The Effects of Lysimachia christinae Hance Extract Fractions on Endothelium-Dependent Vasodilatation.

BACKGROUND: Endothelium-dependent dilatation is a predictor for vascular function. NADPH oxidase-derived O2- can inactivate nitric oxide and induce vascular injury. METHOD: The crude ethanolic extract of Lysimachia christinae Hance were separated out 4 fractions of different olarities by petroleum ether, ethyl acetate, n-butanol (NB), and aqueous. The endothelial integrity was appraised by vascular tension measurement. Dihydroethidium was utilized to observe the vascular reactive oxygen species (ROS) production. Western-blot was adopted to detect protein expression. RESULTS: Among the 4 fractions of L. christinae Hance, the NB fraction showed the most potent capacity of promoting endothelium-dependent vascular relaxation and inhibiting ROS formation in aortic rings, which were likely attributed by suppressing the expression of NAD(P)H oxidase subunit (gp91phox, p47phox, and p67phox) and enhancing the phosphorylation of endothelial NOS in vascular tone. CONCLUSIONS: These results suggest that the NB fraction possess the strongest vascular pharmacological activities among the crude ethanolic extract of L. christinae Hance, which may help us for purifying bioactive constituents and discovering new drugs from this herb in future.

Curcumin protects against diabetic cardiomyopathy by promoting autophagy and alleviating apoptosis.

The effects of curcumin on regulating cardiac apoptosis and autophagy were analyzed in diabetic models both in vivo and in vitro. In vivo, experimental diabetes was induced in mice by low-dose STZ injection combined with a high-fat diet. In vitro, cultured H9c2 cardiomyoblasts were exposed to high d-glucose concentrations combined with palmitate. Our results showed that apoptosis was increased and autophagy was suppressed in the hearts of diabetic mice, which was ameliorated by curcumin treatment, ultimately improving cardiac function. Moreover, the inhibition of autophagy exacerbated apoptotic death in cardiac cells under diabetic condition. Curcumin activated AMPK and JNK1, which phosphorylated Bcl-2 and Bim and subsequently disrupted their interactions with Beclin1, thereby promoting autophagy and alleviating apoptosis respectively. In addition, AMPK-mediated inhibition of mTORC1 pathway likely played a role in regulating autophagy by curcumin under diabetic condition. Our study suggests that curcumin protects against diabetic cardiomyopathy by modulating the crosstalk between autophagic and apoptotic machinery. Modulation of autophagy may be an effective strategy for the treatment of cardiovascular diseases associated with diabetes.

Resveratrol Modulates Apoptosis and Autophagy Induced by High Glucose and Palmitate in Cardiac Cells.

BACKGROUND/AIMS: Diabetic cardiomyopathy is associated with increased apoptosis and suppressed autophagy in cardiac cells. The polyphenol resveratrol has shown beneficial effects in various cardiovascular diseases. This study investigated if resveratrol protected cardiac cells by modulating apoptosis and autophagy in the context of diabetes. METHODS: H9c2 cardiac myoblast cells were exposed to high glucose combined with palmitate. Autophagy was evaluated by estimating LC3-II/I ratio, P62 protein levels, and LC3 fluorescent puncta. Apoptosis was assessed by using terminal deoxynucleotidyl transferase dUTP nick end labelling (TUNEL), flow cytometry, and analysis of the protein expression of apoptotic markers (cleavage of caspase-3 and PARP). RESULTS: High glucose and palmitate suppressed autophagic activity and exacerbated apoptotic cell death in cardiac myoblast cells. Resveratrol restored autophagy and attenuated apoptosis in cells upon diabetic stimuli. Moreover, resveratrol activated AMPK and JNK1, thereby suppressing mTOR and its downstream effectors p70S6K1 and 4EBP1, as well as disrupting the Beclin1-Bcl-2 complex. CONCLUSION: Resveratrol protects cardiac cells by regulating the switch between autophagy and apoptotic machinery under diabetic conditions, which is attributed by AMPK-mediated phosphorylation of mTORC1/p70S6K1/4EBP1 and JNK-mediated dissociation of Beclin1-Bcl-2. Our study suggests that autophagy may be an important target for resveratrol in the treatment of diabetic cardiomyopathy.

Evaluation of the antioxidant and endothelial protective effects of Lysimachia christinae Hance (Jin Qian Cao) extract fractions.

BACKGROUND: Lysimachia christinae Hance is a traditional Chinese medicine with diuretic, detumescent, and detoxifying effects. Our aimed to optimize the extraction protocol to maximize the yield of flavonoids from Lysimachia christinae Hance, and evaluate the pharmacological activities of four fractions, namely, petroleum ether (PE), ethyl acetate (EA), n-butanol (NB), and aqueous (AQ) fractions, of the ethanolic extract of Lysimachia christinae Hance. METHODS: The flavonoid monomers in the crude extract were characterized via high performance liquid chromatography (HPLC), were used as markers for extract quality control and standardization. The total flavonoid, total phenolic, and total polysaccharide contents of each fraction were determined by spectrophotometry. Further, the in vitro free radical (diphenylpicrylhydrazyl, 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid), superoxide, and hydroxyl radicals) scavenging activities, and antioxidant capacity in endothelial cells were evaluated for each fraction. RESULTS: After optimizing the extraction protocol to maximize the total flavonoid yield from L. christinae Hance, the NB fractions had the highest total flavonoid (39.4 ± 4.55 mg RE/g), total phenolic (41.1 ± 3.07 mg GAE/g) and total polysaccharide (168.1 ± 7.07 mg GE/g); In addition, the NB fraction of the ethanolic extract of L. christinae Hance reveal the strongest radical-scavenging activity, antioxidant activity and protective effects against H2O2-induced injury in HUVECs. CONCLUSIONS: Among the four fractions of L. christinae Hance, the NB fraction showed the most potent antioxidant and endothelial protective effects, which may be attributed to its high flavonoid, phenolic contents and optimal portfolio of different active ingredients of NB fractions of the ethanolic extract of L. christinae Hance. This study might improve our understanding of the pharmacological activities of L. christinae Hance, thereby facilitating its use in disease prevention and treatment.