Alkaloids from aerial parts of Annona senegalensis against Streptococcus mutans

Antimicrobial potential of medicinal plants have been explored extensively these days. This study was carried out to evaluate the antibacterial potential from aerial parts of plant, called 'Annona senegalensis' and its constituents. Bioassay guided fractionation led to the isolation of four metabolites, (+)-catechin (1), (-)-anonaine (2), (-)-asimilobine (3) and (+)-nornantenine (4). This is the first report on the isolation of compounds 1, 3 and 4 from this plant. Compounds 2 and 4 showed good activity, whereas 1 and 3 displayed weak inhibition against Streptococcus mutans (ATCC 25175). The results showed that compound 2 and 3 showed significant activity with a minimum inhibition concentration (MIC) of 0.12 and 0.25 mg/mL, respectively. The present study reports for the first time the antibacterial activity of the extract of A. senegalensis and its constituents. As S. mutans is a rather resistant bacteria, the MIC obtained during the present study is significant.