Enhanced absorption and inhibited metabolism of emodin by 2,3,5,4＇-tetrahydroxystilbene-2-O-β-D-glucopyranoside： Possible mechanisms for Polygoni Multiflori Radix-induced liver injury

Polygoni Multiflori Radix(PMR) has been commonly used as a tonic in China for centuries. However, PMR-associated hepatotoxicity is becoming a safety issue. In our previous in vivo study, an interaction between stilbenes and anthraquinones has been discovered and a hypothesis is proposed that the interaction between stilbene glucoside-enriching fraction and emodin may contribute to the side effects of PMR. To further support our previous in vivo results in rats, the present in vitro study was designed to evaluate the effects of 2, 3, 5, 4'-tetrahydroxystilbene-2-O-β-D-glucopyranoside(TSG) on the cellular absorption and human liver microsome metabolism of emodin. The obtained results indicated that the absorption of emodin in Caco-2 cells was enhanced and the metabolism of emodin in human liver microsomes was inhibited after TSG treatment. The effects of the transport inhibitors on the cellular emodin accumulation were also examined. Western blot assay suggested that the depressed metabolism of emodin could be attributed to the down-regulation of UDP-glucuronosyltransferases(UGTs) 1A8, 1A10, and 2B7. These findings definitively demonstrated the existence of interaction between TSG and emodin, which provide a basis for a better understanding of the underlying mechanism for PMR-induced liver injury.

UPLC-Q-TOF-MS法分析枇杷叶的倍半萜苷类化合物

目的采用超高效液相-四级杆-飞行时间串联质谱(UPLC-Q-TOF-MS)技术对分离得到的枇杷叶总倍半萜苷类成分进行定性分析,并对其裂解途径进行研究总结。方法枇杷叶乙醇提取物经大孔树脂、聚酰胺柱色谱和RP-18柱色谱处理后,得到的枇杷叶总倍半萜苷采用Agilent ZORBAX SB-C18色谱柱(4.6 mm×100 mm,1.8μm),甲醇-0.1%甲酸水溶液为流动相进行梯度洗脱,ESI源负离子模式下采集质谱数据。结果从总倍半萜苷中得到5个倍半萜苷类化合物,其二级质谱裂解规律均相同,表现为逐个脱去寡糖链上的糖基,产生特征碎片离子m/z 675、529、383,最后生成m/z 205的特征苷元碎片。结论其中2个倍半萜苷类成分可能是仅在苷元C-6和C-7位上构型有差异的loquatifolin A和6,7-cis-nerolidol-3-O-α-L-rhamnopyranosyl-(1→4)-α-L-rhamnopyranosyl-(1→2)-[α-L-rhamnopyranosyl-(1→6)]-β-D-glucopyranoside。

龙胆泻肝汤中一个新的二氢查尔酮苷(英文)

目的：研究龙胆泻肝汤的化学成分。方法：硅胶柱，反向C18柱，Sephadex LH-20等色谱技术进行分离纯化＇才艮据化合物的理化性质和光谱数据鉴定结构。结果：从龙胆泻肝汤中分离并鉴定了5个化合物，分别为：2′，4′-dihydroxydihydro chalcone-3′-C-β-glucopyranosyl-6′-D-β-D-glucopyranoside（1），异甘草苷元（2），剌甘草查尔酮（3），甘草查尔酮B（4），异甘草苷（5）。结论：化合物1为新化合物，化合物2～5为首次从龙胆泻肝汤中分离得到。

New flavan and unusual chalcone glycosides from Drypetes parvifolia

Two new compounds 7-hydroxy-5-O-（β-D-glucopyranoside） flavan （1） and （Z）-4＇,6＇-dihydroxy-2＇-O-（β-D-glucopyranoside） chalcone （2）, along with eight known compounds, were isolated from the stem bark of Drypetes parvifolia （Euphorbiaceae）. Their structures were established on the basis of spectroscopic analysis and chemical evidence.