Inhibitory activity of Juniperus communis on 12(S)-HETE production in human platelets.

Extracts of Juniperus communis L. (Cupressaceae) have been evaluated for their inhibitory activity on human platelet-type 12(S)-lipoxygenase [12(S)-LOX]. The methylene chloride extracts of Juniperi lignum, Juniperi pseudo-fructus and the ethyl acetate extract of Juniperi pseudo-fructus showed a significant inhibition on the production of 12(S)-HETE [12(S)-hydroxy-5,8,10,14-eicosatetraenoic acid] at 100 microg/mL (54.0 +/- 6.73, 66.2 +/- 4.03 and 76.2 +/- 3.36%, respectively). From the methylene chloride extract of the wood, cryptojaponol and beta-sitosterol were isolated as compounds with inhibitory activity (inhibition at 100 microg/mL = 55.4 +/- 2.80% [IC50 = 257.5 microM] and 25.0 +/- 2.15%, respectively). In addition, a lipid fraction containing unsaturated fatty acids contributed to the in vitro activity of the crude extract.