Enzyme-mediated ultrasound-assisted extraction of rutin, quercetin, and other antioxidant and antidiabetic compounds from Holarrhena antidysenterica seeds and optimization as per RSM

Abstract

Rutin and quercetin are valuable bioactive natural products. The current study successfully discovered an efficient extraction protocol for these and other bioactive compounds from Holarrhena antidysenterica (HA) seeds based on an enzyme-mediated ultrasound-assisted extraction (EM-UAE). Extraction process optimization was done based on response surface methodology with seven response factors including total extraction yield (%), amount of rutin (AOR, mg/g), amount of quercetin (AOQ, mg/g), total phenolic content (TPC, mg gallic acid equivalents/g dry weight (mg GAE/g DW), total flavonoids content (TFC, mg rutin equivalents/g DW (mg RE/g DW) anti-radical activity (ARA, %), and α-amylase inhibitory activity (AIA, %). High-performance liquid chromatography (HPLC) was used for quantification of rutin and quercetin. The optimal extraction yield, AOR, AOQ, TPC, TFC, ARA, and AIA were 32.39 %, 71.43 mg/g, 23.68 mg/g, 178.63 mg GAE/g DW, 100.22 mg RE/g DW, 76.41 %, and 77.48 %, respectively. The optimal conditions were 91 min time, 6.1 mL enzyme cocktail, pH 4.8, and 48 ℃ temperature. For ARA, EC50 (µg/mL) of HA was 9.75 ± 0.27 compared to 6.10 ± 0.38 of ascorbic acid standard. For AIA, IC50 (µg/mL) of HA and acarbose standard were 51.97 ± 0.21 and 47.89 ± 0.61 μg/mL, respectively. The validation study strongly supported the predicted model with a very low relative standard deviation (0.45–3.37 %). The model was statistically significant and efficient for obtaining rutin, quercetin, and other antioxidant and antidiabetic compounds from Holarrhena antidysenterica seeds on the industrial level.