Standardization parameters and synergism of source plant materials for the antidiabetic efficacy of the Rauvolfia-Citrus tea.

The introduction of glucagon-like peptide 1 (GLP-1)-based therapies has greatly improved the management of type 2 diabetes (T2D), as they ensure good blood glucose control and promote weight loss. Ingestion of standardized herbal remedies that promote the same endogenous metabolic processes affected by the GLP-1-based treatments could provide cheaper alternatives in low- and middle-income countries, where there is currently an increase in the incidence of T2D. The focus in this study was to determine quality control parameters and the prime factors for the Rauvolfia-Citrus tea (RC-tea), as used in Nigerian traditional medicine to treat T2D. We have previously shown that the RC-tea that is made by boiling leaves of Rauvolfia vomitoria Afzel. and fruits of Citrus aurantium L. causes normalization of blood glucose and reduction of ectopic lipid accumulation in genetic diabetic (BKS-db) mice and in humans with T2D. The standardized RC-tea was made by boiling 40 g dried R. vomitoria foliage and 200 g fresh C. aurantium fruits per litre. The resulting golden-brown extract is free of microbial contamination, has pH 5 and contains ca. 230 mg naringin (marker compound for C. aurantium) and 25 mg robinin (marker compound for R. vomitoria) per litre. In addition, the herbal extract has the characteristic HPLC-DAD fingerprint where the marker compounds, naringin and robinin have retention times of approximately 26.3 min and 26.9 min, respectively, when using the outlined column and gradient elution conditions. Comparative evaluations of the antidiabetic effects of the standardized RC-tea and boiling water-extracts made with C. aurantium fruits alone (CA), R. vomitoria foliage alone (RV) and a combination of CA and RV, (CA + RV) in BKS-db mice, indicate that components from R. vomitoria foliage drive the reductions in ectopic lipid accumulation, since CA-treated mice lacked this effect. However, the normalization of blood glucose arises from combination of components from the two source plant materials as administration of either CA or RV resulted in hypoglycaemia. Interestingly, treatment with the CA + RV mixture, generated by mixing individually produced CA and RV plant extracts, resulted in hyperglycaemia, possibly due to drug-drug interactions of the blood glucose-reducing components in either plant extract. Hence, our data show that the best antidiabetic outcome results from the traditional practice of boiling R. vomitoria foliage and C. aurantium fruits together.

Tea toxicity and cholinesterase inhibition of Huilliche herbal medicine.

Eleven species of Huilliche medicinal plants used traditionally against infections and for wound healing were tested for their cholinesterase inhibition activity. Two different teas (a 5-7 min infusion and a 1 h decoction, both in water) were tested for their toxicity against Artemia salina. The results from the present study clearly show that teas boiled for 1 h is much more toxic than teas infused for 5-7 min. These results support the different traditional use of the two teas, where the 1h tea is for external use only. Additionally, significant inhibition of cholinesterase has been observed for MeOH extracts of Acaena argentea, Amomyrtas meli and Pseudopanax laetevirens, with that of A. argentea being the most potent. All findings call for further investigations.

Can phylogeny predict chemical diversity and potential medicinal activity of plants? A case study of Amaryllidaceae.

BACKGROUND: During evolution, plants and other organisms have developed a diversity of chemical defences, leading to the evolution of various groups of specialized metabolites selected for their endogenous biological function. A correlation between phylogeny and biosynthetic pathways could offer a predictive approach enabling more efficient selection of plants for the development of traditional medicine and lead discovery. However, this relationship has rarely been rigorously tested and the potential predictive power is consequently unknown. RESULTS: We produced a phylogenetic hypothesis for the medicinally important plant subfamily Amaryllidoideae (Amaryllidaceae) based on parsimony and Bayesian analysis of nuclear, plastid, and mitochondrial DNA sequences of over 100 species. We tested if alkaloid diversity and activity in bioassays related to the central nervous system are significantly correlated with phylogeny and found evidence for a significant phylogenetic signal in these traits, although the effect is not strong. CONCLUSIONS: Several genera are non-monophyletic emphasizing the importance of using phylogeny for interpretation of character distribution. Alkaloid diversity and in vitro inhibition of acetylcholinesterase (AChE) and binding to the serotonin reuptake transporter (SERT) are significantly correlated with phylogeny. This has implications for the use of phylogenies to interpret chemical evolution and biosynthetic pathways, to select candidate taxa for lead discovery, and to make recommendations for policies regarding traditional use and conservation priorities.

