模拟醋制法研究狼毒(月腺大戟)主要萜类效应成分醋制过程结构转化机制

Simulated processing with vinegar changes chemical structures of main terpenoids in Euphorbiae Ebracteolatae Radix

为探究狼毒效应部位中主要萜类成分在醋制过程中的结构转化机制,将狼毒萜类成分ent-11α-hydroxyabicta-8(14),13(15)-dien-16,12-olide(HAO)、jolkinolide B(JNB)、fischeria A(FA)、eupractenoid A(EA)采用模拟醋制法在160℃加6%冰醋酸加热40 min后,以LC-MS/MS分析结构转化规律,并通过分析狼毒生醋品中4种成分及其转化产物的相对含量变化,验证模拟醋制的结构转化规律。同时以HPLC分析3种模拟炮制方法(单加热、加水加热、加醋加热)对JNB和FA相对含量的变化的影响。结果显示,松香烷型二萜HAO、JNB及降二萜内酯型二萜FA结构中的内酯环在醋酸加热作用下可发生开环,当结构中存在羟基时可发生酯化成酯、氧化形成羰基等反应,结构中存在环氧环易发生开环反应;二萜二聚体EA在醋酸加热作用下可发生醚键断裂,生成玫瑰烷型二萜euphebracteolatin A(EHTA)和另一种松香烷型二萜。狼毒生醋品中萜类成分及其转化产物相对含量变化结果与成分模拟醋制结果基本一致。HPLC分析结果显示,不同模拟炮制方法对结构转化的影响差异明显,加酸加热法可促使JNB、FA转化生成新的成分,加水加热法转化率明显低于加酸加热法,直接加热法对JNB无明显影响,可使FA相对含量显著下降但并未生成与加酸加热法类似的转化产物,表明辅料醋是狼毒醋制法炮制过程中二萜类成分结构转化的关键。狼毒在醋制过程中二萜类成分结构发生转化是狼毒醋制法炮制减毒存效的物质基础。

This study aims to explore the chemical structure transformation mechanisms of the main terpenoids in the effective fraction of Euphorbiae Ebracteolatae Radix(EER) during the processing with vinegar. The terpenoids including ent-11α-hydroxyabicta-8(14),13(15)-dien-16,12-olide(HAO), jolkinolide B(JNB), fischeria A(FA), and eupractenoid A(EA) were heated at 160 ℃ with 6% acetic acid for 40 min, and then LC-MS/MS was employed to analyze the structural transformation rules of the terpenoids. Further, we analyzed the changes in the relative content of the four compounds and their transformation products in raw and vinegar processed EER to verify the transformation rules during the simulated processing with vinegar. In addition, JNB and FA were processed with single heating, heating with water or heating with acetic acid. We then employed HPLC to compare the content of these two terpenoids and their transformation products before and after processing, so as to investigate the effect of different processing methods on chemical structure transformation. The results showed that the lactone ring of the abietane-type diterpenoids HAO and JNB and the norditerpene lactone FA were opened by heating with acetic acid. When there were hydroxyl groups in the structures, terpenoids were esterized to esters and oxidized to form carbonyl groups. When there was epoxy ring in the structures, ring opening reaction was easy to occur. During the heating with acetic acid, the heterodimeric diterpenoid EA underwent the cleavage of ether bond to produce the rosane-type diterpenoid euphebracteolatin A(EHTA) and another abietane-type diterpenoid. The changes in the relative content of terpenoids and their transformation products in raw and vinegar-processed EER were basically consistent with those of simulated processing of components with vinegar. The HPLC results revealed that the effect of different simulated processing methods on structural transformation varied. Heating with acid can change JNB and FA into new components. Heating with water can also promote the structural transformation, with the efficiency obviously lower than that of heating with acid. Direct heating had no influence on the structure of JNB, while it significantly reduced the relative content of FA. The components treated with direct heating did not produce the products like those of the heating with acid. These results indicated that vinegar plays a key role in the structural transformation of diterpenoids during the processing of EER with vinegar. The structural transformation of diterpenoids in EER during the processing with vinegar may be the material basis for vinegar processed EER to reduce toxicity and preserve effect.