Optimizing Ultrasound-Assisted Deep Eutectic Solvent Extraction of Bioactive Compounds from Chinese Wild Rice.

Jia Zeng,Ning Yan,Na Li,Yuqing Dou,Huaibao Zhang,Jia-Neng Tan

doi:10.3390/molecules24152718

Abstract

In this study, deep eutectic solvents (DESs) were used for the ultrasound-assisted extraction (UAE) of valuable bioactive compounds from Chinese wild rice (Zizania spp.). To this end, 7 different choline chloride (CC)-based DESs were tested as green extraction solvents. Choline chloride/1,4-butanediol (DES-2) exhibited the best extraction efficiency in terms of parameters such as the total flavonoid content (TFC), total phenolic content (TPC), and free radical scavenging capacity (DPPH● and ABTS●+). Subsequently, the UAE procedure using 76.6% DES-2 was also optimized: An extraction temperature of 51.2 °C and a solid–liquid ratio of 37.0 mg/mL were considered optimal by a Box–Behnken experiment. The optimized extraction procedure proved efficient for the extraction of 9 phenolic and 3 flavonoid compounds from Chinese wild rice as determined by quantification based on ultra-performance liquid chromatography–triple quadrupole tandem mass spectrometry (UPLC-QqQ-MS). This work, thus, demonstrates the possibility of customizing green solvents that offer greater extraction capacity than that of organic solvents.

Highlights

Chinese wild rice (Zizania latifolia), a nutritious whole grain, has been consumed in China for at least 3,500 years
The deep eutectic solvents (DESs) extraction efficiency was evaluated by considering the total flavonoid content (TFC) and total phenolic content (TPC) of the corresponding extract
The wild rice extract prepared using 7 different DESs was studied in comparison with those obtained using pure water and the conventional solvents 30% EtOH

Summary

Introduction

Chinese wild rice (Zizania latifolia), a nutritious whole grain, has been consumed in China for at least 3,500 years It contains proteins; minerals; vitamins; and a variety of phytochemicals such as phenolics, saponins, phytosterols, and anthocyanins [1,2,3], which can be attributed to many bioactivities including antioxidant, anti-inflammatory, antiobesity, and antianaphylactic actions [4,5,6,7,8]. The characterization and quantification of phenolic compounds from Chinese wild rice (Zizania spp.) is a task of high practical significance. These active substances need to be extracted prior to their use.

Methods

Results

Conclusion