Study On Pharmacological Activities And Mechanism Of Auercitrin From The Leaves Of Lindera Aggregate(Sims)Kosterm. About The Cardiovascular Disease

Lindera aggregate(Sims)Kosterm,belonging to the Lauraceae Lindera,the geoherbs of Zhejiang Tiantai area,occurs to have a better effect on prevention and treatment of cardiovascular diseases.In the early exploration on the active ingredient of the leaves of Lindera aggregata,flavonoids were found one kind of the main active ingredients among which quercitrin(QI)was the representative component with the highest content(the content of QI in the original herbs is 9.705 mg/g and more than 50%in the total flavonoids).It has a higher development and utilization value.This study explored the in vivo and in vitro pharmacological activity of QI in cardiovascular disease,and mainly carried out the preliminary mechanism of antioxidant.Firstly,the aging rats and acute blood stasis model was established to evaluate the antioxidant and anti-blood stasis effects of QI.After administration of QI(the dose of QI:4 mg/kg,8 mg/kg and 16 mg/kg)by tail vein injection,the contents of antioxidant enzymes and the oxidation products were measured in serum and tissues,and the blood viscosity,plasma viscosity and hematocrit were analyzed.The results showed that QI 8 mg/kg can significantly improve the level of antioxidant enzymes(T-SOD,GSH)in ageing rats and decreased the content of MDA.The analysis of blood rheology indexes indicated that QI(8 mg/kg and 16 mg/kg)can significantly decrease the blood viscosity,but had no effect on the plasma viscosity and hematocrit.Secondly,the protective effect of oxidative stress of quercitrin on hydrogen peroxide induced human umbilical vein endothelial cells(HUVECs)and H9C2 cells damage was discussed.The data indicated that in the different ways of administration:pre-treatment(APT),co-treatment(ACT)and post-treatment(APOT)of QI,ACT effect was better than the other two ways with the concentrations of QI range at 62.5?M-500?M significantly improving the HUVECs and H9C2 cell vitality in a dose-dependent way.Finally,for HUVECs,MTT assay,flow cytometry,immunofluorescence,western blotting,DNA Ladder and qPCR were used to investigate the influence of QI on the protection mechanism of hydrogen peroxide induced-HUVECs injury based on the content determination of T-SOD,GSH and ROS,the location and expression analysis of the target proteins in cells.The results showed that in HUVECs,APT and ACT both can protect cells from oxidative damage by increasing the activity of T-SOD and GSH in cells,decreasing ROS production,inhibiting cell apoptosis and DNA damage,significantly upregulating the level of NRF2 and OH-1 genes.During the exploration of the pathway,APT and ACT can activate Keap-1/Nrf2 system,promote the nuclear translocation of Nrf2 and inhibit the activation of caspase family.However,in the ACT,QI can inhibit the blocking of autophagy caused by hydrogen peroxide,increase the expression of LC3B and promote the degradation of SQSTM1.When HUVECs were given autophagy inhibitor 3-MA in the ACT,the cell viability of HUVECs was decreased and the phenomenon of Nrf2 nuclear transfer disappeared,suggesting that autophagy process may be one of the reasons that ACT and APT had a different antioxidant effect.This paper first reveals that QI can combine Keap-1/Nrf2 system with autophagy closely to resist oxidant stress in the ACT-treatment HUVECs.In summary,QI from the leaves of Lindera aggregate(Sims)Kosterm has good effects on antioxidant and blood stasis with high development and utilization value.This study establishes a foundation of scientific research on cardiovascular disease and may play a significant role in the development of CVD drugs.