肉桂不同部位及其挥发油的红外光谱宏观表征

目的:考察肉桂不同部位(树皮、嫩枝、叶)及其挥发油的红外指纹图谱差异,为研究其不同部位所含化学成分特征提供参考依据。方法:采用傅里叶变换红外光谱法及二阶导数红外光谱法。结果:肉桂的树皮、嫩枝、叶原粉末红外光谱整体峰形较相似,三者均含有草酸钙、多酚类及糖苷类成分;嫩枝和叶在1 653 cm-1和1 734 cm~(-1)附近的特征峰要明显强于皮,推测嫩枝和叶中饱和脂肪酸酯类成分和黄酮类成分的含量要高于皮。采用二阶导数放大后,发现在1 480~1 435 cm~(-1)和1 630~1 580 cm~(-1)时,嫩枝有2个特征峰,而叶在相应位置只有1个特征峰。树皮、嫩枝、叶挥发油红外光谱与桂皮醛的光谱相近,通过相关系数的计算,发现三者挥发油中桂皮醛含量大小依次为树皮嫩枝叶;在1 734 cm~(-1)处附近,嫩枝和叶挥发油的峰强要明显大于树皮,说明嫩枝和叶的挥发油中还含有其他结构的酯类化合物。通过比较二阶导数光谱中1 275 cm~(-1)处峰附近的高低,可以进一步区分嫩枝和叶的挥发油。结论:红外光谱及二阶导数红外光谱法,不仅可以分析肉桂不同部位及其挥发油的整体化学成分差异,还可以区分含有相似成分的不同部位。

Macroeconomic Characterization of Infrared Spectrum of Different Parts of Cinnamomum cassia and Their Essential Oil

Objective: To investigate the infrared fingerprint differences between different parts of Cinnamomum cassia and their essential oil, and provide a reference basis for studying their chemical composition characteristics. Method: The Fourier transform infrared spectroscopy (FT-IR) method and second derivative infrared spectroscopy (SD-IR) were used. Result: The holistic shape of peaks was similar in the FTIR spectra of the bark, branch and leaf of C. cassia. The structural information of the samples indicated that all of the three parts contained calcium oxalate, polyphenols and polysaccharides. The characteristic peaks of branch and leaf were stronger than that of bark at around 1 653 cm^-1 and 1 734 cm^-1, which proved that the quantity of saturated fatty acid esters and flavones in the branch and leaf was higher than that in the bark. At the range of 1 480-1 435 cm^-1 and 1 630-1 580 cm^-1, the spectra of branch showed two characteristic peaks, while the leaf showed only one peak at the corresponding site in second derivative IR method. The IR spectra of the essential oil of bark, branch and leaf was akin to that of cinnamaldehyde. The similarity calculation results showed that the content of cinnamaldehyde in essential oil was in the order of bark > branch > leaf. Near 1 734 cm^-1, the peak intensity of essential oil in branch and leaf was stronger than that in bark, which indicated that essential oil of branch and leaf contained ester compounds of other structures. By comparing the conditions of the peaks around 1 275 cm^-1 in the second derivative spectra, the essential oil in branch and leaf was further distinguished. Conclusion: The FT-IR and SD-IR can not only analyze the differences in holistic chemical constituents in different parts of C. cassia and their essential oil, but also can identify the different parts with similar components.