Chemical constituents of erythrina fusca and erythrina suberosa stem bark and their biological activities

Abstract

Phytochemical study of the stem bark of Erythrina fusca Lour. led to the isolation of a new pterocarpan, 3-hydroxy-10-(3-hydroxy-3-methylbutyl)-9-methoxypterocarpan, together with 11 known compounds: sandwicensin, lupinifolin, citflavanone, lonchocarpol A, erythrisene galone, liquiritigenin, daidzein, 8-prenyldaidzein, cerinic acid, 1-octacosanol and erythrinassinate B. Phytochemical study of the stem bark of E. suberosa Roxb. yielded 6 known compounds, erythrabyssin II, sandwicensin, erythrinassinate B, 5,7,4'-trihydroxy-8,3',5'-triprenylflavanone, erythratidinone, and a mixtures of beta-sitosterol and stigmasterol. The structures of all these isolates were determined by extensive spectroscopic studies, including comparison of their UV, IR, MS and NMR properties with previously reported data. Some of these compounds were evaluated for its antimalarial activity, antimicrobial activity, free radical scavenging activity, antituberculosis activity and cytotoxic activity against cancer cell. All of the tested compounds showed weak antimicrobial activity except lonchocarpol A and lupinifolin which were strongly active against Bacillus subtilis and moderate active against Enterococcus faecalis and Staphylococcus aureus. Lonchocarpol A showed the highest in vitro antimalarial activity against K1 strain (EC[subscript 50] 1.6 microgram/ml), when compared with 8-prenyldaizein, erythrabyssin II and citflavanone (EC[subscript 50] 3.9, 5.0 and 5.0 microgram/ml, respectively). However, lonchocarpol A exhibited no in vivo antimalarial activity (at 20 mg/kg). In addition, all of tested compounds showed marginal free radical scavenging activity. Almost all of the tested compounds showed weak antituberculosis activity against H37Ra strain, whilst erythrisenegalone and lupinifolin displayed strong cytotoxic activity against breast cancer (BC) cell line