Isolation of (S)-(+)-naproxene from Musa acuminata.: Inhibitory effect of naproxene and its 7-methoxy isomer on constitutive COX-1 and inducible COX-2

The isolation and characterisation of (S)-(+)-6-methoxy-alpha-methyl-2-naphthaleneacetic acid, a well known synthetic non-steroidal anti-inflammatory drug (naproxene), from a natural source is described for the first time. We evaluated the ability of naproxene and its 7-methoxy isomer to abrogate constitutive COX-1 and inducible COX-2 activity in human A549 cells. Naproxene inhibited COX-1 (IC50 = 3.42 mu M) and COX-2 (IC50 = 1.53 mu M), whereas the 7-methoxy isomer had no appreciable effect on COX-1 (IC50 much greater than 100 mu M) but also abrogated the activity of COX-2 enzyme (IC50 = 14.42 mu M).