Zeng Wenliang, Han Han, Tao Yanyan, Yang Li, Wang Zhengtao, Chen Kaixian
The Ministry of Education Key Laboratory for Standardization of Chinese Medicines and the State Administration of Traditional Chinese Medicine, Key Laboratory for New Resources and Quality Evaluation of Chinese Medicines, Institute of Chinese Materia Medica, Shanghai University of Traditional Chinese Medicine, Shanghai 201210, China.
Biomed Chromatogr. 2013 Sep;27(9):1129-36. doi: 10.1002/bmc.2917. Epub 2013 Jun 4.
Gentiopicroside (GPS), the main bioactive component in Gentiana scabra Bge., has attracted our attention owing to its high bioactivity, especially the treatment of hepatobiliary disorders. The aglycone form of GPS, a typical secoiridoid glycoside, is considered to be more readily absorbed than its parent drug. This study aimed to identify and characterize the metabolites after GPS incubated with β-glucosidase in buffer solution at 37°C. Samples of biotransformed solution were collected and analyzed by ultraperformance liquid chromatography (UPLC)/quadrupole-time-of-flight mass spectrometry (Q-TOF MS). A total of four metabolites were detected: two were isolated and elucidated by preparative-HPLC and NMR techniques, and one of those four is reported for the first time. The mass spectral fragmentation pattern and accurate masses of metabolites were established on the basis of UPLC/Q-TOF MS analysis. Structure elucidation of metabolites was achieved by comparing their fragmentation pattern with that of the parent drug. A fairly possible metabolic pathway of GPS by β-glucosidase was proposed. The hepatoprotective activities of metabolites M1 and M2 were investigated and the results showed that their hepatoprotective activities were higher than that of parent drug. Our results provided a meaningful basis for discovering lead compounds from biotransformation related to G. scabra Bge. in traditional Chinese medicine.
龙胆苦苷（GPS）是龙胆的主要生物活性成分，因其高生物活性，尤其是在治疗肝胆疾病方面的活性，而引起了我们的关注。GPS的苷元形式是一种典型的裂环环烯醚萜苷，被认为比其母体药物更容易吸收。本研究旨在鉴定和表征GPS在37°C缓冲溶液中与β-葡萄糖苷酶孵育后的代谢产物。收集生物转化溶液样品，采用超高效液相色谱（UPLC）/四极杆-飞行时间质谱（Q-TOF MS）进行分析。共检测到四种代谢产物：两种通过制备型高效液相色谱和核磁共振技术分离并鉴定，其中一种是首次报道。基于UPLC/Q-TOF MS分析确定了代谢产物的质谱裂解模式和精确质量。通过将代谢产物的裂解模式与母体药物的裂解模式进行比较，实现了代谢产物的结构鉴定。提出了β-葡萄糖苷酶催化GPS的一种相当可能的代谢途径。研究了代谢产物M1和M2的保肝活性，结果表明它们的保肝活性高于母体药物。我们的结果为从与中药龙胆相关的生物转化中发现先导化合物提供了有意义的依据。