Chalcone inhibitors of the NorA efflux pump in Staphylococcus aureus whole cells and enriched everted membrane vesicles.

A library of 117 chalcones was screened for efflux pump inhibitory (EPI) activity against NorA mediated ethidium bromide efflux. Five of the chalcones (5-7, 9, and 10) were active and two chalcones (9 and 10) were equipotent to reserpine with IC(50)-values of 9.0 and 7.7 µM, respectively. Twenty chalcones were subsequently proved to be inhibitors of the NorA efflux pump in everted membrane vesicles. Compounds 5, 7, and 9 synergistically increased the effect of ciprofloxacin on Staphylococcus aureus. Our results suggest that chalcones might be developed into drugs for overcoming multidrug resistance based on efflux transporters of microorganisms.

Novel inhibitory activity of the Staphylococcus aureus NorA efflux pump by a kaempferol rhamnoside isolated from Persea lingue Nees.

OBJECTIVES: To isolate a plant-derived compound with efflux inhibitory activity towards the NorA transporter of Staphylococcus aureus. METHODS: Bioassay-guided isolation was used, with inhibition of ethidium bromide efflux via NorA as a guide. Characterization of activity was carried out using MIC determination and potentiation studies of a fluoroquinolone antibiotic in combination with the isolated compound. Everted membrane vesicles of Escherichia coli cells enriched with NorA were prepared to study efflux inhibitory activity in an isolated manner. RESULTS: The ethanolic extract of Persea lingue was subjected to bioassay-guided fractionation and led to the isolation of the known compound kaempferol-3-O-α-L-(2,4-bis-E-p-coumaroyl)rhamnoside (compound 1). Evaluation of the dose-response relationship of compound 1 showed that ethidium bromide efflux was inhibited, with an IC(50) value of 2 µM. The positive control, reserpine, was found to have an IC(50) value of 9 µM. Compound 1 also inhibited NorA in enriched everted membrane vesicles of E. coli. Potentiation studies revealed that compound 1 at 1.56 mg/L synergistically increased the antimicrobial activity of ciprofloxacin 8-fold against a NorA overexpresser, and the synergistic activity was exerted at a fourth of the concentration necessary for reserpine. Compound 1 was not found to exert a synergistic effect on ciprofloxacin against a norA deletion mutant. The 2,3-coumaroyl isomer of compound 1 has been shown previously not to cause acute toxicity in mice at 20 mg/kg/day. CONCLUSIONS: Our results show that compound 1 acts through inhibition of the NorA efflux pump. Combination of compound 1 with subinhibitory concentrations of ciprofloxacin renders a wild-type more susceptible and a NorA overexpresser S. aureus susceptible.

Evaluation of the antibacterial activity of Chilean plants traditionally used for wound healing therapy against multidrug-resistant Staphylococcus aureus.

Anti-staphylococcal activity of Chilean medicinal plants traditionally used by the Huilliche people for wound healing therapy was evaluated against nine Staphylococcus aureus strains. Three extracts of 26 plant samples (20 species) were evaluated by agar overlay bioautography and MIC determination. Total phenolics and tannins were determined, and the antibacterial contribution of the latter was evaluated. The diffusion assay showed that 17 species were active against susceptible S. AUREUS and that 15 species were active against resistant S. aureus. Removal of tannins from extracts rendered only six species active. MIC-determination showed that 20 extracts had antibacterial activity on all eight strains, and the most potent MIC value was 64 µg/mL. Remarkably, 37 extracts were active against the otherwise multidrug-resistant vanthida strain. Our findings support the wound healing properties of Huilliche medicinal plants and the hypothesis that these plants are promising sources of potential anti-staphylococcal agents towards multidrug-resistant strains.

