Anti-staphylococcal and cytotoxic compounds from Hyptis pectinata

Bioassay-guided fractionation of a CHCl (3) extract prepared from the Mexican medicinal plant Hyptis pectinata led to the isolation of four pyrones, pectinolides A-C ( 1-3) and H ( 4). Activity was tracked using cultured KB cells. Multidrug-resistant strains of Staphylococcus aureus were sensitive to pectinolide H ( 4; KB > 20 microg/mL) in the concentration range of 32-64 microg/mL. The absolute stereochemistry of this new compound was established as 5 S-[(4 S-acetyloxy)-(1 S-hydroxy)-2 Z-octenyl]-2(5 H)-furanone on the basis of spectral, chiroptical data and chemical correlation with pectinolide A ( 1). Mosher ester derivatives were used with pectinolide B ( 2) for confirmation of the 3'-( S) absolute stereochemistry on the side chain chiral center of pectinolides A-C.