红茂草生物碱正交提取工艺模式优化及清除自由基作用的研究

为研究红茂草(Dicranostigma leptodum(Maxim.)Fedde)生物碱的正交提取工艺条件及其清除自由基作用。采用单因素水平测定,从10种相关因素中筛选出乙醇体积分数、超声波作用时间、液料比、回流时间、浸提液pH值、浸泡时间共6种主要影响因素,按照L25(56)正交表进行正交试验,用SPSS 17.0软件进行统计分析,优选出最佳正交提取工艺模式;将正交提取浓缩液进行HPLC检测,并测定其对羟自由基(.OH)和氧自由基(O2.-)的清除作用。结果表明:红茂草生物碱最佳提取工艺条件为乙醇体积分数65%、超声波作用时间20min、液料比15∶1、回流时间2.5h、浸提液pH=8、浸泡时间4h;在最佳提取工艺条件下红茂草提取液中生物碱的含量为9.2794%;红茂草生物碱在25.0和1.8mg.mL-1时,对.OH和O2.-清除效果显著,其清除率为58.70%和49.26%,IC50为23.50和1.75mg.mL-1。该工艺方法简便、可靠、提取率高,提取液清除自由基作用显著。

Optimal Extract Processing of Alkaloids from Dicranostigma leptodum (Maxim.)Fedde by Orthogonal Design Mode and Its Scavenging Activity of Free Radicals

The technology of alkaloid orthogonal extraction from Dicranostigma Leptodum Fedde and its free radical scavenging effect were studied.Six main impact factors(volume fractions of alcohol,time of ultrasound,solid /liquid ratio,the pH of leach liquor and macerating time) were selected from 10 relevant elements by single factor test according to the L25(56) orthogonal table.Data were assessed with statistics analysis of SPSS 17.0.Optimum orthogonal extraction process was obtained.The orthogonal concentrated extract was measured by HPLC and its scavenging effect on hydroxyl radicals(·OH) and oxygen free radicals(O2-·) were also determined.The experimental results showed that the optimum extraction conditions were that volume fractions of alcohol was 65%,time of ultrasound was 20 min,solid/liquid ratio was 15∶1,refluxing time was 2.5 h,the pH of leach liquor was 8 and macerating time was 4 h.Alkaloid content was 9.2794% under the optimum condition.The 58.70% and 49.26% free radicals(both·OH and O2-·) could be scavenged(IC50 were 23.50 and 1.75 mg·mL-1) when alkaloid content were 25.0 and 1.8 mg·mL-1,respectively.These results also demonstrated that the optimum extraction process was simple,high dependability,high extraction rate and high scavenging rate of free radical.