Mapuche herbal medicine inhibits blood platelet aggregation.

12 plant species traditionally used by the Mapuche people in Chile to treat wounds and inflammations have been evaluated for their direct blood platelet inhibition. Seven of the 12 tested plant species showed platelet inhibitory effect in sheep blood, and four of these were also able to inhibit the ADP- (5.0 µM) and collagen- (2.0 µg/mL) induced aggregations in human blood. These four species in respective extracts (in brackets) were Blechnum chilense (MeOH), Luma apiculata (H(2)O), Amomyrtus luma (DCM : MeOH 1 : 1) and Cestrum parqui (DCM : MeOH 1 : 1). The platelet aggregating inhibitory effects of A. luma (DCM : MeOH 1 : 1), and L. apiculata (H(2)O) were substantial and confirmed by inhibition of platelet surface activation markers.

Antimicrobial evaluation of Huilliche plant medicine used to treat wounds.

ETHNOPHARMACOLOGICAL RELEVANCE: The traditional use of 40 plant species used for treatment of wounds and associated infections by the Huilliche people of Chile was evaluated against bacterial and fungal human pathogens, especially including wound pathogens. MATERIALS AND METHODS: The extracts were tested against the fungi Penicillium expansum, Candida albicans and the bacteria Bacillus subtilis, Pseudomonas aeruginosa (four different strains), Staphylococcus aureus, Escherichia coli (four different strains), Streptococcus pneumoniae (four different strains with one being resistance to streptomycin). RESULTS: Thirteen of the plant species have interesting antimicrobial activities, with that of Acaena argentea, Aristotelia chilensis, Blechnum chilense, Francoa appendiculta, Gevuina avellana and Laureliopsis philippiana being the most noteworthy. CONCLUSIONS: The findings in the manuscript support the traditional use by the Huilliche people, and allow enhanced economical benefit and use by the locals. The results obtained on Acaena argentea, Aristotelia chilensis, Blechnum chilense, Francoa appendiculta, Gevuina avellana and Laureliopsis philippiana are of specific scientific interest, and further studies is needed in order to establish the active constituents of the species.

Survey of the antimicrobial activity of commercially available Australian tea tree (Melaleuca alternifolia) essential oil products in vitro.

OBJECTIVES: The aim of this study was to investigate the antimicrobial activity of a range of commercially available tea tree oil (TTO) products and to evaluate whether formulation plays a significant part in their antiseptic activity. METHODS: The antimicrobial activity of the purchased products and control TTO solutions was assessed against Escherichia coli, Staphylococcus aureus, Salmonella typhimurium, Pseudomonas aeruginosa, and Candida albicans using well diffusion, broth microdilution, and broth macrodilution assays. RESULTS: Zone sizes obtained by the agar well diffusion assay ranged from 0 to 49.8 mm, with the more viscous and lipophilic products producing the smallest zones. Micro- and macrodilution methods showed that eight products had minimum inhibitory concentrations that were lower than the nonformulated TTO control. The remaining three products showed activity equivalent to the TTO control. CONCLUSIONS: In general, the commercially available antiseptic TTO products showed antimicrobial activity that was equivalent to, or greater than the nonformulated TTO control. This suggests that the TTO within these products has retained its antimicrobial activity. Furthermore, the enhanced activity of the products may be attributed to other antimicrobial excipients within the products such as preservatives, or to synergistic antimicrobial interactions between the TTO and other product excipients. The observation that the commercially available antiseptic TTO products tested in this study retained adequate antimicrobial activity emphasizes the importance of considering how product bases and excipients may interact with the active compound during formulation to ensure efficacy of the final product. Finally, the current data suggest that these TTO products may also be active in vivo. However, this can only be determined through further studies and in clinical trials.

