Antibacterial And Antioxidant Ingredients Activity Tracking Of Liquidambar Formosana Hance Leaves And Its Effect Of Jujube Preservation

Liquidambar formosana Hance, is the representative plant of Hamamelidaceae families. As a traditional Chinese medicinal herb, the whole-plant can be used as medicine, which helps promote urination, activate collaterals, dispel wind, and eliminate dampness, and treats acute gastroenteritis, edema, dysentery, postpartum pantalgia, and etc. Although the liquidambar is applied to some degree, it still did not get adequate exploitation and utilization. Current researches show that in addition to pharmacological action, Liquidambar formosana Hance also has a variety of active ingredients, antibacterial, and antioxidant activity. Nowadays, traditional synthetic additives are still used to preserve food all the time, which works well. But long-term usage will cause a certain security problem. Food safety issues, arousing increasing attention, has become an outstanding social condition. Therefore, looking for natural, harmfulless, and efficient natural food preservatives is a task which brooks no delay. In this paper, based on previous studies, tracked the antibacterial and antioxidant components of Liquidambar formosana Hance, investigated better antibacterial and antioxidant active components for the application of preservation in fruit, which provided a theoretical basis for the development of natural antioxidants and fruit preservation and the utilization of Liquidambar formosana Hance resources. The following are the conclusions of this paper:1. In order to select the active components of liquidambar with strong inhibitory effect, the author adopt punch method to determine the inhibition zone size of different polar components of Liquidambar leaves(petroleum ether, chloroform, ethyl acetate, n-butanol); adopt tube serial dilution method to determine the minimum inhibitory concentration(MIC) of the four extracts; and studied the antibacterial effects of the four kinds of extracts respectively. The results show that: the four kinds of extracts of Liquidambar leaves inhibit the test strains, and significant differences exist among different concentrations and different strains; the higher the concentration of the sample is, the more obvious the inhibitory effect is; the antibacterial effect of the four kinds of extracts from top to bottom are ethyl acetate > n-butanol> chloroform> petroleum ether, and the inhibitory effect for G- bacteria is larger than G+ bacteria; the inhibition effect of ethyl acetate, n-butanol extract to bacteria is better than that to mold, and the inhibition effect of chloroform, petroleum ether to bacteria and that to mold are no significant difference.2. In order to further track the activity of Liquidambar leaves extract, the author selects n-butanol of Liquidambar leaves, followed by 10%, 30%, 50%, after the resulting product being eluted with 75% ethanol and isolated and identified 4 of monomeric compounds(quercetin-3-O-β-D- galactopyranose, gallic acid, astragalin, ellagic acid) as experimental material, uses punch method to determine the inhibition zone size, uses continuous tube dilution method to determine MIC values, and researches the stability of 50% ethanol elution and gallic acid after change of temperature, PH and UV irradiation. The results show that 50% ethanol elution and gallic acid has best inhibitory effect and exhibits good antimicrobial stability.3. To track the vitro antioxidant activity of Liquidambar leaves components, basing on pre-project studies, taking four monomeric compounds of liquidambar butanol fractionation as test materials, the author studied the vitro scavenging and reducing power to 1,1-diphenyl 2-picrylhydrazyl radical(1,1-diphenyl-2-picryl-hydrazyl free radicals, DPPH.), hydroxyl radical(hydroxyl free radicals, OH), superoxide anion radicals(superoxide anionfree radicals, O2-.). And the author also compared the antioxidant activity of the active ingredient in different separation stage. The results show that in four kinds of monomer compounds, the capacity of scavenging DPPH, OH, O2- in vitro of ellagic acid and reducing power is the strongest, and shows a good stability of inhibition.4. To explore the postharvest storage effect of Liquidambar leaves extract on fruit, taking different concentrations(10,30,50 mg / 100mL) Liquidambar leaves extract(Liquidambar leaves extract followed by alcohol, n-butanol the resulting product was macroporous resin chromatography, eluted with 50% ethanol) as test materials, the author soaks jujube fruit, stores in a low temperature(5 ~ 8 ℃) for 30 days, measures jujube fruits’ turn red index, rot index mass loss rate, vitamin C(ascorbic acid, VC), soluble solids(total soluble solids, TSS), relative conductivity, MDA(malondialdehyde, MDA), superoxide dismutase(superoxide dismutase, SOD), etc. every 5 days, and uses principal component analysis to evaluate the effect of the storage of jujube fruit in each treatment group. The results show that, Liquidambar leaves extract can inhibit the second turn red jujube, reduce jujube fruit rot and quality loss, slow down the reduction of fruit TSS and VC content, inhibit the rising of relative conductivity and MDA content, enhance SOD activity; and the principal component analysis comprehensive evaluation results are consistent with the experimental results.