关键词: 竹柏叶, 总黄酮, 回流提取, 超声波提取

Abstract: In this study,the reflux extraction and ultrasonic extraction processes of total flavonoids from Podocarpus nagi leaves were optimized using orthogonal experiments.Based on single factor experiments,the effects of liquid to solid ratio,ethanol concentration,extraction time and extraction temperature on the yield of total flavonoids were investigated,and orthogonal experiments were applied to further optimize extraction conditions.The results showed that the optimal conditions of reflux extraction were confirmed as follows:liquid to solid ratio of 30:1 (mL:g),70% EtOH as extraction solvent,refluxing for 1.0 h at 80 ℃,and the extraction yield of flavonoids was 15.522%.The optimal conditions of ultrasonic extraction were determined as follows:liquid to solid ratio of 25:1 (mL:g),ultrasonication for 30 min at 60 ℃with 70% EtOH,and the extraction yield of flavonoids was 13.637%.The extraction yield of total flavonoids with reflux extraction method was higher,while ultrasonic extraction was considerable time-saving.This result can provide the basis for the utilization of flavonoids in P.nagi.

Key words: Podocarpus nagi leave, flavonoids, reflux extraction, ultrasonic extraction