喜树叶中生物碱成分提取工艺优化及抗菌抗氧化活性研究

Extraction Condition Optimization for Total Alkaloids from Leaves of Camptotheca acuminata and Its Antibacterial and Antioxidation Activity

运用响应面法优化喜树叶中总生物碱提取工艺并考察总生物碱提取物的抗菌及抗氧化活性。本文在单因素试验基础上,选定超声提取时间为40 min,并进一步选取料液比、超声功率、甲醇比例为自变量,以总生物碱提取率为响应值,利用Box-Benhnken中心组合设计3因素3水平试验,确定最佳提取工艺条件为:超声时间40 min,甲醇:甲酸:水=17. 5∶1∶1. 5,料液比1∶22 g/m L,超声功率240 W。在此条件下,生物碱的得率为1. 67±0. 08 mg/g。抗菌结果表明喜树叶总生物碱提取物(LAE)对S. aureus、E. coli和P. aeruginosa MIC值分别为4. 38,8. 75,8. 75μg/m L。LAE的总抗氧化能力较好,其FRAP值为0. 16±0. 01 mmol·L-1,对DPPH和ABTS自由基清除半抑制浓度分别为4μg/m L和3μg/m L。本研究为喜树次生代谢产物的进一步开发利用提供了参考依据。

Response surface methodology was applied to optimize the extraction condition for total alkaloids from the leaves of Camptotheca acuminate,and investigating their antibacterial and antioxidant activities.Preliminary single factor experiments show that solid-liquid ratio,ultrasonic power and methanol concentration notably altered the extraction efficiency,thus a Box-Behnken second-order polynomial model involving three factors at three levels was developed to investigate the favourable alkaloids extraction condition,while ultrasonic time was fixed as40min.The optimal conditions were determined as followings:methanol concentration(methanol∶formic acid∶water=17.5∶1∶1.5),solid-liquid ratio(1∶22g/mL),ultrasonic power(240W).Under these conditions,the extraction yield of total alkaloids is1.67±0.08mg/g.Leaf alkaloid extract(LAE)displays antibacterial activity against S.aureus,E.coli and P.aeruginosa,with MIC value4.38,8.75,8.75μg/mL,respectively.LAE displays significant antioxidant activity in ferric reducing antioxidant power(FRAP)and the IC50value for ABTS and DPPH scavenging tests is4μg/mL and3μg/mL.These results proved that the optimized extraction technology was reliable and provides a reference for further development and utilization of the metabolite resources of Camptotheca acuminata Decne.