ABSTRACT
The phytochemical investigation of extracts of Dalea jamesii root and aerial portions led to the isolation of ten phenolic compounds. Six previously undescribed prenylated isoflavans, summarily named ormegans Aâ-âF (1â-â6: ), were characterized, along with two new arylbenzofurans (7, 8: ), a known flavone (9: ), and a known chroman (10: ). The structures of the new compounds were deduced by NMR spectroscopy, supported by HRESI mass spectrometry. The absolute configurations of 1â-â6: were determined by circular dichroism spectroscopy. Compounds 1â-â9: exhibited in vitro antimicrobial activities, causing 98% or greater growth inhibition at concentrations as low as 2.5â-â5.1 µM against methicillin-resistant Staphylococcus aureus, vancomycin-resistant Enterococcus faecalis, and Cryptococcus neoformans. Interestingly, the most active compound was the dimeric arylbenzofuran 8: (> 90% growth inhibition at 2.5 µM) against both methicillin-resistant S. aureus and vancomycin-resistant E. faecalis, tenfold more active than its corresponding monomer (7: ).