为了研究陈皮中黄酮类化合物太赫兹波段的指纹特征与其结构信息之间的变化关系，利用太赫兹时域光谱技术并结合密度泛函理论对陈皮中黄酮类化合物的太赫兹吸收光谱进行了仿真模拟和实验分析。首先，利用黄酮类化合物压片实验得到了在0.2~2.0 THz频段中橙皮苷、川陈皮素和橘皮素的太赫兹吸收谱，发现橙皮苷在1.63和1.89 THz处呈现出2个明显特征吸收峰，川陈皮素在0.42、0.66、0.97和1.51 THz处具有4个特征吸收峰，橘皮素在0.41、0.53和1.03 THz处可以观察3个吸收峰，接着，基于密度泛函理论的B3LYP杂化泛函方法，采用6-31G（d, p）和6-311G（d, p）基组对陈皮中橙皮苷、川陈皮素和橘皮素等典型黄酮类化合物分子进行太赫兹振动光谱的模拟计算。结果表明，酮类化合物的吸收峰大部分来自于其二面角的扭转振动，最大比例分别为13.0%、17.0%和25.2%。该研究揭示了酮类化合物太赫兹特征峰的响应机理，对开展陈皮中黄酮类化合物的太赫兹光谱快速检测具有重要的参考价值。

To study the changing relationship between the fingerprint characteristics of tangerine peel’s flavonoids in the terahertz band and their structural information, terahertz time-domain spectroscopy (THz-TDS) technique combined with density functional theory (DFT) was used for simulation and experimental analysis of the terahertz absorption spectra of the flavonoids in thetangerine peel. First, the terahertz absorption spectra of hesperidin, nobiletin and tangeretin in the 0.2~2.0 THz frequency band were obtained by using flavonoid compound tablet experiments. It was found that hesperidin exhibited two distinct characteristic absorption peaks at 1.63 and 1.89 THz. Nobiletin has four characteristic absorption peaks at 0.42, 0.66, 0.97 and 1.51 THz, tangeretin can observe three absorption peaks at 0.41, 0.53 and 1.03 THz. Then, the B3LYP hybrid functional method based on density functional theory used the 6-31G (d, p) and 6-311G (d, p) basis groups to analyze the hesperidin, nobiletin and tangeretin in the tangerine peel, and their terahertz vibrational spectra were simulated and calculated. The results showed that most of the absorption peaks of flavonoids came from the torsional vibration of their dihedral angles, and the highest proportion was 13.0%, 17.0% and 25.2%, respectively. This study reveals the response mechanism of terahertz characteristic peaks of flavonoids, which has important reference value for rapid detection of flavonoids in the tangerine peel by terahertz spectroscopy.

广东省乡村振兴战略专项项目（2022KJ101）