Search

Background: In recent years, plant materials have been widely explored as sources of insect pest control agents with little or no study on their toxicity. The present study aimed to detect the biochemical alterations in liver and kidney associated with acute oral toxicity of the extracts of B. micrantha and M. villosus in albino rats. Methods: Twenty seven albino rats, weighing between 150-180g were used and divided into nine groups of three rats each, administered with different doses of each extracts (0, 500, 1000, 1500 and 2000mg/kg). The plasma and homogenates of liver and kidney of the rats were investigated for the activities of alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALT), total protein, urea and creatinine, using standard laboratory kits. Results: The administration of either extract did not cause death or any hazardous symptoms of acute toxicity, nor resulted in any evident changes in the body weight. However, the extracts caused significant decreases in the levels of ALT, AST, ALP and total protein, urea and creatinine in biochemical parameters. They also caused a significant decrease in the serum parameters of treated rats’ liver and kidney at all doses. Conclusions: The results demonstrated that the oral administration of B. micrantha ethyl acetate extract and of M. villosus petroleum ether extract may be considered as moderately free of toxicity. This was based on our findings that two compounds were moderately safe with respects to their effects on the liver and kidney functions at concentrations of up to 2000 mg/kg body weight of the rats.

Introduction: Despite concerns about toxicity, potentially harmful effects and herb-drug interactions, the use of herbal medicines remains widely practiced by people living with HIV/AIDS (PLHIV) in Uganda.Objective: The objective of the paper was to comprehensively review the literature on the toxicity and chemical composition of commonly used medicinal plant species in treating PLHIV in Uganda.Methods: We reviewed relevant articles and books published over the last sixty years on ethnobotany, antiviral/anti-HIV activity, toxicity, phytochemistry of Vachellia hockii, Albizia coriaria, Bridelia micrantha, Cryptolepis sanguinolenta, Erythrina abyssinica, Gardenia ternifolia, Gymnosporia senegalensis, Psorospermum febrifugium, Securidaca longipendunculata, Warburgia ugandensis and Zanthoxylum chalybeum and their synonyms. We searched PubMed, Web of Science, Scopus, Science Direct and Google Scholar.Discussion: Most of the plant species reviewed apart from P. febrifugium, S. longipedunculata and C. sanguinolenta lacked detailed phytochemical analyses as well as the quantification and characterization of their constituents. Crude plant extracts were the most commonly used. However, purified/single component extracts from different plant parts were also used in some studies. The U87 human glioblastoma was the most commonly used cell line. Water, ethanol, methanol and DMSO were the commonest solvents used. In some instances, isolated purified compounds/extracts such as Cryptolepine and Psorospermin were used.Conclusion: Cytotoxicity varied with cell type, solvent and extract type used making it difficult for direct comparison of the plant species. Five of the eleven plant species namely, A. coriaria, C. sanguinolenta, G. ternifolia, P. febrifugium and Z. chalybeum had no cytotoxicity studies in animal models. For the remaining six plant species, the crude aqueous and ethanol extracts were mainly used in acute oral toxicity studies in mice. Herbalists reported only A. coriaria and W. ugandensis to cause toxic side effects in humans. However, selective cytotoxic plant extracts can potentially be beneficial as anticancer or anti-tumour drugs.

