An updated inventory of medicinal and ritual plants of southern Africa.

ETHNOPHARMACOLOGICAL RELEVANCE: For the first time in two decades, a comprehensive, up-to-date overview of the medicinal and ritual plants of southern Africa is presented. This data is analysed and compared with a previous survey done in 2002. STUDY AIM: The main aim is to update the checklist of medicinal and ritual plants of southern Africa and to determine the number of new records since 2002. We also provide a high-level perspective on the selection of medicinal and ritual plant species in southern Africa, a taxonomic analysis of the new checklist as well as a chronological perspective on the citation of medicinal and ritual species before and after 2002. MATERIALS AND METHODS: The most recently published medicinal and ritual plants checklist for southern Africa was reviewed and updated. A wide range of ethnobotanical literature, including books, field guides and electronic journals, was used. All calculations were done by using formulas and functions in Microsoft Excel and R Studio. RESULTS: 4120 medicinal and ritual taxa and 3784 medicinal and ritual species have been recorded. Compared with the 2002 checklist, there are 1239 new taxa (1228 new species). A strong correlation between available taxa and selected medicinal taxa exists on order level, which corresponds with the results of an analysis done in 2008. The top 10 species-rich medicinal plant families of southern Africa are Asteraceae, Fabaceae, Apocynaceae, Euphorbiaceae, Asphodelaceae, Malvaceae, Lamiaceae, Poaceae, Rutaceae and Rubiaceae. Different patterns of plant family representation can be seen across certain cultural healing systems of southern Africa. The species popularity (number of citations) of Hypoxis hemerocallidea Fisch. & C.A.Mey. Has increased substantially after 2002. Other medicinal and ritual plant species have been consistently researched, such as Artemisia afra Jacq. ex Willd., Carpobrotus edulis (L.) L.Bolus, Aloe ferox Mill., Leonotis leonurus (L.) R.Br. and Gunnera perpensa L. CONCLUSIONS: The numerous new medicinal and ritual plant records that have been reported in the last two decades provide evidence of an incompletely documented ethnobotanical heritage that urgently requires documentation. Patterns of taxonomic diversity on family level indicate distinctive differences between cultural healing systems. Signs of the adaptability and dynamics of traditional healing systems in southern Africa can be seen in the changes in the citation of species over time.

Stevens' Cure (Umckaloabo)-the vindication of a patent medicine.

Stevens' Cure (Umckaloabo) emerged as a patent medicine claiming to treat tuberculosis in the United Kingdom at the beginning of the 20th century. However, due to its identity being shrouded in secrecy, it was never truly accepted by the medical community. It was "rediscovered" in the 1970s and subsequently developed into a very popular and successful phytopharmaceutical for the treatment of upper respiratory tract infections. Whether Stevens' Cure contained the same ingredient(s) as the modern Umckaloabo has not yet been demonstrated. We attempted to elucidate for the first time the identity of the original ingredient by comparative analysis of historical product samples. Three historical samples of Stevens' Cure were compared with Pelargonium sidoides DC. and P. reniforme Curt. root per UPLC-MS analysis. We confirm that the ingredient-P. sidoides DC.-is indeed the same as used in modern phytotherapy. We also attribute the first ethnopharmacological record of P. sidoides DC. being used for the treatment of tuberculosis to C. H. Stevens, the "creator" of Umckaloabo.

Fatal pyrrolizidine alkaloid poisoning of infants caused by adulterated Senecio coronatus.

Senecio coronatus (known as izonkozonko and ubulibazi in Zulu) is commonly used in traditional medicine in South Africa as purification purgative and enemas for infants during weaning. We show for the first time that this species does not contain pyrrolizidine alkaloids and that reported cases of fatal hepatic sinusoidal obstruction syndrome in infants were caused by wrongly identified Senecio species containing large amounts of retrorsine-N-oxide. A validated ultra performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) method for the detection and quantitation of pyrrolizidine alkaloids is described.

Two-year viral load suppression among adolescents receiving antiretroviral therapy in the Cape Metropole, South Africa, 2013 - 2015: A retrospective cohort analysis.

