Traditional Uses and Anticancer Potential of the Combretum Genus: A Literature Review

Background: Cancer incidence is increasing annually in all countries. So, it is nowadays a great burden for the different nations of the world. Research for new therapeutics is becoming an urgent need, particularly for intractable and chemoresistant cancer cases. The solutions can still be found by investigating natural products which are recognized as promising sources of bioactive compounds with a potential for the discovery of new preventive and therapeutic anticancer agents. Methodology: The present work used databases such as Pubmed, Science Direct and Google scholar to investigate the ethnobotanical uses of some Combretum species in the literature. It also allowed us to summarize some pharmacological studies on Combretum species. Results: This review gathers all available traditional uses and cytotoxicity studies of Combretum species in the literature. Special focus is given to pharmacological studies highlighting isolated potential anticancer molecules. These molecules present potent cytotoxic effect on various cancer cell lines and may contribute to improving the health of people suffering from various cancer diseases. Conclusion: The Combretum species are widely used in folk medicine for the treatment of several pathologies including cancers. This study is of fundamental importance in highlighting Combretum species as a potential source for research of new anticancer compounds.

Research on historical evolution of Combretum indicum / 药学实践杂志

Combretum indicum can kill insects and benefit the spleen and stomach, which is the most important medicine to treat children's diseases. The classics of materia medica, calendar edition of Chinese Pharmacopoeia, local processing standards and related literature were reviewed to sort out the processing history of Combretum indicum, compare the ancient medicinal parts and processing methods, and summarize the inclusion in national and local standards. The history of the evolution of Combretum indicum was summarized in order to provide ideas for rational drug use in clinical and standard improvement.

Optimization of the Extraction Technology of Total Flavonoids from Combretum alfrdii / 中国药房

OBJECTIVE： To establish the method for content determination of total flavonoids from Combretum alfrdii， and to optimize the extraction technology of total flavonoids from C. alfrdii. METHODS： Using aluminium trichloride as， chromogenic agent， UV spectrum was adopted to determine the content of total flavonoids from C. alfrdii. Based on single factor test， ethanol volume fraction， material-liquid ratio， extraction time， extraction temperature and times were selected as investigation factors， and the content of total flavonoids was selected as response value， Plackett-Burman design was used to screen the factors that had significant influence on the content of total flavonoidsfrom C. alfrdii. Then steepest climbing test was adopted to confirm the optimum valuing range； the extraction technology of total flavonoids was optimized by Box-Behnken response methodology. RESULTS： The linear range of total flavonoids were 0.012-0.036 mg/mL （r＝0.999 9）； RSDs of precision， stability and repeatability tests were less than 3％； the recovery ranged from 92.98％ to 99.86％ （RSD＝2.71％， n＝6）. The optimal extraction technology included that 60％ ethanol， material-liquid ratio of 1 ∶ 34 （g/mL）， extracting for 3 times， lasting for 60 min， extraction temperature of 80 ℃. Under this technology， average content of total flavonoids from C. alfrdii was 2.71％ （RSD＝1.69％， n＝6）， and the relative error was 2.65％ compared with predicted value of the model （2.64％）. CONCLUSIONS： Established method is stable and reproducible， and can be used for content determination of total flavonoids from C. alfrdii. The optimized extraction method is stable and feasible.

Antimalarial activities of butanol and ethylacetate fractions of Combretum nigricans leaf

Objective: To evaluate the antimalarial activity of the ethylacetate and butanol fractions of Combretum nigricans (C. nigricans) leaf extract in mice. Methods: C. nigricans solvent (butanol and ethylacetate) fractions were screened for their phytochemical constituents using standard procedures illustrated by Harborne and Evans. The Peters' 4-day suppressive test against early malaria infection, Rane's curative test against established malaria and prophylactic test for residual activity were employed for evaluating the antimalarial potential in mice. Results: The phytochemical screening revealed the presence of alkaloids, terpenoids, saponins, and flavonoids in both fractions at different intensity. Both fractions exhibited significant antimalarial activity in all test models (P<0.05). The ethylacetate fraction of C. nigricans had better chemosuppressive and curative effects compared to the butanol fraction, which however, elicited a better chemoprophylactic effect. The chemosuppressive effect of C. nigricans ethylacetate fraction (200-800 mg/kg) was 77.6%, 69.1% and 86.1%; curative effect was 62.3%, 71.3% and 72.4%; while the chemoprophylactic activity was 32.1%, 48.6% and 61.2% respectively. C. nigricans butanol fraction (200-800 mg/kg) had 40.3%, 54.1% and 69.1% chemosuppression; 26.2%, 36.9% and 34.5% curative effect; and 48.4%, 70.0% and 87.4% chemoprophylaxis. Conclusions: Both solvent fractions of C. nigricans possess antimalarial activity, and may be useful at different stages of malaria therapy.

