Antibacterial and anticoagulant activities of coumarins isolated from the flowers of Magydaris tomentosa

The phytochemical investigation of the acetone and methanol extracts of the flowers of Magydaris tomentosa (Desf.) DC afforded six known coumarins as well as (+)-meranzin hydrate (7), not previously reported as a natural product. The antibacterial activity of umbelliprenin (1), osthol (2), imperatorin (3), citropten (4) and (+)-meranzin hydrate (7) was tested against Gram-positive and Gram-negative bacteria. All coumarins (1-7) isolated in this study inhibited growth of all bacterial strains tested (MIC between 16 and 256 mu g/mL), the most active being imperatorin (3) (MICs between 32 and 128 mu g/mL) and citropten (4) (MICs between 16 and 256 mu g/mL). The anticoagulant activity of compounds 1-4 and 7 was also evaluated.