α-Glucosidase inhibitory pentacyclic triterpenes from the stem bark of Fagara tessmannii (Rutaceae)

Two pentacyclic triterpene acetates derivatives were isolated from Fagara tessmannii Engl. Compounds 1 and 3a showed significant inhibition of α-glucosidase. In addition to fatty acids, a mixture of sterols (β-sitosterol, stigmasterol, campesterol and stigmastanol), lupeol, arctigenin methylether, sesamin, vanillic acid ( 1), 2,6-dimethoxy-1,4-benzoquinone ( 2), betulinic acid and two pentacyclic triterpene acetates were isolated from Fagara tessmannii Engl. They were identified as 3β-acetoxy-16β-hydroxybetulinic acid ( 3a) and 3β,16β-diacetoxybetulinic acid ( 3b), and their structures were established using 1 and 2D NMR spectra and by comparison with published data. Two derivatives of the compounds were prepared. Some isolated compounds were evaluated for their antifungal and antibacterial activities. Compounds 1 and 3a showed significant inhibition of α-glucosidase.