Lipoxygenase inhibition by anadanthoflavone, a new flavonoid from the aerial parts of Anadenanthera colubrina.

Chemical investigation of the aerial parts of Anadenanthera colubrina led to the isolation of a new flavonoid named anadanthoflavone (1), along with 11 known compounds: alnusenol, lupenone, lupeol, betulinic acid, α-amyrin, β-amyrin, β-sitosterol, stigmasterol, apigenin, 4-hydroxybenzoic acid and cinnamic acid. The isolated compounds were evaluated for their inhibitory activity on human platelet 12-lipoxygenase (12-hLO), human reticulocyte 15-lipoxygenase (15-hLO) and soybean lipoxygenase-1 (15-sLO). Compound 1 was found to be active against 12-hLO and 15-hLO with IC 5 0 values of 13 ′ 3 pM and 17 ′ 3 μM, respectively. Apigenin selectively inhibited the activity of 15-hLO (IC 5 0 :4.0 ′ 1 μM), while lupenone, lupeol and α-amyrin were found active against 15-sLO (IC 5 0 : 22 ′ 3 μM, 35 ′ 9 pM and 15 ′ 3 pM, respectively).