Antimalarial activities of butanol and ethylacetate fractions of Combretum nigricans leaf

Objective: To evaluate the antimalarial activity of the ethylacetate and butanol fractions of Combretum nigricans (C. nigricans) leaf extract in mice.Methods: C. nigricans solvent (butanol and ethylacetate) fractions were screened for their phytochemical constituents using standard procedures illustrated by Harborne and Evans.The Peters' 4-day suppressive test against early malaria infection, Rane's curative test against established malaria and prophylactic test for residual activity were employed for evaluating the antimalarial potential in mice.Results: The phytochemical screening revealed the presence of alkaloids, terpenoids, saponins,and flavonoids in both fractions at different intensity. Both fractions exhibited significant antimalarial activity in all test models (P<0.05). The ethylacetate fraction of C. nigricans had better chemosuppressive and curative effects compared to the butanol fraction, which however,elicited a better chemoprophylactic effect. The chemosuppressive effect of C. nigricans ethylacetate fraction (200-800 mg/kg) was 77.6％, 69.1％ and 86.1％; curative effect was 62.3％, 71.3％ and 72.4％; while the chemoprophylactic activity was 32.1％, 48.6％ and 61.2％ respectively. C. nigricans butanol fraction (200-800 mg/kg) had 40.3％, 54.1％ and 69.1％ chemosuppression; 26.2％, 36.9％ and 34.5％ curative effect; and 48.4％, 70.0％ and 87.4％ chemoprophylaxis.Conclusions: Both solvent fractions of C. nigricans possess antimalarial activity, and may be useful at different stages of malaria therapy.

Anthelmintic effect of Cassia fistula and Combretum leprosum protein fractions against goat gastrointestinal nematodes / Efeito antihelmíntico das frações proteicas de Cassia fistula e Combretum leprosum contra nematodeos gastrintestinais de caprinos

Abstract In this study, we evaluated the ovicidal and larvicidal activity of protein preparations obtained from Cassia fistula L. and Combretum leprosum Mart. leaves on the gastrointestinal parasites of goats. Protein preparations were obtained after the extraction of C. fistula L. and C. leprosum Mart. leaves, followed by protein fractionation (with ammonium sulfate saturation percentages of 30%, 30%-60%, and 60%-90%) and dialysis, which resulted in protein fractions (called F1, F2, and F3, respectively). The fractions were evaluated by egg hatching (the eggs were recovered in stool samples from naturally infected goats) and larval development tests. The results reveled that the inhibition of hatching of eggs caused by the protein fractions of C. fistula (38%) were similar to that of the control drug, thiabendazole. In addition, the fractions of C. fistula caused significant inhibition (61-69%) of larval development also. However, C. leprosum did not reveal significant inhibition of egg hatching and larval development. We conclude that C. fistula L. showed better ovicidal and larvicidal activity against endoparasites.

Resumo Neste estudo, foram avaliadas as atividades ovicida e larvicida de preparações proteicas de Cassia fistula L. e Combretum leprosum Mart. em parasitas gastrointestinais de caprinos. As preparações proteicas foram obtidas por extração das folhas de C. fistula L. e C. leprosum Mart. seguido pelo fracionamento proteico (com porcentagens de saturação de sulfato de amônio de 30%, 30-60%, 60-90%) e diálise, resultando nas frações proteicas (intituladas F1, F2 e F3, respectivamente). As frações foram avaliadas nos testes de eclosão de ovos (os ovos foram recuperados em amostras de fezes de cabras naturalmente infectadas) e de desenvolvimento larvar. Os resultados revelaram que a inibição da eclosão de ovos causada pelas frações proteicas de C. fistula (38%) foi semelhante à do fármaco controle, o tiabendazol. Além disso, as frações de C. fistula também causaram inibição significativa (61-69%) do desenvolvimento larvar. No entanto, C. leprosum não revelou inibição significativa na eclosão dos ovos e no desenvolvimento larvar. Concluiu-se que C. fistula L. mostrou uma melhor atividade ovicida e larvicida contra endoparasitas.

