Chemical Composition, Antimicrobial And Antioxidative Properties From Leaves Of Eucalyptus Growing In Guangdong

Eucalyptus belongings to the family of Myrtaceae. The chemical components fromthe leaves of Eucalyptus are complicated, including volatile oil, favone, triterpene, tannin.Some of compounds posses antibacterial, antitumour, antihyperglycemic and antioxidantactivities.In this study, we chose five Eucalyptus species (Eucalyptus exserta, Eucalyptus ABL12W5, Eucalyptus urophylla×E.grandh(Guanglin9), Eucalyptus urophylla L.U6,Eucalyptus Guangzhou NO.1), which picked from Gangdong, as research object. Thenprobing into the analysis of chemical composition, volatile components, antimicrobialactivity and antioxidant capacity. Evaluating the oxyradical scavenging capacity of variouseffective position by adopting different methods. Response surface methodology (RSM)was employed to optimize the extraction technology of total flavonoids from leaves ofEucalyptus. The research results will have the important significance of investigating thechemical composition, part of biological activity and comprehensive utilization of fiveEucalyptus species which picked from Guangdong. The main research findings are asfollows:(1) The orthogonal test design was adopted to study the optimal techniques ofextracting Volatile Oil from leaves of Eucalyptus (Eucalyptus exserta).The chemicalcomponents of volatile oil from leaves of Eucalyptus(Eucalyptus exserta, Eucalyptus ABL 12W5, Eucalyptus urophylla×E.grandh(Guanglin9), Eucalyptus urophylla L.U6,Eucalyptus Guangzhou NO.1) were analyzed by GC/MS. The results show that theoptimum extraction process are as follows: water dosage7time, immersing4h, extractingtime3h.The total extraction rate ranged from0.36%to0.86%. The constituents ofvolatile components from leaves of the five Eucalyptus species are summarized:Eucalyptus exserta: The main constituents in volatile oil were terpenoids and terpenoidcompounds, and the major component were1,8-cineole, a-pinene, pinene and isopropyltoluene. Eucalyptus ABL12W5: The main constituents in volatile oil were terpenoids andterpenoid compounds, and the major component were a-pinene,1,8-cineole, Terpinene,β-pinene, isopulegol and α-terpineo. Eucalyptus urophylla×E. grandh(Guanglin9): Themain constituents in volatile oil were terpenoids and terpenoid compounds, and the majorcomponent were1,8-cineole, a-pinene,Terpinyl Acetate, β-pinene,1-methyl-4-(1-methylethyl)-1,4-cyclohexadiene. Eucalyptus urophylla L.U6: The main constituents in volatileoil were terpenoids and terpenoid compounds, and the major component were1,8-cineole,a-pinene, Terpinene, β-pinene, α-terpineol and Terpinyl Acetate. Eucalyptus GuangzhouNO.1:1,8-cineole (49.51%), a-pinene, Terpinene, Terpinyl Acetate, β-pinene,1-methyl-4-(1-methyl ethyl)-1,4-cyclohexadiene and α-terpi.(2)The technology of extracting flavonoids from leaves of Eucalyptus was optimized.The effects of ethanol concentration, extracting temperature, material/liquid ratio andextracting time were inversigated by single-factor experments. GLM (General LinerModel) univariate was used to analyse the experiment data in software SPSS to determinethe optimum extracting condition by the response surface analysis in softwareDesign-expert7.1.3with Box-Behnken Design. The optimum values of these four factorswere as follows:40:1of liquid/material ratio,80℃of extracting temperature,3hours ofextracting time and70%of ethanol concentration.(3) Study on the bactericidal effect of Volatile Oil from Eucalyptus globulusagainst Staphylococcus aureus and Escherichia Coli by observing the effects ofanti-bacteria in vitro. The results showed that the volatile oil has bacteriostatic actionand the minimal inhibitory concentration exists difference between different kind of volatile oil.The minimal inhibitory concentration of five kind of volatile oil toEscherichia Coli are as follows:6.25%、12.5%、6.25%、12.5%and6.25%. Thebacteriostatic ability of Eucalyptus exserta oil, Eucalyptus ABL12W5oil andEucalyptus Guangzhou NO．1oil are higher than others. The minimal inhibitoryconcentration to Staphylococcus aureus are as follows:6.25%、6.25%、12.5%、12.5%and25%, various volatile oil had the following order of bacteriostatic ability:Eucalyptus exserta oil, Eucalyptus urophylla×E．grandh(Guanglin9) oil> EucalyptusABL12W5oil, Eucalyptus urophylla L. U6oil> Eucalyptus Guangzhou NO.1oil(4) Antioxidative activity of five kind of volatile oil was characterized by applyingmethods of1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenger. The volatile oil hasthe following order of DPPH radical scavenging activity: Eucalyptus exserta oil>Eucalyptus ABL12W5oil> Eucalyptus Guangzhou NO.1oil> Eucalyptus urophylla U6oil> Eucalyptus urophylla×E. grandh(Guanglin9) oil.(5) Study on the radical scavenging activity of various effective position by usingthree different kind of methods. In DPPH system, different effective parts had thefollowing order of DPPH radical scavenging activity: Ethyl acetate soluble portion>n-butyl alcohol soluble portion> trichloromethane soluble portion>water solubleportion>the petroleum ether soluble portion. Their radical scavenging activity was muchlower than the solution of the same concentration Vc. In O2-system, various effectiveposition had the following order of O2-radical scavenging activity: the petroleum ethersoluble portion> trichloromethane soluble portion> n-butyl alcohol soluble portion> Ethylacetate soluble portion> water soluble portion. In·OH system,different effective partshad the following order of Hydroxyl radical scavenging activity: Ethyl acetate solubleportion> water soluble portion> n-butyl alcohol soluble portion> the petroleum ethersoluble portion> trichloromethane soluble portion, their radical scavenging activity wasalso lower than the solution of the same concentration Vc.