三种石斛及其提取物的红外光谱法整体结构解析与鉴定

运用红外光谱法对铁皮石斛、金钗石斛、鼓槌石斛及其两种提取物所含化学成分的红外谱图整体变化规律进行解析和鉴定。采用傅里叶变换红外光谱对三种石斛及其提取物进行结构分析及鉴别。原药材粉末一维红外光谱图反映出铁皮石斛、金钗石斛和鼓槌石斛均含有2 920，2 852，1 737和1 509 cm-1附近的特征峰；1 000~1 200 cm-1波段内的特征峰，推测三种石斛均含有脂类、芳香类和淀粉类成分。二阶导数谱进一步佐证了以上结果。根据峰强来判断三种石斛所含化合物含量的差别，得出铁皮石斛和金钗石斛中的脂类和淀粉类成分含量较鼓槌石斛高，三者中以金钗石斛的脂类成分、铁皮石斛的多糖成分含量较高。三种石斛原药材粉末二阶导数光谱中观察到1 318和782 cm-1处草酸钙的吸收峰。三种石斛的两种提取物中的成分种类和含量与其原药材均有所不同，且不同种石斛之间也存在峰形、峰位、峰强的差别。在水提醇沉提取物、无水乙醇提取物中均发现油脂类、芳香类和多糖类成分的特征吸收峰。与标准品比对分析发现，金钗石斛和鼓槌石斛的多糖成分以淀粉为主，而铁皮石斛则以黏多糖为主；三种石斛无水乙醇提取物的红外光谱分析更清楚地发现脂类成分和芳香类成分的存在，且脂类成分以金钗石斛提取物的含量相对较高。芳香类成分以鼓槌石斛提取物的含量相对较高，红外光谱整体结构解析与鉴定方法能够递进式地验证铁皮石斛、金钗石斛和鼓槌石斛所含物质结构和量的差异，适合于不同种石斛的快速鉴别及质量评价与控制。

Analysis and Identification of Integral Structure of Dendrobium officinale Kimura et Migo,Dendrobium nobile Lindl. and Dendrobium chrysotoxum Lindl. and Their Extracts by Infrared Spectroscopy

To analyze and identify the Dendrobium officinale Kimura et Migo., Dendrobium nobile Lindl. and Dendrobium chrysotoxum Lindl. as well as their two extracts by using the Fourier transform infrared spectroscopy (FTIR). Fourier transform infrared spectroscopy (FTIR) was used to analyze and identify the structures of Dendrobium officinale Kimura et Migo., Dendrobium nobile Lindl., and Dendrobium chrysotoxum Lindl. as well as their extracts. The structural information of samples showed that all the Dendrobium officinale Kimura et Migo., Dendrobium nobile Lindl., and Dendrobium chrysotoxum Lindl. contained the characteristic absorption peaks in the range of 2 920, 2 852, 1 737 and 1 509 cm-1. Additionally, the presence of characteristic absorption peaks in the range of 1 000～1 200 cm-1 presumed that lipids, aromatics and starches were contained in all of these three Dendrobium samples. The above results were confirmed by the secondary derivative infrared spectra (SD-IR). In addition, according to the peak strength determine the difference in compound content contained in the three kinds of Dendrobium, and the secondary derivative infrared spectra also showed that the contents of lipids and starches were higher in the Dendrobium officinale Kimura et Migo. and Dendrobium nobile Lindl. than those in the Dendrobium chrysotoxum Lindl.. The content of lipids in the Dendrobium nobile Lindl. and the content of polysaccharides in the Dendrobium officinale Kimura et Migo were higher than those in the other two samples. Meanwhile, the characteristic absorption peaks of the calcium oxalate at 1 318 and 782 cm-1 were observed in the secondary derivative infrared spectra (SD-IR). The component and content of both two extracts were different from each corresponding samples, and the differences of peak shape, peak location and peak strength in different Dendrobium samples were also observed. The characteristic absorption peaks of lipids, aromatics and polysaccharides were observed in both water extraction and alcohol precipitation extract and anhydrous ethanol extract. Further comparison with the standard substance indicated that the main polysaccharides in Dendrobium nobile Lindl., and Dendrobium chrysotoxum Lindl. were starches which were mucopolysaccharide in Dendrobium officinale Kimura et Migo. The lipide and aromatic series were confirmed by infrared spectrum, and the aromatic series in the Dendrobium chrysotoxum Lindl was higher. Integral structure analysis based on infrared spectrum contributed to the identification of differences in the Dendrobium officinale Kimura et Migo., Dendrobium nobile Lindl., and Dendrobium chrysotoxum Lindl. The method is suitable to be used for rapid identification, quality evaluation and control for various cultivars, which provides the foundation for systemic identification of Dendrobium.