绿色高效液相色谱法分析四种虫草药材的游离和总甾醇含量

虫草类药材采用85%乙醇超声提取游离甾醇、采用0.5 mol/L氢氧化钾-乙醇溶液回流提取总甾醇，并用绿色溶剂(乙醇和水)固相萃取法纯化分析溶液。用HPLC-ELSD法测定麦角甾醇、胆甾醇和谷甾醇的含量，色谱柱为Poroshell 120 EC-C₁₈ (100 mm×4.6 mm, 2.7 μm)，绿色流动相乙醇-水(89:11)，流速为0.5 mL/min，结果表明所建立的分析方法3种甾醇成分在考察的浓度范围内，线性关系好、精密度和准确度高。20批虫草类样品均含结合型甾醇和游离型甾醇；冬虫夏草繁育品与野生品均含3种甾醇，两者含量相当；凉山虫草(野生品)、蛹虫草(培植品)、蝉花(野生品)可检测到麦角甾醇。该方法可有效鉴别冬虫夏草和其他3种虫草产品，为虫草类产品质量评价提升提供了依据。

Determination of free and total sterols in four cordyceps species by green HPLC method

Cordyceps herbal samples were extracted by ultrasonic extraction with 85% ethanol for obtaining free sterols, and extracted by reflux extraction with 0.5 mol/L potassium hydroxide-ethanol solution for total sterols. The sample solution was purified by solid phase extraction with green solvent (ethanol and water). Determination of three kinds of sterols (ergosterol, cholesterol and sitosterol) separated from the samples was carried out by HPLC-ELSD, and performed on a Poroshell 120 EC-C₁₈ column (100 mm×4.6 mm, 2.7 μm) with green mobile phase (ethanol:water=89:11) at flow rate of 0.5 mL/min. The results showed that the developed analytical method had a good linear relation, precision and accuracy. All the 20 batches of cordyceps samples contain free and conjugated sterols. All the samples of cultivated and wild Ophiocordyceps sinensis contain three kinds of sterols of similar content. Cordyceps liangshanensis (wild), C. militaris (cultivated) and C. chanhua (wild) contain ergosterol. This method can be used to determine sterol content of cordyceps samples for improving the quality evaluation of cordyceps products.