Antifungal Activities Of The Extracts From Inula Britannica L.

To discover anti-fungi active compounds from plants is an important way to develop new Reduced Risk Pesticides. At present, there were few reports about the fungicidal activity of Inula Britannica L. Inhibitory effect of extracts from roots, stems, leaves and flowers in different solventswith different polarity agains mycelium growth was tested to make a good foundation for searching for antifungal activity substances. The main findings and conclusions are as follows.Inhibitory effect of extracts from roots, stems, leaves and flowers in 4 solvents (petroleum ether, chloroform, ethylacetate and n-butyl alcohol) with different polarity agains mycelium growth of Phytophthora capsici Len. and Gaeumannomyces graminis var. tritici. was tested using plate growth rate method and spore release method . The results showed that extracts from different parts of Inula britannica exhibited different inhibitory activities, the inhibition rates of extracts from leaves and flowers were higher than that of extracts from roots and stems. The inhibition rates of the petroleum ether extract, chloroform extract, ethylacetate extract and n-butyl alcohol extract from leaves against Phytophthora capsici Len. were 81.17%, 88.29%, 95.43% and 87.16%, and the inhibition rates against Gaeumannomyces graminis var. tritici were 100%; The inhibition rates of the petroleum ether extract, chloroform extract,ethylacetate extract and n-butyl alcohol extract from flowers against Phytophthora capsici Len. were 81.19%, 93.15%, 100% and 95.43%, and the inhibition rates against Gaeumannomyces graminis var. tritici were 100%.95% ethanolic extract of its flower(10 kg) was separated by different solvents and The results showed the extraction rates of petroleum ether, chloroform, ethylacetate and n-butyl alcohol were 34.89%, 8.99%, 8.63% and 22.72%, respectively. The total extraction rate was 75.23%. In order to separate the fungicidal activity substanes from the ethanol extracts partitioned with four solvents (petroleum ether, chloroform, ethylacetate and n-butyl alcohol). The activities against fourteen plant pathogenic fungi were tested in vitro and in vivo. Chloroform extract at the concentration of 1.0 mg·mL?1 exhibited strongly fungicidal activities to mycelium growth of the investigated fungi, and the inhibition rates against Phytophthora capsici, Gaeumannomyces graminis var. tritici and Sclerotinia sclerotiorum were 73.77% 91.67%and 66.25%; With the same application rate as above, the chloroform extract could inhibit the spore germination of Colletotrichum dematium, Fusarium oxysporum on the cotton, Colletotrichum gloeosporioides, Fusarium graminearum and Fusarium oxysporum on the capsicum, and the inhibition rates were 96.00%, 92.44%, 80.43%, 78.45% and 71.84%, respectively; The protective and therapeutic efficacies of chloroform extract against the B. cinerea were 57.65% and 50.60% (6 d) on the tomato treated at the concentration of 2.0 mg·mL?1, respectively, and its therapeutic efficacy wasn’t significant different with the control fungicide-pyrimethanil at 0.4 mg·mL?1The results show that the fraction in chloroform phase was more efficient than the fractions inhibiting the other 3 solvents.The toxicity of the fraction in chloroform phase from ethanol extract from flowers of Inula britannica to the Gaeumannomyces graminis var. tritici was measured in lab and one toxicity curve and corresponding EC50 value were obtained. The results showed the fraction in chloroform phase was the cruelest to the Phytopathogenic fungi. Toxic regression equation on Gaeumannomyces graminis var. tritici in laboratory test were as follows: Y= 4.1819X+1.8639(r=0.9508),EC50=2.747 mg·mL?1.In order to understand its fungicidal control spectrum, chloroform flower extract of Inula britannica were bioassayed in vitro against nine economically important plant pathogenic fungi. The results showed chloroform extract at the concentration of 1.0 g·L?1 exhibited significantly fungicidal activities to mycelium growth of Colletotrichum orbiculare,and Botrytis cintrea The chloroform extract at 1.0 g·L?1 could strongly inhibit spore germination of Alternaria alternate, Colletotrichum orbiculare, Phytophthora capsici and inhibition rates were 63.33%, 92.90% and 82.92%, respectively. The protective and therapeutic efficacies of chloroform extract against the B. cinerea in were 54.27% and 76.68% (48 h) on cucumber treated at the concentration of 10.0 g·L?1. The protective efficacy wasn’t different with the control fungicide-pyrimethanie at 0. 4 g·L?1.