Inhibition of COXs and 5-LOX and activation of PPARs by Australian Clematis species (Ranunculaceae).
The species of Clematis (Ranunculaceae) have been traditionally used for inflammatory conditions by indigenous Australians. We have previously reported that the ethanol extract of Clematis pickeringii inhibited COX-1. In this study, we examined the ethanol extracts and fractions of three Clematis species, Clematis pickeringii, Clematis glycinoides and Clematis microphylla, on cyclooxygenase-1 (COX-1), cyclooxygenase-2 (COX-2) and 5-lipoxygenase (5-LOX). We further examined the activating effects on the protein expression of peroxisome proliferator-activated receptor alpha (PPARalpha) and gamma (PPARgamma) in HepG2 cells. The ethanol extracts of three Clematis species inhibited the activities of COX-1, COX-2 and 5-LOX in the different extents. The stem extract of Clematis pickeringii showed the highest inhibitory activities among the three species on COX-1, COX-2 and 5-LOX with the IC(50) values of 73.5, 101.2 and 29.3 microg/mL. One of its fractions also significantly elevated PPARalpha expression by 173, 280 and 435% and PPARgamma expression by 140, 228 and 296% at 4, 8 and 16 microg/mL, respectively.
Li
Rachel W
RW
Australian Centre for Complementary Medicine Education and Research, A Joint Venture of the University of Queensland and Southern Cross University, P.O. Box 157, Lismore, NSW 2480, Australia. rachelli@hawaii.edu
Lin
G David
GD
Leach
David N
DN
Waterman
Peter G
PG
Myers
Stephen P
SP
D000818:Animals; D001094:Arachidonate 5-Lipoxygenase / Q000378:metabolism; D001315:Australia; D002460:Cell Line; D039324:Clematis; D051545:Cyclooxygenase 1 / Q000378:metabolism*; D051546:Cyclooxygenase 2 / Q000378:metabolism*; D016861:Cyclooxygenase Inhibitors / Q000302:isolation & purification / Q000494:pharmacology*; D006801:Humans; D016859:Lipoxygenase Inhibitors; D047492:Peroxisome Proliferator-Activated Receptors / Q000378:metabolism*; D010936:Plant Extracts / Q000302:isolation & purification / Q000494:pharmacology; D018515:Plant Leaves; D018547:Plant Stems; D029626:Ranunculaceae; D012756:Sheep
D016861:Cyclooxygenase Inhibitors; D016859:Lipoxygenase Inhibitors; D047492:Peroxisome Proliferator-Activated Receptors; D010936:Plant Extracts; D001094:Arachidonate 5-Lipoxygenase; D051545:Cyclooxygenase 1; D051546:Cyclooxygenase 2