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考察芫花氯仿萃取物对尿苷二磷酸葡萄糖醛酸转移酶(UGTs)及UGT1A1活性的影响,为预测芫花致肝损伤可能发生机制提供实验依据。采用体外肝微粒体孵育模型,分别以4-硝基酚和β-雌二醇为底物检测UGTs及UGT1A1活性;利用UV和HPLC测定底物或代谢物含量。结果表明,HPLC测得氯仿萃取物中3种黄酮类成分芹菜素、羟基芫花素和芫花素质量分数分别为1.00%,6.40%,18.38%;UV法测得总二萜质量分数为37.39%。与空白组相比,在大鼠肝微粒体(RLM)孵育体系,氯仿萃取物能显著抑制UGTs活性,而在人肝微粒体(HLM)孵育体系,抑制作用不明显;对UGT1A1,在RLM和HLM孵育体系中,氯仿萃取物均表现为中等强度的抑制作用(以芫花素计,IC50=8.76,10.36μmol·L-1);抑制类型分别为非竞争性抑制和反竞争性抑制。综上,氯仿萃取物对UGTs及UGT1A1活性均可产生抑制作用且存在种属差异性,推测这种抑制作用可能是芫花致肝损伤的机制之一。
To investigate the effect of chloroform extract of ungualicum on uridine diphosphate glucuronosyltransferase (UGTs) and UGT1A1 activity, to provide experimental evidence for predicting the possible mechanism of liver injury induced by Daphne genkwa. The in vitro liver microsomal incubation model was used to detect UGTs and UGT1A1 activity using 4-nitrophenol and β-estradiol as substrate respectively. The contents of substrate or metabolite were determined by UV and HPLC. The results showed that the content of apigenin, hydroxy-genkwanin and genkwanin in chloroform extract were 1.00%, 6.40% and 18.38%, respectively. The total content of diterpene in the chloroform extract was 37.39% %. Compared with the blank group, the chloroform extract could significantly inhibit the activity of UGTs in the rat liver microsomes (RLM) incubation system, but not in the HLM incubation system. The inhibitory effect of UGT1A1 on RLM and In the HLM incubation system, the chloroform extract showed moderate inhibitory effect (in terms of Daphnetin, IC50 = 8.76,10.36μmol·L-1). The inhibition types were noncompetitive and anti-competitive. In summary, the chloroform extract of UGTs and UGT1A1 activity can produce inhibition and the existence of species diversity, speculated that this inhibition may be one of the mechanisms of liver injury caused by Daphne genkwa.