Ethnopharmacological relevance The geographical location of Kakamega County proximal to the Kakamega Rain Forest in Kenya and its rich flora represents an interesting resource of traditional medicinal plants. The medicinal plants in the present study are traditionally used to treat cancer in Kakamega County as recorded in published literature. Aim of the study Due to multidrug resistance (MDR) and severe side effects of currently used drugs in clinical oncology, new candidate compounds are urgently required to improve treatment outcome. The present study explored the in vitro cytotoxic potential of 34 organic and 19 aqueous extracts of Kakamega medicinal plants towards sensitive and multidrug-resistant cancer cell lines. Methods and results The cytotoxicity was determined using the resazurin assay. Eight organic and two aqueous plant extracts inhibited the growth of CCRF-CEM leukemia cells by more than 50%. The organic extracts were Harungana madagascariensis Lam. ex poir (6.6% of untreated control), Prunus africana (Hook.f.) Kalkman (19.4%), Entada abyssinica Steud. ex A. Rich (38.6%), Phyllanthus fischeri Pax (40.7%), Shirakiopsis elliptica (Hochst.) Esser Synonym: Sapium ellipticum (Hochst. kraus) Pax (41.8%), Bridelia micrantha (Hochst.) Baill (45.4%) and Futumia africana Benth. (45.8%) and Microglossa pyrifolia (Lam.) Kuntze (48%). The aqueous extracts were Bridelia micrantha (Hochst.) Baill (31.3%) and Shirakiopsis elliptica (Hochst.) Esser Synonym: Sapium ellipticum (Hochst. Kraus) Pax (48.2%). In addition to P-glycoprotein-expressing tumor cells, we also investigated other mechanisms of drug resistance, i.e. BCRP- or EGFR-transfected and TP53-knockout tumor cells. Some extracts also showed considerable cytotoxic activity against these drug-resistant cell lines. As demonstrated for selected examples, some extracts exhibited enhanced cytotoxicity towards cancer cells, if applied in combination with other extracts. Discussion The panel of medicinal plants used in the Kakamega County for cancer treatment revealed indeed cytotoxicity to various extent towards cancer cells in vitro. Hence, our results may at least in part substantiate the traditional use of these compounds to treat cancer. Even more interesting, several extracts inhibited otherwise drug-resistant tumor cell lines with similar or even better efficacy than their drug-sensitive counterparts. This provides an attractive perspective for further exploration of their anticancer potential to combat drug resistance of refractory tumors.

Bridelia micrantha is a medicinal plant used traditionally for the treatment of wounds. However, there are no documented scientific reports on the wound healing activities of this plant. This study was conducted to investigate the antimicrobial, antioxidant and wound healing activities of methanol leaf extract of B. micrantha (BME). The antimicrobial activity was determined using the agar well diffusion and broth dilution methods. Antioxidant activity was performed in vitro using the DPPH scavenging antioxidant activity followed by in vivo wound healing activities using the excision wound model. Preliminary phytochemical screening of BME showed the presence of saponins, tannins, flavonoids, alkaloids, triterpenes, glycosides, steroids and coumarins. BME exhibited dose-dependent antimicrobial activities. The most susceptible organism to BME was N. gonorrhoeae with mean zones of inhibition ranging from 20.50 ± 1.00 to 28.50 ± 1.00 mm. The least susceptible organism was S. typhi with mean zones of inhibition in the range of 15.50 ± 0.00 to 21.50 ± 0.00 mm. The MICs of BME against the test organisms were in the range of 1.25 to 2.5 mg/mL. Sub-inhibitory concentrations of BME potentiated the activities of ciprofloxacin and ketoconazole. BME showed a dose-dependent increase in antioxidant activity with IC50 of 0.2626 µg/mL. The BME formulated creams at concentrations of 0.625, 2.5, and 10% w/w showed a significant (p

Introduction People living with HIV/AIDS (PLHIV) widely use medicinal plants for boosting immunity and managing infections. The aim of this study was to document the medicinal plant species used by herbalists to boost the immune system of people living with HIV/AIDS in Uganda. Methods Semi-structured questionnaires were administered to 90 herbalists to obtain ethnobotanical information on medicinal plant species used in different parts of Uganda. A detailed literature review of the pharmacology, phytochemistry, toxicology and other traditional used of the documented medicinal plants was also conducted. Results Seventy-one medicinal plant species from 37 families and 64 genera were identified. Trees contributed 38.0 % of the species used and herbs 35.2 %. The majority of the herbal medicines were made from leaves (35.6 %), bark (24.1 %) and roots (20.7 %). Zanthoxylum chalybeum Engl. and Psidium guajava L. were the most widely used species with citation frequencies (CF) of 11 each. These were followed by Warburgia ugandensis Sprague, Acacia hockii De Wild. and Bridelia micrantha (Hochst.) Baill (CF = 8 each), Mangifera indica L., Markhamia lutea (Benth.) K. Schum., Aloe vera (L.) Burm.f. and Erythrina abyssinica DC. (CF = 7 each). Most traditional medicine practitioners (TMP) (85.6%) used herbs for boosting immunity for PLHIV, whether or not the patients were on antiretroviral treatment. The patients often disclosed their sero-status to the TMP who considered all PLHIV to be immunocompromised. Conclusion Herbalists widely prescribe medicinal plant species for boosting or restoring the immunity in PLHIV in Uganda.

