Robinetin is a flavonol that has been found in R. pseudacacia and has diverse biological activities.1,2,3,4,5 It inhibits NADH oxidase with an IC50 value of 19 nmol/mg of protein in isolated beef heart mitochondria.2 Robinetin scavenges DPPH radicals in a cell-free assay and inhibits glutathione S-transferase (GST; IC50 = 1.39 ?M for the equine liver enzyme).3,4 It also inhibits multidrug resistance-associated protein 1 (MRP1) and MRP2 in MDCK-II cells (IC50s = 13.6 and 15 ?M, respectively, for the human proteins).5
1.Charlesworth, E.H., and Robinson, R.Anthoxanthins. Part XIII. Synthesis of a colouring matter of Robinia pseudacaciaJ. Chem. Soc.268-270(1933) 2.Hodnick, W.F., Duval, D.L., and Pardini, R.S.Inhibition of mitochondrial respiration and cyanide-stimulated generation of reactive oxygen species by selected flavonoidsBiochem. Pharmacol.47(3)573-580(1994) 3.Hyun, J., Woo, Y., Hwang, D.-S., et al.Relationships between structures of hydroxyflavones and their antioxidative effectsBioorg. Med. Chem. Lett.20(18)5510-5513(2010) 4.Bou?ová, I., Hájek, J., Dr?ata, J., et al.Naturally occurring flavonoids as inhibitors of purified cytosolic glutathione S-transferaseXenobiotica42(9)872-879(2012) 5.van Zanden, J.J., Wortelboer, H.M., Bijlsma, S., et al.Quantitative structure activity relationship studies on the flavonoid mediated inhibition of multidrug resistance proteins 1 and 2Biochem. Pharmacol.69(4)699-708(2005)