3-O-Methylquercetin

3-O-methyl Quercetin is a flavone that has been found in C. balchaschensis and has diverse biological activities.^1,2,3,4 It is an inhibitor of β-secretase (IC₅₀ = 6.5 ?M).¹ It scavenges DPPH radicals and superoxide anions in cell-free assays (IC₅₀s = 14.17 and 17.39 ?M, respectively), as well as inhibits lipid peroxidation and hydrogen peroxide-induced neuronal cell death in primary rat cortical cells (IC₅₀s = 19 and 3.5 ?M, respectively).² 3-O-methyl Quercetin inhibits poliovirus RNA synthesis in infected HeLa cells when used at concentrations of 2 and 20 ?g/ml.³ It also inhibits LPS-induced nitric oxide (NO) production in BV-2 microglia (IC₅₀ = 3.8 ?M) and reduces LPS-induced increases in the levels of inducible nitric oxide synthase (iNOS) in BV-2 microglia.⁴

1.Zhumanova, K., Lee, G., Baiseitova, A., et al.Inhibitory mechanism of O-methylated quercetins, highly potent β-secretase inhibitors isolated from Caragana balchaschensis (Kom.) PojarkJ. Ethnopharmacol.272113936(2021) 2.Kim, S.H., Kumar, C.N., Kim, H.J., et al.Glucose-containing flavones—their synthesis and antioxidant and neuroprotective activitiesBioorg. Med. Chem. Lett.19(21)6009-6013(2009) 3.Castrillo, J.L., and Carrasco, L.Action of 3-methylquercetin on poliovirus RNA replicationJ. Virol.61(10)3319-3321(1987) 4.Kim, J.Y., Lim, H.J., and Ryu, J.-H.In vitro anti-inflammatory activity of 3-O-methyl-flavones isolated from Siegesbeckia glabrescensBioorg. Med. Chem. Lett.18(4)1511-1514(2008)