BACKGROUND: In 2018, 4% of all people living with HIV globally were adolescents aged 10 - 19 years. It is reported that adolescents on antiretroviral therapy (ART) are at increased risk of poor viral load suppression (VLS) compared with children and adults. OBJECTIVES: To determine the 24-month prevalence of VLS among adolescents initiated on ART in 2013 in public health facilities in the Metro District Health Services of Western Cape Province, South Africa. METHODS: A retrospective cohort analysis was done on 220 adolescents initiated on ART in 2013; they were followed up for 24 months. Data were extracted from the provincial Tier.Net electronic database and patients' clinical records, and captured in Excel. SPSS statistical software was used for descriptive and inferential analysis; bivariate analysis was used to determine significance and strength of associations between VLS and various sociodemographic and clinical characteristics at 4, 12 and 24 months (with significance set at p<0.05). RESULTS: VLS declined over the study period, with rates of 59.5%, 40.0% and 25.0% at 4, 12 and 24 months post initiation on treatment, respectively. In bivariate analysis, VLS was significantly associated with younger age (10 - 14 years) at month 12 (crude risk ratio (RR) 1.83 (95% confidence interval (CI) 1.35 - 2.49)) and month 24 (RR 3.38 (95% CI 2.24 - 5.10)) after initiation on ART. Male adolescents were significantly more likely to achieve VLS than females (month 4: RR 1.49 (95% CI 1.22 - 1.81); month 12: RR 1.50 (95% CI 1.07 - 2.12); and month 24: RR 2.33 (95% CI 1.50 - 3.62)). Pregnant adolescents were significantly less likely to attain VLS (month 4: RR 0.69 (95% CI 0.53 - 0.89); month 12: RR 0.64 (95% CI 0.44 - 0.94); and month 24: RR 0.24 (95% CI 0.11 - 0.50)) compared with those who were not pregnant. However, of those adolescents who were retained in care, VLS was higher at months 4, 12 and 24, with rates of 86.8%, 79.3% and 68.8%, respectively. CONCLUSIONS: Targeted interventions are required to improve retention in care and VLS among adolescents on ART, with specific focus on older (15 - 19-year-olds) and pregnant adolescents.

A family-level floristic inventory and analysis of medicinal plants used in Traditional African Medicine.

ETHNOPHARMACOLOGICAL RELEVANCE: Floristic diversity patterns of medicinal plants in sub-Saharan Africa are compared to global patterns to gain insights into the selection of plants used in Traditional African Medicine. AIMS OF THE STUDY: To answer two questions: Firstly, is the selection of medicinal plants used in Traditional African Medicine in sub-Saharan Africa based on availability or is it biased towards certain plant families? Secondly, does the floristic composition of African medicinal plants differ from the global pattern and from other healing systems of the world? MATERIALS AND METHODS: Data edited and summarized from recent reviews and on-line databases were compiled into an inventory of all vascular plant families of the world, showing the global numbers of species per family, the numbers of African taxa per family, the numbers of African medicinal plant species per family and the numbers of commonly traded African medicinal plants. These data were subjected to linear regression analyses, as well as Bayesian analysis and Imprecise Probability calculation (using the Imprecise Dirichlet model). RESULTS: At least 4576 vascular plant species from 1518 genera are used in Traditional African Medicine in sub-Saharan Africa, representing 192 families (out of 254 African families). Traditional African Medicine is dominated by Fabaceae (567 spp., 156 genera), Rubiaceae (318 spp., 99 genera), Asteraceae (314 spp., 112 genera), Malvaceae (202 spp., 46 genera), Euphorbiaceae (197 spp., 47 genera), Apocynaceae (167 spp., 68 genera), Lamiaceae (142 spp., 37 genera), Acanthaceae (106 spp., 40 genera), Asparagaceae (90 spp., 18 genera) and Poaceae (85 species, 47 genera). Regression analysis of the African medicinal flora shows that the Fabaceae (576 medicinal species/residual +136), Malvaceae (202/+105), Rubiaceae (318/+85), Lamiaceae (142/+55), Euphorbiaceae (197/+54) and Combretaceae (72/+49) are overused, while Aizoaceae (10/-136), Orchidaceae (34/-127), Iridaceae (16/-101) and Poaceae (85/-87) are underused. Bayesian and IDM analysis showed that a large number of smaller families are also overused and underused. Commonly traded African medicinal plants species are mostly from Fabaceae (27 species), Apocynaceae (16), Burseraceae (12) and Rubiaceae (9). CONCLUSION: The selection of African medicinal plants appears to be based on availability (for some families) and apparently cultural and other criteria, such as the presence of alkaloids, terpenoids and volatile compounds for others (e.g., Fabaceae, Apocynaceae and Burseraceae). In terms of commercialised species in international trade, Traditional African Medicine differs from the global pattern (and other healing systems) in the dominance of Fabaceae and Apocynaceae and the relatively low numbers of Asteraceae, Lamiaceae, Apiaceae and Rosaceae.

