Choudhury M. Hasan

Antimicrobial and cytotoxic constituents from leaves of Sapium baccatum

Six compounds, namely, Lupeol (1), Betulin (2), beta-Taraxerol (3), Taraxerone (4), Stigmasterol (5) and beta-Sitosterol (6) were isolated from the petroleum ether extract of the leaves of Sapium baccatum based on spectroscopic evidence. Lupeol (1), Betulin (2) and Stigmasterol (5) were isolated for the first time from this plant. The cytotoxic potential of the different solvent extracts (methanol, petroleum ether, carbon-tetrachloride and dichloromethane); six column fractions (F-4, F-7, F-10, F-12, F-18 and F-22) of petroleum ether extract and three pure compounds 1, 4 and 6 were determined by using brine shrimp lethality bioassay. The LC50 of all the tested samples were showed to be lethal to brine shrimp nauplii. However, petroleum ether, carbon-tetrachloride extract, column fractions F-4 and F-18 of petroleum ether extract and pure compound 6 showed quite potent activity in brine shrimp lethality bioassay with LC50 1.33, 1.35, 1.40, 1.58 and 1.58 microg/ml, respectively. These result suggested that they might be contain antitumor or pesticidal activity. Further, the methanol extract and four column fractions (F-7, F-12, F-18 and F-22) of petroleum ether showed significant activity against the tested microorganisms.

Antimicrobial activity of Toona ciliata and Amoora rohituka

The extracts of two Bangladeshi medicinal plants, Toona ciliata (stem bark) and Amoora rohituka (stem bark), along with siderin, a major coumarin from T. ciliata, exhibited significant in vitro antibacterial activity. The extracts also demonstrated mild antifungal effect.

A novel antibacterial and cardiac steroid from the roots of Nerium oleander

Abstract The roots of Nerium oleander yielded a new cardenolide, 12β-hydroxy-5β-carda-8,14,16,20(22)-tetraenolide (2). Biological screening of the compound revealed antibacterial and digoxin-like cardiac activities.

Gageotetrins A-C, noncytotoxic antimicrobial linear lipopeptides from a marine bacterium Bacillus subtilis.

Gageotetrins A-C (1-3), a unique class of linear lipopeptides, consisting of di- and tetrapeptides and a new fatty acid were isolated from a Marine Bacillus subtilis. The structures of 1-3 were assigned by spectroscopic data and their absolute stereochemistries were ascertained by chemical derivatization. Compounds 1-3 displayed good antimicrobial activities with MIC values of 0.01-0.06 μM. However, these compounds failed to register any cytotoxicity (GI50 > 30 μg/ml) against human cancer cell lines.

Antibacterial activity of Barringtonia racemosa

The antibacterial activity of the ethanol extract of Barringtonia racemosa roots, its chloroform soluble fraction and, a there from an isolated clerodane diterpenoid is reported.

Antitumor activity of epifriedelanol from Vitis trifolia.

The isolation and NMR spectral data of epifriedelanol from Vitis trifolia are reported. It demonstrated antitumor activity in a potato disc bioassay.

Pharmacological Evaluation of Bangladeshi Medicinal Plants — a Review

The results of pharmacological studies on 64 medicinal plants of Bangladesh have been reviewed. The results encountered in various investigations reveal important pharmacological activities of the plants which may be used as leads in developing novel therapeutic agents.

Capsugenin, a dammarane triterpene from Corchorus capsularis

Abstract From the leaves of Corchorus capsularis a new dammarane triterpene glycoside, capsin, has been isolated. Capsin was identified as the 3-glucoside of 20,24-epoxy-3β,12β,25,30-tetrahydroxydammarane from spectral data. Capsin was tentatively assigned the (20 S , 24 S )-configuration by comparison with data available for similar compounds. One of the oxidation products of the aglycone appears to be a friedo-type derivative, formed by concerted methyl migration on decarboxylation of a C-30 carboxylic acid intermediate.

Bismurrayafoline E: a new dimeric carbazole alkaloid from Murraya koenigii

The ethanolic extract of the leaves of M. koenigii afforded a new carbazole alkaloid, which was identified as bismurrayafoline E (1) on the basis of spectroscopic analysis.

Constituents and cytotoxicity of Zanthoxylum rhesta stem bark

3,5-Dimethoxy-4-geranyloxycinnamyl alcohol (1), 8-methoxy-N-methylflindersine (2), xanthyletin and sesamin have been isolated from petroleum ether extract of the stem bark of Zanthoxylum rhesta. The petroleum ether extract and 8-methoxy-N-methylflindersine showed cytotoxicity on brine shrimp nauplii.