| Natural products are a general term for biological components or their metabolites,they mostly belong to “medicine-eating homologs” in the plant kingdom,and have complex chemical composition and diverse biological activities.For example,glycoside compounds are widely presented in botanicals and have special biological activities and medicinal properties;while anthocyanidins also widely existing in nature which have health and pharmacological functions such as antioxidant,hypolipidemic,anti-atherosclerotic,enhanced immunity anemia and anti-tumor.With the increasing research on the functional activity of natural compounds,its green and efficient extraction and preparation technology has gradually become a research hotspot in this field.Deep eutectic solvent(DES)is a green solvent that can replace traditional organic solvents because of its biodegradability,non-toxicity,easy preparation and high atomic utilization which has shown great potential in the separation and enrichment of natural products.In this study,37 DES of four categories were selected for solvents while using polygonum cuspidatum and black plum as the extraction models of glycosides and anthocyanidins.The extraction reaction conditions of high efficiency were obtained by optimizing the molar ratio of DES,water content,liquid-material ratio,extraction temperature and extraction time.Taking the extraction of polydatin and heptophan as a model,the application of choline chloride: lactic acid in the extraction of glycosides and anthocyanidin was discussed,which provided a basis for the efficient extraction of these two substances.In the water bath extraction,when the extract solvent,liquid-to-liquid ratio,extraction temperature and extraction time were choline chloride: lactic acid(1:3,water content 25%),15:1 mL/g,55 °C and 25 min,respectively,the extraction rate of glycosides was 15.60 mg/g.Furthermore,ultrasonic assisted extraction was applied under these conditions,when the ultrasonic power was 200 W and theultrasonic time was 30 min,the extraction rate was 18.52 mg/g.Compared with DES-water bath,the extraction yield was increased by about 20%,it was indicated that ultrasound could significantly improve the extraction of polydatin.On the other hand,when the extract solvent was Choline chloride: lactic acid(1:2,water content 20%),liquid-to-liquid ratio was 15:1,extraction temperature 65 °C and extraction time 60 min,the extraction rate of anthocyanidin from black plum was reached up to 5.81 mg/g.Ultrasonic assisted extraction of anthocyanidin was performed under the optimal condition.When the ultrasonic power was 250 W,the extraction rate of the anthocyanidin of Heblin was 7.58 mg/g,which was 30%higher than that of the water bath.The extraction rate was 7.63 mg/g for 30 min of ultrasonic time,which was about 20% higher than that of DES-water bath extraction,and the extraction time was shortened by 30 min.The optimal conditions for extraction of polydatin and black plum anthocyanidin by DES after response surface optimization were used to extract other glycosides and anthocyanidin,respectively.It was found that DES had a good extraction effect among 8 glycosides and 9 sources anthocyanidins. |
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