Volatiles from African species of Croton (Euphorbiaceae), including new diterpenes in essential oil from Croton gratissimus.

The chemistry of essential oils from the leaves of three African species of Croton (C. gratissimus, C. pseudopulchellus and C. sylvaticus) is comprehensively characterised. Two new volatile diterpenes were isolated from C. gratissimus and the structures assigned using 1D and 2D NMR. One is a furanyl-halimane methyl ester (1) assigned as 12-ß-furanyl-halima-5,9-dien-4-methylcarboxylate (gratissihalimanoic ester); the other is an abietane ketone (2) assigned as ent-abiet-8(14), 13(15)-dien-3-one, which we have named gratissimone. High relative abundance of diterpenes in a hydrodistilled essential oil is rare and may be considered an interesting discovery. Known non-volatile diterpenes were also isolated, which were assigned as crotohalimaneic acid (3) and hardwickiic acid (4). All diterpenes occur in fresh leaves prior to distillation and extract into apolar or moderately polar solvents, which demonstrates that the two volatiles are not generated during the hydrodistillation. At this stage it is not clear how widespread this diterpene essential oil chemotype is within the species distribution or if any therapeutic effects can be attributed to them. No antimicrobial activity was observed at 1 mg/ml against a range of bacterial strains.

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 commercially important African medicinal plants.

ETHNOPHARMACOLOGICAL RELEVANCE: Data on the relative importance and research status of commercially relevant African medicinal plants are needed for developing new research strategies in order to stimulate much-needed ethnopharmacological research and to promote the commercialization of African plants. AIM OF THE STUDY: To present an illustrated bird's eye view and comparative analysis of the relative popularity and importance of commercialized African medicinal plants. A comparison is made between the general popularity and commercial importance of the species (as indicated by their footprint on the World Wide Web) and their scientific popularity and importance (as indicated by the number of research publications). The inventory and review is strongly focussed to cover all or most of the medicinal plant raw materials in the international trade that are exported from African countries, with less emphasis on those that are regularly traded on local and regional markets within Africa. MATERIALS AND METHODS: The review is based on literature data, Scopus and Google searches, commercial information and the author's own experience and observations. RESULTS: More than 5400 plant species are used in traditional medicine in Africa, of which less than 10% have been commercially developed to some extent. Africa is home to more than 80 valuable commercial species that are regularly traded on international markets, including phytomedicines (e.g. Harpagophytum procumbens and Pelargonium sidoides), functional foods (e.g. Adansonia digitata and Hibiscus sabdariffa) and sources of pure chemical entities (e.g. caffeine from Coffea arabica and yohimbine from Pausinystalia johimbe). According to the Scopus results, about 60% of all recent publications on African medicinal plants appeared in the last decade, with an average of 280 papers (28 per year) for 85 prominent species of international trade. The most popular African species for research (number of publications in brackets) were: Ricinus communis (5187), Aloe vera (2832), Catharanthus roseus (2653), Sesamum indicum (2534), Strophanthus gratus (2514), Coffea arabica (2431), Citrullus lanatus (2215), Momordica charantia (2047), Withania somnifera (1767), Trigonella foenum-graecum (1687), Acacia senegal (1373), Centella asiatica (1355), Griffonia simplicifolia (1010), Hibiscus sabdariffa (987), Tamarindus indica (973) and Catha edulis (947). The top species in terms of recent research interest (% of publications in last decade) were: Hoodia gordonii (95%), Cyclopia genistoides (93%), Sceletium tortuosum (90%), Agathosma betulina (89%), Pelargonium sidoides (86%), Boswellia papyrifera (85%), Lessertia (Sutherlandia) frutescens (84%), Boswellia sacra (83%), Mondia whitei (81%), Hibiscus sabdariffa (80%), Hypoxis hemerocallidea (80%) and Tylosema esculentum (80%). Both lists reflect the recent interest in functional foods and dietary supplements. CONCLUSION: Despite a marked recent increase in the number of publications on indigenous medicinal plants and dietary supplements, Africa lags behind Europe and Asia in terms of the number of products that have been commercialised and the percentage of the flora that is utilized for international trade. There is a tremendous potential for developing new crops and new products but much work remains to be done to generate more focussed and relevant pre-clinical data and convincing proof of concept through clinical studies.

