Evaluation of the in vivo antioxidant, toxicological and chromatographical profiling of leaf extract and fractions of Crescentia cujete Linn. (Bignoniaceae)

Abstract

Oxidative stress has been reported to be involved in many diseases pathogenesis. This study evaluated the antioxidant potentials of Crescentia cujete leaf. The leaves were extracted in methanol by cold maceration and fractionated into n-hexane (NHF), ethyl acetate and butanol fractions. The in vitro antioxidant activity was evaluated using 2,2-diphenyl-1-picrylhydrazil (DPPH) and ferric reducing antioxidant power (FRAP) tests while Catalase (CAT), Superoxide dismutase (SOD) and Lipid peroxidation (LPO) assays were used to evaluate in vivo antioxidant potentials. The constituents of the extract and fractions where analyzed using high performance liquid chromatography coupled to diode array detector (HPLC-DAD). The median lethal dose (LD50) of CME and serum liver marker (SLM) enzymes were evaluated using standard protocols. The crude methanol extract (CME) and the fractions showed concentration dependent in vitro antioxidant activity (EC50 values of 15.22 to 569.22 μg/ml for DPPH and 54.69 to 581.40 μg/ml for FRAP) with ethyl acetate fraction (EAF) showing the highest activity. The CME at 400 mg/kg and EAF at 200 mg/kg showed more than 3-fold increase in CAT and SOD activities compared with the vehicle treated group. EAF (400 mg/kg) significantly (p< 0.05) inhibited LPO. HPLC-DAD analysis of CME and EAF revealed the presence of phenolic compounds (chlorogenic acid, protocatechuic acid and several quercetin derivatives). The LD50 of CME was above 5000 mg/kg. The CME and EAF showed significant (p< 0.05) reduction of SLM enzymes. The study validated the antioxidant activity of C. Cujete, which may be connected to high abundance of the detected phenolic compounds.