-2H-tetrazolium bromide (MTT) cellular viability assay on the human embryonic kidney epithelial (Graham, HEK-293) cell line. RESULTS: For the antimicrobial studies, U. urealyticum was the most sensitive of the six test organisms, with the aqueous extract of Ranunculus multifidus (0.02mg/ml) and the organic extract of Peltophorum africanum (0.04mg/ml) being the most antimicrobially active plant species studied. Sclerocarya birrea was found to have the broadest spectrum of activity (mean MIC of 0.89mg/ml). The only plant species to exhibit some degree of cytotoxicity against the kidney epithelial cell line was Kigelia africana (100µg/ml), with 22% and 16% cell death for the aqueous and organic extracts, respectively. Of the 13 combinations studied, several synergistic combinations were evident, the most prominent being the combination of Albizia adianthifolia and Trichilia dregeana (aqueous extract) with an ΣFIC value of 0.15 against O. ureolytica. Synergistic interactions were observed regardless of the ratio of the aqueous mixtures of the two plants. Syzygium cordatum and S. birrea (aqueous extract) was also a combination of interest, demonstrating synergistic (ΣFIC=0.42) interactions against O. ureolytica. This combination, however, also displayed some cytotoxicity towards the human epithelial cell line. CONCLUSION: This study demonstrated that anecdotal evidence of plant use does not always correlate with in vitro activity. Furthermore, the toxicological profiling is of utmost importance as if not combined in its correct ratio can lead to potential adverse effects.

Antimicrobial interactions of Khoi-San poly-herbal remedies with emphasis on the combination; Agathosma crenulata, Dodonaea viscosa and Eucalyptus globulus.

ETHNOPHARMACOLOGICAL RELEVANCE: Plants are often combined in traditional herbal remedies to increase medicinal efficacy, thus this investigation provides some insight into the antimicrobial efficacies of selected combinations. AIMS OF THE STUDY: The first aim was to scientifically validate antibacterial efficacy of plant mixtures that are traded within peri-urban centres of Cape Town (Western Cape, South Africa). This was followed by an in-depth evaluation of the most antimicrobially active mixture; Agathosma crenulata, Dodonaea viscosa with Eucalyptus globulus. MATERIALS AND METHODS: Methanol and aqueous extracts of six plant mixtures were screened for antibacterial properties against two Gram-negative and two Gram-positive bacteria using the minimum inhibitory microdilution method. Thereafter, chloroform: methanol (1:1; v/v) extracts, essential oils and aqueous extracts of Agathosma crenulata, Dodonaea viscosa and Eucalyptus globulus were assayed for antimicrobial activity independently and in various combinations. The fractional inhibitory concentration indices (Æ©FIC) were determined for double and triple plant combinations to establish antimicrobial interactions. RESULTS: From the six plant mixtures prepared by herbalists, a methanol extract derived from combining Agathosma crenulata, Dodonaea viscosa and Eucalyptus globulus showed the best antibacterial activity. The MIC values of 49µg/ml for Staphylococcus aureus and Bacillus subtilis, and 98µg/ml for Klebsiella pneumoniae and Escherichia coli were recorded. When Agathosma crenulata, Dodonaea viscosa and Eucalyptus globulus were mixed in various 1:1 combinations, mostly additive and synergistic interactions were noted. The most noteworthy synergistic (ΣFIC value 0.07) 1:1 combinations were observed for the chloroform: methanol extracts of Agathosma crenulata mixed with Eucalyptus globulus against Klebsiella pneumoniae, Staphylococcus aureus and Bacillus subtilis. When combined in a mixture of three plants (1:1:1), enhanced efficacy was evident against most of the pathogens, for both organic and aqueous extracts. The triple combination against Bacillus subtilis demonstrated the greatest synergy (ΣFIC values of 0.03). CONCLUSIONS: The enhanced antimicrobial efficacy and synergistic interactions noted for some of the mixtures, particularly the combination of Agathosma crenulata, Dodonaea viscosa and Eucalyptus globulus support the Western Cape Khoi-San traditional medicinal practices of combining plants for enhanced efficacy.

An antimicrobial evaluation of plants used for the treatment of respiratory infections in rural Maputaland, KwaZulu-Natal, South Africa.

ETHNOPHARMACOLOGICAL RELEVANCE: Abundant availability of medicinal plants in the study area offers low cost health care, but scientific validation is needed in order to lend credibility to the traditional use against respiratory infections. AIM OF THE STUDY: This study focussed on determining the antimicrobial efficacies of 30 plant species (independently and in various combinations) used for respiratory related infections in rural Maputaland. MATERIALS AND METHODS: In vitro minimum inhibitory concentration (MIC) assays were undertaken on dichloromethane-methanol (CH(2)Cl(2): MeOH) and aqueous extracts, as well as the hydro-distilled essential oils (for aromatic plants). Selected plant parts were assessed for antimicrobial activity against a range of respiratory pathogens i.e. Cryptococcus neoformans (ATCC 14116), Klebsiella pneumoniae (ATCC 13883), Moraxella catarrhalis (ATCC 23246), Mycobacterium smegmatis (ATCC 14468) and Staphylococcus aureus (ATCC 6538). The sum of the fractional inhibitory concentrations (∑FIC) was determined for plants traditionally used in combination. Isobolograms represent MIC values for a selection of interactions where two plants were combined in various ratios. RESULTS: The most antimicrobially active aqueous extracts were that of Ozoroa obovata and Sclerocarya birrea (0.10 mg/ml) while organic extracts from Parinari capensis subsp. incohata and Tetradenia riparia demonstrated the most noteworthy (0.03 mg/ml) activity. Although both Lippia javanica and Eucalyptus grandis were by far the most popular plants traditionally used for respiratory infections, the antimicrobial activity was mostly only moderate. Furthermore, the traditional use in a 1:1 combination did not display strong antimicrobial interactions, but isobolograms demonstrate (against some test organisms) that when combined in various ratios, predominant additive interactions are evident where E. grandis was present in larger proportions. The combination of E. grandis with O. obovata demonstrated synergism against both C. neoformans and K. pneumoniae, with ∑FIC values of 0.34 and 0.28 respectively. Various ratios of these two plants also demonstrated a predominantly synergistic profile. CONCLUSION: Although this in vitro study supports the traditional use of some plants independently and in combination for the treatment of respiratory ailments in rural Maputaland, results demonstrate that the traditional selection of plants in higher frequency do not necessarily correlate with higher antimicrobial efficacy.