Optimization of pulsed mode sonication and in silico molecular docking study for antioxidant properties of mandarin (Citrus reticulata Blanco) peels

The present study is aimed to investigate the extractability of bioactive compounds from mandarin (Citrus reticulata Blanco) peel using a pulsed mode of ultrasonic treatment. Box-Behnken experimental design associated with response surface methodology (RSM) was used for the process optimization. Ultrasound amplitude (60%-80%), time (5-15 min), and duty cycle (.30-.90) were the independent variables investigated to maximize the yield of total phenolic content (TPC), total saponin content (TSC), total flavonoid content (TFC), total condensed tannin (TCT), and antioxidant activity (DPPH and FRAP methods). The optimum predicted values of the TPC (27.23 g GAE/100 g dry weight [DW]), TFC (5.64 g QE/100 g DW), TCT (3.17 mg CE/g DW), TSC (42.36 mg EE/g DW), DPPH (4.01 mg GAE/g DW) and FRAP (13.71 mg TE/g DW) were obtained at conditions: 11.19 min of sonication at a duty cycle of .30 and 77.70% amplitude. Furthermore, in silico investigations of anti-oxidant properties of major flavonoids were done using molecular docking. The analysis showed a better binding affinity of narirutin for Cytochrome P450 and myeloperoxidase, while hesperidin showed a better binding affinity with lipoxygenase. The results obtained from the study showed better phenolic extraction and high antioxidant activity using pulsed mode sonication. The high binding scores of hesperidin and narirutin for all three key enzymes, as obtained by molecular docking, have shown their therapeutic potential in the development of antioxidant drugs. Practical Applications A practical insight of the present research suggests the applicability of optimized pulsed mode extraction conditions for industrial processing of Citrus reticulata Blanco peel, a green technology useful in terms of its biomedical application. The optimized extraction conditions will give a higher yield with reduced time and with less use of extraction solvents. The in silico analysis provides scope for predictive modeling of novel antioxidative drug development using major flavonoid compounds of Citrus reticulata Blanco peel.