| The peel of mango extracted with ethanol or methanol respectively, then two kinds of crude extractions extracted with ethyl acetate and methylene chloride, four extracts were obtained.the antifungal activities of 4 extracts were tested against ten species of pathogenic fungus such as Rhizoctonia solani, Rhizoctonia cerealis , et al.. The results are as follows:First, First, the result of a bore method showed that under the concentration of 0.095 g dry matter/mL, only the methanol - methylene chloride extraction had clear inhibition to Pyricularia oryzae and Fusarium oxysporum. The other two kinds of ethyl acetate extractions had only inhibition to Rhizoctonia cerealis under the concentration of 0.200 g dry matter/mL.The result of growing rate method indicated that when acetone was a medium, under the concentration of 0.012 g dry matter/mL, only the methanol-methylene chloride extraction had clear inhibition to Fusarium oxysporum, Fusarium graminearum and Rhizoctonia cerealis, with inhibition rate was 100%, 90.9% and 89.3% respectively. While sterilization water and acetone were used as a ratio of 3:1 under concentration of 0.012 g dry matter/mL, only ethanol- methylene chloride extraction had the best inhibition to Rhizoctonia cerealis, which reached to 72.5%. When acetone was used as a medium, under the concentration of 0.100 g dry matter/mL, two kinds of ethyl acetate extractions had clear inhibition to Fusarium graminearum, Rhizoctonia cerealis and Rhizoctonia solani with inhibition rate of 100%. The control experiment of Botrytis cinerea and Rhizoctonia solani exhibited teratogenesis and abnormal colour of bacterial colony when the medium contained acetone. When sterilization water was used as a medium, two kinds of ethyl acetate extractions had the best inhibition to Rhizoctonia solani and Rhizoctonia cerealis, the next one was Fusarium graminearum, the inhibition rate to these three pathogens was all over 80% which closed to 50% carbendazim WP 1000 times with an inhibition rate of 100%.The toxicity of the methanol - methylene chloride extraction hadn't big difference against Rhizoctonia solani, Fusarium graminearum and Rhizoctonia cerealis, the highest toxicity was against to Rhizoctonia cerealis (EC50 = 0.003632 g dry substance/mL), The toxicity of two kinds of ethyl acetate extractions also hadn't big difference against these three pathogens, the highest toxicity was also against to Rhizoctonia cerealis (EC50 =0.024330 g dry substance/mL).The result of tissue filtration method showed that two kinds of ethyl acetate extractions had the clear control to Rhizoctonia solani, with the control rate closed to 50% carbendazim WP 1000 times in therapy. The antifungal activity of extracts showed more fruitfully when used the growing rate method instead of a bore method after considering the pervasion of the extraction in the culture medium.Acetone can effect the growth of some pathogens to some degree, so the sterilization water was used as a medium. this text choosed ethanol - ethyl acetate extraction for further study.Second, the different antifungal activity was big for mango peels at different maturity. The extraction from 3 kinds mango peels had inhibition to Rhizoctonia solani with no difference, The extraction from green mango peels had the best inhibition to Fusarium graminearum, while the extraction from half ripe and ripe peels had the best inhibition to Rhizoctonia cerealis. Therefore Rhizoctonia solani was selected as sensitive fungus for further study.Third, different extraction methods showed different antibacterial activity. The extract from the method of oscillation had the best antibacterial activity to Rhizoctonia solani. The biggest affection on the the extraction's antibacterial activity was temperature. Based on mono-element and cross experimental method, the optimum extraction conditions were as follows: temperature 20℃; velocity 200 revolution; the ratio of material and solvent 1:5 and the extraction time 2 h.Fourth, The stability of the ethanol - ethyl acetate extraction was also studied. The result showed the extract was stable to acid, alkali, ultraviolet and two metal ions (Na+, K+ ), but it was very sensitive to temperature and another four metal ions(Ca2+, Mg2+ , Fe2+ , Fe3+).Fifth, the ingredient initial measurement showed that flavone, sugar, phenolic acids, tannins, organic acids and naphtha were found in the ethanol - ethyl acetate extraction after colligating relative literature .Sixth, the extraction was isolated with the method of combining column chromatography and testing of antibacterial activity. The results showed that the most suitable chromatographic system for separation of antibacterial compounds was n-Hexane: methylene chloride: mthanol dried (60:40:20), in which the part of 5, 7, 8～10 and 11～13 had very strong antibacterial activity and the inhibition rate of focused on the part of 11～13 up to 62.2%.Seventh, the ingredient initial measurement showed that flavone, phenolic acids and organic acids were found in the part of 11～13. But the exact active substance need farther isolation , purification and identification. |
