Antifungal Avtivity And Chemical Composition Of Wisteria Sinensis Extract

Fungal diseases of plants is an important hazard for agricultural product, chemical fungicides for controlling plant diseases have the problems of pesticide residues, environmental pollution and endanger human and animal health. Botanical pesticides which are developed upon plant extract with bactericidal active substances have the advantages of low toxicity and low residue and environmental compatibility.To utilization of the resource of Wisteria Sinensis for developing botanical fungicide, the extracts of Wisteria sinensis were prepared which collected from different regions. The antifungal activity of the extracts were evaluated against three important plant pathogenic fungus, namely Valsa mali, Fusarium graminearum and Botrytis cinerea. Extract essential oil from Wisteria sinensis seed with two kinds of methods, namely CO2 supercritical fluid extraction and steam distillation. The chemical composition of the essential oil were determined by GC-MS.The main results are as follows:1. Extracts of the leave, seed and stem bark of Wisteria sinensis, which were collected from Beijing, Jiangsu, Hefei and Huangshan were prepared with ethanol extraction, CO2 supercritical fluid extraction and steam distillation. The results showed that the extract ratios of different extracts between 8.56%-13.76%. The preferred conditions of SFE were optimized by orthogonal test. The parameters were as following, Pressure 25MPa, Temperature 40℃, Ethanol content 5%, Extract time 2.5h, and the extract rate was 10.50% under the SFE conditions. The extract rate of steam distillation was 0.011%.2. The antifungal activities were evaluated against 3 fungus, namely Valsa mali, Fusarium graminearum and Botrytis cinerea, using mycelial growth rate.The results showed that the extracts had a certain inhibitory activity. The EC50 against Valsa mali between 0.191 mg/mL-9.346 mg/mL, against Fusarium graminearum between 0.375 mg/mL-17.003 mg/mL and against Botrytis cinerea between 0.455 mg/mL-15.326 mg/mL. Essential oil extracted by SFE showed the best activity. The activities of the extracts of leaves collected from different locations had a significant difference against Fusarium graminearum. The EC50 value of the extracts collected from Beijing and Huangshan were 17.003 mg/mL and 2.258 mg/mL, respectively. The activities of the extracts of seeds collected from different locations had an obvious difference against Botrytis cinerea. The EC50 value of the extracts collected from Jiangsu and Hefei were 1.819 mg/mL and 15.433 mg/mL, respectively.3. The ethanol extracts of leaves (Beijing), seeds (Jiangsu) and stem barks (Huangshan) of Wisteria sinensis were separated by liquid-liquid extracted with petroleum ether, ethyl acetate and n-butanol. The fractions of petroleum ether, ethyl acetate, n-butanol and water were obtained respectively.The results showed that the antifungal activity of fraction extracted with petroleum ether fraction and ethyl acetate fraction were better than crude extracts significantly, n-butanol fraction and water fraction had no visible activity. The ethyl acetate fraction of leaves (Beijing) showed the best activity against Valsa mali, the EC50 value was 0.262 mg/mL, enhanced 29.66 times compared to its’crude extract; the petroleum ether fraction showed the best activity against Fusarium graminearum and Botrytis cinerea, the EC50 value were 0.316 mg/mL and 0.148 mg/mL, enhanced 53.81 and 110.31 times compared to its’crude extracts, respectively. Hence, the antifungal active ingredients of leaves, seeds and stem barks of Wisteria sinensis were primarily exsisted in the fractions of petroleum ether and ethyl acetate, presumably for a number of lower-middle-polar substances. The results contributed to the further study.4. The essential oil extracted by CO2 supercritical fluid extraction and steam distillation was analyzed by gas chromatography-mass spectrometry (GC-MS) techniques. The results showed that 21 kinds of compounds were determined from the essential oil extracted by SFE, the main components were Linoleic acid(63.13%), n-Hexadecenoic acid(17.46%), G-tocopherol(4.5773%),G-sitosterol(4.343%),beta-amyrin(2.95%),β-amyrinacetate(1.4204%) etc.47 kinds of compounds were determined from the essential oil extracted by steam distillation, the main components were n-Hexadecanoic acid(19.096%), Linoleic acid (4.201%), Oleic Acid(7.579%), Hexadecanoic acid, ethyl ester(3.290%),13-Docosenamide, (Z)-(5.298%) etc.