Constituents of Psoralea corylifolia Fruits and Their Effects on Methicillin-Resistant Staphylococcus aureus

Two new flavonoids, bakuisoflavone (1) and bakuflavanone (2), together with 15 known compounds, were isolated from the fruits of Psoralea corylifolia, and their structures were characterized by spectroscopic data. The effects of the isolated compounds on methicillin-resistant Staphylococcus aureus were also examined. We found that two compounds, isobavachalcone (10) and bakuchiol (12), showed noticeable antibacterial effects on the MRSA strains examined. Quantitation of the major constituents, including anti-MRSA constituents, was then performed. The results showed individual contents of 1.26%–16.49% (w/w) among the examined compounds in the ethyl acetate extract from P. corylifolia fruits.