Purification of the extract from pigeonpea leaves was studied.Multi-stage membrane separation and concentration using microfiltration,ultrafiltration,and nanofiltration membranes were conducted on the extract at room temperature.Concentrations of the major active ingredients in the filtrates were determined.The results indicated that 15.78% of the total flavonoids in the extract could be retained by the microfiltration membrane, 62.52% by the ultrafiltration membrane, and 97.92% by the nanofiltration membrane. By combining the membranes,the multi-stage filtration could remove as much as 50% of the solvent yielding a concentrated extract containing 50.13% flavonoids.The ultrafitration alone retained a vitexin concentration of 0.069 mg · g-1 and isovitexin of 4.31 mg/g,as determined by HPLC.It appeared that the multi-stage membrane filtration could significantly improve the efficiency of pigeon pea extract separation resulting in a highly concentrated filtrate as well as desired energy conservation.%在室温下采用微滤-超滤-纳滤多级膜分离纯化木豆叶提取液，分析木豆叶提取液主要有效成分在膜处理前后的保留情况。结果表明，微滤能截留提取液中15.78%的黄酮类物质，超滤能截留提取液中62.52%的黄酮类物质，而纳滤能截留提取液中97.92%的黄酮类物质，溶剂除去率达到了50%，木豆叶提取物中黄酮纯度可达50.13%。超滤浓缩液中牡荆苷含量可达0.069 mg·g-1(HPLC)，异牡荆苷含量为4.31 mg·g-1(HPLC)。经过膜处理，显著提高了木豆叶提取液的分离效率，达到了较好的高效浓缩和节能效果。
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