Medicinal plants of the Kamiesberg, Namaqualand, South Africa.

ETHNOPHARMACOLOGICAL RELEVANCE: Qualitative and quantitative data is presented that gives a new perspective on the traditional medicinal plants of the Khoisan (Khoe-San), one of the most ancient of human cultures. The data is not only of considerable historical and cultural value, but allows for fascinating comparative studies relating to new species records, novel use records and the spatial distribution of traditional plant use knowledge within the Cape Floristic Region. AIM OF THE STUDY: A detailed documentation and quantitative analysis of medicinal plants of the Kamiesberg area (an important Khoisan and Nama cultural centre) and their traditional uses, which have hitherto remained unrecorded. MATERIALS AND METHODS: During four study visits to the Kamiesberg, semi-structured and structured interviews were conducted with 24 local inhabitants of the Kamiesberg, mostly of Khoisan decent. In addition to standard methodology, a newly developed Matrix Method was used to quantity medicinal plant knowledge. RESULTS: The Kamiesberg is an important center of extant Nama ethnomedicinal information but the knowledge is rapidly disappearing. Of a total of 101 medicinal plants and 1375 anecdotes, 21 species were recorded for the first time as having traditional medicinal uses and at least 284 medicinal use records were new. The relative importance, popularity and uses of the plants were quantified. The 97 newly documented vernacular names include 23 Nama (Khoekhoegowab) names and an additional 55 new variations of known names. The calculated Ethnobotanical Knowledge Index (EKI) and other indices accurately quantified the level of knowledge and will allow for future local, regional and even global comparisons. CONCLUSION: The results showed that the Kamiesberg is an important focal point of Khoisan (Nama) traditional knowledge but that the medicinal plants have not yet been systematically recorded in the scientific literature. There are numerous new use records and new species records that are in need of scientific study. Comparative data is now available for broader comparisons of the pattern of Khoisan plants use in southern Africa and the study represents another step towards a complete synthesis of Cape Herbal Medicine.

Bitterness values for traditional tonic plants of southern Africa.

ETHNOPHARMACOLOGICAL RELEVANCE: Bitterness values have been determined for southern African plant species that are traditionally used as tonics (imbizas or 'musa-pelo) to alleviate the symptoms of stress and a variety of ailments related to the digestive system. AIM OF THE STUDY: To measure and present, for the first time, the bitterness values of 15 of the best-known and most widely used tonic plants in southern Africa in order to find a rationale for their traditional use in improving appetite and treating digestive ailments. RESULTS: Most of the plants were found to be very bitter, with bitterness values comparable to those reported for internationally well-known bitter tonics such as Artemisia absynthium L. and Gentiana lutea L. CONCLUSIONS: The relatively high bitterness values obtained for all of the plants indicate that their alleged value in improving digestion and appetite may at least be partly ascribed to the bitter tonic (amarum) effect, i.e., the stimulation of gastric juices via the nervus vagus. It may be interesting to examine the chemical compounds responsible for the bitter taste, as well as the possible links between bitterness and the anecdotal anti-stress properties ascribed to these species.

Antimicrobial and antimalarial activity of Cussonia species (Araliaceae).

