Bioactive constituents of the stem bark of Bersama abyssinica Fresen subsp. abyssinica Verdc. (Melianthaceae)

A new xanthone glycoside (1) and a new bufadienolide (2) named bersamaxanthoside and bersamabufadienolide, respectively, together with seventeen known compounds (3-19) were isolated from the stem bark of Bersama abyssinica Fresen subsp. abyssinica Verdc. Their structures were elucidated based on their spectroscopic data. The extract, fractions and compounds were assessed for their cytotoxicity on the cervix carcinoma cell line KB-3-1. The MeOH extract and the EtOAc and n-BuOH soluble fractions exhibited weak activity with IC50 values of 0.085, 0.084 and 0.075 mg/mL, respectively. The other tested samples were inactive. In addition, some of the isolates were tested for their DPPH radical scavenging activity and only compounds 1, 11-13, 16, and 17 displayed antioxidant properties with IC50 values ranging from 2.9 to 38.1 mu g/mL.