Solvent–solvent fractionations of Combretum erythrophyllum (Burch.) leave extract: Studies of their antibacterial, antifungal, antioxidant and cytotoxicity potentials

Objective To evaluate the biological activities of Combretum erythrophyllum (C. erythrophyllum) leaf extracts against infectious diseases’ pathogenesis and their cytotoxicity potentials. Methods Powdered leaf material (300 g) of C. erythrophyllum was extracted (1:10 w/v) using acetone to obtain the crude extract. Liquid–liquid fractionation was performed on the crude acetone extract (30 g) using solvents of different polarity. The bioautographic method was used to detect the inhibition of bacterial and fungal growth by active compounds present in the crude and fractions. The extracts were then tested on bacterial strains: Staphylococcus aureus, Enterococcus faecalis, Escherichia coli, Pseudomonas aeruginosa; fungal strains: Candida albicans (C. albicans), Cryptococcus neoformans, and Aspergillus fumigatus, by microtitre dilution method for MIC determination. Results The extracts MIC values ranged between 0.08 and 2.50 mg/mL against the tested pathogens. Water fraction had the highest activity against bacteria strains, while the fungal assay revealed crude acetone extract and ethyl acetate fraction to be active against C. albicans (1.25 mg/mL), dichloromethane extract against C. albicans and A. fumigatus (0.16 mg/mL). Extract fractions showed a good antioxidant activity via DPPH, ABTS and hydroxyl radical scavenging assays, in the order: ethyl acetate > water > acetone > dichloromethane > hexane. The toxicity level of crude extract and fractions evaluated in Vero monkey kidney cells ranged from 34 to 223 μg/mL, while doxorubicin (IC

Solvent-solvent fractionations of Combretum erythrophyllum (Burch.) leave extract: Studies of their antibacterial, antifungal, antioxidant and cytotoxicity potentials

OBJECTIVE@#To evaluate the biological activities of Combretum erythrophyllum (C. erythrophyllum) leaf extracts against infectious diseases' pathogenesis and their cytotoxicity potentials.@*METHODS@#Powdered leaf material (300 g) of C. erythrophyllum was extracted (1:10 w/v) using acetone to obtain the crude extract. Liquid-liquid fractionation was performed on the crude acetone extract (30 g) using solvents of different polarity. The bioautographic method was used to detect the inhibition of bacterial and fungal growth by active compounds present in the crude and fractions. The extracts were then tested on bacterial strains: Staphylococcus aureus, Enterococcus faecalis, Escherichia coli, Pseudomonas aeruginosa; fungal strains: Candida albicans (C. albicans), Cryptococcus neoformans, and Aspergillus fumigatus, by microtitre dilution method for MIC determination.@*RESULTS@#The extracts MIC values ranged between 0.08 and 2.50 mg/mL against the tested pathogens. Water fraction had the highest activity against bacteria strains, while the fungal assay revealed crude acetone extract and ethyl acetate fraction to be active against C. albicans (1.25 mg/mL), dichloromethane extract against C. albicans and A. fumigatus (0.16 mg/mL). Extract fractions showed a good antioxidant activity via DPPH, ABTS and hydroxyl radical scavenging assays, in the order: ethyl acetate > water > acetone > dichloromethane > hexane. The toxicity level of crude extract and fractions evaluated in Vero monkey kidney cells ranged from 34 to 223 μg/mL, while doxorubicin (IC = 7.19 μg/mL) served as the positive control.@*CONCLUSIONS@#It can be concluded that the extracts of C. erythrophyllum are safe for medicinal use in folk medicine for treating infectious and stress related diseases.

Long-lasting endothelium-dependent relaxation of isolated arteries caused by an extract from the bark of Combretum leprosum / Extrato das cascas de Combretum leprosum causa relaxamento dependente de endotélio de longa duração em artérias isoladas

