Preliminary Studies On Antifungal Activity Of Glechoma Longituba (Nakai) Kupr.

The plant is the natural treasure-house of biological active compounds. It is aimed at findingantifungal active compounds from plant and using them as leading structure of new synthetic fungicides.On these grounds, the antifungal activities from extracts of16species of plant were tested against fourplant pathogenic fungi. And then, Glechoma longituba (Nakai) Kupr was further investigated theantifungal compounds and structure evaluated with method of activity-guided isolation and purification.Our results will provide basic information for the further development and utilization of Glechomalongituba (Nakai) Kupr as pesticides and for the study of leading structure of new agrochemicals.16species of plant extracts were extracted through Ultrasonic extraction. The result showed thatthe output of Inula helenium L. extract was highest with the value of45.50%. The output of Evodiarutaecarpa(Juss.)Benth. extract was followed with the value of34.93%. With the growth rate method,16species of plant extracts were screened for antifungal activities against three plant pathogenic fungi,i.e., Valsa mali Miyabe et Yamada, Thanatepephorus cucumeris Donk and Botrytis cinerea Pers.Rhaponticum uniflorum (L.) DC., Glechoma longituba (Nakai) Kupr., Inula helenium L. and Litseacubeba (Lour.) Pers.exhibited the potent activity against Valsa mali Miyabe et Yamada,Thanatepephorus cucumeris Donk and Botrytis cinerea Pers. At10mg/mL concentration, the growthinhibition rate of Glechoma longituba (Nakai) Kupr extracts against Thanatepephorus cucumeris Donk,Botrytis cinerea Pers and Valsa mali Miyabe et Yamada was90.14%,57.85%,50.46%, respectively.The essential oil of aerial parts of Glechoma longituba (Nakai) Kupr was obtained fromhydro-distillation. The output of essential oil was0.14%(v/w). And the essential oil of Glechomalongituba (Nakai) Kupr was measured by GC–MS. Thirty two different components were identified,which constituted99.97%of the oil. The oil contained a complex mixture consisting of alcohols(42.85%), ketones (19.28%) and alkenes (3.70%). The major components detected in the oil wereβ-Spathulenol (12.27%), Pinocamphone (9.76%), Isopinocamphone (7.62%), Palmitic acid (7.50%) etc.The antifungal activity of the oil was tested by poisoned food technique. The results are as follows: theessential oil of Glechoma longituba (Nakai) Kupr exhibited a moderate to high antifungal activityagainst all the tested plant pathogenic fungi. And with the increase of the concentration, the inhibitionenhanced. The IC50of the oil against Valsa mali Miyabe et Yamada, Thanatepephorus cucumeris Donk,Fusarium oxysporium f.cucumerinum and Botrytis cinerea Pers was0.4742，0.1255，0.2752，0.2110mg/mL, respectively. Compared to the essential oil of Glechoma longituba (Nakai) Kupr, the positivecontrol (Carbendazim) showed weaker antifungal activity against all four pathogenic fungi.By the systematic preliminary examination of chemical components of Glechoma longituba (Nakai)Kupr extract, the major components detected in the extract were phenolics, terpenoids and steroids,flavonoids, organic acids, greases and volatile compunds. Glechoma longituba (Nakai) Kupr wasextracted through Ultrasonic extraction and Liquid-liquid distributed extraction. The result showed theoutput of petroleum ether extract, chloroform extract, ethyl acetate extract, butylalcohol extract andwater extract was0.22%,0.74%,0.68%,1.39%and19.63%, respectively. Growth rate method wasemployed to evaluat the antifungal activity of Glechoma longituba (Nakai) Kupr extracts against four plant pathogenic fungi viz Valsa mali Miyabe et Yamada, Thanatepephorus cucumeris Donk, Fusariumoxysporium f.cucumerinum and Botrytis cinerea Pers. Results of the bioassay showed the extracts ofGlechoma longituba (Nakai) Kupr exhibited a moderate to high antifungal activity against all the plantpathogenic fungi tested. The IC50of the chloroform extracts against Valsa mali Miyabe et Yamada,Thanatepephorus cucumeris Donk, Fusarium oxysporium f.cucumerinum and Botrytis cinerea Pers was4.4586，0.6193，1.6898，1.5563mg/mL, respectively. Petroleum ether, chloroform, ethyl acetate andbutylalcohol extract of Glechoma longituba (Nakai) Kupr all showed strong antifungal activity againstThanatepephorus cucumeris Donk. At5mg/mL concentration, the growth inhibition rate against testedfungi was92.61%,99.60%,88.90%and78.31%, respectively. Overall, chloroform extract of Glechomalongituba (Nakai) Kupr showed stronger antifungal activity than that of petroleum ether extract andethyl acetate extract.With the method of activity-guided column chromatography, the chloroform extract of Glechomalongituba (Nakai) Kupr was isolated and purified, which led to obtain two compounds, Z5-2-6-2and Z3.At2.5mg/mL concentration, the antifungal rate of Z3against Fusarium oxysporium f.cucumerinum was60.33%. At0.125mg/mL concentration, the antifungal rate of Z5-2-6against Fusarium oxysporiumf.cucumerinum was44.13%. After the structure identification with method of melting point, nuclearmagnetic resonance, mass spectrometry chromatography, Z5-2-6-2was confirmed as a new compound,and its molecular formula was C25H26N, and Z3was inferred as Betulinic acid.