Extraction, Preconcentration and Isolation of Flavonoids from Apocynum venetum L. Leaves Using Ionic Liquid-Based Ultrasonic-Assisted Extraction Coupled with an Aqueous Biphasic System.

Zhijian Tan,Yongjian Yi,Chaoyun Wang,Hongying Wang,Wanlai Zhou

doi:10.3390/molecules21030262

Abstract

Background: Ionic liquids (ILs) are considered as green solvents, and widely applied for the extraction of various compounds. Methods: The present research focuses on the extraction of flavonoids from Apocynum venetum L. leaves by ultrasound-assisted extraction (UAE). Several major influencing factors were optimized. Then, an aqueous biphasic system (ABS) was applied for further isolation of flavonoids. Results: The flavonoids were mainly distributed in the top phase, while impurities were extracted to the bottom phase. The parameters influencing the extraction, namely type and concentration of salt, temperature, and pH, were studied in detail. Under optimized conditions (72.43% IL extract, 28.57% (NH4)2SO4, 25 °C temperature, pH 4.5), the preconcentration factor and extraction efficiency were found to be 3.78% and 93.35%, respectively. Conclusions: This simple and efficient methodology is expected to see great use in the extraction and isolation of pharmaceutically active components from medicinal plant resources.

Highlights

Apocynum venetum L., belonging to the family Apocynaceae, is a traditional medicinal plant distributed throughout mid- and north-western China, mainly in the Xinjiang Uygur AutonomousRegion
Some other assisted technologies coupled with Ionic liquids (ILs), such as ionic liquid-based ultrasonic-assisted extraction (IL-ultrasound-assisted extraction (UAE)) [13], ionic liquid-based microwave-assisted extraction (IL-MAE) [14], and ionic liquid-based negative pressure cavitation-assisted extraction (IL-NPCE) [15], provide remarkable advantages in the extraction and separation field
IL-UAE coupled with aqueous biphasic system (ABS) were applied for the extraction of flavonoids from

Summary

Introduction

Apocynum venetum L., belonging to the family Apocynaceae, is a traditional medicinal plant distributed throughout mid- and north-western China, mainly in the Xinjiang Uygur AutonomousRegion. A. venetum has several pharmacological effects such as lowering blood pressure, antidepressant, anti-anxiety, antinephritis and antineurasthenia [1,2,3,4]. The flavonoids present as the major active constitutes in A. venetum leaf are responsible for the pharmacological effect of lowering blood pressure, scavenging free radicals and anti-inflammatory action [6,7,8]. Room temperature ionic liquids (ILs) are molten salts with a melting point below 100 ̋ C. They are composed of organic cations and inorganic anions. Methods: The present research focuses on the extraction of flavonoids from Apocynum venetum L. leaves by ultrasound-assisted extraction (UAE). Conclusions: This simple and efficient methodology is expected to see great use in the extraction and isolation of pharmaceutically active components from medicinal plant resources

Methods

Results

Conclusion