ETHNOPHARMACOLOGICAL RELEVANCE: Cussonia species are used in African traditional medicine mainly against pain, inflammation, gastro-intestinal problems, malaria and sexually transmitted diseases. AIM OF THE STUDY: To summarise ethnomedicinal uses of Cussonia and to find scientific evidence in support of selected main uses. MATERIALS AND METHODS: Using the minimum inhibitory concentration (MIC) method, leaves of 13 Cussonia species, Schefflera umbellifera and Seemannaralia gerrardii were tested against pathogens associated with diarrhoea (Enterococcus faecalis and Escherichia coli), sexually transmitted infections (Neisseria gonorrhoeae and Trichomonas vaginalis) and general infectious diseases (Staphylococcus aureus and Pseudomonas aeruginosa). Antimalarial sensitivity was studied using Plasmodium falciparum and the [(3)H]-hypoxanthine incorporation assay. Cytotoxic effects on a T-cell leukaemia (Jurkat) cell line were determined using the tetrazolium-based cellular toxicity assay. RESULTS: Methanolic extracts were active against Pseudomonas aeruginosa (MIC of 1.0-1.5 mg/mL), Trichomonas vaginalis (MIC of 0.8-1.3 mg/mL) and Staphylococcus aureus (Cussonia arborea, 1.8 mg/mL). All samples were active against Neisseria gonorrhoeae (MIC of 0.02-0.7 mg/mL). The methanol extract of Cussonia arborea was the most active against Plasmodium falciparum (13.68 microg/mL) and showed anticancer properties (5.60 microg/mL). CONCLUSIONS: The traditional use of Cussonia species to treat sexually transmitted diseases and Plasmodium infections appears to have a scientific basis.

A review of the taxonomy, ethnobotany, chemistry and pharmacology of Sutherlandia frutescens (Fabaceae).

Sutherlandia frutescens (tribe Galegeae, Fabaceae), a popular plant in traditional medicine, is indigenous to South Africa, Lesotho, southern Namibia and southeastern Botswana. It is chemically, genetically and geographically extremely variable and has been divided into three subspecies and several regional forms. A second species, Sutherlandia tomentosa, is localized along the Cape coast. Sutherlandia is sometimes treated as part of the genus Lessertia. There are numerous vernacular names and a wide diversity of uses, including poor appetite, indigestion, stomach complaints, dysentery, colds, influenza, kidney conditions, fever, diabetes, internal cancers, uterine troubles, liver conditions, backache, rheumatoid arthritis, urinary tract infections, stress and anxiety, dropsy and heart failure. Notable is the use as a bitter tonic ("blood purifier"), anti-stress medication ('musa-pelo) and, at least since 1895, specifically as a cancer tonic (both as treatment and as prophylaxis). Externally it is applied to haemorrhoids, inflamed wounds and eye infections. Recent in vitro and in vivo studies have shown antiproliferative, anti-HIV, anti-diabetic, anti-inflammatory, analgesic, antibacterial, anti-stress, anticonvulsant and antithrombotic activities. Aqueous extracts often differ in activity from organic solvent extracts. The presence of high levels of free amino acids, non-protein amino acids such as canavanine and GABA, the cyclitol pinitol, flavonols and triterpenes (including SU1, a cycloartane-type triterpene saponin) provide plausible hypotheses on how these compounds, individually or collectively, may be responsible for the reputed efficacy in a wide range of ailments. Results of animal studies, as well as a phase I clinical study, have shown no indications of toxicity. Sufficient preclinical data are now available to justify controlled clinical studies.

A review of Khoi-San and Cape Dutch medical ethnobotany.

UNLABELLED: ETHNOPHARMACOLOGICAL CONTEXT: Cape herbal medicine as a distinct and unique healing system is conceptualized for the first time, together with a first compilation of the authentic materia medica of the system. MATERIALS AND METHODS: The early literature on Khoikhoi (Hottentot), San (Bushman) and Cape Dutch medicinal plants and medical practices is reviewed, with a focus on the Cape Floristic Region (from Namaqualand to the Eastern Cape). To avoid recent additions and modern cultural influences in the results, the date of publication of the last volume of Marloth's Flora of South Africa (1932) was chosen as a cut-off date. RESULTS: The recorded Cape materia medica (up to 1932) is briefly summarized, giving the scientific names, vernacular names (in Afrikaans or Khoi-San/Nama) and main uses. It comprises about 170 items and includes mainly indigenous and endemic plant species, some exotic (garden) plants, and a few other items (fungi, seaweeds, lichens, hyraceum and natural potassium nitrate). Most of the plants (and hyraceum) are still widely used today, especially in rural areas. CONCLUSIONS: The combination of unique cultural practices and a diverse, highly endemic flora has led to the development of a distinct herbal healing system, here called Cape herbal medicine, but hitherto rather vaguely and inaccurately referred to as Khoi-San medicine, Cape Dutch medicine or boererate (farm remedies). The data allows for a more informed consideration of indigenous knowledge and intellectual property rights associated with particular plants (e.g. Hoodia and Pelargonium). It also offers opportunities for linking modern ethnobotanical field studies with historical data.