Objective To describe and to characterize the relaxing effect of an extract of the bark of Combretum leprosum on isolated arterial rings from different animals.Methods Rings (3 to 4mm) from rabbit, rat, or porcine arteries rings were suspended in an organ bath (Krebs, 37°C, 95%O2/5%CO2) to record isometric contractions. After the stabilization period (2 to 3 hours) contractions were induced by the addition of phenylephrine (0.1 to 0.3µM) or U46619 (10 to 100nM), and Combretum leprosum extract was added on the plateau of the contractions. Experiments were performed to determine the potency, duration, reversibility, and to get insights on the potential mechanism involved in extract-induced relaxations.Results In all rings tested, Combretumleprosum extract (1.5μg/mL) was able to cause relaxations, which were strictly endothelium-dependent. In rabbit or rat thoracic aorta rings, the relaxations were reversed by vitamin B12a or L-NG-nitroarginine. In porcine right coronary arteries and rabbit abdominal aorta, extract caused both L-NG-nitroarginine-sensitive and L-NG-nitroarginine-resistant relaxations. In rabbit thoracic aorta, the extract was relatively potent (EC50=0.20µg/mL) and caused relaxations; intriguingly the endothelium continued to produce relaxing factors for a long period after removing the extract. The magnitude of extract-induced relaxations was significantly reduced in the absence of extracellular Ca2+; in addition, the TRPs channels blocker ruthenium red (10µM) was able to revert extract-induced relaxations. Phytochemical analyses indicated that the extract was rich in polyphenol-like reacting substances.ConclusionsCombretum leprosum extract contains bioactive compounds capable of promoting Ca2+-dependent stimulation of endothelial cells which results in a prolonged production of relaxing factors.

Objetivo Descrever e caracterizar os relaxamentos induzidos por um extrato das cascas de Combretum leprosum em anéis de artérias de diferentes espécies de animais.Métodos Anéis (3 a 4mm) de artérias de coelho, rato e porco foram montados em cubas para órgão isolado (Krebs, 37°C, 95%O2/5%CO2) para registro das contrações isométricas. Após um período de estabilização (2 a 3 horas), as contrações foram induzidas com fenilefrina (0,1 a 0,3µM) ou U46619 (10 a 100nM); no platô dessas contrações, adicionamos o extrato Combretum leprosum. Diferentes protocolos foram realizados para determinar potência, duração, reversibilidade e mecanismo dos relaxamentos induzidos pelo extrato.Resultados Em todas as preparações testadas, o extrato de Combretum leprosum (1,5µg/mL) provocou relaxamentos dependentes de endotélio. Em aorta torácica de coelho ou rato, os relaxamentos foram revertidos pela vitamina B12a ou L-NG-nitro-arginina. Em anéis de aorta abdominal de coelho e de artérias coronárias de porco, o extrato causou relaxamentos sensíveis e resistentes à L-NG-nitro-arginina. Em aorta torácica de coelho, o extrato foi relativamente muito potente (EC50=0,20μg/mL) e quando causou relaxamentos; intrigantemente o endotélio continuou a produzir fatores relaxantes por um longo período após remoção do extrato. A magnitude dos relaxamentos induzidos pelo extrato foi significativamente reduzida em ausência Ca2+ extracelular; ademais, o vermelho de rutênio (10μM), um bloqueador de canais TRPs, foi capaz de reverter os relaxamentos induzidos pelo extrato. Análises preliminares indicaram que o extrato continha compostos com reatividade química semelhante à polifenóis.Conclusão O extrato de Combretum leprosum contem compostos bioativos capazes de promover estimulação dependente de Ca2+ das células endoteliais a qual resulta numa produção prolongada de fatores relaxantes.

Changes in the Oxidative Stress Biomarkers in Liver of Streptozotocin-diabetic Rats Treated with Combretum lanceolatum Flowers Extract.

Aims: The study investigated the in vivo antioxidant activity and the in vitro radical scavenging capacity of the Combretum lanceolatum Pohl (Combretaceae) flowers ethanolic extract (ClEtOH) in streptozotocin-diabetic rats. Place and Duration of Study: Department of Chemistry, Federal University of Mato Grosso, Cuiabá, Brazil; between February 2012 and December 2012. Methodology: Male Wistar rats were divided into four groups: Normal rats treated with water/vehicle (N); diabetic rats treated with water (DC); diabetic rats treated with 250 mg/kg (DT250) or with 500mg/kg (DT500) of ClEtOH. After 21 days of treatment, liver samples were used for the analysis of the oxidative stress biomarkers and activity of antioxidant enzymes. In vitro radical scavenger capacity was investigated by the following methods: DPPH radical scavenging, ABTS radical cation decolorization and crocin bleaching assays. Results: Significant oxidative stress was observed in liver of DC, since the malondialdehyde (MDA, biomarker of lipoperoxidation) levels were increased in comparison with N. Increased activities of the antioxidant enzymes superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) were also observed in DC, which could represent a compensatory mechanism against oxidative stress. Glutathione (GSH) levels were lower and similar between N and DC. The MDA levels were significantly decreased in liver of rats from DT250 and DT500, reaching levels similar those of N, suggesting that ClEtOH prevented lipoperoxidation. The treatment of diabetic rats with ClEtOH also increased the GSH levels, as well as increased the GSH-Px activity, and did not change the SOD activity. The results of in vitro radical scavenging capacity indicated that ClEtOH is highly active. Conclusion: These findings indicate that ClEtOH has antioxidant properties in liver of diabetic rats, decreasing lipoperoxidation and increasing the endogenous antioxidant responses. Both the antihyperglycemic effect and the capacity to scavenge free radicals may be related to the antioxidant activity of ClEtOH in diabetes.