Bridelia micrantha is traditionally used in tropical Africa to treat a wide range of human and animal diseases. The aim of this study was to summarise the research that has been done on the ethnomedicinal uses, phytochemistry and pharmacological properties of B. micrantha so as to understand its importance and potential value in primary healthcare systems. The literature search for information on ethnomedicinal uses and pharmacological activities of B. micrantha was undertaken using databases such as Web of Science, Scopus, Google Scholar, Science Direct, BioMed Central (BMC), PubMed and Springerlink. Other relevant literature sources included books, book chapters, websites, theses, conference papers and other scientific publications. This study showed that B. micrantha is used as herbal medicine in just over half (57.3%) of the countries in tropical Africa where it is indigenous. A total of 54 ethnomedicinal uses of B. micrantha have been recorded with a high degree of consensus on burns, wounds, conjunctivitis, painful eyes, constipation, gastric ulcers, cough, headache, rheumatism, painful joints, dysentery, ethnoveterinary medicine, malaria, sexually transmitted infections, stomach ache, tape worms and diarrhoea. Different plant parts, aqueous and organic extracts exhibited anthelmintic, antimicrobial, anticonvulsant and sedative, antidiabetic, antidiarrhoeal, antinociceptive, antioxidant, antiplasmodial, antischistosomal, hepatoprotective, insecticidal and β-lactamase inhibitory activities.

Schistosomiasis in humans is a major public health problem worldwide. Schistosomiasis occurs in 76 tropical countries and it is estimated that 85% of the infections are in Africa. In Kenya, it is estimated that 3 million people are infected. The Conventional drugs are effective in the treatment of the disease but very little progress has been achieved on treatment of Schistosomiasis in Kenya. Any effort towards developing alternative drugs for the disease is worthwhile. Praziquantel is the most effective drug against all adult stages of human Schistosomiasis, being the drug of choice for morbidity control of Schistosomiasis. However it is not a satisfying situation to have one drug used for the treatment. Ideally other drugs should be availed in order to avoid development of drug resistance. The use of plant extracts in treatment of diseases is universal. The results obtained showed that Ocimum americanum and Bridelia micrantha plant extracts had antischistosomal activity as indicated by high worm reduction and reduced gross pathology. Histopathology showed no or few granuloma in the liver tissue. Further work should be done on the efficacious extracts, towards drug development.

Bridelia micrantha and Croton macrostachyus are medicinal plants used empirically in traditional medicine to treat epilepsy. In vivo mice model (maximal electroshock, strychnine, pentylenetetrazol, picrotoxin, isonicotinic hydrazide acid)-induced convulsions were used to evaluate the anticonvulsant activities of those plants. Diazepam-induced sleep was used for the evaluation of the sedative properties. B. micrantha protected 100, 80, 80, and 80% of mice against PIC, STR, PTZ and MES-induced seizures, respectively. C. macrostachyus at the doses 34 and 67 mg/kg protected 80, 80, 80 and 60% of mice from PIC, STR, PTZ and MES-induced seizures, respectively. B. micrantha and C. macrostachyus also delayed the onset to seizures in INH test. B. micrantha was more potent than C. macrostachyus in protecting mice against convulsions. The co-administration of the sub effective dose of the decoction of B. micrantha or C. macrostachyus with the sub effective dose of diazepam or clonazepam resulted in a synergistic effect. The decoctions of B. micrantha and C. macrostachyus also exerted sedative activity by increasing the total duration of sleep induced by diazepam and by reducing the latency time to sleep. The effect of the decoctions of B. micrantha and C. macrostachyus suggests the presence of anticonvulsant activities that might show efficacy against secondarily generalized tonic-clonic seizures and primary generalized seizures in humans.

