忧遁草总皂苷的提取工艺及其抗氧化活性研究

Extraction of Total Saponins from Clinacanthus nutans and Its Antioxidant Activity

摘要:

为了探究忧遁草中总皂苷的最佳提取工艺条件、组成成分和抗氧化能力，采用单因素和响应面设计实验，优化超声辅助提取忧遁草总皂苷的工艺条件，采用超高效液相色谱-四级杆飞行时间串联质谱（UPLC-QTOF-MS） 分析最佳工艺条件下的总皂苷组成并进行抗氧化活性的检测。结果表明：最佳提取参数为乙醇体积分数92%，料液质量体积比1 g∶44 mL，提取时间0.6 h，温度66 ℃，此时忧遁草总皂苷的提取率为2.30%，并且从中鉴定出5种三萜皂苷；抗氧化实验表明，忧遁草总皂苷具有较强的抗氧化活性，其质量浓度与ABTS+清除率、DPPH+清除率和Fe3+还原力呈现较好的相关性，对应自由基清除率的半抑制质量浓度分别为0.407 mg/mL和0.562 mg/mL。研究结果为进一步开发利用忧遁草皂苷提供了有益的参考信息。

Abstract:

In order to explore the optimal extraction conditions, composition and antioxidant capacity of total saponins from Clinacanthus nutans, single factor and response surface methodology were used to optimize the ultrasonic-assisted extraction conditions of total saponins from Clinacanthus nutans. The composition of total saponins under the optimal extraction conditions was analyzed by ultra-performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-QTOF-MS) and the antioxidant activity was detected. The results indicated that the optimal extraction parameters included 92% volume fraction of ethanol, solid-liquid ratio of 1 g∶44 mL, extraction time of 0.6 h, and extraction temperature of 66 ℃, which yielded a total saponin extraction rate of 2.30%. Five triterpene saponins were then identified. The antioxidant experiment showed that the total saponins of Clinacanthus nutans had strong antioxidant activity, and there was a good correlation between their mass concentration and their ABTS+ scavenging rate, DPPH+ scavenging rate, and Fe3+ reduction ability. The corresponding semi-inhibitory concentrations to free radical scavenging rate were 0.407 mg/mL and 0.562 mg/mL, respectively. The results provide beneficial reference information for further development and utilization of saponins from Clinacanthus nutans.