Effects of Teucrium polium spp. capitatum flavonoids on the lipid and carbohydrate metabolism in rats.

CONTEXT: The main objective of the study was to investigate the biochemical mechanism of the antidiabetic activities of the dry extracts of Teucrium polium L. ssp. capitatum (L.) Arcangeli (Lamiaceae), from Republic of Macedonia, traditionally used to treat diabetes. MATERIALS AND METHODS: Aerial parts of the plant were extracted in alcohol and freeze- or spray-dried, analyzed by high performance liquid chromatography (HPLC) and examined for insulinotropic effect in INS-1E cells in vitro. Their effect on blood glucose, lipids and carbohydrate-related enzymes was tested in normo- and streptozotocin hyperglycemic rats. RESULTS AND DISCUSSION: HPLC analyses revealed several flavonoids: luteolin, apigenin, cirsiliol, diosmetin, cirsimaritin and cirsilineol as both free aglycons and glycosides. The extract and mixture of commercial flavonoids showed a distinct insulinotropic effect on INS-1E cells at 500 µg/ml. Intragastric (i.g.) administration of identical doses of the extract (125 mg/kg) in both normo- and hyperglycemic rats was more efficient in lowering the blood glucose than intraperitoneal injection (35% vs. 24% reduction) with highest effect (50% reduction) 8 h after administration. After 10 days of treatment, the magnitude of the effect was comparable to i.g. administration of 2.5 mg/kg of glibenclamide (38% reduction). No effect was seen on blood lipid profiles. In OGTT (oral glucose tolerance test), the extract lowered blood glucose levels by ~35%. The treatment reduced hepatic glycogen and tended to normalize the activity of gluconeogenic enzymes. CONCLUSION: The results demonstrate that examined plant extracts contain flavonoids with insulinotropic and antihyperglycemic effects.

Randomized and double-blinded pilot clinical study of the safety and anti-diabetic efficacy of the Rauvolfia-Citrus tea, as used in Nigerian traditional medicine.

AIM OF THE STUDY: The aim of this randomized and double blinded pilot clinical trial was to investigate the anti-diabetic efficacy of the Rauvolfia-Citrus (RC) tea in humans. We have earlier shown that a combination of calorie-restriction and chronic administration of the RC tea to the genetic diabetic (BKS-db) mice resulted in the normalization of blood sugar, reduction in lipid accumulated in the mice eyes and prevention of the degeneration of the otherwise brittle BKS-db pancreas. The tea is made by boiling foliage of Rauvolfia vomitoria and fruits of Citrus aurantium and is used to treat diabetes in Nigerian folk medicine. MATERIALS AND METHODS: The RC tea was produced using the Nigerian traditional recipe and tested in the traditional dosage on 23 Danish type 2 diabetes (T2D) patients. The participants were divided into two equivalent groups after stratification by sex, age and BMI, in a 4-month double-blinded, placebo-controlled and randomized clinical trial. Most of the study subjects (19/23) were using oral anti-diabetic agents (OADs). Mean disease duration was 6±4.6 years, mean age was 64±7 years and mean BMI was 28.7±3.8 kg/m(2). Prior to starting the treatment, the participants received individual dietician consultations. RESULTS: At the end of the 4-month treatment period, the treated group showed an 11% decrease in 2-h postprandial plasma glucose relative to the 3% increase in the placebo group (p=0.004). The improvement in blood glucose clearance with RC tea treatment was reflected in a 6% reduction in HbA(1c) (p=0.02) and in a 10% reduction in fasting plasma glucose (p=0.02), when comparing the post 4-month treatment to pre-treatment baseline values. Though the basal levels of phosphorylated acetyl CoA carboxylase enzyme in skeletal muscle were significantly reduced in the treated group (p=0.04), as compared to the placebo, only the pattern of reductions in the tissue fatty acids (FAs) differed in the two groups. While all types of FAs were reduced in placebo, only saturated (SFA) and monounsaturated (MUFA) FAs were reduced with treatment. Interestingly, a modest increase in the polyunsaturated FAs fraction was observed in the RC treated group. In addition, the reduction in SFA and MUFA with RC tea treatment came solely from the triglyceride fractions, as there was an increase in the skeletal muscle phospholipids. CONCLUSIONS: Chronic administration of the RC tea to overweight T2D on OADs caused significant improvements in markers of glycaemic control and modifications to the fatty acid profile of skeletal muscle, without adverse effects or hypoglycaemia. Further exploration of the anti-diabetic effects of the RC tea is warranted.

