Two New Prenylated 3-Benzoxepin Derivatives as Cyclooxygenase Inhibitors from Perilla frutescens var. acuta

Two novel prenyl 3-benzoxepin derivatives, perilloxin (1) and dehydroperilloxin (2), were isolated from the dichloromethane extract of the stems of Perilla frutescens var. acuta. Their structures were elucidated as (-)-(R)-5-methoxy-2,3-dihydrofuro[2, 3-g][3]benzoxepin and 5-methoxyfuro[2,3-g][3]benzoxepin, respectively, based on UV, MS, (1)H and (13)C NMR, NOE, (1)H-(13)C COSY, and HMBC spectral data. They were isolated following bioassay-guided fractionation, using an in vitro cyclooxygenase-1 test. Compounds 1 and 2 possess inhibitory activities, with IC(50) values of 23.2 microM and 30.4 microM, respectively.