A new flavan-3-ol and the anti-inflammatory effect of flavonoids from the fruit peels of Wisteria floribunda

Abstract

A new flavan-3-ol, (+)-afzelechin 5-O-β-d-glucopyranoside (2), together with 13 known flavonoids (1, 3–14), was isolated from the fruit peels of Wisteria floribunda. Their structures were assigned by detailed interpretation of NMR, MS, and CD spectroscopic data, as well as by comparing with published reports. The in vitro anti-inflammatory activity of the isolated compounds (1–14) was examined. Among them, compounds 3, 6, and 9 produced highest inhibitory effects on tumor necrosis factor alpha (TNF-α)-induced nuclear factor kappa-B activation in HepG2 cells with IC₅₀ values of 14.1, 16.5, and 11.9 μM, respectively. With the exception of compound 6, the compounds significantly inhibited the accumulation of pro-inflammatory inducible nitric oxide synthase and cyclooxygenase-2 proteins in TNF-α-stimulated HepG2 cells at a concentration as low as 0.1 μM.

Keywords:

• COX-2
• flavonoids
• iNOS
• NF-κB
• Wisteria floribunda

Acknowledgements

This work was supported partly by Priority Research Centers Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education, Science, and Technology (2009-0093815), Republic of Korea. We are grateful to the Korean Basic Science Institute for spectroscopic measurements.

Notes

^† These authors contributed equally to this work.