| In this paper, Atractylodes lancea (Thunb.) DC. that collected from Chinese medicine market of Guilin in Guangxi province was studied. The active ingredients were extracted by organic solvent extraction method. The antifungal activity of the methanol extracts of A. lancea against ten kinds of plant pathogenic fungi Exserohilum turcicum (Pass) Leonard et Suggs, Bipolaris maydis (Nisikado et Miyake) Shoeml, Diaporthe citri (Fawcett) Wolf, Alternaria oleracea M.Ibrath, Ceratocystis paradoxa (Dode) Moreau, Pestalotiopsis theae (Sawada) Steyaert, Cochliobolus miyabeanus (Ito et Kubibay) Drechsler et Dastur, Colletotrichum capsici (syd.) Butl, Alternaria citri, Phytophthora parasitica var. Nicotianae (Breda de Hean) Tucker were determined by mycelium growth rate method and conidia germination method. The active ingredients were determinated by activity-directed isolation method, what were isolated by organic solvent extraction, silica gel column chronmatography and thin-layer chronmatography (TLC) and so on. The structure of active ingredients was validated by mass spectrum and Msgnetic resonance spectrum. The antifungal mechanism of A. lancea was also preliminarily studied.This paper explored the antifungal activity of methanol extracts of Atractylodes lancea (Thunb.)DC, which were collected from the Chinese medicine market of Guilin in Guangxi province, against ten typs of plant pathogenic fungi including Exserohilum turcicum (Pass) Leonard et Suggs, Bipolaris maydis (Nisikado et Miyake) Shoeml, Diaporthe citri (Fawcett) Wolf, Alternaria oleracea M.Ibrath, Ceratocystis paradoxa (Dode) Moreau, Pestalotiopsis theae (Sawada) Steyaert, Cochliobolus miyabeanus (Ito et Kubibay) Drechsler et Dastur, Colletotrichum capsici (syd.) Butl, Alternaria citri, Phytophthora parasitica var. Nicotianae (Breda de Hean) Tucker by mycelium growth rate method and conidia germination method. The active ingredients of A. lancea were extracted by organic solvent extraction method, activity-directed isolation method, isolated by organic solvent extraction, silica gel column chronmatography and thin-layer chronmatography (TLC). The structure of these active ingredients was examined by mass spectrum and Msgnetic resonance spectrum. By the end of this reaseh, the antifungal mechanism of A. lancea was studied.The antifungal activity of the methanol extracts of A. lancea against ten types of plant pathogenic fungi were testedby mycelium growth rate method. The results indicatedthat the methanol extracts of A. lancea showedbroad-spectrum antifungal activity against nine of the ten plant pathogenic fungi with the inhibitory rates of above 70% at 10g/L. The highest inhibition against E. turcicum, D. citri, P. parasitica were 91.01%,100%,100%, while the lowest inhibition against B. maydis was only 8.23%.Further test of the methanol extracts of A. lancea against the specific nine plant pathogenic fungi found that it had strong toxicity againstthese plant pathogenic fungi, when the EC50 value was between 0.1316-2.7264g/L. The highest toxicity of E. turcicum was 20.72 times higher than the lowest toxicity of A. citri. The extract of A. lancea had the highest toxicity to E. turcicum with the EC50 value of 0.1316 g/L and the lowest toxicity to A. citri with the EC50 value of 2.7264 g/L.The antifungal activity of the methanol extracts of A. lancea against spores germination of ten types of plant pathogenic fungi were testedby the method of conidia germination. The results indicated that the inhibition rates of the methanol extracts of A. lancea against the spores were above 70% at lOg/L, except the low inhibition to B. maydis which was only 7.29%, and the highest inhibition to E. turcicum, D. citri, C. paradoxa, P. theae, P. parasitica were 95.24%, 100%,95.36%,90.11%,100%.The methanol extracts of A. lancea was conducted in four steps by liquid-liquid extract method. Bioactivity measurement showed that the active ingredients mainly consisted in the ethyl acetate fraction and petroleum ether fraction. The active ingredient was extractedfrom ethyl acetate fraction by silica gel colum chromatography and TLC using activity-directed methodwhich were identified as Atractylenolide Ⅲ by NMR and MS.The antifungal activity of Atractylenolide Ⅲ against ten types of plant pathogenic fungi were testedby mycelium growth rate method. The results showed that Atractylenolide III had high antifungal activity to D. citri, A. oleracea and P. parasitica, with the inhibitory rates of above 70% at 0.1 g/L, and the value of 78.20%,70.75%,80.83%, respectively. However,it had low antifungal activity to B. maydis and C. miyabeanus, with the inhibitory rates of below 50%, and the value of 33.41%,29.78%, respectively.Further test The toxicity of Atractylenolide Ⅲ to eight types of plant pathogenic fungi showed that the EC50 value of Atractylenolide Ⅲ to D. citri, C. paradoxa were 6.0919×10-2 g/L, 0.0551 g/L, respectively, and the antifungal activity of Atractylenolide Ⅲ to D. citri, C. paradoxa was lower than carbendazim, but, the activity of Atractylenolide III to E. turcicum, A. oleracea, P. theae, C. capsici, Alternaria citr, P. parasitica was higher than that of carbendazim, with the EC50 value of 0.0302 g/L,0.0410 g/L,0.0727 g/L,0.0845 g/L,0.0612 g/L,0.0434 g/L, respectively.In conclusion, this paper preliminary studiedon the mechanism of Atractylenolide III against P. parasitica. The results showed that after adding Atractylenolide Ⅲsome of the mycelium were intumescent, monstrous, increased formation of branches andcrackes. Moreover, the penetrability of cell membrance changed resultedin leakage of inclusion of mycelium. The conductivity of the culture medium showed an increasing trend; the content of soluble protein was declined; the activity of pectase was declined; the activities of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT) were declined resulting in reduction of detoxification. The celles of fungi were death. |
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