Li Yujuan, Zhang Yushi, Wang Rui, Wei Lizhong, Deng Yulin, Ren Wei
School of Life Science, Beijing Institute of Technology, Beijing, China.
Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing, China.
J Chromatogr B Analyt Technol Biomed Life Sci. 2017 May 1;1052:91-102. doi: 10.1016/j.jchromb.2017.03.022. Epub 2017 Mar 27.
Although much is known about the pharmacological activities of Dragon's Blood (DB, a traditional Chinese herb), its metabolism in human liver microsomes (HLMs) and the cytochrome P450 (CYP) enzymes has not been studied. This study aims to identify the metabolic profile of five flavonoids (loureirin A, loureirin B, loureirin C, 7,4'-dihydroxyflavone and 5,7,4'-trihydroxyflavanone) from DB in HLMs as well as the CYP enzymes that are involved in the metabolism of them. High-resolution mass spectrometry was used to characterize the structures of their metabolites and 10 cDNA-expressed CYP enzymes (CYP1A2, CYP2A6, CYP2B6, CYP2C8, CYP2C9, CYP2C19, CYP2D6, CYP2E1, CYP3A4 and CYP3A5) were used to verify which isozymes mediate in the metabolism of the metabolites. Totally, 29 metabolites including 10 metabolites of loureirin A, 10 metabolites of loureirin B, 4 metabolites of loureirin C, 2 metabolites of 7,4'-dihydroxyflavone and 3 metabolites of 5,7,4'-trihydroxyflavanone were elucidated and identified on the basis of the high-resolution MS data. The metabolic profile of the five flavonoids in HLMs involved hydroxylation, oxidation and demethylation. Among them, hydroxylation was the predominant biotransformation of the five flavonoids in HLMs, occurring in combination with other metabolic reactions. Assay with recombinant P450s revealed that CYP2C9 and CYP2C19 played an important role in the hydroxylation of flavonoids in HLMs. To the best of our knowledge, this is the first in vitro evaluation of the metabolic profile of loureirin A, loureirin B, loureirin C, 7,4'-dihydroxyflavone and 5,7,4'-trihydroxyflavanone in HLMs.
尽管对血竭（一种传统的中国草药）的药理活性已了解很多，但其在人肝微粒体（HLMs）中的代谢及细胞色素P450（CYP）酶尚未得到研究。本研究旨在确定血竭中五种黄酮类化合物（龙血素A、龙血素B、龙血素C、7,4'-二羟基黄酮和5,7,4'-三羟基黄烷酮）在HLMs中的代谢谱以及参与其代谢的CYP酶。采用高分辨率质谱对其代谢产物的结构进行表征，并使用10种cDNA表达的CYP酶（CYP1A2、CYP2A6、CYP2B6、CYP2C8、CYP2C9、CYP2C19、CYP2D6、CYP2E1、CYP3A4和CYP3A5）来验证哪些同工酶介导这些代谢产物的代谢。基于高分辨率质谱数据，共阐明并鉴定了29种代谢产物，包括10种龙血素A的代谢产物、10种龙血素B的代谢产物、4种龙血素C的代谢产物、2种7,4'-二羟基黄酮的代谢产物和3种5,7,4'-三羟基黄烷酮的代谢产物。这五种黄酮类化合物在HLMs中的代谢谱涉及羟基化、氧化和去甲基化。其中，羟基化是这五种黄酮类化合物在HLMs中主要的生物转化方式，且与其他代谢反应同时发生。重组P450s检测表明，CYP2C9和CYP2C19在HLMs中黄酮类化合物的羟基化过程中发挥重要作用。据我们所知，这是首次对龙血素A、龙血素B、龙血素C、7,4'-二羟基黄酮和5,7,4'-三羟基黄烷酮在HLMs中的代谢谱进行体外评估。