Bioassay Guided Isolation and Evaluation of the Antidiabetic Principles of Combretum dolichopetalum Root.

Aims: The present study was aimed at investigating the antidiabetic potentials of Combretum dolichopetalum root in alloxan-induced animals with the hope of isolating its antidiabetic principles. Study Design: Sixty four Wistar albino rats of either sexes were randomly segregated into 16 groups (n=4). Also, thirty two albino mice were segregated into 8 groups. These received various doses of the plant sample, vehicle or glibenclamide for the antidiabetic study. Place and Duration of Study: This study was done in the laboratory of the Department of Pharmaceutical and Medicinal Chemistry, University of Nigeria, Nsukka between March and October, 2013. Methodology: The root of C. dolichopetalum was extracted with methanol (ME) and fractionated successively with various solvents (n-hexane, chloroform, ethylacetate, methanol and water) to afford the respective fractions: HF, CF, EF, MF and AF. CF was further fractionated to afford six sub-fractions: C1-C6. Acute toxicity study was done using ME. Antidiabetic activity of various doses (p.o.) of ME (100, 200, 400 and 600 mg/kg body weight), its fractions (200 and 400 mg/kg) and sub-fractions (200 mg/kg), glibenclamide (0.2 mg/kg) and vehicle (control) were investigated in alloxan-induced (i.p.) diabetic animals for 9 h. Phytochemical analysis was also carried on ME and fractions. Results: The extract was considered safe with LD50 greater than 5000 mg/kg. ME (400 mg/kg), CF (400 mg/kg) and C3 (200 mg/kg) produced maximum reduction (36.78%, 72.43% and 83.17% respectively) in fasting blood glucose of animals after 9 h which were significantly (P < .01, P < .001) different from the control and better than glibenclamide (48.18%). Phytochemical analysis showed alkaloids, flavonoids, terpens and steroids as the likely antidiabetic agent(s). Conclusion: The root of C. dolichopetalum possesses potent antidiabetic activity which increases as the extract is purified. The antidiabetic effect of the plant may likely be due to the presence of alkaloids, flavonoids, terpens or steroids.

Phytochemical study and antinociceptive effect of the hexanic extract of leaves from Combretum duarteanum and friedelin, a triterpene isolated from the hexanic extract, in orofacial nociceptive protocols

Combretum duarteanum Cambess, Combretaceae, is a plant widely distributed in Northeastern Brazil and, in folk medicine, stems and leaves are used for pain treatment. We investigated the antinociceptive effects of the hexanic extract of leaves from C. duarteanum and of friedelin, its main compound, in formalin-, glutamate- and capsaicin- induced orofacial nociception models. In order to isolate friedelin from the hexanic extract, flash chromatography technique was used. Male mice (n = 8/group) were pretreated with hexanic extract, friedelin, morphine or vehicle, before the injection of algogen agents into the right upper lip (perinasal area). The test of formalin-induced orofacial nociception showed that hexanic extract and friedelin significantly reduced nociception (p < 0.001) in both phases of testing. In the glutamate and capsaicin-induced orofacial nociception tests, pre-treatment with hexanic extract produced a significant reduction of orofacial nociception (p < 0.001) at all doses tested.The results suggest the hexanic extract and friedelin possess antinociceptive effects in models of orofacial nociception in rodents.