A historical, scientific and commercial perspective on the medicinal use of Pelargonium sidoides (Geraniaceae).

UNLABELLED: ETHNOPHARMACOLOGICAL CONTEXT: A detailed review of the ethnobotany and commercial history of Pelargonium sidoides is presented, together with a brief summary of pre-clinical and clinical scientific results that support the use of the plant in modern, evidence-based phytomedicines. The aim is to identify the main factors responsible for the success in product development. MATERIALS AND METHODS: The literature studied includes all modern scientific papers and also old documents and books that are no longer readily accessible. RESULTS: Available ethnobotanical information shows that several tuberous Pelargonium species (including Pelargonium sidoides) are important traditional medicines with a rich ethnobotanical history. A summary of the interesting history of the commercial development of Stevens' Cure or Umckaloabo in Europe is presented. Scientific evidence for the efficacy of the product, mainly as a treatment for acute bronchitis, is reviewed. These include numerous in vitro studies as well as 18 clinical studies. The botanical identity of the plant and its complex mixture of coumarins and other chemical constituents are summarised. CONCLUSIONS: The use of Pelargonium stems or tubers for a variety of ailments (including the complications of dysentery) is an important but hitherto under-estimated part of traditional medicine in southern Africa. Key elements in the successful development of Pelargonium sidoides from a profound traditional remedy to a highly successful phytomedicine include the choice of species, a favourable cost-benefit ratio, innovative marketing over many years, good scientific evidence of the botanical and chemical identity of the product and convincing proof of concept.

A broad review of commercially important southern African medicinal plants.

AIMS OF THE STUDY: Commercially important indigenous medicinal plants of southern Africa are reviewed in the context of fundamental knowledge about their ethnobotany, phylogeny, genetics, taxonomy, biochemistry, chemical variation, reproductive biology and horticulture. The aim is to explore the rapidly increasing number of scientific publications and to investigate the need for further research. MATERIALS AND METHODS: The Scopus (Elsevier) reference system was used to investigate trends in the number of scientific publications and patents in 38 medicinal plant species. Fifteen species of special commercial interest were chosen for more detailed reviews: Agathosma betulina, Aloe ferox, Artemisia afra, Aspalathus linearis, Cyclopia genistoides, Harpagophytum procumbens, Hoodia gordonii, Hypoxis hemerocallidea, Lippia javanica, Mesembryanthemum tortuosum, Pelargonium sidoides, Siphonochilus aethiopicus, Sutherlandia frutescens, Warburgia salutaris and Xysmalobium undulatum. RESULTS: In recent years there has been an upsurge in research and development of new medicinal products and new medicinal crops, as is shown by a rapid increase in the number of scientific publications and patents. Despite the fact that an estimated 10% of the plant species of the world is found in southern Africa, only a few have been fully commercialized and basic scientific information is often not available. CONCLUSIONS: The limited available information indicates that some of the plants display remarkable regional variation in morphological, genetic and chemical characters that should be more thoroughly investigated. Basic biological information is needed to guide the rapidly accelerating commercialization process, especially the selection of superior clones, the development of new cultivars and the standardization of raw materials.

Identification of atractyloside by LC-ESI-MS in alleged herbal poisonings.

An LC-MS screening method was developed to detect the presence of atractyloside (ATR), the toxic principle of a commonly used medicinal plant in South Africa, Callilepis laureola, in biological matrices such as body fluids and human viscera.

Fatal Datura poisoning: identification of atropine and scopolamine by high performance liquid chromatography/photodiode array/mass spectrometry.

