Anti-HIV-1 protease activities of crude extracts of some Garcinia species growing in Tanzania

Eighteenth ethanol extracts from some Garcinia species in the Guttiferae (Clusiaceae) family collected in Tanzania were investigated for their HIV-1 protease (HIV-1 PR) inhibitory activities using high performance liquid chromatography (HPLC). Among the tested extracts, the fruit hulls of Garciniasemseii showed the most potent inhibitory activity against HIV-1 PR with an IC50 value of 5.7 ìg/ml followed by the stem bark extracts of Garcinia edulis and Garcinia kingaensis with IC50 values of 9.2 and 15.2 ìg/ml, respectively. Phytochemical screening of extracts indicated mostly the presence of phenolicand steroidal compounds

In vitro antioxidant and anti-HIV-1 protease (PR) activities of two Clusiaceae plants endemic to Tanzania

In this study, the ethanol extracts from Allanblackia ulugurensis Engl. and Mammea usambarensis Verdc. were evaluated for their antioxidant and anti-HIV PR activities. Among the tested extracts, the stem bark extract of M. usambarensis showed the highest DPPH activity value of 6,165 ± 152 ìmol TE/g, which is more than twice as higher as that of the standard (Chlorogenic acid, 3,056 ± 157 ìmol TE/g). Furthermore, in the Oxygen Radical Absorbance Capacity (ORAC) assay, the crude extracts of the stem bark of M. usambarensis and root bark of A. ulugurensis showed significant activity at 12,282 ± 413 and 10,342 ± 562 ìmol TE/g respectively with standard compound (Chlorogenic acid) showing ORAC activity at 11,077 ± 236 ìmol TE/g. For anti-HIV-1 PR assay from the same extracts, the root bark and stem bark of A. ulugurensis showed strong inhibitory activities against HIV-1 protease with IC50 values of 4.1 and 5.6 ìg/ml, respectively while that of the standard, Acetyl pepstatin, was at 2.2 ìg/ml. This study has shown the potential of the Clusiaceae extracts as the source of possible lead compounds for antioxidants and anti-HIV drugs. Phytochemical screening indicated the presence of phenolic compounds while isolation of active principles from active fractions is inevitable

Brine shrimp lethality of a glutarimide alkaloid from Croton sylvaticus Hochst

No Abstract.The East and Central African Journal of Pharmaceutical Sciences Vol. 8(1) 2005: 3-

Variations of anti-mosquito larvicidal constituents in the Harrisonia abyssinica species of Tanzania

Harrisonia abyssinica (Simaroubaceae) is widely distributed and used in traditional medicine in Tanzania. Phytochemical studies of the plant report the presence of steroid and limonoid compounds while much of its biological studies were concentrated on its pharmacological activity on human pathogens. In the present study, eight extracts from plant materials collected from the Moist forest mosaic (Zone I) and the Coastal forest and thicket zone (Zone II) were tested against Culex quinquefascintus Say larvae. Detailed analysis of mosquito larvicidal activity of the eight extracts showed a dose dependent (p>0.05) trend with the dichloromethane and ethanol extracts of the root bark plant materials collected from Zone I having higher effectiveness. In 24 h, the dichloromethane and ethanol extracts of the root bark from Zone I achieved mortality of 90% and 100%, respectively, at 50 ppm. Likewise, at 5 ppm the two extracts were having 60% and 58% mortality, both been not significant different (p>0.05) but significantly different (

Brine Shrimp Lethality of Alkaloids from Croton sylvaticus Hoechst

Three compounds were isolated from the leaves of Croton sylvaticus (Euphorbiaceae) and evaluated for their brine shrimp lethality. Julocrotine, a glutarimide alkaloid, was very toxic in vitro with a LC50 (95% confidence interval) value of 0.074 (0.052-0.105) μg/ml. Lupeol and penduliflaworosin were not toxic. The structures of the isolated compounds were determined by spectroscopic methods.Keywords: Croton sylvaticus, Euphorbiaceae, julocrotine, lupeol, penduliflaworosin, brine shrimp lethalityEast and Central African Journal of Pharmaceutical SciencesVol. 15 (2012) 35-3