Comparison of the effect of extraction methods on the waste cotton (Gossypium hirsutum L ) flowers: metabolic profile, bioactive components, antioxidant, and α-amylase inhibition.

Abstract

Waste cotton flowers, as a by-product of cotton cultivation, are enriched with bioactive substances that render them a promising natural source of health-promoting benefits. In this study, ultrasound-assisted extraction (UAE), subcritical water extraction (SWE) and conventional extraction (CE) approaches were applied to extract bioactive compounds from waste cotton flowers, and metabolic profile, bioactive components, antioxidant, and α-amylase inhibition of different extractions were systematically analyzed and compared. It was observed that the UAE and CE extract had similar metabolic profiles compared with SWE. The flavonoids and amino acids and derivatives were more prone to be extracted by UAE and CE, while phenolic acids tended to accumulate in SWE extract. The UAE extract had the highest amounts of total polyphenols (214.07 mg GAE/g DW) and flavonoids (33.23 mg RT/g DW) as well as the strongest inhibition on oxidation (IC50 =10.80 μg/mL) and α-amylase activity (IC50 =0.62 mg/mL), indicating that chemical composition was closely related to biological activity. Additionally, microstructures and thermal behaviors of the extract were investigated and highlighted the ability of UAE. Overall, it can be concluded that UAE is an efficient, green, and economical extraction method to produce bioactive compounds from cotton flowers, and the UAE extracts could be used in food and medicine industries because of their high antioxidant and α-amylase inhibitory activity. This study provides scientific basis for the development and comprehensive utilization of cotton by products. This article is protected by copyright. All rights reserved.