藏药白沙蒿挥发油超临界CO2萃取工艺优化及其抗氧化活性研究

目的 采用Box-Behnken响应面法优化白沙蒿挥发油超临界CO₂萃取的最佳萃取工艺，并考察萃取物的抗氧化活性。方法 以白沙蒿挥发油的萃取得率为响应值，通过单因素试验筛选出萃取时间、萃取温度和萃取压力3个主要因素，进行Box-Behnken中心组合试验设计，建立挥发油提取得率的二次回归方程，得到优化组合条件。通过测定挥发油对1，1-二苯基-2-三硝基苯肼（1，1-diphenyl-2-picrylhydrazyl，DPPH）和2，2'-联氮-双-3-乙基苯并噻唑啉-6-磺酸[2，2'-azino-bis（3-ethylbenzothiazoline-6-sulfonic acid），ABTS]自由基的清除能力评价其抗氧化活性。结果 白沙蒿挥发油的最佳萃取工艺为萃取时间55 min，萃取温度59℃，萃取压力32 MPa，在此条件下挥发油萃取得率为（1.99±0.087）%，约为传统的水蒸气蒸馏法（萃取得率为1.05%）的1.9倍。超临界CO₂萃取的白沙蒿挥发油DPPH和ABTS自由基的IC₅₀值分别为0.264和0.045 mg·mL^-1。结论 优化后的白沙蒿挥发油萃取工艺稳定可靠，萃取的挥发油具有良好自由基清除作用，有望成为一种新的天然抗氧化剂。

Study on the Extraction Process and Antioxidant Activity of Volatile Oil from Tibetan Medicine Artemisia Sphaerocephala Krasch.

OBJECTIVE To optimize the supercritical CO₂ extraction process of volatile oil of Artemisia sphaerocephala Krasch. by Box-Behnken response surface methodology and the antioxidant activity of the extract was investigated. METHODS With the extraction yield of Artemisia sphaerocephala Krasch. volatile oil as the response value, three main factors of extraction time, extraction temperature and extraction pressure were screened out through a single factor experiment. The Box-Behnken central combination test design was conducted to establish a secondary regression of the extraction yield of volatile oil. Optimal combination conditions was obtained. The antioxidant activity was evaluated by measuring the scavenging ability of volatile oil to 1,1-diphenyl-2-picrylhydrazyl(DPPH) and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)(ABTS) free radicals. RESULTS The best extraction process of Artemisia sphaerocephala Krasch. volatile oil was extraction time 55 min, extraction temperature 59 ℃, extraction pressure 32 MPa. Under this condition, the extraction yield of volatile oil was(1.99±0.087)%, which was about 1.9 times that of the traditional steam distillation method(extraction yield rate was 1.05%) 1.9 times. The IC₅₀ values of DPPH and ABTS radicals of Artemisia sphaerocephala Krasch. volatile oil extracted by supercritical CO₂ were 0.264 and 0.045 mg·mL^-1, respectively. CONCLUSION The optimized extraction process of Artemisia sphaerocephala Krasch. volatile oil is stable and reliable, and the extracted volatile oil has good free radical scavenging effect, which is expected to be a new kind of natural antioxidant.