Isolation of linoleic and α ‐linolenic acids as COX‐1 and ‐2 inhibitors in rose hip

Rose hip has previously shown clinical efficacy in the treatment of osteoarthritis, and organic solvent extracts of rose hip have showed inhibition of cyclooxygenase‐1 and ‐2. A petroleum ether extract of rose hip was fractioned by VLC on silica; on a C‐18 column and by HPLC. Each step was COX‐1/2 activity‐guided. The bioassay‐guided fractionation led to the isolation of linoleic acid (the IC 50 for COX‐1 was 85 µ m and 0.6 µ m for COX‐2) and α ‐linolenic acid (the IC 50 for COX‐1 was 52 µ m and 12 µ m for COX‐2). The COX‐2/COX‐1 ratio was 0.007 for linoleic acid and 0.2 for α ‐linolenic acid. Linoleic acid and α ‐linolenic acid contribute to the COX‐1 and ‐2 inhibitory activity of rose hip. Copyright © 2008 John Wiley & Sons, Ltd.