Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:1.13.11.31 (12-lipoxygenase)
 860 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The influence of 22 flavonoids was studied on the arachidonic acid metabolism in sonicated sheep platelets. Flavones and flavonols possessing catechol groups inhibited 12-lipoxygenase. Sideritoflavone and quercetagetin-7-O-beta-D-glucoside were more selective than quercetin. Cirsiliol, hypolaetin, hypolaetin-8-O-beta-D-glucoside, gossypetin, gossypin, hibifolin and leucocyanidol were also 12-lipoxygenase inhibitors with some differences in potency and selectivity. Xanthomicrol was a weak cyclooxygenase inhibitor. These results suggest that lipoxygenase inhibition can play a role in the anti-inflammatory activity of hypolaetin-8-O-beta-D-glucoside, sideritoflavone, gossypin and hibifolin. On the other hand, the presence of sideritoflavone, hypolaetin-8-O-beta-D-glucoside, cirsiliol and xanthomicrol in several species of Sideritis may provide a basis for the use of such plants as anti-inflammatory agents.
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PMID:Inhibition of sheep platelet arachidonate metabolism by flavonoids from Spanish and Indian medicinal herbs. 211 28

Arachidonate 5-lipoxygenase plays a pivotal role in the biosynthesis of leukotrienes. Cirsiliol (3',4',5-trihydroxy-6,7-dimethoxyflavone), a selective inhibitor of the enzyme, was derivatized by introducing alkyl groups of various chain lengths at positions 5, 6, 7, and 8 of the A ring of the flavone skeleton. Modification of the positions 5 and 6 with an alkyl group of 5-10 carbons markedly decreased the IC50 values for 5-lipoxygenase inhibition to the order of 10 nM. As tested with 5- or 6-hexyloxy derivatives, a relatively selective inhibition of 5-lipoxygenase was shown. Inhibition of 12-lipoxygenase required much higher concentrations of these compounds, and cyclooxygenase was not inhibited. Modification of positions 7 and 8 did not increase the inhibitory effect of most flavone compounds.
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PMID:Syntheses of 5,6,7- and 5,7,8-trioxygenated 3',4'-dihydroxyflavones having alkoxy groups and their inhibitory activities against arachidonate 5-lipoxygenase. 378 88