Study On Chemical Composition And Biological Activity Of Four Juniperus Species In Qinghai Province

Juniperus Linn.have a wide range of applications.This study mainly selected four Juniperus species,Juniperus formosana Hayata、Juniperus przewalskii Komarov、Juniperus tibetica Komarov and Juniperus convallium Rehder et E.H.Wilson as a research objects,systematically studied the main chemical components and contents of phenolic extracts and essential oils,as well as their antioxidant capacity,antibacterial activity and cholinesterase inhibitor activity,and constructed HPLC fingerprints Map.The main results obtained are as follows:1.The chemical constituents of essential oils and phenolic extracts in 4 species of juniperus were analyzed.The main results are:(1)The identified compounds in the four species of juniperus essential oils were 61(Juniperus formosana),35(Juniperus przewalskii),49(Juniperus tibetica),and 43(Juniperus convallium).A total of 112 compounds were identified from the four plant species of the essential oils.Among them,α-pinene(5.58~17.31%)and terpene(4.91~16.13%)had the largest difference in the essential oils of 4 species of juniperus.In addition,the highest yield of essential oil of Juniperus convallium was 4.13%,and the highest content of essential oil of Juniperus przewalskii was 76.63%.(2)There were significant differences in the total phenolic and flavonoid contents in phenolic extracts of four Juniperus species,and the total phenolic and flavonoids in the phenolic extracts of the Juniperus convallium were the highest(46.85±0.02 mmol equiv.GAE/100 g,1.18±0.01 mmol equiv.QUE/100 g);A total of four compounds were identified in four species of Juniperus: Quercetin,Amentoflavone,Formononetin and Galangal.A total of four compounds were identified in the phenolic extracts of Juniperus formosana and Juniperus przewalskii,and three compounds were confirmed in the phenolic extracts of Juniperus convallium and Juniperus tibetica(Quercetin,Amentoflavone and Formononetin).Among them,Quercetin(0.04~4.76 mg/g)had the highest content in the needles of 4 species of Juniperus,and the highest content of phenolic extracts in the leaves of Juniperus formosana(10.14mg/g).2.The biological activities of the four species of Juniperus essential oils and phenolic extracts were studied.The main results are:(1)The antioxidant capacity of four juniperus needles was studied.Comprehensive analysis shows,the order of antioxidant capacity of the four species of Juniperus essential oils is:Juniperus formosana> Juniperus convallium>Juniperus tibetica>Juniperus przewalskii.Comprehensive analysis shows,the order of antioxidant capacity of the four species of Juniperus phenolic extracts is: Juniperus tibetica> Juniperus formosana>Juniperus convallium>Juniperus przewalskii.(2)Using 9 kinds of bacterias as test strains,the antibacterial activity of four species of Juniperus was evaluated.Comprehensive analysis shows,the order of antibacterial strength of four species of Juniperus essential oils was: Juniperus tibetica> Juniperus convallium >Juniperus formosana > Juniperus przewalskii.Comprehensive analysis shows,the order of antibacterial strength of four species of Juniperus phenolic extracts was:Juniperus convallium>Juniperus tibetica >Juniperus formosana> Juniperus przewalskii.(3)The ChE inhibitory activity of the four species of Juniperus of phenolic extracts was studied.Comprehensive analysis shows,the order of the(ChE)strength of the four plant species of phenolic extracts is: Juniperus convallium>Juniperus przewalskii>Juniperus tibetica > Juniperus formosana.3.HPLC fingerprints of four species of Juniperus phenolic extracts were constructed.(1)HPLC fingerprints identified 12 common peaks,and the similarity between chromatograms ranged from 0.192 ~ 1.The cluster analysis divided 4 plants into 3categories: G1:contained 1 species(S1(Juniperus formosana));G2:contains 1 species(S2(Juniperus przewalskii));G3:contains 2 species(S3(Juniperus convallium)and S4(Juniperus tibetica)).(2)Principal component analysis results the indicated compounds for judging the quality evaluation of Juniperus were the Amentoflavone and Galangal.