The efficacy of the crude root bark extracts of Erythrina abyssinica on rifampicin resistant Mycobacterium tuberculosis.

Introduction: Tuberculosis (TB) is one of the leading causes of morbidity and mortality with a global mortality rate at two million deaths per year while one third of the world's population is infected with the TB bacillus.

Objective: To determine the efficacy of the crude extracts of Erythrina abyssinica root bark on rifampicin-resistant TB.

Methods: Crude extracts of root bark of Erythrina abyssinica, were screened against three strains of Mycobacterium tuberculosis including rifampicin-resistant TMC-331.

Methanolic extracts of Aloe secundiflora Engl. inhibits in vitro growth of tuberculosis and diarrhea-causing bacteria.

Background: The emergence of resistance to antimicrobials by pathogens has reached crisis levels, calling for identification of alternative means to combat diseases.

Objective: To determine antimicrobial activity of crude methanolic extract of Aloe secundiflora Engl. from Lake Victoria region of Kenya.

Brine shrimp toxicity of some plants used as traditional medicines in Kagera Region, north western Tanzania.

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.

Bioactive isoflavones from Dalbergia vacciniifolia (Fabaceae).

Three new 5-dehydroxy isoflavone compounds, 6,2'-dimethoxy-7,4'-dihydroxyisoflavone (1), 6,2',4'-trimethoxy-7-hydroxyisoflavone (2), and 6,2',4',5'-tetramethoxy-7-O-[beta-D-apiofuranosyl-(1 --> 6)-beta-D-glucopyranoside] isoflavone (3), along with a known isoflavone, 6,2',4',5'-tetramethoxy-7-hydroxyisoflavone (4), were isolated from the ethanolic extract of Dalbergia vacciniifolia Vatke. Their structures were established by spectroscopic techniques including one- and two-dimension NMR. Compound 1 showed mild cytotoxic activity against brine shrimp larvae with a LC50 value of 266 microg/mL.

A bioactive isoprenylated xanthone and other constituents of Garcinia edulis.

Phytochemical investigation on the root bark of Garcinia edulis (Clusiaceae) gave a new isoprenylated xanthone, 1,4,6-trihydroxy-3-methoxy-2-(3-methyl-2-butenyl)-5-(1,1-dimethyl-prop-2-enyl)xanthone (1), a known xanthone, forbexanthone (2) together with three known pentacyclic triterpenoids, friedelin, lupeol and lupeol acetate. The structure of the new compound was fully characterised by NMR spectroscopic analysis. Compound 1 showed significant anti-HIV-1 protease activity with IC(50) value of 11.