Optimization of NADESs-UAE extraction of phytochemicals from African nutmeg (Monodora myristica (Gaertn.) Dunal) Peels: antioxidant and antiradical scavenging activity by Rotatable Center Composite Design-Response Surface Methodology (RCCD-RSM)

Abstract A RCCD-RSM was used to optimize the extraction of bioactive compounds from African nutmeg peels based on UAE-NADESs. Four independent factors determined in previous studies that significantly affect bioactive molecule extraction were optimized to elucidate the best conditions that produce the maximum TPC and TFC extracts, with high antiradical scavenging activity through CUPRAC, FRAP, and DPPH inhibition. The optimized conditions with maximum desirability for TPC, TFC, CUPRAC, FRAP, and DPPH were temperature, time, volume, and concentration of 45ºc, 5 min, 25 ml, & 90%; 30ºc, 5min, 25 ml, & 90%; 30ºc, 5 min, 25 ml, % 90%; 45ºc, 25 min, 25 ml, & 50%; and 50ºc, 15 min, 15 ml, & 70%, respectively. CaFr11 performs highest for TPC and TFC extraction as well as in CUPRAC antiradical scavenging activity at the optimized conditions than the rest of the NADESs studied. CaSu11 had the highest FRAP power, while CaXy12 gave the highest DPPH inhibition at optimized conditions. Besides, all the studied NADESs were better than water in TPC, TFC extraction, and in DPPH inhibition. Our results are similar to results obtained by other researchers who performed optimization of extraction based on UAE-NADESs using other plant materials.