In Vitro Hepatoprotective and Antioxidant Activities of Diprenylated Isoflavonoids from Erythrina Senegalensis (Fabaceae)

Abstract

Summary The 40% hydroethanolic stem bark extract (HE40) from Erythrina senegalensis was subjected to purification by repeated column chromatographies. Three diprenylated isoflavonoids were isolated and identified as 2,3-dihydro-2’-hydroxyosajin (1), osajin (2) and 6,8-diprenylgenistein (3). These compounds were tested for hepatoprotective activities against in vitro CCl4-induced hepatitis in rat liver slices. The following four model systems were used to measure the antioxidant activity of these three isoflavones: 2,4-dinitrophenyl-1-picrylhydrazyl (DPPH) radical scavenging activities, sCarotene-Linoleic Acid Model System (s-CLAMS), Ferric-Reducing Antioxidant Power (FRAP) assay and microsomal lipid peroxidation. The obtained hepatoprotective percentages of compounds (1) (2) (3) were respectively 71.8±1.45, 67.54±3.56 and 69.41±2.56. By comparison to compound (2) and (3), compound (1) showed significant antioxidant effect with EC50 values of 41.28±1.2, 31.27± 2.14, 19.17±1.2 and 15.99±0.49 µg/ml respectively for the radical-scavenging action, inhibition of microsomal lipid peroxidation, s-CLAMS and FRAP assays. The hepatoprotective activity of silymarin used as reference compound was lower than the activities of isolated compounds. The results obtained provide promising baseline information for the potential use of this crude extract as well as some of the isolated compounds for their hepatoprotective and antioxidant activities. It is also worth noting that these results validate, by in vitro tests, the therapeutic use of the plant in traditional medicine.