α-Glucosidase Inhibitory and Anti-Inflammatory Coumestans from the Roots of Dolichos trilobus

Four new coumestans dolichosins A - D (1: -4: ) were isolated from the roots of Dolichos trilobus, together with four known compounds: isosojagol (5: ), phaseol (6: ), psoralidin (7: ), and 4″,5″-dehydroisopsoralidin (8: ). Their structures were elucidated on the basis of spectroscopic data interpretation, mass spectrometric analyses, and the comparison with literature data of related compounds. The anti-inflammatory activity of these compounds (1: -8: ) was evaluated through the inhibition of nitric oxide production in lipopolysaccharide-activated murine macrophage RAW 264.7 cells, in which compounds 1: and 6: displayed moderate inhibitory activity and no cytotoxic effects. In a α-glucosidase inhibitory assay, compounds 1: and 5: -8: exhibited appreciable inhibition on α-glucosidase. Especially compounds 1, 7: , and 8: showed IC₅₀ values lower than 20.0 µM.