Benzofurans from Eupatorium chinense enhance insulin-stimulated glucose uptake in C2C12 myotubes and suppress inflammatory response in RAW264.7 macrophages.

Fourteen acetylbenzofuran derivatives, including three undescribed carbon skeletons with a newly formed hexane or benzene ring on the other side of the benzofuran ring, (±)-eupatonin A (1), (±)-eupatonin B (2), and eupatonin C (3), two new benzofurans (-)-12ß-hydroxygynunone (4) and (+)-12-hydroxyl-13-noreuparin (5), as well as 9 known ones (6-14), were isolated from 95% ethanol extract of the roots of Eupatorium chinense. Their structures were determined by spectroscopic methods and quantum chemical DFT and TDDFT calculations of the NMR chemical shifts and ECD spectra, which helped in the determination of the relative configurations of 1 and 2 and the absolute configurations of 4 and 5, respectively. 1 and 2 were further identified to be racemic mixtures by chiral HPLC analysis. All compounds were evaluated for insulin-stimulated glucose uptake in differentiated C2C12 myotubes. Compounds 1, 3, 4, 5, 11, 12, and 13 markedly enhanced insulin-mediated glucose uptake. (±)-Eupatonin A (1) activated the IRS-1/Akt/GSK-3ß signaling pathway and enhanced insulin stimulated GLUT4 membrane translocation in C2C12 myotubes. On LPS stimulated RAW264.7 macrophages, several compounds exhibited significant inhibitory effect on NO production with IC50 values ranging from 4.94 to 9.70 µΜ. (±)-Eupatonin A (1) again dose-dependently suppressed LPS-induced NO production and decreased the expression of inducible NO synthase (iNOS), through inhibiting NF-κB activity.

[Effect of electroacupuncture on nitric oxide synthase in rats with cerebral ischemia-reperfusion injury].

OBJECTIVE: To study the effect of electroacupuncture on nitric oxide synthase (NOS) in rats with cerebral ischemia-reperfusion injury. METHODS: Focal cerebral ischemia-reperfusion model was established using modified intravascular suture technique. The NO content in the brain tissue was detected by nitrite reduction and the expressions of nNOS and iNOS were detected by immunohistochemistry. Eighty rats in this experiment were divided into the normal group, the cerebral ischemia-reperfusion injury model group (as the model group), the cerebral ischemia-reperfusion injury + electroacupuncture group (as the acupuncture group), and the cerebral ischemia-reperfusion injury + phosphatidylinositol 3 kinase (PI3-K) inhibitor group (as the inhibitor group). Each group consisted of twenty rats. Five microL PI3-K inhibitor LY294002 (400 microL) was slowly injected at the lateral cerebral ventricle of rats in the inhibitor group at a constant speed using microinjector according to Konig Klippel atlas of the stereotaxis instrument. Shuigou (DU26) and Chengjiang (RN24) were selected to determine levels of NO and NOS. RESULTS: After 24-h ischemia-reperfusion, the NO levels of the hippocampus and the cerebral cortex increased abnormally, and the expressions of nNOS and iNOS increased, showing significant difference when compared with those of the normal group (P<0.05). By electroacupuncture at Shuigou (DU26) and Chengjiang (RN24), the ischemic cerebral ischemia-reperfusion injury neuron loss was inhibited. Meanwhile, the high levels of NO, nNOS and iNOS in the cerebral cortex and the hippocampus were significantly inhibited (P<0.05). The abnormally increased expressions of nNOS and iNOS were reversed, showing significant difference when compared with the model group (P<0.05). But when compared with the normal group, there was no significant difference (P>0.05). The effects of electroacupuncture reversed the abnormally increased NO levels of the hippocampus and the cerebral cortex and expressions of nNOS and iNOS after LY294002 oppressed anti-PI3K to block the TrkA acceptor circuit. The NO levels of the hippocampus and the cerebral cortex and expressions of nNOS and iNOS increased again, showing significant difference when compared with the acupuncture group (P<0.05). CONCLUSIONS: Acupuncture fought against cerebral ischemia and reperfusion in the loss of neurons, at the same time, the abnormal regulation of NOS had reverse effect partly through TrkA/PI3K mediated signal transduction pathway.