Helicobacter pylori is a major risk factor for gastritis, ulcers and gastric cancer. This study was aimed to determine the antimicrobial activity of the stem bark of Bridelia. micrantha on H. pylori isolated in South Africa. Extracts and clarithromycin were tested against 31 clinical strains, including a standard strain (NCTC 11638) of H. pylori, by measuring the diameters of the corresponding inhibition zones, followed by determination of the Minimum Inhibitory Concentration (MIC) (using metronidazole, and amoxicillin as control antibiotics) and the rate of kill. Preliminary phytochemical screening was also done. Inhibition zone diameters which ranged from 0–23 mm were observed for all five of the extracts and 0–35 mm for clarithromycin. Marked susceptibility of strains (100%) was noted for the acetone extract (P < 0.05), followed by ethyl acetate extract (93.5%). The MIC50 values ranged from 0.0048 to 0.156 mg/mL for the ethyl acetate extract and 0.0048 to 0.313 mg/mL for the acetone extract. The MIC90 values ranged from 0.0048 to 2.5 mg/mL for the ethyl acetate extract and 0.078 to >0.625 mg/mL for the acetone extract, respectively. Insignificant statistical difference in potency was observed when comparing the crude ethyl acetate extract to metronidazole and amoxicillin (P > 0.05). Complete killing of strain PE430C by the ethyl acetate extract was observed at 0.1 mg/mL (2 × MIC) and 0.2 mg/mL (4 × MIC) at 66 and 72 h. For strain PE369C, 100% killing was observed at 0.1 mg/mL (2 × MIC) in 66 and 72 h. The ethyl acetate extract could thus be a potential source of lead molecules for the design of new anti-Helicobacter pylori therapies as this study further confirmed the presence of phytochemicals including alkaloids, flavonoids, steroids, tannins and saponins.

Bridelia micrantha (Hochst) Baill. (Euphorbiaceae), commonly known in English as “coast gold leaf” or “ogaofia” (the boss of the bush) in Igbo, is a semi-deciduous to deciduous tree up to 20 m tall with a dense rounded crown and tall, and bare stem indigenous to southern part of Nigeria. Its stem bark, which is yellow grey and smooth to slightly rough, has been of interest to researchers because of its use in the treatment of various disease conditions in Nigerian traditional medicine. The present study was targeted at investigating the antidiabetic and antioxidant effects of the methanol extract of B. micrantha leaves using alloxan-induced diabetic mice in vivo and in vitro. The extract, at the dose of 250, 500, and 1,500 mg/kg, showed a remarkable time-dependent decrease in blood glucose level in alloxan-induced diabetic mice. There was no significant difference between the extract-treated groups and the groups treated with 10 mg/kg distilled water and glibenclamide (2 mg/kg), respectively. Six hours posttreatment, the blood glucose level for the groups treated with 250 mg/kg of B. micrantha and glibenclamide (2 mg/kg), respectively, were lower than the normal blood glucose level respectively for the groups before the induction of diabetes. B. micrantha showed its optimum antioxidant activity in DPPH spectrophotometric assay at the concentration of 400 μg/ml. The ferric reducing antioxidant power showed a significant concentration-dependent increase in the total antioxidant power. These findings demonstrate that B. micrantha has both antidiabetic and antioxidant effects on experimental model of diabetes in mice and validate its use in Nigerian traditional medicine for the treatment of diabetes. Even in its crude form, the effects were comparable to that of glibenclamide, an oral sulfonylurea with proven antidiabetic activity. This finding suggests that the extract could be a potential source of a novel antidiabetic and antioxidant agent for the management of diabetes mellitus.

Ethnopharmacological relevance Tuberculosis (TB), caused by Mycobacterium tuberculosis (MTB) is the most commonly notified disease and the fifth largest cause of mortality. One in 10 cases is resistant to treatment in some areas. Several plants are used locally to treat TB-related disease. Aims of the study The aim was to screen selected South African medicinal plants used to treat TB and related symptoms by traditional healers for antimycobacterial activity. Materials and methods Ethnobotanical information on these plants was obtained. Crude acetone, methanol, hexane and ethanol extracts of 21 selected medicinal plants obtained in Venda, South Africa were screened for their ability to inhibit MTB H 37 Ra and a clinical strain resistant to first-line drugs and one second-line drug using tetrazolium microplate assay to determine the minimum inhibitory concentration (MIC). Results were analyzed using Microsoft Excel 2007 and One way ANOVA; p Results Few acetone extracts were active against MTB with MIC under 100 μg/mL. Four plants showed lower MIC values; Berchemia discolor Klotzsch Hemsl 12, 5 μg/mL on H 37 Ra and 10.5 μg/mL on the clinical isolate, Bridelia micrantha Hochst. Baill (25 μg/mL), Warbugia salutaris Bertol. F Chiov (25 μg/mL), and Terminalia sericea Burch ex D. F (25 μg/mL) on both H 37 Ra and clinical isolate. However, the roots of Ximenia caffra Sond. Var. caffra, barks of Sclerocarya birrea (A Rich) Hochst, Asclepias fruticosa L, tubers of Allium sativum L, leaves of Carica papaya L, Solanum panduriforme E. Mey C, and roots of Securidaca longepedunculata Fresen gave MIC greater than 100 μg/mL. Conclusion The acetone extracts of Berchemia discolor , Bridelia micrantha , Terminalia sericea and Warbugia salutaris could be important sources of mycobactericidal compounds against multidrug-resistant MTB.