A forensic method comprising solid phase extraction and HPLC analysis was developed for the detection and confirmation of atropine and scopolamine, the main toxic alkaloids of Datura stramonium and Datura ferox. This method allowed the direct coupling of an electrospray (ZMD) mass selective detector to the HPLC system. Under these conditions, atropine and scopolamine were well separated from other components and detected on the PDA (LOD = 1 microg/ml) and ZMD (LOD(atropine) = 10 pg/ml; LOD(scopolamine) = 100 pg/ml) detectors. Four geographically isolated populations of each of D. stramonium and D. ferox were analysed for seed alkaloids and it was found that the two species were diagnostically different in their atropine-scopolamine ratios. The optimised HPLC method was used to analyse three viscera samples of an adult Caucasian male whose death was ascribed to a fatal heart attack. Atropine and scopolamine were detected in the stomach and its contents, which contained Datura seeds. The chemical profile of the seeds found in the stomach contents was similar to those from four geographically different D. ferox plants.

Accidental fatal poisoning by Nicotiana glauca: identification of anabasine by high performance liquid chromatography/photodiode array/mass spectrometry.

A method, based on reversed phase high performance liquid chromatography (HPLC) was developed for the detection and quantification of anabasine, the toxic alkaloid of Nicotiana glauca, in forensic applications. A standard solid phase extraction (SPE) method was used for the extraction of anabasine from viscera, but was optimized for the extraction of this alkaloid from plant material. The careful selection of mobile phase components allowed the direct coupling of electron impact (EI) and Z spray mass selective detector (ZMD) of the HPLC. Under these conditions, anabasine was well separated from nicotine and could be detected on the PDA (limit of detection, LOD = 250 ng/ml), TMD (LOD = 10 microg/ml) and ZMD (LOD =1 ng/ml) detectors. Three geographically isolated N. glauca trees were analyzed for alkaloid content and it was found that both the leaves and the flowers contain anabasine. The optimized HPLC method was used to analyze two viscera samples (the stomach and contents of a mother and child who putatively died from food poisoning) and a flower exhibit. Anabasine was detected in both the viscera samples, supporting the finding that these fatalities were due to the ingestion of N. glauca accidentally collected with traditional spinach (marog). The alkaloid profile of the flower exhibit submitted with the viscera samples was similar to those obtained from flowers collected from three different N. glauca trees. The results show that anabasine and/or N. glauca poisoning can easily be confirmed using the forensic methodology described.

A chemotaxonomic and morphological appraisal of Aloe series Purpurascentes, Aloe section Anguialoe and their hybrid, Aloe broomii.

Evidence is presented to suggest the hybrid origin of Aloe broomii, with the one putative parent belonging to Aloe series Purpurascentes and the other a member of Aloe series Anguialoe. A chemotaxonomic and morphological assessment is presented for both infrageneric groups and their hypothesised hybrid. Four of the species belonging to the series Purpurascentes display a characteristic leaf exudate profile containing the chemotaxonomic marker microstigmin. Aloe gariepensis and A. succotrina lack the diagnostic leaf exudate compounds. The distinct morphological apomorphies for Aloe section Anguialoe are supported on the chemical level reinforcing the monophyly of this group.

A review of the use of allozyme electrophoresis in plant systematics.

The role of electrophoretic data is discussed as it applies to plant taxonomy and systematic studies. Nei's (Am. Nat. 106 (1972) 283-292; Genetics 89 (1978) 583-590) genetic distances calculated for a large number of populations, species and genera were taken from published data. The relation between Nei's genetic identity measures and taxonomic rank (populations, species and genera) are shown graphically. The graphs obtained in this way (from 3021 pairs of plant taxa) differ substantially from previous graphs published by Thorpe (Ann. Rev. Ecol. Syst. 13 (1982) 139-168; in: G.S. Oxford, D. Rollinson (Eds.), Protein Polymorphism: Adaptive and Taxonomic Significance, Academic Press, London, 1983, pp. 131-152) and Thorpe and Solé-Cava (Zool. Scripta 23 (1994) 3-18). These authors suggested that the divergence between the different taxonomic ranks is roughly similar across a wide range of taxa. The latter was based on values for 2664 (Thorpe, 1982) and 8060 (Thorpe, 1983) pairs of animal and plant taxa, but the plant data contributed little to the total. For any given taxonomic rank, we found that plants are genetically more closely related than animals (possibly with the exception of birds). This result is important because the empirical relationships of genetic distance measures, to different levels of taxonomic separation, is often used for distinguishing and identifying cryptic or sibling species where conventional methods are unable to resolve systematic problems.