A new limonoid, digsecokigelianolide, among the secondary metabolites from kigelia africana (lam.) benth. and evaluation of their antibacterial and antioxidant activity

The present work investigates the phytochemical study and the antibacterial and antioxidant activities of Kigelia africana (Lam.) Benth. Column chromatography separation on silica gel of fractions led to the isolation of a new limonoid derivative named digsecokigelianolide (1), as well as nine known compounds (2-10). The structures of the isolated compounds were determined by comprehensive spectroscopic analysis, including 1 & 2D NMR, IR, UV, mass spectrometry and comparison with previous reported data. Compound 1 showed moderate antiradical activity (IC50 = 181.12 µg/mL) against ABST•+ radical compared to BHT (159.48 µg/mL) used as standard, and a good antibacterial activity against Salmonella typhi (MIC: 22.0 mm), Escherichia coli (MIC: 15.0 mm) and Pseudomonas aeruginosa (MIC: 20 mm) at the concentration of 25 mg/mL. Compound 9 and 10 showed good antiradical (which ranges from 56.39 to 61.16% of inhibition) and antibacterial (which ranges from 12 to 20 mm of inhibition zone) activities.