Combretum lanceolatum flowers extract shows antidiabetic activity through activation of AMPK by quercetin

The present study evaluated the antidiabetic activity of the Combretum lanceolatum Pohl ex Eichler, Combretaceae, flowers extract (ClEtOH) in diabetic rats. Streptozotocin-diabetic rats were divided into four groups: diabetic control, diabetic treated with 500 mg/kg of metformin and diabetic treated with 250 or 500 mg/kg of ClEtOH for 21 days. The treatment of diabetic rats with 500 mg/kg of ClEtOH promoted an increase in the weight of liver, white adipose tissues and skeletal muscles, improving body weight gain. Diabetic rats treated with 500 mg/kg of ClEtOH also presented reduction in glycemia, glycosuria and urinary urea levels, and increase in liver glycogen content. HPLC chromatogram showed that quercetin is the major compound in the extract. The phosphorylation levels of adenosine monophosphate-activated protein kinase were increased in liver slices incubated in vitro with 50 µg/mL of ClEtOH, similarly to the incubation with metformin (50 µg/mL) or quercetin (10 µg/mL). The antihyperglycemic effect of ClEtOH was similar to that of metformin and appears to be through inhibition of gluconeogenesis, since urinary urea was reduced and skeletal muscle mass was increased. These data indicate that the antidiabetic activity of the Combretum lanceolatum extract could be mediated, at least in part, through activation of adenosine monophosphateactivated protein kinase by quercetin.

Physico-Technical Properties of Tablets Formulated with Ethanolic Extract of Fresh Leaves of Combretum Micranthum G. Don.

This study is a follow-up to our recent study published elsewhere. It is aimed at determining the physico – technical and antibacterial profiles of tablets formulated using ethanolic extracts of Combretum micranthum, and also determine if they meet pharmacopoeial specifications. The fresh leaves of Combretum micranthum were harvested during the rainy season in Akwa Ibom State, Nigeria. They were thoroughly washed and rinsed with distilled water, divided into three portions, and dried in hot air oven at 48 ºC (Sample A), sun (Sample B) and at room temperature (Sample C). They were pulverized, macerated in a transparent extraction tank using 70 % ethanol for 72 h at room temperature, and concentrated. The activity of each extract was tested on typed cultures of Staphylococcus aureus (ATCC 6538) and Escherichia coli (ATCC 25922). The extract with the highest activity (Sample B) was selected for further studies. Phytochemical screening was carried out using standard methods. Six batches of granulations for tablets were produced using a predetermined formula. The flow rate, angle of repose, and compressibility indices of the granules were determined, and uniformity of weight, hardness, friability and disintegration time of the tablets were determined using pharmacopoeial methods. The results show that the sun-dried leaves of C. micranthum have constituents that exhibited the highest activity against cultures of S. aureus and E. coli. The phytochemical screening on the sun-dried leaves extract revealed that tannins were present in large quantities while phlobatannins and anthraquinones were absent. The results of the flow and compressibility properties of the granules from sun-dried extract revealed generally poor flow and high compressibility for all the batches. The tablet hardness values for all the batches were greater than 5 kg. The friability value for each batch was less than 1 %. The tablets have maximum disintegration time of 101 min. These results showed that the extract could be used to produce sustained release or delayed release tablets.

Antibacterial profile of extracts of Combretum micranthum G. Don against resistant and sensitive nosocomial isolates.

Combretum micranthun G. Don (Combretaceae) is reputed in folk medicine for its anti-infective properties. In this study, we screened aqueous and methanol extracts of Combretum micranthun for antibacterial activities against nosocomial bacterial isolates. The methanolic and aqueous extracts of the leaves, root-bark and stem-bark were screened against the 25 different nosocomial isolates each of Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, Pseudomonas aeruginosa, Enterococcus faecalis, Streptococcus pyogenes and Streptococcus pneumoniae isolated from patients presenting with various ailment at the University of Nigeria Teaching Hospital, Enugu using the agar well diffusion technique. The extracts of Combretum micranthun exhibited antimicrobial activities against both Gram-negative and the Gram-positive isolates including Pseudomonas aeruginosa and Staphylococcus aureaus. Generally, Pseudomonas aeruginosa and Streptococus pyogenes showed the highest level of susceptibility to the extracts of Combretum micranthun. The hot aqueous, the methanol and the cold aqueous extracts were more effective than other extracts in inhibiting all the isolates tested. The extracts of the plant C. micranthum G. Don showed high antimicrobial effectiveness against the different 200 clinical isolates of both Gram positive and Gram negative isolates screened and could therefore be harnessed as a potent antibacterial agents or could possibly provide leads for the synthesis of novel anti-infective agents.

