Isoprenylated flavonoids from the root bark of Morus alba and their hepatoprotective and neuroprotective activities.

Abstract

A new isoprenylated flavonoid, 2S-5,7,2',4'-tetrahydroxy-3',5'-di-(γ,γ-dimethylallyl)flavanone, sanggenol Q (1), along with seven known isoprenylated flavonoids, sanggenol A (2), sanggenol L (3), kuwanon T (4), cyclomorusin (5), sanggenon F (6), sanggenol O (7), and sanggenon N (8), three known Diels-Alder type adducts, sanggenon G (9), mulberrofuran G (10), and mulberrofuran C (11), and a known benzofuran, moracin E (12), were isolated from the root bark of Morus alba using silica gel, ODS, and Sephadex LH-20 column chromatography. Chemical structures were determined based on spectroscopic data analyses including NMR, MS, CD, and IR. For the first time, compounds 1 and 7 were isolated from the root bark of M. alba. All compounds were evaluated for hepatoprotective activity on t-BHP-induced oxidative stress in HepG2 cells and neuroprotective activity on glutamate-induced cell death in HT22 cells. Compounds 1, 4, 8, 10, and 11 showed protective effects on t-BHP-induced oxidative stress with EC50 values of 6.94±0.38, 30.32±6.82, 23.45±4.72, 15.31±2.21, and 0.41±0.48μM, respectively, and compounds 1, 2, 10, 11, and 12 showed protective effects on glutamate-induced cell death with EC50 values of 5.54±0.86, 34.03±7.71, 19.71±0.71, 16.50±7.82, and 1.02±0.13μM, respectively.