Dihydromyricetin increases endothelial nitric oxide production and inhibits atherosclerosis through microRNA-21 in apolipoprotein E-deficient mice.

Natural products were extracted from traditional Chinese herbal emerging as potential therapeutic drugs for treating cardiovascular diseases. This study examines the role and underlying mechanism of dihydromyricetin (DMY), a natural compound extracted from Ampelopsis grossedentata, in atherosclerosis. DMY treatment significantly inhibits atherosclerotic lesion formation, proinflammatory gene expression and the influx of lesional macrophages and CD4-positive T cells in the vessel wall and hepatic inflammation, whereas increases nitric oxide (NO) production and improves lipid metabolism in apolipoprotein E-deficient (Apoe-/- ) mice. Yet, those protective effects are abrogated by using NOS inhibitor L-NAME in Apoe-/- mice received DMY. Mechanistically, DMY decreases microRNA-21 (miR-21) and increases its target gene dimethylarginine dimethylaminohydrolase-1 (DDAH1) expression, an effect that reduces asymmetric aimethlarginine (ADMA) levels, and increases endothelial NO synthase (eNOS) phosphorylation and NO production in cultured HUVECs, vascular endothelium of atherosclerotic lesions and liver. In contrast, systemic delivery of miR-21 in Apoe-/- mice or miR-21 overexpression in cultured HUVECs abrogates those DMY-mediated protective effects. These data demonstrate that endothelial miR-21-inhibited DDAH1-ADMA-eNOS-NO pathway promotes the pathogenesis of atherosclerosis which can be rescued by DMY. Thus, DMY may represent a potential therapeutic adjuvant in atherosclerosis management.

Dihydromyricetin affect the pharmacokinetics of triptolide in rats.

1. Dihydromyricetin (DMY) has anti-tumor and hepatoprotective activities and inhibits the activity of CYP enzymes and P-gp. In this research, we explored the effect of DMY on the pharmacokinetics of triptolide (TP), an anti-tumor Chinese medicine that is mainly metabolized by CYP enzymes and is the substrate of P-gp.2. Rats were administrated TP (1.2 mg/kg) with and without DMY in different dosage regimens, then a sensitive and reliable LC-MS/MS method was developed and applied to assess the pharmacokinetics of TP. The blood samples for TP were collected from each rat up to 120 min after administration of TP.3. When co-administrated with single dose of DMY (100 mg/kg), the AUC, Cmax and T1/2 of TP were significantly enhanced by 98, 83 and 66%, respectively. The T1/2 of TP was significantly prolonged from 23.6 ± 6.4 to 70.5 ± 12.5 min with 14-doses pretreatment of DMY (500 mg/kg), conversely, the Cmax was decreased by 30% and the AUC was enhanced by 24%.4. These results hinted that administration of DMY with TP did alter the pharmacokinetics of TP, and provided the theoretical pharmacokinetic basis to study on the protective effects of DMY against acute liver injury caused by TP.

[Chemical constituents from Ajuga nipponensis].

OBJECTIVE: To study the chemical constituents of Ajuga nipponensis. METHODS: The chemical constituents were isolated by repeated silica gel column chromatography and their structures were elucidated by phyisochemical properties and spectral analysis. RESULTS: Ten compounds were isolated and identified as:hexadecanoic acid(1), ajuforrestin A(2), beta-sitosterol(3), acacetin(4), apigenin(5), ajugamacrin B(6), ursolic acid(7), beta-ecdysone(8), 8-acetylharpagide(9) and daucosterol(10). CONCLUSION: Compounds 1-7 and 10 are isolated from this plant for the first time.

[Studies on chemical constituents in stems of Zanthoxylum dissitum].

