Study On The Preparation Of Fig Leaves’ Extracts And Their Antibacterial Effect

Fig leaves contain many active constituents (for example, psoralen, bergapten, flavone and benzaldehyde), which play an important role in anticancer,liver protection, hypoglycemic, bacteriostatic and so on. Psoralen is the main active ingredient of the fig leaves, which belongs to furan coumarin. Its good antibacterial activity has attracted the attention of the researchers and recognition. So if we studied the active ingredient and activity of fig leaves, we wil maximize the utilization of resources and fully exert the value of the cultivated plants.The research project briefly reviews the current research situation of fig leaves. The extraction, purification, antibacterial and fruit fresh keeping were studied. At present the main findings were as follows:(1) On the selection of extracting method, through comparing the contents of psoralen (7.110 mg·g-1、8.805 mg·g-1、8.450 mg·g-1) and the extraction yield(0.711%、 0.881%%、0.845%) of ethanol reflux extraction, ultrasonic assisted extraction and microwave assisted extraction, we finally determine the ultrasonic assisted extraction as the experimental methods.(2) In the optimization of preparing condition of psoralen extracts, ultrasonic frequency (40 KHz) and mesh (100 mesh) were fixed, The factors and levels of response surface methodology determined by single factor experiment were that:the time of ultrasonic extraction was 35min,45min,55min, the material liquid was 1:5,1:8, 1:11, the ethanol concentration was 70%,80%,90%, the temperature of solvent initial was 40℃,50℃,60 ℃. The optimum process conditions of ultrasonic extraction was that:the ultrasonic frequency was 40 KHz, the 100 mesh sieve of fig leaves powder, the ultrasonic extraction time was 55min, the temperature of solvent initial was 60℃, the material liquid was 1:11, the ethanol concentration was 76.6%.In this condition, the extraction rate of theory was 1.234%. After 3 times test, the measured values was 1.182%, agreed with the theoretical value.(3) In the research of purification of psoralen extracts, we confirmed the best adsorption time, adsorption capacity and elution solvent dosage of D101 macroporous resin. On the basis of optimal purification condition, the total recovery of samples was above 81.86%, and by the analysis of high performance liquid chromatograpHy (HPLC),the purity of sample was 85.34%,which has met the requirements of activity expertment.(4) By the comparision in content of psoralen in different period, we found the content of psoralen in antumn is higher than that in summer. For the purpose of extracting psoralen, it is advisable to advice in October.(5) In the research of inhibitory effect of psoralen extracts, by measuring MIC value on StapHylococcus aureus(a gram-positive bacterium G+), Escherichia coli(a gram-negative bacterium G"), Saccharomyces cerevisiae and Aspergillus Niger, investigating concentration,time and other factors on the effect of the total number of colonies and inhibition zone, we found psoralen extracts has good antibacterial effect, especially for G+and G" bacteria and Saccharomyces cerevisiae. The antimicrobial activity was positively correlated with its concentration and processing time. But for the mold, bacteriostatic effect is not obvious.(6) In applying test of fruits preservation, figs and grapes were chosen as goal object. To study the effect of different components and concentration of fresh-keeping agents to the figs and grape weightlessness rate, total number of colonies, decay rate, titratable acid and vitamin C content by compounding psoralen extracts with chitosan. It was observed that the inhibitory effect of psoralen and chitosan compounds is good. To some extent, it can prolong the freshness of figs and grapes. When the compound concentrate was 0.15% of psoralen extracts and 0.15% of chitosan, the preservation effect is best.