小檗碱与表小檗碱结构和光谱差异的理论研究

Theoretical Study on Structural and Spectral Differences between Berberine and Epiberberine

摘要: 小檗碱和表小檗碱互为同分异构体，两者无论在药理活性还是在体内吸收、分布等药动学特性上均存在差异和选择性。本文采用量子化学方法系统地研究了小檗碱和表小檗碱的结构、紫外光谱和红外光谱特征。研究表明，小檗碱、表小檗碱均是单重态的形式最稳定。相对于小檗碱，亚甲二氧基和二个甲氧基位置的互换，导致表小檗碱的紫外光谱发生了红移，并出现了肩峰，该峰主要由于p电子和苯环上的π电子组成的p-π共轭的电子跃迁引起。表小檗碱的骨架振动、杂环c的C-N和C-C的伸缩振动相对于小檗碱的发生了红移，而苯环a的呼吸振动发生了蓝移。表小檗碱的偶极矩和极化率大于小檗碱。

Abstract: Berberine and epiberberine are isomers of each other, and there are differences and selectivity in pharmacokinetic properties such as pharmacological activity, absorption and distribution in vivo. The structures, UV and IR spectra of berberine and epiberberine were studied by quantum chemistry methods. The results show that the most stable form of berberine and epiberberine are singlet state. Relative to berberine, the exchange of the positions of methylene dioxygen and two methoxy groups leads to the redshift of the ultraviolet spectrum of epiberberine and the appearance of the acromion, which is mainly caused by the electron transition of the p-π conjugate composed of the p electron of the O and the π electron in the benzene ring. The skeleton vibration of epiberberine and the stretching vibrations of the C-N and C-C of heterocyclic c have redshifts, compared with these of berberine, while the respiratory vibration of benzene ring a showed a blue shift. The dipole moment and polarization of epiberberine are greater than these of berberine.