Aim of study This study screened for anthelmintic activity of plant species traditionally used in the treatment of intestinal parasites and their symptoms in Sub-Saharan Africa in an effort to confirm their local use and aid in the search for new compounds since resistance is a growing concern. Materials and methods Aqueous and organic extracts of 33 plant parts from 17 plant species traditionally used in the treatment of intestinal infections in Sub-Saharan Africa were evaluated for their anthelmintic activity. This activity was assessed using a standard motility assay against a levamisole resistant strain of the nematode Caenorhabditis elegans. Results and conclusions Anthelmintic activity was confirmed in 12 plant species. Of these, eight showed strong evidence of activity (p

Ethnopharmacological relevance Plants from Kenyan flora are traditionally used against many ailments, including cancer and related diseases. Cancer is characterized as a condition with complex signs and symptoms. Recently there are recommendations that ethnopharmacological usages such as immune and skin disorders, inflammatory, infectious, parasitic and viral diseases should be taken into account when selecting plants that treat cancer. Aim The present study was aimed at investigating the cytotoxicity of a plethora of 145 plant parts from 91 medicinal plants, most of which are used in the management of cancer and related diseases by different communities in Kenya, against CCRF-CEM leukemia cell line. Materials and methods Extracts from different plant parts (leaves, stems, stem bark, roots, root barks, aerial parts and whole herb) were obtained by cold percolation using different solvent systems, such as (1:1 v/v) dichloromethane (CH2Cl2) and n-hexane (1), methanol (MeOH) and CH2Cl2 (2); neat MeOH (3), 5% H2O in MeOH (4) and with ethanol (EtOH, 5); their cytotoxicities were determined using the resazurin reduction assay against CCRF-CEM cells. Results At a single concentration of 10 μg/mL, 12 out of 145 extracts exhibited more than 50% cell inhibition. These include samples from the root bark of Erythrina sacleuxii (extracted with 50% n-hexane-CH2Cl2), the leaves of Albizia gummifera, and Strychnos usambarensis, the stem bark of Zanthoxylum gilletii, Bridelia micrantha, Croton sylvaticus, and Albizia schimperiana; the root bark of Erythrina burttii and E. sacleuxii (extracted with 50% CH2Cl2–MeOH), the stem bark of B. micrantha and Z. gilletii (extracted using 5% MeOH–H2O) and from the berries of Solanum aculeastrum (extracted with neat EtOH). The EtOH extract of the berries of S. aculeastrum and A. schimperiana stem bark extract displayed the highest cytotoxicity towards leukemia CCRF-CEM cells, with IC50 values of 1.36 and 2.97 µg/mL, respectively. Other extracts having good activities included the extracts of the stem barks of Z. gilletii and B. micrantha and leaves of S. usambarensis with IC50 values of 9.04, 9.43 and 11.09 µg/mL, respectively. Conclusions The results of this study provided information related to the possible use of some Kenyam medicinal plants, and mostly S. aculeastrum, A. schimperiana, C. sylvaticus, Z. gilletii, B. micrantha and S. usambarensis in the treatment of leukemia. The reported data helped to authenticate the claimed traditional use of these plants. However, most plants are used in combination as traditional herbal concoctions. Hence, the cytotoxicity of corresponding plant combinations should be tested in vitro to authenticate the traditional medical practitioners actual practices.

Twenty plants identified and selected from Southwest and Middle belt Nigerian antimalarial ethnopharmacology were evaluated for in vitro cytotoxicity using the brine shrimp lethality assay. The methanol extracts of 20 plant samples from 11 plant families were subjected to the assay. Of the studied plants, Lippia multiflora and Morinda lucida bark were found to be cytotoxic, with LC 50 values of 1.1 and 2.6 μg/ml, respectively. The least toxic plant extract was Bridelia micrantha (LC 50 value >9.0×10 6 μg/ml). Most of the plants were found to be relatively non-toxic.

