Phenolic Compounds and Hepatoprotective Activity of Centaurea aegyptiaca L. on Carbon Tetrachloride-induced Hepatotoxicity in Rats

Objectives: This study aimed to isolate phenolic compounds from the 70% aqueous methanol extract of the aerial parts (leaves, flowers and stems) of Centaurea aegyptiaca , evaluate in-vivo hepatoprotective activity and determine total phenolic and total flavonoid contents. Methods: 70% aqueous methanol extract of the aerial parts subjected to different chromatographic separation techniques. The identities of the isolated compounds were established on the basis of their spectral data and comparing with previously reported data. The crude extract was evaluated for in-vivo hepatoprotective activity on CCl4-induced hepatotoxicity in rats. Total phenolic and total flavonoid contents of the aqueous methanol extract were determined using Folin-Ciocalteu and aluminum chloride colorimetric methods, respectively. Results: The aqueous methanol extract of the aerial parts of Centaurea aegyptiacaafforded seven compounds. A phenolic acid ester; protochatechuic acid methyl ester (1) along with six known flavonoids; apigenin-6-C-β-D-glucopyranoside (isovitexin) (2), apigenin-8-C-β-D-glucopyranoside (vitexin) (3), quercetin-3-O-b-D-glucopyranoside (isoquercetin) (4), apigenin (5), 3-O-methylquercetin (6) and quercetin (7). Administration of the extract at doses of 100 and 200 mg/kg b.wt showed a hepatoprotective activity similar to that of the standard drug; silymarin at a dose of 25 mg/kg b.wt. Comparative histopathological study of liver exhibited moderate changes in liver histoarchitecture when compared to the CCl4 group. The methanolic extract showed high concentration of phenolic and flavonoid contents. Conclusion: The aqueous methanol extract of the aerial parts of C. aegyptiaca afforded seven phenolic compounds for the first time from this species, with promising in-vivo hepatoprotective activity.