Abstract: In order to evaluate the antioxidant activity and antibacterial activity of the medicinal plants Capparis zeylanica Linn.,the chemical constituents of the methanol extracts of C.zeylanica were determined by GC-MS.The total polyphenols and flavonoids components,as well as the clearance rate of DPPH radical,ABTS radical,hydroxyl radical and superoxide anion radicalwere detectedwith UV-Visible spectrophotometricmethods.In addition,the inhibitory effect on three foodborne pathogenic bacteria and six plant pathogenic fungi were also determined.The results of GC-MS analysis showed that the major component of methanol extracts were esters (45.03%),followed by heterocyclic (33.74%) and butyl-4-heptyl-o-xylene acid ester (20.58%) was the main single component material.The total phenolics content of the methanol extracts was 1.93% and the total flavonoid content was 2.3%.Further studies showed that the methanol extracts of C.zeylanica had certain scavenging ability on DPPH and ABTS free radicals,the IC₅₀  were 0.454 mg/mL and 0.297 mg/mL,respectively,while the hydroxyl radical and superoxide anion were stronger and the IC₅₀ were 0.937 mg/mL and 2.261 mg/mL,respectively,which were lower than those of rutin and TBHQ.Furthermore,the chloroform phase extracts of C.zeylanica had certain inhibitory effectfor three food-borne pathogenic bacteria and six plant pathogenic fungi.The inhibitory rate of the chloroform phase extracts of C.zeylanica to Lasiodiplodia theobromae was the highest with 43.97%,followed by Neoscytalidium dimidiatum,the inhibition rate was 37.5%.

Key words: Capparis zeylanica Linn., antioxidation, antibacterial activity