霍山石斛生物碱的提取及铁皮石斛的鉴别

采用超声波辅助酶法提取霍山石斛中的生物碱，通过对固液比、超声时间、超声功率、酶解时间、复合酶（纤维素酶和果胶酶1∶1等活力混合）质量分数的单因素试验和正交试验，确定提取最佳的条件；通过气相色谱-质谱法对霍山石斛中生物碱的组成成分进行分析；通过傅里叶变换红外光谱及二阶导数变换谱图快速鉴定霍山石斛和铁皮石斛。结果表明，当固液比为1:40（g·mL^-1），超声时间为20 min，超声波功率为200 W，复合酶（纤维素酶和果胶酶1∶1等活力混合）添加量1.5%，酶解时间1.5 h为提取条件时，提取效率最佳，生物碱得率为0.053%。根据气相色谱-质谱法检测结果可得知，相对于铁皮石斛，霍山石斛的石斛碱和6-羟基石斛次碱为其特殊生物碱。二阶导数变换谱图可更直观地通过二者峰形状、个数和强度的不同来区分。因此，可以将气相色谱质谱联用和傅里叶红外光谱结合在一起来高效鉴定霍山石斛与铁皮石斛。

Extraction of alkaloids from Dendrobium huoshanense and its identification with Dendrobium officinale

The alkaloids from Dendrobium huoshanense were extracted by ultrasound-assisted enzyme method, and single factor and orthogonal tests were used to determine the best conditions for extraction, which were solid-liquid ratio, ultrasonic time, ultrasonic power, enzymolysis time, and mass fraction of complex enzyme (cellulase and pectinase at 1:1). The constituents of alkaloids in D. huoshanse were analyzed by gas chromatography-mass spectrometry; D. huohanense and D. officinale were identified by Fourier transform infrared spectroscopy and second derivative transform. The results showed that when the ratio of solid to liquid was 1:40 (g·mL^-1), ultrasonic time was 20 min, ultrasonic power was 200 W, the addition of compound enzyme (cellulase and pectinase at 1:1) was 1.5%, enzymatic hydrolysis time was 1.5 h, the best extraction efficiency and 0.053% alkaloid yield were obtained. According to the detection results of gas chromatography-mass spectrometry, it could be known that compared with D. officinale, dendrobine and 6-hydroxycornerstone dendrobium of D. huoshanense were special alkaloids. The second derivative transformation spectrum could be more intuitively distinguished by the differences in the peak shape, number and intensity. In conclusion, the combination of gas chromatography-mass spectrometry and Fourier transform infrared spectroscopy can be used to efficiently identify D.huohanense and D. officinale.