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Aconitine is a well-known arrhythmogenic toxin and induces triggered activities through cardiac voltage-gated Na+ channels. However, the effects of aconitine on intracellular Ca2+ signals were previously unknown. We investigated the effects of aconitine on intracellular Ca2+ signals in rat ventricular myocytes and explored the possible mechanism of arrhythmogenic toxicity induced by aconitine. Ca2+ signals were evaluated by measuring L-type Ca2+ currents, caffeine-induced Ca2+ release and the expression of NCX and SERCA2a. Action potential and triggered activities were recorded by whole-cell patch-clamp techniques. In rat ventricular myocytes, the action potential duration was significantly prolonged by 1 µM aconitine. At higher concentrations (5 µM and 10 µM), aconitine induced triggered activities and delayed after-depolarizations (6 of 8 cases), which were inhibited by verapamil. Aconitine (1 µM) significantly increased the ICa-L density from 12.77 ± 3.12 pA/pF to 18.98 ± 3.89 pA/pF (n=10, p<0.01). The activation curve was shifted towards more negative potential, while the inactivation curve was shifted towards more positive potential by 1 μM aconitine. The level of Ca2+ release induced by 10 mM caffeine was markedly increased. Aconitine (1 µM) increased the expression of NCX, while SERCA2a expression was reduced. In conclusion, aconitine increased the cytosolic [Ca2+]i by accelerating ICa-L and changing the expression of NCX and SERCA2a. Then, the elevation of cytosolic [Ca2+]i induced triggered activities and delayed after-depolarizations. Arrhythmogenesis toxicity of aconitine is related to intracellular Ca2+ signals.

Cucurbitacin B (CuB), the active component of a traditional Chinese herbal medicine, Pedicellus Melo, has been shown to exhibit antitumor and anti-inflammation effects, but its role in tumor angiogenesis, the key step involved in tumor growth and metastasis, and the involved molecular mechanism are unknown. Tumor angiogenesis is one of the hallmarks of the development in malignant neoplasias and metastasis. Effective targeting of tumor angiogenesis is a key area of interest for cancer therapy. Here, we demonstrated that CuB significantly inhibited human umbilical vascular endothelial cell (HUVEC) proliferation, migration, tubulogenesis in vitro, and blocked angiogenesis in chick embryo chorioallantoic membrane (CAM) assay in vivo. Furthermore, CuB induced HUVEC apoptosis and may induce apoptosis by triggering the mitochondrial apoptotic pathway. Finally, we found that CuB inhibiting angiogenesis was associated with inhibition of the activity of vascular endothelial growth factor receptor 2 (VEGFR2). Our investigations suggested that CuB was a potential drug candidate for angiogenesis related diseases.

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BackgroundIn folklore, some people take the decoction of Calyx seu Fructus Physalis (CSFP) for lowering blood lipids. The present study is designed to evaluate the lipid-lowering activities of CSFP, and search for its pharmacodynamical material.MethodsCSFP was extracted by water and 75% ethanol, respectively. The extracts of CSFP for reducing serum lipid levels were evaluated on mouse model of hyperlipidemia. The optimized extract was subjected to the bioactivity-guided fractionation in which the liquid-liquid extraction, collumn chromatography, the in vivo and in vitro models of hyperlipidemia were utilized. The structure of active component was determined by 13 C-NMR and 1H-NMR.ResultsThe 75% ethanol extract of CSFP decreased the serum total cholesterol (TC) and triglyceride (TG) levels in mouse model of hyperlipidemia. Followed a separation process for the 75% ethanol extract of CSFP, the fraction B was proved to be an active fraction for lowering lipid in vivo and in vitro experiments, which could significantly decrease the serum TC and TG levels in mouse model of hyperlipidemia, and remarkably decrease the increase of TG in primary mouse hepatocytes induced by high glucose and the increase of TG in HepG2 cells induced by oleic acid. The fraction B2, isolated from B on bioactivity-guided fractionation, could significantly decrease TG level in HepG2 cells. One compound with the highest content in B2 was isolated and determined as luteolin-7-O-beta-D-glucopyranoside by NMR spectra. It could significantly reduce the TG level in HepG2 cells, and inhibited the accumulation of lipids by oil red O stain.ConclusionOur results demonstrated that the 75% ethanol extract of CSFP could improve in vitro and in vivo lipid accumulation. Luteolin-7-O-beta-D-glucopyranoside might be a leading pharmacodynamical material of CSFP for lowering lipids.