Seven methanol extracts of seven plants from seven plant families were screened for antimalarial properties. The plants were identified and selected from Gboko and Kastina-Ala local government areas in the Tivland ethnobotany in the Middle Belt Zone of Nigeria. Methanol plant extracts were evaluated for in vitro. antimalarial properties using the lactate dehydrogenase technique, with a multiresistant strain of Plasmodium falciparum. K1. Quantification of activity was by estimation of the concentration of extracts that inhibited 50% growth of parasite (IC50) in µg/ml. Of the seven plants screened, Erythrina senegalensis. DC (Leguminosae), Pericopsis elata. Harms (Papilionaceae), and Bridelia micrantha. Benth (Fabaceae) had IC50 values of 99.7, 124.8, and 158.7 µg/ml, respectively. Nauclea latifolia. SM (Rubiaceae) extract exhibited the least activity in the assay with an IC50 value of 478.9 µg/ml.

Tanzania has over 12,000 plant species, some of which are endemic and have potential to yield useful medicines. This study seeks to document such plants used as traditional medicines for treatment of malaria in Kagera region of northwestern Tanzania and Lindi region in south eastern Tanzania. The study also reports on the antiplasmodial activity against chloroquine-resistant Plasmodium falciparum (Dd2) strain of some of the documented plants using the parasite lactate dehydrogenase method. A total of 108 plant species, among which the families Compositae (14; 12.96%), Fabaceae (12; 11.11%), Euphorbiaceae (8; 7.41%), Melastomataceae (6; 5.56%) and Myrtaceae (4; 3.70%) were documented. Sixteen (16; 44.4%) of 36 extracts from 31 plant species that were tested inhibited malaria parasites growth by more than 50%. Bersema abyssinica stem bark extract was the most active with 86.67% inhibition rate followed by Bridelia micrantha stem bark extract with 71.87% inhibition rate. These results confirm the potential for plants used in traditional medicine to yield active antimalarial compounds. Further in vitro and in vivo screening supported by bioassay-guided isolation of active compounds from plants showing good safety margin is suggested. Key words: Ethnobotanical survey, medicinal plants, malaria, treatment, in vitro antiplasmodial, Tanzania.

ObjectiveTo explore the hepatoprotective and anti-oxidant activities of the methanolic leaf extract of Bridelia micrantha (B. micrantha) on paracetamol induced liver damage in Wistar rats.MethodsParameters were measured including alanine aminotransaminase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), bilirubin and total protein. The anti-oxidant effects were studied using the 1, 1-Diphenynl-2-Picrylhydrazyl (DPPH) and Ferric Reducing Antioxidant Power (FRAP) assay methods.ResultsB. micrantha extract decreased the level of AST in the rats given PCM from (129.47±0.92I) IU/L to (57.78±1.71) IU/L (P

The methanolic leaf extract of Bridelia micrantha was tested for subacute antidiabetic and in vivo antioxidant effects in alloxan-induced hyperglycaemic rats. The subacute treatment of the extract (125, 250 and 500 mg/kg) produced 75, 68 and 63% reduction in fasting blood sugar level respectively, on day 14 of treatment. The extract produced time-dependent effect, but did not show a dose-dependent effect. Its optimum antidiabetic activity was noted at the dose of 125 mg/kg and this was comparable to glibenclamide 2 mg/kg (positive control). The extract (125 mg/kg) showed good oral glucose tolerance test (OGTT) effect in both normoglycaemic and hyperglycaemic rats. The OGTT effect of the extract (125 mg/kg) did not differ significantly (p>0.05) from glibenclamide (2 mg/kg). The antioxidant effect of the extract was assayed through the determination of the level of thiobarbituric acid reactive substance (TBARS) and catalase activity. The extract produced a dose-dependent decrease in the serum level of TBARS and gave its optimum catalase activity at the dose of 500 mg/kg. This study suggests that the B. micrantha extract has antihyperglycaemic and antioxidant activities. Therefore, could be a potential source of novel antidiabetic and antioxidant agent for the management of diabetes mellitus.

