Two new xanthones, characterized as 4-(1,1-dimethylprop-2-enyl)-1,3,5,8-tetrahydroxyxanthone (1) and penangianaxanthone (2), with three known xanthones, cudratricusxanthone H (3), macluraxanthone C (4) and gerontoxanthone C (5), as well as friedelin and stigmasterol were isolated from the leaves of Garcinia penangiana. Their structures were elucidated by analysis of spectroscopic data and compa...

Lipídeos inéditos foram isolados de matéria insaponificável extraída de sementes de Nigella sativa Linn, usando-se n-hexano. O dienoato e os dois monoésteres inéditos foram identificados por técnicas espectrométricas, incluindo IV, RMN de H e C, espectrometria de massas, e análise química. O dienoato (1) foi identificado como metilnonadeca-15, 17-dienoato e os dois monoésteres foram identificad...

Phytochemical investigations of chloroform and ethyl acetate extracts from the aerial parts of Warionia saharae Benth. & Coss. from Algeria resulted in the isolation of ten known compounds: β-sitosterol, stigmasterol, scopoletin, cirsimaritin, chrysoeriol, hispidulin, luteolin, esculetin, (2R,3R) taxifolin, quercetin. Their structures were elucidated on the basis of extensive spectroscopic anal...

Schleichera oleosa (Lour.) Oken. is a medicinal plant of Bangladesh with enormous traditional applications in folk medicine. The current study was designed to isolate the secondary metabolites by successive chromatographic separation n-hexane and dichloromethane soluble fractions methanol extract leaves S. oleosa. A total four compounds were separated identified as 5,7-dihydroxy-4'-methoxyflavo...

Phytosterols are steroid compounds structurally similar with cholesterol and vary in the nature of carbon side chain. β-Sitosterol is commercially available in preparative amount only as mixtures with other phytosterols. New semipreparative synthesis of pure β-sitosterol and sidechain-modified phytosterols is discussed in this dissertation. This new synthesis is achieved via a temporary masking...

This study investigated bioactive extracts of Polyalthia debilis (Annonaceae) with antimicrobial, antimalarial and cytotoxic activities. Extensive chromatographic isolations provided azafluorenone alkaloids; onychine (1) and 7-methoxyonychine (2) together with a mixture of beta-sitosterol and stigmasterol. The two alkaloids were isolated from the P. debilis for the first time. Isolated fraction...

The new diterpene methoxy-ent-8(14)-pimarenely-15-one (1) and three known metabolites: ent-8(14)-pimarene-15R,16-diol (2), stigmasterol (3) and beta-sitosterol (4), were isolated from the roots of the mangrove plant Ceriops tagal. Their structures and relative stereochemistry were elucidated by means of extensive NMR, IR and MS analysis. Compounds 1, 2, 3 and 4 exhibited significant antifouling...

The study of the chemical constituents of the whole plant of Geranium wallichianum (Geraniaceae) has resulted in the isolation and characterization of six compounds. These six compounds were identified as ursolic acid (1), β-sitosterol (2), stigmasterol (3), β-sitosterol galactoside (4), herniarin (5), and 2,4,6-trihydroxyethylbenzoate (6) which were isolated for the first time from Geranium wa...