Asháninka medicinal plants: a case study from the native community of Bajo Quimiriki, Junín, Peru.

BACKGROUND: The Asháninka Native Community Bajo Quimiriki, District Pichanaki, Junín, Peru, is located only 4 km from a larger urban area and is dissected by a major road. Therefore the loss of traditional knowledge is a main concern of the local headman and inhabitants. The present study assesses the state of traditional medicinal plant knowledge in the community and compares the local pharmacopoeia with the one from a related ethnic group. METHODS: Fieldwork was conducted between July and September 2007. Data were collected through semi-structured interviews, collection of medicinal plants in the homegardens, forest walks, a walk along the river banks, participant observation, informal conversation, cross check through voucher specimens and a focus group interview with children. RESULTS: Four-hundred and two medicinal plants, mainly herbs, were indicated by the informants. The most important families in terms of taxa were Asteraceae, Araceae, Rubiaceae, Euphorbiaceae, Solanaceae and Piperaceae. Eighty-four percent of the medicinal plants were wild and 63% were collected from the forest. Exotics accounted to only 2% of the medicinal plants. Problems related to the dermal system, digestive system, and cultural belief system represented 57% of all the medicinal applications. Some traditional healers received non-indigenous customers, using their knowledge as a source of income. Age and gender were significantly correlated to medicinal plant knowledge. Children knew the medicinal plants almost exclusively by their Spanish names. Sixteen percent of the medicinal plants found in this community were also reported among the Yanesha of the Pasco Region. CONCLUSIONS: Despite the vicinity to a city, knowledge on medicinal plants and cultural beliefs are still abundant in this Asháninka Native Community and the medicinal plants are still available in the surroundings. Nevertheless, the use of Spanish names for the medicinal plants and the shift of healing practices towards a source of income with mainly non-indigenous customers, are signs of acculturation. Future studies on quantification of the use of medicinal plants, dynamics of transmission of ethno-medicinal knowledge to the young generations and comparison with available pharmacological data on the most promising medicinal plants are suggested.

New bisbenzylisoquinoline alkaloid from Laureliopsis philippiana.

Phytochemical investigation of Laureliopsis philippiana resulted in isolation of a new bisbenzylisoquinoline alkaloid (1) named laureliopsine A. The structure was established by spectroscopic methods, including 2D homo- and heteronuclear NMR experiments. This finding of a bisbenzylisoquinoline alkaloid in Laureliopsis supports its close relationship to Atherosperma and its taxonomic segregation from Laurelia.

Increased lipids in non-lipogenic tissues are indicators of the severity of type 2 diabetes in mice.

We hypothesised that the molecular changes triggered in type 2 diabetes might cause phenotypic changes in the lipid fraction of tissues. We compared tissue lipid profiles of inbred lean B6-Bom with those of the obese B6-ob/ob and diabetic BKS-db/db mice and found that genetically diabetic mice significantly accumulate fat (especially monounsaturated fatty acids, MUFA) in non-lipogenic tissues such as the eye (MUFA, 2-fold), skeletal muscle (MUFA, 13-fold) and pancreas (MUFA, 16-fold). In contrast, the B6-ob/ob mice which manifest a milder form of type 2 diabetes use the liver as their predominant lipid depot (MUFA 91-fold increase, as compared to lean mice values). The lipids in the BKS-db/db skeletal muscle and pancreas were also significantly enriched with linoleic acid (LA, (9-fold and 6-fold, respectively); and alpha-linolenic acid (ALA, 8.5-fold and 8-fold, respectively). MUFA, LA and ALA accumulation in the non-lipogenic tissues of BKS-db/db mice was associated with reduced liver stearoyl-CoA desaturase-1 expression.

