Heliconia rostrata rhizomes mitigate chemical-induced liver injury by debilitating oxidative stress in HepG2 cells and rats

Abstract

Ethnopharmacological relevance: Heliconia rostrata Ruiz and Pav. belongs to the family Heliconiaceae. Plant was traditionally used to cure jaundice, intestinal pain, diabetes and hypertension.

Aim of the experiment: Present study evaluated hepatoprotective efficacy of ethanol (REE) and methanol (RME) extracts of H. rostrata rhizomes in HepG2 cell lines and rats. Antioxidant efficacy of extracts was determined using ex vivo and in vivo methods.

Materials and methods: Before conducting efficacy studies, safety of REE and RME was established using toxicity studies which included Oral acute-fixed dose toxicity using OECD TG420, 28-days repeated dose oral toxicity by OECD TG407 and cytotoxicity studies by brine shrimp lethality (BSL) bioassay and MTT assay taking HepG2 cell line. Ex vivo (Extracts: 0-250 μg/ml) and in vivo (Extracts: 50, 100 and 200 mg/kg) antioxidant studies were performed on fresh goat liver and rats (N = 45) of either sex, respectively. In vitro hepatoprotective efficacy of extracts was evaluated against ethanol induced toxicity in HepG2 cell line. In vivo study was performed at 50, 100 and 200 mg/kg/day doses in rats by CCl₄-induced hepatotoxicity study.

Results: No mortality was observed during single and repeated dose toxicity studies. 50% lethal dose >2000 mg/kg, confirmed category 5 toxicity level of extracts, according to Globally Harmonized System. No signs of toxicity and treatment or dose related changes recorded in rats under repeated dose toxicity study. No-observed-adverse effect-level of 200 mg/kg/day was observed for both extracts. Median lethal concentration of REE and RME were 1291.30 and 1045.89 μg/ml, respectively in BSL bioassay and 50% cytotoxicity concentration >1000 μg/ml was obtained for both extracts from MTT assay. Calculated 50% inhibitory concentration and median effective dose of extracts obtained from different antioxidant assays in ex vivo and in vivo antioxidant studies, respectively indicated REE has more antioxidant efficacy than RME. In in vitro hepatoprotective efficacy study, extracts demonstrated dose dependent protection against ethanol induced hepatotoxicity. At 400 μg/ml, REE and RME demonstrated percentage protection of 65.53% and 57.98%, respectively. Results of liver function test and histopathological evaluation of liver in in vivo hepatoprotective study confirmed dose dependent protection provided by the extracts against CCl₄ -induced hepatotoxicity.

Conclusion: Both REE and RME were found safe to be considered for therapeutic uses. Both REE and RME were found to exhibit antioxidant efficacy in ex vivo and in vivo models. Results ascertained that H. rostrata rhizomes possess significant hepatoprotective potency.

Keywords: Acute toxicity; Antioxidant; Cytotoxicity; Hepatoprotective; Repeated dose toxicity.