低共熔溶剂提取光果甘草渣中光甘草定和总黄酮及预处理效果

Extraction of glabridin and total flavonoids from Glycyrrhiza glabra L.residues using deep eutectic solvents and its pretreatment effect

甘草的根茎是一种常用中药材,其原料利用率较低.因此以富含光甘草定的光果甘草渣为原料,开展微波辅助低共熔溶剂提取光甘草定等黄酮类化合物的研究.优化后的提取条件为:氯化胆碱:丙酸=1:4,含水率10%,液固比30 mL/g,80℃提取60 min。在此条件下,光甘草定和总黄酮提取率分别为0.58 mg/g和29.68 mg/g.经低共熔溶剂提取后,甘草渣中的木质素和半纤维素去除率均超过60%,超过80%的纤维素得以保留;纤维素的可及度提高,聚合度降低;纤维素晶体粒径增大,表面积增加;甘草渣孔隙度增大,生物质半透明化.这些变化共同导致了提取后甘草渣酶解效率的提高.本研究表明微波辅助低共熔溶剂提取甘草渣中功效组分的同时具有预处理的效果,研究结果为后续甘草渣中纤维素的利用提供了基础.(图9表2参31)

Radix glycyrrhizae was a commonly used herbal drug in traditional Chinese medicine;however,the raw material utilization ratio was often low.Glycyrrhiza glabra L.residues rich in glabridin were used as raw materials for extracting glabridin and total flavonoids using deep eutectic solvents(DES)in this study.This study revealed that the optimum extraction conditions were a mole ratio of choline chloride to propanoic acid of 1:4,10%water in DES,a liquid-to-solid ratio of 30:1(V/m,mL/g),a temperature of 80℃,and an extraction time of 60 min.With these conditions,the study achieved a glabridin yield of 0.58 mg/g and a total flavonoid yield of 29.68 mg/g.After DES extraction,over 60%of the lignin and hemicellulose in G.glabra L.residues were removed,while over 80%of the cellulose was retained.After DES extraction,cellulose became more accessible,and its degree of polymerization decreased.X-ray diffraction analysis revealed an increase in the size and surface area of the cellulose crystals.Scanning electron microscopy demonstrated visible pores and cracks on the surface,and the biomass appeared translucent.These changes had a significant impact on the enzymatic digestion efficiency of G.glabra residues after extraction.Consequently,this study demonstrated that microwave-assisted deep eutectic solvent extraction simultaneously had a pretreatment effect on the G.glabra residue,which created a basis for subsequent cellulose utilization.