Ethnopharmacological evaluation of radal (leaves of Lomatia hirsuta) and isolation of 2-methoxyjuglone.

BACKGROUND: Leaves of Lomatia hirsuta are used in traditional medicine in Chile under the common name of "radal". A tea of radal is traditionally used for treatment of cough, bronchial troubles, and asthma. In a preliminary screening, extracts of the leaves revealed antifungal activity, and the present phytochemical study was undertaken to explain this activity and support the traditional use. METHODS: Along with the traditional tea, extracts of the leaves were screened for antifungal and toxic activities. The profile of secondary constituents was obtained using GC-MS. RESULTS: 2-Methoxyjuglone was isolated from the leaves of Lomatia hirsuta and found to be active against the pathogenic fungus Candida albicans (MIC = 8 microg/mL). Cinnamic acid and vanillic acid were identified as major constituents in the tea by GC-MS. The tea was found not to be toxic against Artemia salina. CONCLUSION: The presence of phenolic acids with antimicrobial properties supports the traditional use of Radal, and encourages further studies.

Tissue lipid lowering-effect of a traditional Nigerian anti-diabetic infusion of Rauwolfia vomitoria foilage and Citrus aurantium fruit.

The toxicity and anti-diabetic properties of an aqueous plant extract made by boiling Rauwolfia vomitoria foilage and Citrus aurantium fruits were evaluated in mice. A single dosage corresponding to 70x the human-daily-dose was non-toxic when administered to 6-week-old NMRI lean mice or 6- or 11-week-old C57BL/6J lean mice. Daily treatment of 11-week-old C57BL/KsBom-db (db/db) genetic diabetic mice with a dose corresponding to 10x human-daily-dose for 6 weeks facilitated a significant weight loss as compared to the untreated controls. During treatment, the db/db mice were maintained on the carbohydrate-deficient Altromin C1009 diet. Although the food intake in the treated mice was not statistically significant from that in the controls, the treated animals had significantly higher serum triglyceride contents, suggesting that the treatment induced lipid mobilization from internal stores. Moreover, the fatty acid profile of the eyes from the treated animals showed a significant reduction in total fatty acid content accompanied by a 33% reduction in estimated Stearoyl-CoA desaturase activity (p = 0.039) as compared with controls. The fatty acid mobilization and a protection of the brittle C57BL/KsBom-db pancreas were observed 5 weeks after cessation of treatment when the treated animals were maintained on the poorer Altromin C1009 diet.

Synergistic antioxidative effects of alkamides, caffeic acid derivatives, and polysaccharide fractions from Echinacea purpurea on in vitro oxidation of human low-density lipoproteins.

