Optimization of microwave-assisted extraction for quercetin (prebiotic) and the effect of its symbiotic combination with Lactobacillus acidophilus (probiotic) in NAFLD induced rat model.

INTRODUCTION: Changing dietary patterns, lifestyle related disorders and associated metabolic syndromes have increased the prevalence of NAFLD over the last few years. It has been observed that there is a direct association between intestinal dysbiosis and NAFLD truly depicted by interconnected complex mechanisms. Besides its antioxidant activity, quercetin serves prebiotic functions as well. OBJECTIVE: The objective of the current research was to determine the synbiotic effect of quercetin and Lactobacillus acidophilus on non-alcoholic fatty liver disease (NAFLD) induced rat models. METHODS: Quercetin was extracted from red onions via microwave-assisted extraction technique (MAE). Response Surface Methodology (RSM) was employed to optimize MAE parameters. 25 female albino rats were divided into 5 groups of 5 rats each; 2 control (untreated and negative control) and 3 treatment groups (G1, G2, G3). High fat diet (HFD) (40% fat) in combination with 15% sucrose water and 440 mg cholesterol/100 g feed was given to rats over a period of 6 weeks to induce NAFLD. For the efficacy trial, treatment groups received different doses of quercetin; 50 mg, 80 mg and 100 mg in G1, G2 and G3, respectively, with a dose of 10(2) CFU of Lactobacillus acidophilus/200 μL of PBS in all three groups. RESULTS: The results revealed optimal MAE conditions for maximum amount of quercetin as 600 W microwave power, 3 min irradiation time and distilled water as a solvent. Resultantly, 86.10 mg quercetin/gram of red onion extract (32.7mgQ/g onion powder) was obtained. There was no significant difference in HDL, VLDL, triglycerides, serum AST and serum ALP levels (p-value > 0.05) between all groups. However, total cholesterol, LDL cholesterol and serum ALT significantly improved in G3 (p-value < 0.05). CONCLUSION: The synbiotic combination is effective at lowering total cholesterol, LDL cholesterol as well as serum ALT levels at a dose of 100 mg of quercetin/kg body weight for rats.