Synergy effects of metformin and berberine on glyoxal-induced carbonyl stress in isolated rat liver mitochondria

Objective: Carbonyl stress, resulting from toxic effects of alpha-dicarbonyls such as glyoxal (GO), plays an important role in the mitochondrial dysfunction and subsequent development of diabetic complications. This study evaluated the ability of metformin (MET), berberine (BBR), and their combination to prevent GO-induced carbonyl stress in isolated rat liver mitochondria. Design: Mitochondria (0.5 mg protein/mL) were isolated from the Wistar rat liver and incubated with various concentrations of GO (1, 2.5, 5, 7.5 and 10 mM) for 30 minutes and IC50 for GO was calculated. The suspensions of mitochondria were incubated with various concentrations of MET (2.5, 5, 10 and 20 mM) or BBR (2.5, 5, 10 and 20 µM) for 30 min and then GO in dose of IC50 at 37 ºC for 30 min. Mitochondrial complex II activity, mitochondrial membrane potential (MMP), MDA level, reactive oxygen species (ROS) formation, reduced glutathione (GSH) content and protein carbonylation were assessed. The combination index and isobologram of MET and BBR on GO toxicity was calculated. Results: IC50 of GO was assigned approximately 3 mM. GO disrupted the electron transfer chain and significantly increased mitochondrial ROS formation, protein carbonylation and MDA level. GO decreased mitochondrial viability, MMP and GSH content. Pre-treatment with MET and BBR could potentially reverse GO-induced deleterious effects in a concentration-dependent manner. Results of drug combination indicated that CI for Fa 0.5 (Effect 50 %) was 0.83. Conclusion: These results suggest that BBR in combination with MET have a moderate synergistic effect on GO-induced carbonyl stress in isolated rat liver mitochondria.

Synthesis and preliminary hepatotoxicity evaluation of new caffeine-8-(2-thio)-propanoic hydrazid-hydrazone derivatives

New series of caffeine-8-(2-thio)-propanoic hydrazid-hydrazone derivatives were designed and synthesized. The targed compounds were obtained in yields of 51 to 96% and their structures were elucidated by FTIR, 1H NMR, 13C NMR, MS and microanalyses. All of the compounds were found to be “drug-like” as they fulfill the criteria of drug-likeness, which includes the MDDR-like rule. The tested compounds were subjected to in silico prediction of substrate/metabolite specificity and Drug Induced Liver Injury (DILI). The prediction for indicated that the evaluated compounds would most probably act as CYP1A2 substrates. The performed in vitro studies didn’t reveal statistically significant hepatotoxicity of the tested compounds, probably due to the pro-oxidant effects expressed on sub-cellular (isolated rat liver microsomes) level. The obtained experimental results confirmed the predicted low hepatotoxicity for the tested structures. Based on these results the compounds may be considered as promising structures for design of future molecules with low hepatotoxicity.