Preparations of Echinacea are widely used as alternative remedies to prevent the common cold and infections in the upper respiratory tract. After extraction, fractionation, and isolation, the antioxidant activity of three extracts, one alkamide fraction, four polysaccharide-containing fractions, and three caffeic acid derivatives from Echinacea purpurea root was evaluated by measuring their inhibition of in vitro Cu(II)-catalyzed oxidation of human low-density lipoprotein (LDL). The antioxidant activities of the isolated caffeic acid derivatives were compared to those of echinacoside, caffeic acid, and rosmarinic acid for reference. The order of antioxidant activity of the tested substances was cichoric acid > echinacoside > or = derivative II > or = caffeic acid > or = rosmarinic acid > derivative I. Among the extracts the 80% aqueous ethanolic extract exhibited a 10 times longer lag phase prolongation (LPP) than the 50% ethanolic extract, which in turn exhibited a longer LPP than the water extract. Following ion-exchange chromatography of the water extract, the majority of its antioxidant activity was found in the latest eluted fraction (H2O-acidic 3). The antioxidant activity of the tested Echinacea extracts, fractions, and isolated compounds was dose dependent. Synergistic antioxidant effects of Echinacea constituents were found when cichoric acid (major caffeic acid derivative in E. purpurea) or echinacoside (major caffeic acid derivative in Echinacea pallida and Echinacea angustifolia) were combined with a natural mixture of alkamides and/or a water extract containing the high molecular weight compounds. This contributes to the hypothesis that the physiologically beneficial effects of Echinacea are exerted by the multitude of constituents present in the preparations.

HPLC method validated for the simultaneous analysis of cichoric acid and alkamides in Echinacea purpurea plants and products.

A reversed-phase high-performance liquid chromatography (HPLC) method has been developed to determine caffeic acid derivatives, for example, cichoric acid, and alkamides in plant parts and herbal products of Echinacea purpurea. The method consists of an extraction procedure whereby the hydrophilic phenolics as well as the lipophilic alkamides are released from the samples, followed by the analytical HPLC procedure for quantitative determination of these compounds. The method is the first one validated for the determination of these two groups of compounds in the same procedure. Naringenin has been used as an internal standard, as no other flavanones are present in the extract and it does not interfere with any of the compounds under investigation. Analysis of Danish-grown plant material shows that it is possible to raise plants of a very high chemical quality in Denmark. A selection of international herbal products available on the Danish market show surprisingly variable quality, not necessarily reflecting the product information given on the labels.

Community participation as an interactive learning process: experiences from a schistosomiasis control project in Zimbabwe.

A schistosomiasis control project was undertaken from 1994 to 1998 in Guruve District, Zimbabwe, based on the active involvement of local communities in the growing and application of the molluscicidal plant Phytolacca dodecandra as a supplement to other control measures such as chemotherapy and health education. The berries of P. dodecandra are highly molluscicidal to the intermediate host snails of schistosomiasis and is rapidly degradable in water. It was observed that plant care fluctuated during the study period. Only a few households participated in snail control activities, although 97% of respondents in a baseline survey had stated a willingness to take part. This invoked an investigation to explore the reality from a user perspective. Focus group discussions, semi-structured interviews and observations were used to solicit information. In spite of a cultural inclination for collective work, many reasons for low-level involvement emerged, inter alia the low perceived value of the project, demands for tangible benefits, inaccessible fields and weak leadership. This study shows that community participation is a complex process upon which a multiplicity of social and cultural determinants have an impact. If community participation is to become successful in development programmes it ought to be viewed as a mutual learning process where obstacles are identified and discussed and solutions shared among community members and project staff.

Medicinal plants used by Luo mothers and children in Bondo district, Kenya.

In a follow-up to studies of school-children's medical knowledge among the rural Luo of western Kenya, seven mothers were asked for their knowledge of plant medicine, and the 91 plant remedies mentioned by them were collected, 74 of these remedies were identified as 69 different species (in 13 cases, the material did not allow identification of the species, in two cases, only the family could be identified, and in two, not even this was possible). The results of this survey and some comments on Luo illness concepts are presented below and briefly discussed in relation to the earlier work on school-children and to another survey of Luo plant medicine in the same district. The article concludes that the consensual core of Luo plant medicine is known by ordinary mothers and their children as well as by recognised healers. It is a shared resource, that is used by women, mainly in the care for their children, and it is not an expert domain of knowledge, as is often, in studies of herbal or 'traditional' medicine are studied. The medicinal plants, upon which many mothers as well as healers agree should be examined further pharmacologically in order to assess their efficacy against the common infectious and parasitic diseases found in this area of western Kenya.