Study On Extraction And Antifungal Activity Of Essential Oil From The Seeds Of Daucus Carota

Wild carrot （Daucus carota Linn.） commonly known as “heshicao and sha luobo”belongs to the family Apiaceae （Umbelliferae）, is widely distributed in many parts of theworld and its habitats include thickets, areas along railroads and roadsides, lawns, pasturesand other waste areas. Wild carrot seed oil is a slightly sweet, dry and earthy aroma and richin a variety of chemical constituents. However, its extraction process, especially the SFEextraction and antifungal effect are poorly understood. In this study, the supercritical fluidextraction （SFE） was applied for the extraction of essential oil from wild carrot （D. carotaLinn.） seeds, and the extraction process and its antifungal effect against phytopathogenicfungi were also studied.In this study, supercritical CO₂fluid extraction was applied to extracting the essential oilfrom wild carrot seeds （Daucus carota Linn）. The effect factors on the supercritical extractionwere determined. And the inhibitory effects of the essential oil were tested against mycelialgrowth and conidia germination of plant pathogens in vitro. The main results were as follows:1. The effect of extraction pressure, extraction temperature, extraction time, amount ofentrainer, and CO₂flow rate on the extraction rate were analyzed by the Minitab software andPB experiment. The results indicated that extraction pressure, extraction temperature, andamount of entrainer are the most important factor.2. The central composition design and response surface methodology were used toinvestigate the influence of three variables on the extraction rate of essential oil. The secondorder polynomial equation was found to give an adequate description describe the extractioncondition: Y=17.78﹣0.58X1﹣0.69X2＋0.66X3﹣1.15X12﹣1.06X22﹣0.36X32﹣0.63X1X2﹣0.60X1X3﹣0.86X2X3. The determination coefficient was R2=0.9392. These measures indicatethat the accuracy and general ability of the polynomial model are good and that analysis of theresponse trends using the model is reasonable.3. The optimum technological condition of extraction: extraction pressure13.46MPa,extraction temperature40.16℃, amount of entrainer3.25%. In this condition, the extractionrate of wild carrot seeds oil is17.68%.4. The antifungal effect of wild carrot seeds oil against various pathogens wasdetermined by measuring mycelial growth rate in vitro. The results indicated that the essential oil could inhibit the mycelial growth of7experimental strains. The order of EC50value is:Fusarium graminearum＜Fulvia fulva＜Sclerotinia sclerotiorum＜Alternaria brassicae＜Glomerella cingulata＜Pyricularia oryza＜Botrytis cinerea.5. The inhibitory effect of wild carrot seeds oil against conidia germination of6testedpathogens was conducted. The essential oil showed a strong inhibition effect on conidiagermination. The EC50value of essential oil on conidia germination is significantly differentamong different pathogens tested. The order of EC50value is: F. graminearum＜F. fulva＜A.brassicae＜G. cingulata＜P. oryza＜B. cinerea. Furthermore, the wild carrot seeds oil hadthe inhibitory effect on the sclerotia germination of S. sclerotiorum.