Optimization of β-cyclodextrin based ultrasound-assisted extraction: A green strategy to enhance the extraction of bioactive compounds from taro leaf byproduct

The present study aims to develop a green and sustainable process for the effective extraction of phytochemicals bearing antioxidant potency from Colocasia esculenta L. leaves, the by-product of taro cultivation, using beta- cyclodextrin (beta-CD) beta- CD) as a green booster for polyphenol isolation, along with ultrasound irradiation. Process optimization based on response surface methodology demonstrated that the maximum total phenolic content (11.90 mg gallic acid equivalents g-1 - 1 sample), total flavonoid content (4.66 mg catechin equivalents g-1 - 1 sample), and antioxidant activity in terms of 2,2-diphenyl-1-picrylhydrazyl radical inhibition (80.70%) and ferric-reducing antioxidant power (85.39 mu mol trolox equivalents g-1 - 1 sample) could be obtained by ultrasonication of leaves at 59.6 degrees C for 55.4 min using an ethanolic solution (50% v/v) of beta- CD (15 mM) and a solvent-solid ratio of 25.4 mL g-1. - 1 . The extract obtained with beta- CD was significantly enriched in flavonoids and, in particular, flavone derivatives (mainly apigenin and luteolin glucosides). The outcomes of the present study suggest that the proposed extraction procedure can serve as a highly effective and green strategy for the recovery of taro leaf polyphenols opening new horizons in the valorization of underutilized by-products from food and pharmaceutical sector.