17.

Antioxidant and Hepatoprotective Activities of Flavonoids from Bauhinia hookeri

Eman Al-Sayed, Mai F. Tolba and Maarit Karonen

Department of Pharmacognosy, Faculty of Pharmacy, Ain-Shams University, Cairo, 11566, Egypt

Department of Pharmacology and Toxicology, Faculty of Pharmacy, Ain Shams University, Cairo, 11566, Egypt

Department of Biology, School of Science and Engineering, the American University in Cairo, Egypt

Laboratory of Organic Chemistry and Chemical Biology, Department of Chemistry, University of Turku, FI-20014 Turku, Finland

Abstract: In a previous study, the total ethanol extract of Bauhinia hookeri  showed a significant hepatoprotective effect in CCl 4-induced toxicity model in mice. However, the active components responsible for the activity were not identified. Therefore, this study was undertaken to determine if the activity of B. hookeri extract is due to its flavonoid content. The hepatoprotective activity of B. hookeri flavonoids was determined by measuring the activities of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) in the culture medium of HepG2 cells challenged with CCl 4. The lipid peroxidation and antioxidant parameters, superoxide dismutase (SOD) and glutathione (GSH) were estimated in the cell lysates. The isolated flavonoids were identified by mass, UV and NMR spectral data. This study revealed that B. hookeri flavonoid fraction and its pure compounds ( kaempferol 3-O-β- D-glucoside, quercetin 3-O-β- D-glucoside and c atechin 3-O-α- L-rhamnoside) possess a promising hepatoprotective activity as evidenced from the normalized levels of ALT and AST. This was attributed partly to their potent antioxidant activity as demonstrated by the increased GSH levels, SOD activity and reduced lipid peroxidation. The whole flavonoid fraction showed the highest cytoprotective activity and was more effective than silymarin. This study highlights a promising natural hepatoprotective remedy derived from B. hookeri.

Keywords: Antioxidant; Bauhinia hookeri; cytoprotection; flavonoids; lipid peroxidation; oxidative stress. © 2016 ACG Publications. All rights reserved.