Antioxidant And Antibacterial Activity Of Flowers And Leaves From Paeonia Rockii

Background:Paeonia rockii(S.G.Haw&Lauener)T.Hong&J.J.Li is an important ancestral species of cultivated tree peony which naturally thrives in the provinces of Gansu,Qinghai,Tibet,Henan and southwest Sichuan and other regions in Northern China.Paeonia rockii grows in areas at an altitude of 1100–2800 m.Which Was listed as the national rare and endangered three key protected plants,included in the"Gansu Province,Chinese herbal medicine standards"and"Chinese plant".The genus Paeonia be called the“King of Flowers”in China,it has ornamental value and variety of pharmacological activity,it be used in traditional Chinese medicine widely.The roots of Peaonia have a long medicinal history due to their wide range of biological activities,such as analgesic,sedative,anti-inflammatory,antimicrobial,cardiovascular protection activities and so on.Earlier studies have shown that the flowers and leaves from Paeonia has strong antioxidant,antibacterial,hypolipidemic and vascular activities to treat gynecological and cardiovascular disease.However,the antioxidant mechanism of activity and the secondary metabolites antibacterial activity of Paeonia rockii has not been reported.Aims:The aim of this study was to investigate the antioxidant and antibacterial activity of flowers and leaves from Paeonia rockii,to identify their antioxidant compounds and to screen their antibacterial active components.To identification the potential antioxidant compounds and antibacterial mechanism of flowers and leaves from Paeonia rockii.Methods and Results:1.In vitro antioxidant experiments were using DPPH,ABTS radical scavenging,reduction ability and metal ion chelating ability.The results showed that flowers and leaves from Paeonia rockii have a strong antioxidant activity,even stronger than the ascorbic acid.2.In vivo antioxidant activity was tested by D-galactose-induced mouse model.The antioxidant activity was determined by 8-iso PGF2?,SOD,MDA,GSH and protein carbonyl as biochemical indexes.Results showed the level of 8-iso PGF2?and protein carbonyl decreased(P<0.01),and the increase of SOD level(P<0.05)showed that flower of Paeonia rockii had antioxidant activity in vivo.3.Potential antioxidant constituents were screened and identified by ultra-high pressure liquid chromatography and electrospray ionization coupled with high resolution mass spectrometry(UHPLC-ESI-HRMS~n)combined with the DPPH assay.The result detected 25 potential antioxidant compounds,including 18 compounds were tentatively identified,most of which belong to flavonoids,phenolic acids and Tannins.4.The antibacterial activity determined the extracts of flower and leaves from Paeonia rockii the minimal inhibitory concentration(MIC)of seven strains bacterial by microdilution method.The results showed that flowers and leaves from Paeonia rocki had antibacterial activity,and the methanol extracts had the strongest antibacterial effect.5.The method of network pharmacology was used to predict the antibacterial active ingredient and target of flower and leaves from Paeonia rockii.QuickVina 2 software was used to molecular docking.Besides,the Cytoscape 3.5.1 software was used to construct activity compounds of flowers and leaves from Paeonia rockii ingredients-targets network.The network pharmacology indicated that total 29activity ingredients and 18 targets were screened in flowers and leaves from Paeonia rockii.It is predicted that the antibacterial components are mainly flavonoids and phenolic acids,and main mechanism of antibacterial is to inhibit the synthesis of bacterial proteins.Conclusion:By the detection of this study,it was found that flowers and leaves from Paeonia rockii had good antioxidant activity and antibacterial activity,and provided new ideas and clues for the development of new natural antioxidants and antibacterial agents.