Aqueous Extract of Combretum dolichopentalum Leaf - a Potent Inhibitor of Carbon Tetrachloride Induced Hepatotoxicity in Rats.

The aqueous extract of Combretum dolichopentalum leaves were evaluated for its protective activity against CCl4- induced liver damage. The concentration of 250 and 500 mg/kg b.w of C. dolichopentalum leaf extract were administered to different group of rats prior to CCl4 administration. Both 250 and 500 mg/kg of the extract significantly (P<0.05) reduced the activity of alanine aminotransferase, aspartate aminotransferase and alkaline phosphatase when compared to rats administered CCl4 only. Also the concentration of non-enzyme markers of hepatic dysfunction such as total bilirubin and lipid peroxidation product-malonyldialdehyde was reduced by C. dolichopentalum. But the concentration of total protein and total cholesterol was increased when compared to rats administered CCl4 only. This finding suggests that C. dolichopentalum leaves possessed rich hepatoprotective principles against CCl4 induced toxicity of the liver.

Inhibitory and Bactericidal Potential of Crude Acetone Extracts of Combretum molle (Combretaceae) on Drug-resistant Strains of Helicobacter pylori.

Infection with Helicobacter pylori is strongly associated with a number of gastroduodenal pathologies. Antimicrobial resistance to commonly-used drugs has generated a considerable interest in the search for novel therapeutic compounds from medicinal plants. As an ongoing effort of this search, the susceptibility of 32 clinical strains of H. pylori and a reference strain—NCTC 11638—was evaluated against five solvent extracts of Combretum molle, a plant widely used for the treatment of gastric ulcers and other stomach-related morbidities in South Africa. The extracts were screened for activity by the agar-well diffusion method, and the most active one of them was tested against the same strains by micro-broth dilution and time kill assays. Metronidazole and amoxicillin were included in these experiments as positive control antibiotics. The solvent extracts all demonstrated anti-H. pylori activity with zone diameters of inhibition between 0 and 38 mm. The most potent anti-H. pylori activity was demonstrated by the acetone extract, to which 87.5% of the clinical strains were susceptible. The minimum inhibitory concentration (MIC90) values for this extract ranged from 1.25 to 5.0 mg/mL while those for amoxicillin and metronidazole ranged from 0.001 to 0.94 mg/mL and from 0.004 to 5.0 mg/mL respectively. The acetone extract was highly bactericidal at a concentration of 2.5 and 5.0 mg/mL, with complete elimination of the test organisms in 24 hours. Its inhibitory activity was better than that of metronidazole (p<0.05) as opposed to amoxicillin (p<0.05). The results demonstrate that C. molle may contain therapeutically-useful compounds against H. pylori, which are mostly concentrated in the acetone extract.

Antinociceptive effect on mice of the hydroalcoholic fraction and (-) epicatechin obtained from Combretum leprosum Mart & Eich

Previous studies on Combretum leprosum, a tree growing in the Northeastern states of Brazil, have shown antinociceptive effects of the ethanol extract of its leaves and bark, but studies examining its constituents are rare. The objective of this study was to evaluate the antinociceptive effect of the hydroalcoholic fraction (HF) of one of its constituents, the flavonoid (-) epicatechin (EPI), administered orally to mice (20-30 g) in models of chemical nociception, and the possible mechanisms involved. Different doses of HF (62.5 to 500 mg/kg) and EPI (12.5 to 50 mg/kg) were evaluated in models of abdominal writhing, glutamate, capsaicin, and formalin in animals pretreated with different antagonists: naloxone, ondansetron, yohimbine, ketanserin, pindolol, atropine, and caffeine in the abdominal writhing test. To determine the role of nitric oxide, the animals were pretreated with L-arginine (600 mg/kg, ip) in the glutamate test. The HF was effective (P < 0.05) in all protocols at different doses and EPI was effective in the abdominal writhing, capsaicin and glutamate tests (P < 0.05) at doses of 25 and 50 mg/kg. However, in the formalin test it was only effective in the second phase at a dose of 25 mg/kg. The antinociceptive effect of HF was inhibited when HF was associated with yohimbine (0.15 mg/kg), ketanserine (0.03 mg/kg), and L-arginine (600 mg/kg), but not with the other antagonists. HF and EPI were effective in models of chemical nociception, with the suggested participation of the adrenergic, serotonergic and nitrergic systems in the antinociceptive effect of HF.