FTIR光谱快速鉴别刺梨黄酮的研究

采用傅里叶变换红外光谱（FTIR）分析了新鲜野生刺梨果肉、烘干刺梨果肉以及室温存放数日后刺梨果肉的红外光谱特性。为对比新鲜果肉与烘干果肉样品中刺梨黄酮的红外光谱特性，以新鲜野生刺梨果实为研究对象，分别采用了超声辅助溶剂萃取法和超声结合酶辅助半仿生法提取刺梨黄酮。并使用无水乙醇作为超声辅助溶剂萃取法的萃取剂萃取刺梨黄酮，以及使用胃蛋白酶，胰酶和胆汁等模仿胃肠消化的环境，在模拟半仿生条件下提取刺梨黄酮。在两种提取方法中，新鲜果肉和烘干果肉分别反应了0，0.5，1，1.5，2和2.5 h。分别测定了新鲜果肉刺梨黄酮和烘干果肉刺梨黄酮的红外光谱数据。然后，通过分析刺梨黄酮的红外光谱特性，比较了两种方法所提取刺梨黄酮的最佳特征波长组合，得知在相同的反应条件下，反应时间为1.5 h时，超声辅助溶剂萃取法中新鲜果肉与烘干果肉提取物红外光谱对应的透射率强度分别为83.5%和84%；超声结合酶辅助半仿生法中新鲜果肉与烘干果肉提取物红外光谱对应的透射率强度分别为32%和38%。因此，结合郎伯-比尔定律可知，反应时间相同时，对于刺梨黄酮的提取，超声结合酶辅助半仿生法优于超声辅助溶剂萃取法。除此之外，我们发现随着反应时间延长，两种提取方法所获提取物的红外光谱吸收峰强度均呈上升趋势，但是反应2 h后该提取物的红外光谱吸收峰强度趋于平稳。结果表明，刺梨黄酮在3 419 cm-1（羟基O-H伸缩振动）、1 615 cm-1（羰基C═O键伸缩振动）和1 053 cm-1（烷基）处的红外吸收峰对刺梨的新鲜程度具有较好的识别效果；通过比较分析，新鲜果肉与室温存放数日后果肉中的刺梨黄酮物质的红外光谱吸收峰分别与槲皮素和山奈酚吸收峰波数一致；在相同实验条件下，两种提取方法中烘干果肉刺梨黄酮提取物浓度均高于新鲜刺梨果肉。该研究可为刺梨功能化药品和食品的制作及鉴定提供参考。

Study on the Rapid Identification of Flavonoids in Chestnut Rose (Rosa Roxburghii Tratt) by FTIR

The fresh, dried chestnut rose (CR) (Rosa roxburghii Tratt) and stored for several days wild CR pulp were analyzed by using the infrared spectral technology of Fourier transform infrared spectrometer (FTIR) at room temperature in this paper. To compare the spectral characteristics of fresh and dried CR pulp, we extracted their flavonoids by the ultrasonic-assisted solvent extraction (UASE) method and ultrasonic combined enzyme-assisted semi-bionic (UCES) method, respectively. Moreover, absolute ethanol was used to extract CR flavonoids in the UASE method for the extraction of CR flavonoids. And then Pepsin, tryps in and bile were used to simulate the environment of enzyme assisted gastrointestinal digestion for the extraction of Flavonoids from Rosa roxburghii Tratt. The Fresh pulp and Dried pulp were respectively reacted for 0, 0.5, 1, 1.5, 2 and 2.5 h in the two extraction methods. First of all, the infrared spectra data of fresh pulp and dried pulp were measured. Then, by comparing the optimal characteristic wavelength combination of the two methods for extracting CR flavonoids, we found that under the same reaction conditions, when the reaction time is at 1.5 h, the transmittance intensities of the infrared spectrum from the fresh CR and the dried CR in the UASE method were 83.5% and 84%, respectively; in the UCES method, their transmittance intensities were 32% and 38%, respectively. Therefore, combined with Lambert-Beer’s law, when the reaction time was the same, the UCES method was superior to the UASE method for extracting CR flavonoids. Besides, with the increase of reaction time, the infrared absorption peak intensity of the two extraction methods showed an upward trend. After being reacted for 2 h, the absorption peak was gradually stable. The results showed that the infrared absorption peaks at 3 419 cm-1 (hydroxyl group O-H stretching vibration), 1 615 cm-1 (Carbonyl C═O bond stretching vibration) and 1 053 cm-1 (alkyl group) of the CR flavonoids could be distinguished. The infrared absorption peaks of flavonoids in fresh pulp and stored at room temperature for several days were consistent with that of quercet in and kaempferol. Under the same experimental conditions, the flavonoids concentration of dried CR was higher than that of fresh CR pulp. This research can provide references for identifying the production of functional medicines and foods of chestnut rose.