Study On Dactylogyrus-killed Active Compounds From Datura Metel L.

Dactylogyriasis is one of the serious verminosis in aquaculture. At present, preventionand cure of Dactylogyriasis take mainly advantage of chemical at home and abroad, butlong-term using of chemical lead Dactylogyrus to grow resistance to drugs day by day, dosageof drugs increasing, remedial effect decreasing , cost adding, even it maybe bring someside-effect, such as causing monstrosity, cancer and break and so on. Therefore, the dominantdirection and hotspot in the future are to develop natural drug of low toxicity,unresidual andunresistance, to isolate active compounds from natural plants, to biomimetic synthesis ofeffective components. In order to look for new pesticide and lead compound from plants,experiments of screening for bioactivity, pretest for chemical components, isolation for activecompounds, analysis for spectrum, elucidation for chemical structure were conducted. Theresults were obtained as follows:1. Screening of parasiticidally active plants: the parasiticidal activity of ethyl alcoholextracts from 15 plants on D.intermedius was investigated. The results showed: The rate ofkilling Dactylogyrus was over 70ï¼…in 48 hours for Datura metel L.,Cnidium monnieri(L).Cuss,Brucea jaranica,Semen arecae,Paris polyphlla Smith var. Yunnanensis,Akebia quinata(Thunb.) Dence.,Cynanchum komarovii,Evadia rutaecarp(Juss.) Benth,and Nerium indicumMill., the rate of Dactylogyrus for Datura metel L.,Cnidium monnieri(L). Cuss,Bruceajaranica was 100ï¼…, they had higher safety to fish; additionally, extracts of Pharbits nid(L).Choisy and Artemisia annua to Dactylogyriasis have little effect, the rate of parasite were55ï¼…and 30ï¼…. Comparing with other 14 plants, the ethyl alcohol extract frompresented the best parasiticidal activity. Considering the resource in Shaan Xi province, wechoosed Datura metel L. as the material to further study.2. Pretest for chemical constituents and screening of parasiticidally active part of Daturametel L.: The possible chemical constituents of Datura metel L. were checked by means oftube-test method. The results revealed: The main components ofwere suggested to be alkaloids; Datura metel L.was respectively distilled by petroleum ether,chloroform,acetone,ethyl acetate,ethyl alcohol,distilled water, each extract was used tokill Dactylogyrus. The results showed: the active part of Datura metel L is chloroform extract, parasiticidal concentration of is 200 mg.L^-1 (according to raw-herb count), the highparasiticidal rate is 100ï¼…,ethyl acetate and ethyl alcohol extract were 250 mg.L^-1 and 400mg.L^-1 respectively, the high parasiticidal rate were over 85ï¼…, their concentration didn'thave the effect to kill Dactylogyrus; the extracts of petroleum ether,acetone and distilledwater couldn't hardly kill Dactylogyrus in concentration scope tested. So chloroform extract,with the stronggest parasiticidal activity, was main parasiticidally active part of Datura metelL..3. Isolation,purification and identification of compounds with parasiticidal activity inDatura metel L.: The extract of chloroform was separated into 6 parts(A,B,C,D,E and F) bythe first of silica gel column chromatography with gradually increasing polarity of chloroform:methanal. The part C was demonstrated to be the most effective part by parasiticidal activitytest, its killing rate was 95ï¼…in 48 hours averagely. Through isolated and purified by thesecond of silica gel column chromatography, the part C was separated 7 parts (C1-C7). Theparasiticidal activity test showed that the parasiticidal activity of part C6 was the highest, theparasiticidal rate was over 95ï¼…in 48 hours averagely. The compound of C5,C6 and C7 wasisolated by the third of silica gel column chromatography with steady polarity of petroleumether: ethyl acetate(1.5:1),3 compounds (â… ,â…¡,â…¢)were isolated from part C6. killing rate ofcompoundâ…¡reached 100ï¼…in 48 hours, parasiticidal effect of compoundâ…¡was superior tocompoundâ… andâ…¢.The chemical structure of compoundâ…¡was analysed by UV and MS,compared with the thesis of Yang Bing-you. The result showed compoundâ…¡could been oneof Withanolides.