Background: Bridelia micrantha, Chenopodium ambrosoides and Ocimum americanum plant species are commonly used in traditional medicine for a number of ailments. The extracts of these plants have been shown to have anti-schistosomal activity suggesting that they could be used for the development of new chemical entities (NCEs) for the treatment of schistosomiasis. However there is limited knowledge on their toxicological profile and their use in traditional medicine may not be a satisfactory safety indication. Methods: In this study the extracts were first screened for bioactivity using brine shrimp lethality test for the determination of LC50 followed by rodent acute toxicity and 28 day subchronic studies. Results: B. micrantha water extract with a LC50 of 77µg/ml was deemed toxic while C. ambrosoides methanol and water extracts were moderately toxic with LC50 of 104.63µg/ml and 696.44µg/ml respectively. O. americanum hexane and water extracts toxicity varied from moderate to slightly toxic with LC50 of 887.59µg/ml and 2254.60µg/ml respectively. C. ambrosoides and O. americanum water extracts which were preferentially selected for subsequent studies were found to have mild to no irritation to rodent eyes and skin. Moreover, the aminotransferases AST and ALT which were used to detect liver injury suggested negligible effect. Conclusions: This therefore confirms that C. ambrosoides and O. americanum water extracts are safe for clinical use with O. americanum water extract having a slight edge.

The present study was designated to evaluated the antimicrobial activities of methanol, ethanol, hexane, ethyl acetate, aqueous, mixture methanol/water and ethanol/water extracts of Pentadiplandra brazzeana, Erythrina sigmoidea, Petersianthus macrocarpus, Clerodendrum umbellatum , Sida acuta , Eleusine indica , Bridelia micrantha and Musanga cecropioides which are plants used as traditional folk medicine in Cameroon for the treatment of different infections and disorders as gastrointestinal disorders. The antimicrobial activities of the extracts against 17 laboratory strains belong to 15 bacterial species and 2 yeasts implicated in gastrointestinal disorders were evaluated based on the inhibition zone using the disc diffusion assay, minimal inhibition concentration and minimal bactericidal concentration values. 89.6% of the extracts tested have an inhibitory effect at 1.25 mg against at least one of the microorganism tested with the diameter of inhibition zone values ranging from 8 to 27 mm. 62.5% of the broader spectrum of antimicrobial activity of plant material was obtained with methanol extract. The most susceptible bacterium was Shigella flexneri and Enterobacter cloacae the most resistant. Ethanol/Water extract of Pentadiplandra brazzeana presented a good activity against Proteus vulgaris with MIC and MBC of 78 and 250 µg/ml respectively. The weak activity was obtained with Methanol extract of Musanga cecropioides against Klebsiella pneumonia. The results might explain the ethnobotanical use of the studied species for the treatment of gastrointestinal infections.

The anti-diabetic activity of extracts and fractions from leaves of Bridelia micrantha was investigated in alloxan diabetic rats. Powdered leaves of B. micrantha were macerated with 80% MeOH for five days. The petroleum ether, CHCl3 and MeOH/H20 soluble portions were prepared from the crude aqueous MeOH extract and tested on the diabetic rats. Hyperglycaemia was induced by intraperitoneal injection of alloxan monohydrate (80mg/kg) and blood glucose monitored for seven days using a glucometer. The MeOH/H2O residue exhibited significant (p

In efforts to find new bioactive β-lactamase inhibitors, this study investigated 16 Cameroonian plants belonging to 10 families which were evaluated for anti-β-lactamase activity. The investigation showed that extracts 2, 6, 3 and 5 of the 16 plants investigated presented interesting in vitroβ-lactamase inhibition (over 90%), respectively, of the β-lactamases TEM-1, OXA-10, IMP-1 and P99. These extracts were from Mammea africana (all β-lactamases), Garcinia lucida, G. kola (OXA-10, IMP-1 and P99), Bridelia micrantha (OXA-10, P99), Ochna afzelii (OXA-10, P99), Prunus africana (IMP-1) and Adenia lobata (TEM-1). After elimina tion of tannins (according to the European Pharmacopoeia) the extracts from B. micrantha, G. lucida and M. africana were tested further for their anti-β-lactamase activity. The extracts from B. micrantha and G. lucida exhibited potent inhibitory activity, respectively, of β-lactamase OXA-10 (IC50 = 0.02 mg/mL) and P99 (IC50 = 0.01 mg/mL). The anti-β-lactamase activity of M. africana extract was weak. The isolation and the structural elucidation of the active constituents of G. lucida and B. micrantha will provide useful leads in the development of β-lactamase inhibitors. Copyright © 2007 John Wiley & Sons, Ltd.

