Enzyme kinetic and in silico characterization of cytochrome P450 2E1 inhibition by hydro-ethanolic extract of Entada africana and its protective role in acetaminophen-induced hepatotoxicity.

ETHNOPHARMACOLOGICAL RELEVANCE: Acetaminophen (APAP) poisoning accounts for over 50 % of acute liver failure cases, with N-acetylcysteine remaining the sole antidote despite its limitations. Entada africana, used in ethnomedicine to treat liver disorders, has demonstrated promising antihepatotoxic properties. However, its effects on cytochrome P450 2E1 (CYP2E1) in APAP-toxicity model remain unexplored.

AIMS OF THE STUDY: This study investigated the inhibitory effects of the hydro-ethanolic stem bark extract of E. africana (HEA) on CYP2E1 activity and assessed its hepatoprotective potential against APAP-induced hepatotoxicity.

MATERIALS AND

METHODS

Phytochemical profiling of HEA was conducted using UHPLC/MS. Concentration-response and enzyme kinetics studies determined the IC50 and the inhibition mechanism of HEA, respectively. Molecular docking predicted interactions between identified compounds and CYP2E1. The hepatoprotective effects were evaluated through co-treatment of L-02 hepatocytes (10 mM APAP + 25-100 μg/mL HEA or 4-methylpyrazole [4-MP]) and mice (300 mg/kg APAP + 50-200 mg/kg HEA or 4-MP).

RESULTS

HEA inhibited CYP2E1 activity via a mixed-inhibition mechanism, with an IC50 comparable to that of 4-MP, a CYP2E1 inhibitor. Identified phytochemicals including ellagic acid, kaempferol-3-O-glucuronide, and luteolin-7-O-glucoside exhibited strong binding affinities with CYP2E1. In APAP-treated cells, HEA maintained cell viability and preserved membrane integrity. In APAP-intoxicated mice, HEA reduced serum alanine aminotransferase levels, decreased hepatic malondialdehyde content, preserved normal liver architecture, restored hepatic glutathione levels, enhanced superoxide dismutase and catalase activities, and suppressed CYP2E1 expression and activity.

CONCLUSION

These findings support the ethnopharmacological use of E. africana for liver disorders and highlight its potential as a source of bioactive compounds for the prevention and treatment of drug-induced liver injury.