Antidiabetic and hepatoprotective potential of whole plant extract and isolated compounds of Aeginetia indica

Background: Aeginetia indica, a perennial herb from the Orobanchaceae family, generally grows as a root parasite and is widely distributed in the forests of South and South-Asian countries. The plant has valuable uses in herbal medicine against various diseases, such as diabetes, liver diseases, and arthritis.

Aim of the study: The present study was designed to investigate the antidiabetic and hepatoprotective effects of the methanol extract of the whole plant of A. indica in a mouse model followed by the isolation of bioactive compounds and their in-silico studies.

Methods: The hepatoprotective effects were evaluated in a paracetamol-induced hepatotoxicity mouse model. The antidiabetic effects were examined by an oral glucose tolerance test and in an alloxan-induced diabetes mouse model.

Results: The plant extract, at a dose of 400 mg/kg, caused a significant reduction (p < 0.001) in liver enzyme concentrations, including alanine aminotransferase, aspartate aminotransferase, and alkaline phosphatase, similar to the effects of standard drug silymarin. The plant extract, at 400 mg/kg, also significantly reduced (p < 0.001) the fasting blood glucose concentration by 27.33 % after 3 h, compared with a reduction of 45.31 % in response to glibenclamide. In the alloxan-induced diabetes model mice, significant reductions (p < 0.05) in elevated glucose concentrations were observed on days 10 and 20 in mice treated with plant extract and glibenclamide. Chromatographic analyses and nuclear magnetic resonance (NMR) studies identified the presence of β-sitosterol, stigmasterol, and oleic acid in the extract. The possible mechanism underlying the antidiabetic effects was revealed by molecular docking analyses examining the binding of β-sitosterol and stigmasterol with sirtuin 4, an NAD-dependent deacylase enzyme that downregulates leucine-induced and glutamate dehydrogenase-induced insulin secretion. The binding affinities between sirtuin 4 and β-sitosterol, stigmasterol, and NAD were found to be -8.6 kcal/mol, -7.2 kcal/mol and -9.5 kcal/mol, respectively, indicating the probable competition between NAD and the isolated components for sirtuin 4.

Conclusion: The present study revealed that A. indica exerted protective effects against alloxan-induced diabetes and paracetamol-induced hepatotoxicity in mice, which supports the findings regarding the use of A. indica during traditional medical practice.