Aqueous and methanolic extracts of several medicinal plants, Psidium guajava (leaves), Aristea spp., Iridaceae family (stem), Bridelia micrantha (bark) and Eleutherina bulbosa (bulb), used by Zulu traditional healers were evaluated for anti-diarrhoeal activity against different experimental models of diarrhoea in rats as well as for anti-microbial activity against different pathogenic microorganisms that cause diarrhoea. The methanolic extract of P. guajava (leaves) was the only agent showing significant inhibitory activities against the growths of Salmonella spp. (two isolates), Shigella spp. (S. flexneri, S. virchow and S. dysenteriae) and enteropathogenic Escherechia coli (two isolates). The methanolic extract of B. micrantha (Bark) demonstrated weak inhibitory activities against S. flexneri and S. plesiomonas. Based on the results in experimental rat models, there were significant reductions in faecal output and frequency of droppings when plant extracts were administered compared with castor-oil treated rats. All plant extracts also significantly retarded the propulsion of charcoal meal and significantly inhibited the PGE(2)-induced enteropooling. The results have confirmed the effectiveness of all these Zulu medicinal plants as anti-diarrhoeal agents.

Background Tuberculosis, caused by Mycobacterium tuberculosis (MTB), is the most notified disease in the world. Development of resistance to first line drugs by MTB is a public health concern. As a result, there is the search for new and novel sources of antimycobacterial drugs for example from medicinal plants. In this study we determined the in vitro antimycobacterial activity of n-Hexane sub-fraction from Bridelia micrantha (Berth) against MTB H37Ra and a clinical isolate resistant to all five first-line antituberculosis drugs. Methods The antimycobacterial activity of the n-Hexane sub-fraction of ethyl acetate fractions from acetone extracts of B. micrantha barks was evaluated using the resazurin microplate assay against two MTB isolates. Bioassay-guided fractionation of the ethyl acetate fraction was performed using 100% n-Hexane and Chloroform/Methanol (99:1) as solvents in order of increasing polarity by column chromatography and Resazurin microtiter plate assay for susceptibility tests. Results The n-Hexane fraction showed 20% inhibition of MTB H37Ra and almost 35% inhibition of an MTB isolate resistant to all first-line drugs at 10 μg/mL. GC/MS analysis of the fraction resulted in the identification of twenty-four constituents representing 60.5% of the fraction. Some of the 24 compounds detected included Benzene, 1.3-bis (3-phenoxyphenoxy (13.51%), 2-pinen-4-one (10.03%), N(b)-benzyl-14-(carboxymethyl) (6.35%) and the least detected compound was linalool (0.2%). Conclusions The results show that the n- Hexane fraction of B. micrantha has antimycobacterial activity.

Dichloromethane and/or ethanol extracts of 30 plants used as traditional medicines in Bukoba district, northwestern Tanzania were evaluated for brine shrimp toxicity. Among the 50 extracts tested, 32 extracts (64%) showed very low toxicity with LC50 values above 100 microg/ml. Among these 12 (24%) which had LC50 >500 microg/ml can be categorized as being practically non-toxic. Among the remaining extracts 19 (38%) which showed LC50 > 100 < 500 microg/ml are also considered to be non-toxic. Extracts that showed LC50 results between 30-100 microg/ml have been categorized as mildly toxic; these include ethanol extracts of Lantana trifolia (LC50 32.3 microg/ml), Vernonia bradycalyx (LC50 33.9 microg/ml), Antiaris toxicaria (LC50 38.2 microg/ml) and Rubus rigidus (LC50 41.7 microg/ml) and the dichloromethane extracts of Gynura scandens (LC50 36.5 microg/ml) and Bridelia micrantha (LC50 32.0 microg/ml). The dichloromethane extracts of Picralima nitida (LC50 18.3 microg/ml) and Rubus rigidus (LC50 19.8 microg/ml), were only moderately toxic. Picralima nitida and Rubus rigidus extracts are only 1.1 and 1.2 less toxic than the standard drug, cyclophosphamide (LC50 16.3 microg/ml). In conclusion, the results indicate that among the 30 plants used as traditional medicines, 28 are safe for short term use. Picralima nitida and Rubus rigidus extracts are mildly toxic, but by comparison have a remote possibility to yield active anticancer compounds.

The compounds friedelin, taraxerone, epifriedelinol, taraxerol, gallic acid and ellagic acid have been isolated from Bridelia micrantha. The presence of leucodelphinidin and caffeic acid was also indicated.