Isolation and characterization of flavonoids fromTapirira guianensisleaves with vasodilatory and myeloperoxidase-inhibitory activities

The aim of this study was to perform the isolation and characterization of vasodilatory flavonoids fromTapirira guianensisAubl. (Annacardiaceae) leaves. In this context, ethyl acetate fraction (EA fraction) was obtained and subjected to fractionation batches by HSCCC affording: myricetin 3-O-alpha-L-rhamnopyranoside (myricitrin,1); quercetin 3-O-(6"-O-galloyl)-beta-D-galactopyranoside (2); quercetin 3-O-alpha-L-arabinofuranoside (avicularin,3); and quercetin 3-O-alpha-L-rhamnopyranoside (quercitrin,4). Myricitrin (1) induced a relaxation of 56.07 +/- 13.04% at 300 mu M (P < 0.05; n = 5), indicating that this flavonoid contributes to the vasodilatory activity of EA fraction. In addition, all EA fraction flavonoids were evaluated for their capacity of inhibiting myeloperoxidase activity and flavonoid (2) (IC(50)1.0 +/- 0.3 mu M) was the strongest peroxidase inhibitor. In conclusion, it was possible to verify that myricitrin together with quercetin are mainly responsible for vasodilatory potential, besides flavonoid2for myeloperoxidase inhibition. Together these flavonoids seem to be responsible forTapirira guianensiscardiovascular effects.