OBJECTIVE: To study the chemical constituents from the stems of Zanthoxylum dissitum. METHOD: Column chromatography on macroporous resin and silica gel, and spectral analysis were used to isolate and elucidate the constituents. RESULT: Seven compounds were isolated and identified as 5,8-dimethoxyethane-3,4-epoxy-furanocoumarin (1), isoimpinellin (2), beta-sitosterol (3), lupeol (4), neohesperidin (5), beta-daucosterol (6), ursolic acid (7). CONCLUSION: All above the compounds were isolated from the plant for the first time and the compound 1 is a new compound.

Antiproliferative activity of the total saponin of Solanum lyratum Thunb in Hela cells by inducing apoptosis.

Total saponin of Solanum lyratum Thunb (TSSLT), a species of natural biologically active substances isolated from Solanum lyratum Thunb, possesses various bioactivities. It has been proposed that the induction of apoptosis may be the basis of its antitumor activity. However, the molecular mechanism underlying the total saponin-induced apoptotic process remains unknown. In the present study, we describe the anti-proliferative effect of TSSLT on human cervical cancer cells (Hela). The TSSLT induced apoptosis of Hela in a time-dependent manner with an IC50 for cell viability of 6 microg/ml. The TSSLT-induced cell death was characterized by changes in cell morphology, DNA fragmentation, activation of caspase-like activities, poly (ADP-ribose) polymerase (PARP) cleavage and release of cytochrome c (cyt c) into cytosol. TSSLT activated various caspases such as caspase-3, -8, and -9 (like) activities but not caspase-1 like activity. The cell death was completely prevented by the pan caspase inhibitor benzyloxy carbonyl-Val-Ala-Asp- fluoromethyl-ketone (Z-VAD-FMK). More than 80% cell survival was observed in the presence of a caspase-3 inhibitor. In addition, treatment with TSSLT induced the increase of Bax:Bcl-2 ratio in Hela cells. These results suggest that the induction of apoptosis by TSSLT involves multiple pathways antigen including death receptor and mitochondrial pathway and strongly suggest that the mitochondrial pathway was mediated by low expression of Bcl-2 and upregulation of Bax, release of cyt c and subsequent activation of caspase-3 followed by down stream events leading to apoptotic cell death.

A novel alkaloid from Huperzia crispate.

A novel alkaloid, hupcrispatine (1), has been isolated from the unique Chinese species Huperzia crispate Ching. The structure of hupcrispatine has been elucidated as 9-amino-6-methyl-3-quinolone on the basis of spectral evidence.

[Effects of tengcha flavonoids on scavenging oxygen free radicals and inhibiting lipid-peroxidation].

OBJECTIVE: To study the effects of Tengcha flavonoids (TCF) on scavenging oxygen free radicals and inhibiting lipid-peroxidation. METHODS: The effects of TCF on scavenging superoxide anion radical induced by xanthine-xanthine oxidase, inhibiting lipid-peroxidation of heart, liver, brain tissue homogenate and mitochondria induced by Fe2+ -VitC, Fe2+ -H2O2, Fe-Cys were discussed by TBA spectrometric method. RESULTS: TCF could significantly inhibit the superoxide anion radical, IC50 is 14.7 mg/L, and the lipid peroxidation of liver homogenate and mitochondria induced by auto-oxidation and induced-oxidation. The inhibition exhibited concentration-dependent manner. CONCLUSION: It indicated that TCF could scavenge oxygen free radicals and was capable of prophylacticly antagonizing against the oxidative injury by superoxide anion.

[Studies on the effect of dihydromyricetin on antilipid-peroxidation].

OBJECTIVE: To study the effects of Dihydromyricetin (DMY) on antilipid-peroxidation. METHOD: The antilipid-peroxidation of DMY on heart, liver, brain tissue homogenate and mitochondria was measured by the determination of malondiadehyde (MDA) induced by Fe2+ -Vit C, Fe2+ -H2O2, Fe-Cys with TBA spectrometric method. RESULT: DMY could inhibit the lipid peroxidation of homogenate and mitochondria. The inhibition exhibited concentration-dependent manner. CONCLUSION: DMY has good antilipid-peroxidation effect, which is worth studing further.