Antidiabetic potential of methanol extracts from leaves of Piper umbellatum L. and Persea americana Mill

Objective: To determine inhibitory activity of methanolic leaf extract of Piper umbellatum and Persea americana (P. americana) (traditionally used in Cameroon against diabetes) on α-glucosidase, β-glucosidase, maltase-glucoamylase, aldose reductase and aldehyde reductase activities, enzymes involved in starch digestion or diabetic complications. Methods: The methanol extracts from Piper umbellatum and P. americana were prepared by maceration. To assess relative efficacy of these extracts, the determination of concentrations that were needed to inhibit 50% of enzyme activity was done, whereas, gas chromatography-mass spectrum was used to identify components from extracts that may be responsible for the activities. Results: The tested extracts strongly inhibited α-glucosidase, maltase-glucoamylase, aldose reductase and aldehyde reductase activities with IC

Antidiarrhoeal and antibacterial activity of aqueous and methanolic leaves extracts of Dissotis thollonii Cogn. (Melastomataceae)

Objective: To investigate the phytochemical test and selected pharmacological activities (antidiarrhoeal and antibacterial activity) of the aqueous and methanolic leaves extracts of Dissotis thollonii Cogn. (Melastomataceae) (D. thollonii). Methods:The aqueous and methanolic extracts were evaluated for their antibacterial activities on the in vitro growth of 2 clinical isolates (Staphylococcus aureus and Shigella flexneri), and 5 reference bacteria strains [Escherichia coli ATCC 8739 (E. coli), E. coli ATCC 10536, Salmonella typhi ATCC 6539, Enterobacter aerogenes ATCC 13048 and E. coli ATCC 11775] by determining the minimum inhibitory concentrations (MICs) and bactericidal concentrations using broth microdilution method as well as on the infectious, secretory and osmotic induced diarrhoea models in rats. Results:The aqueous extract inhibited the in vitro growth of all bacteria tested (the 05 reference bacteria strains and the 02 clinical isolates), with MICs values comprised between 32 and 512 μg/mL, whereas the methanolic extract has done the same with the MICs values located between 128 and 512 μg/mL. In vivo, the methanolic and aqueous extracts provoqued at all doses, a significant decrease (P Conclusions:The leaves of D. thollonii thus have antibacterial and antidiarrhoeal effects, which could result from their activities on blocking the inhibiting effects of the bacterial enzymes, inhibiting the bacterial protein synthesis, allowing the rupture of the lipopolysaccharidic membrane, as well as on inhibiting prostaglandins-E2 synthesis or increasing the hydroelectrolytic reabsorption. These results attestted the ethnopharmacological use of D. thollonii leaves in the treatment of diarrhoea and gastro-intestinal infections.

Antidermatophytic and toxicological evaluations of dichloromethane-methanol extract, fractions and compounds isolated from Coula edulis

Coula edulis Bail [Olacaceae], is an evergreen tree growing to a height of 25-38 m. This study aimed at evaluating the antidermatophytic and toxicological properties of the stem bark of C. edulis extract as well as fractions and compounds isolated from it. The plant extract was prepared by maceration in CH[2]Cl[2]-MeOH [1:1 v/v]. The fractionation of this extract was done by silica gel column chromatography. Antidermatophytic activities were assayed using agar dilution method. The acute and sub-acute toxicities of oral administrations of the extract were studied in rodents. The crude extract of C. edulis displayed antidermatophytic activity against the tested microorganisms with highest activity against Microsporum audouinii and Trichophyton mentagrophytes. The fractionation enhanced the antidermatophytic activity in fraction F[3] [MIC=0.62-1.25 mg/ml] compared to the crude extract [MIC=1.25-5 mg/ml]. Further fractionation and purification of the fractions F[2] and F[3] gave respectively 3-O- beta -D-glucopyranoside of sitosterol [MIC=0.20-0.40 mg/ml] and a mixture of beta -sitosterol, stigmasterol and n-hexadecanoid acid [MIC=0.80 mg/ml]. The median lethal doses [LD[50]] of the crude extract were 16.8 and 19.6 g/kg body weight [BW] in male and female mice, respectively. At 200 mg/kg BW, there was a decrease in body weight gain, food and water consumptions. Gross anatomical analysis revealed white vesicles on the liver of the rats treated with the extract at 200 mg/kg BW. This dose also induced significant [P<0.05] changes on hematological and biochemical parameters in rats after 28 days of treatment. These data suggest that the CH[2]Cl[2]-MeOH [1:1 v/v] extract of C. edulis stem bark possesses antidermatophytic properties. They also show that at high doses [>/= 200 mg/kg BW], the extract has significant hepatotoxic and nephrotoxic activities

antimicrobial activities of extract and compounds isolated from Brillantaisia lamium

Brillantaisia lamium is an erect branched herb, which grows to a height of 1.50 m in moist tropical areas, both in full sun and partial shade. In Cameroon, the aerial part of this plant is used in the treatment of various microbial infections such as skin diseases and infections of urinary tract. The aim of this study was to evaluate the antimicrobial activities of CH[2]Cl[2]: MeOH [1:1] extract, fractions and compounds from the aerial part of B. lamium. The plant was dried and extracted by maceration in CH[2]Cl[2]: MeOH [1:1 v/v]. Structures of the compounds from the CH[2]Cl[2]: MeOH [1:1] soluble fraction were determined by spectroscopic methods and compared with published data. The broth micro dilution method was used to evaluate the antimicrobial activities against bacteria and fungal species. Four known compounds: aurantiamide acetate [1], lupeol [2], lespedin [3], sitosterol 3-O-beta-D-glucopyranoside [4] and a mixture of sterols: campesterol [5], stigmasterol [6] and beta-sitosterol [7] were isolated from CH[2]Cl[2]: MeOH [1:1] extract of B. lamium aerial parts. The crude extract, fractions and isolated compounds exhibited both antibacterial and anti-fungal activities that varied with microorganism [MIC=6.25 - 1000 micro g/ml]. Compound 3 was the most active [MIC=6.25 - 100 micro g/ml] while Staphylococcus aureus, Enterococcus faecalis, Candida tropicalis and Cryptococcus neoformans were the most sensitive to all the tested compounds. The overall results of this study indicate that the CH[2]Cl[2]: MeOH [1:1] extract and some of isolated compounds have interesting antimicrobial properties and can be used for the treatment of fungal and bacterial infections