In vitro antioxidant effects and in vivo hepatoprotective effects of Osbeckia octandra, Vernonia cinerea and Atalantia ceylanica on a high fat diet induced metabolic dysfunction-associated steatotic liver disease mouse model.

Abstract

Background: Metabolic dysfunction-associated steatotic liver disease (MASLD), which was formerly known as nonalcoholic fatty liver disease (NAFLD) has become a global epidemic that is predicted to affect more than 50% of the world population by 2040. However, except for Resmetiron, there are no approved drugs in conventional medicine to treat MASLD. The aim of this study was to explore the hepatoprotective effects of the aqueous extracts (AEs) of Osbeckia octandra (O. octandra), Vernonia cinerea (V. cinerea), and Atalantia ceylanica (A. ceylanica) which have been extensively used to treat hepatic diseases in the Sri Lankan traditional medicine.

Methods: During initial in vitro experiments, aqueous extracts (AEs) of these three medicinal plants were prepared and evaluated for antioxidant potential using 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay and Trolox Equivalent Antioxidant Capacity (TEAC) assay. Cytotoxicity was assessed using the MTT assay on Vero cells to determine non-toxic doses for in vivo studies. For in vivo experiments, a high-fat diet (HFD)-induced MASLD mouse model was used. After co-treating the mice with AEs of the tested medicinal plants, their body weight gain was evaluated. Serum ALT, cholesterol, and triglyceride levels were analyzed using standard chemical methods. Hepatic lipid aggregation was evaluated by histopathology. Expression of TNF-α, IL-6, and PPAR-α genes was quantified using qRT-PCR. Data were analyzed using one-way ANOVA followed by Tukey's post hoc test or LSD test. The level of significance was (p < 0.05).

Results: Initial in vitro experiments revealed that AEs of these medicinal plants are rich sources of natural antioxidants with low cytotoxic effects. Subsequent in vivo experiments on the HFD-induced MASLD mouse model also demonstrated that AEs of these medicinal plants can ameliorate HFD-induced weight gain, dyslipidemia, and hepatic lipid aggregation. Reversal of downregulated PPAR-α gene expression confirmed their positive impact on lipid metabolism. Attenuation of increased serum ALT concentration provides evidence for their protective role against hepatic injury. In addition, these extracts could suppress the upregulation of TNF-α and IL-6 genes, which are crucial for inducing steatohepatitis.

Conclusion: Aqueous extracts of O. octandra, V. cinerea, and A. ceylanica are rich in antioxidants and have the ability to suppress HFD-induced weight gain, dyslipidemias, hepatic steatosis, and hepatic inflammation providing solid evidence for their beneficial effects against initiation and progression of MASLD. Among these extracts, O. octandra stands out with the highest antioxidant activity, lowest cytotoxicity, and most promising hepatoprotective effects.