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

Abstract

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 β-cyclodextrin (β-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 sample), total flavonoid content (4.66 mg catechin equivalents g−1 sample), and antioxidant activity in terms of 2,2-diphenyl-1-picrylhydrazyl radical inhibition (80.70%) and ferric-reducing antioxidant power (85.39 μmol trolox equivalents g−1 sample) could be obtained by ultrasonication of leaves at 59.6 °C for 55.4 min using an ethanolic solution (50% v/v) of β-CD (15 mM) and a solvent-solid ratio of 25.4 mL g−1. The extract obtained with β-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.