Phytochemical analysis, antioxidant activity, and hepatoprotective effects of Zizyphus xylopyrus (Retz.) Willd leaves extracts against carbon tetrachloride-induced hepatotoxicity in in vitro and in vivo models

Abstract

Introduction: This work was done to determine phytochemical content, antioxidant activity, and hepatoprotective effects of Zizyphus xylopyrus leaves extracts against carbon tetrachloride-induced hepatotoxicity in in vitro and in vivo models. Materials and Methods: The total flavonoids content (TFC), total phenolic content (TPC), and total tannin content (TTC) were determined using quercetin and tannic acid equivalents, as standard while antioxidant activities of extracts were determined using the standard in vitro methods. All the extracts subjected to in-vitro HepG2 cell line study as well as to evaluate in vivo hepatoprotective effects against carbon tetrachloride (CCl4) intoxicated rats. Results: Among all extracts, ethyl acetate extract (EAE) possess potent antioxidant activity, viz., ferric reducing ability of plasma (abs = 0.379 ± 0.07), 2,2-diphenyl-1-picrylhydrazyl (inhibitory concentration 50% [IC50]: 103.50 ± 2.05 μg/mL), OH• (89.33 ± 1.79 μg/mL), NO• (IC50 129.34 ± 1.29 μg/mL), O2ˉ (IC50 62.03 ± 2.78 μg/mL), and inhibition of lipid peroxidation (110.05 ± 2.96 μg/mL). Treatment with EAE significantly increased the cell viability (IC50 80.93 ± 1.02 μg/mL) by preventing CCl4 induced cell damage in in-vitro HepG2 cell line. In case of both prophylactic and curative study, EAE extract significantly (P < 0.001) decreased CCl4-induced increased serum liver enzymes activities in CCl4-intoxicated rats, comparable to silymarin. Hepatoprotective potential further supported by pentobarbitone induced sleeping time and improved hepatic tissue histopathology. Study results suggest that antioxidant activity and hepatoprotective effect of EAE might be due to presence of polyphehols, viz., TFC (43.76 ± 0.78 Quercetin equivalent [QE] mg/g extract), TPC (194.16 ± 0.74 gallic acid equivalent [GAE] mg/g extract), and TTC (20.45 ± 2.31 GAE mg/g extract). Reversed-phase high-performance liquid chromatography analysis results showed highest quercetin content (32.8 ± 0.24 mg/g) in EAE. Conclusion: This study advocated that due to the presence of flavonoids, Z. xylopyrus leaves exhibited marked antioxidant and hepatoprotective activities.