Optimization of Extraction of Bioactive Compounds from Baphicacanthus cusia Leaves by Hydrophobic Deep Eutectic Solvents.

Zhiqin Xu,Xinjun Xu,Zhimin Zhao,Yini Cai,Qing Ma,Depo Yang

doi:10.3390/molecules26061729

Zhiqin Xu, Xinjun Xu + Show 4 more

Open Access

https://doi.org/10.3390/molecules26061729

Copy DOI

Abstract

Deep eutectic solvents (DESs) are considered as efficient and green solvents for the extraction of bioactive compounds from medicinal plants. In this work, a novel method of DES-based ultrasound-assisted extraction of bioactive compounds from Baphicacanthus cusia leaves (BCL) was established. Systematic screening and the morphology of the original and treated BCL were observed with scanning electron microscopy to determine the extraction efficiency of different solvents. The extraction conditions were optimized by Box–Behnken design (BBD) tests and the optimal extraction conditions were as follows: lactic acid/L-menthol ratio of 5: 2 (mol/mol), solid–liquid ratio of 80.0 mL/g and temperature of 60.5 °C. The extraction yields of tryptanthrin, indigo and indirubin reached 0.356, 1.744 and 0.562 mg/g, respectively. The results of a 2,2-diphenyl-1-picrylhydrazy (DPPH) radical scavenging activity test indicated the feasibility of DESs in the extraction of bioactive compounds. This study indicated that L-menthol/lactic acid was a green and efficient solvent for the extraction of bioactive compounds from BCL, and DES-based ultrasound-assisted extraction could be used as an effective application strategy for the extraction of bioactive compounds from medicinal plants.

Highlights

The preliminary experiments found that hydrophilic Deep eutectic solvents (DESs) with choline chloride and betaine as hydrogen bond acceptors (HBA) have low extraction yields of three bioactive compounds of Baphicacanthus cusia leaves (BCL)
The extraction of the three target compounds was suitable for hydrophobic DES extraction
In order to reveal the effect of DESs, under the same ultrasound-assisted conditions, tryptanthrin, indirubin and indigo were extracted from BCL by using various kinds of DESs and traditional solvents, respectively

Summary

Introduction

Baphicacanthus cusia (Nees) Bremek is an herbal plant of the family Acanthaceae, mainly distributed in southern China, India and Myanmar. It is widely used as folk and clinical medicine [1,2,3]. The roots, stems and leaves of Baphicacanthus cusia can all be used as medicine and are commonly used in antiviral therapy. Tryptanthrin, indirubin and indigo (Figure 1) are the main chemical constituents in Baphicacanthus cusia leaves (BCL), which display diverse activities. Indirubin is a treatment for chronic myeloid leukemia and has antiviral [13], anti-inflammatory [14] and antioxidant [15]

Methods

Results

Conclusion