Abstract:Limonins from Eureka lemon peel and lemon seed was extracted by organic solvent method and its content was determined，meanwhile，antioxidant and antibacterial activities of limonins in vitro were explored in this paper.Results showed that lemon seeds contain more limonins than lemon peel，the concentratin of the citrate contained in lemon seeds reached 2.766 4×10-1mg/mL；limonoids from lemon peel and seeds had no significant scavenging effects on DPPH free radical，the highest clearance rate under experimental conditions reached only 14.58%，far lower than that of the same concentration of TBHQ.Meanwhile，limonins extracted from lemon peel and lemon seeds had a certain delaying effect on storage period of lard under dosage of 2 mg/mL.Antibacterial activity test results indicated that Limonins extracted from lemon peel and lemon seed exhibited certain antibacterial effects onEscherichia coli，Rhizopus，Bacillus subtilisandStaphylococcus aureusand both showed a best efficiency for Bacillus subtilis with MIC and MBC were 0.5 mg/mL and 0.75 mg/mL respectively.