AUTHOR=Yang Zhao , Yue Shi-Jun , Gao Huan , Zhang Qiao , Xu Ding-Qiao , Zhou Jing , Li Jia-Jia , Tang Yu-Ping TITLE=Natural deep eutectic solvent-ultrasound assisted extraction: A green approach for ellagic acid extraction from Geum japonicum JOURNAL=Frontiers in Nutrition VOLUME=9 YEAR=2023 URL=https://www.frontiersin.org/journals/nutrition/articles/10.3389/fnut.2022.1079767 DOI=10.3389/fnut.2022.1079767 ISSN=2296-861X ABSTRACT=Introduction

In China and other Asian nations, Geum japonicum (GJ) is used as functional vegetables or as a type of folk medicine. Ellagic acid (EA) is one of the main active ingredients in GJ and has been utilized in food, cosmetics, and medicinal goods worldwide. Natural deep eutectic solvents (NADESs) have gradually replaced organic solvents for efficient extraction of plant-derived active compounds due to its environmental protection, low toxicity, low solubility, reusability, etc.

Methods

NADES with the highest EA yield was selected and the extraction conditions were optimized by response surface methodology (RSM), the antioxidant activity of NADES extract was determined, and finally Fourier transform infrared (FT-IR) and scanning electron microscopy (SEM) were used to explain the mechanism for the increase of EA yield in GJ.

Results

In this work, several NADESs were tailored for the ultrasound assisted extraction (UAE) of EA from GJ, among which choline chloride-oxalic acid (ChCl:Oa) was the most effective. In optimal conditions, ChCl:Oa extract produced higher EA yields than common organic solvents including methanol, ethanol, and acetone. In vitro antioxidant experiments showed that ChCl:Oa extract had stronger DPPH radical scavenging ability than other solvent extracts. Mechanically, FT-IR results indicated that ChCl:Oa could form a hydrogen bonding with EA, which enhanced the stability of EA. Meanwhile, ChCl:Oa-UAE treatment could destroy the tissue structure of GJ, thereby improving EA yield.

Discussion

In conclusion, these results imply that the ChCl:Oa-UAE method might be an environmentally friendly approach for extracting EA from GJ.