| Taken Tetranychus urticae as the object mites, the acaricidal activity of32plants(these plants were collected toxic weeds and commonly herbal medicine in GansuProvince) was determinated. And the extraction system of acaricidal activitycomposition and mechanism of action of Hypecoum leptocarpum was researched.Finally, the acaricidal activity substance of Hypecoum leptocarpum was obtained bythe column chromatography, biological activity tracing and GC-MS analysis. Themain results are as follows:1. Five plants with strong activity against Tetranychus urticae was determined byselecting research on acaricidal activity of32plants in20families. The methanolextracts of Hypecoum leptocarpum had high activity against female mites and miteeggs of Tetranychus urticae. The LC50of acaricidal and ovicidal was9.010and20.194mg/mL treated after48h, and the respective corrected mortality was90.77%and91.43%(concentration was100mg/mL), which had not significant difference withMacleaya microcarpa and Artemisia annua with strong activity at the sameconcentration levels. Methanol extracts of Artemisia argyi, Pulsatilla chinensis,Pedicularis resupinata and Aconitum szechenyianum also had high activity, the LC50of acaricidal activity was14.139,14.891,15.485,17.706mg/mL, respectively and theLC50of ovicidal activity was30.299,23.815,29.225,20.421mg/mL treated after48h.By cluster analysis on acaricide and ovicidal activity of32kinds of plant, extracts ofthe five plants can be classified into one group.2. The mode of acaricidal of Hypecoum leptocarpum, Artemisia argyi, Pulsatillachinensis, Pedicularis resupinata and Aconitum szechenyianum was compared findingthat the mode of acaricidal of extracts of the five plants against Tetranychus urticaewas in decreasing order of repellent effects>contact effects>ovicidaleffects>systemic>effects according to LC50. Hypecoum leptocarpum extractsperformed best repellent effects, its LC50was1.868mg/mL. Artemisia argyi,Pulsatilla chinensis, Aconitum szechenyianum took the second. Pedicularisresupinata showed the weakest, its LC50was4.037mg/mL. Hypecoum leptocarpumextracts stilled showed the best contact and ovicidal effects, Artemisia argyi, Pulsatilla chinensis, Pedicularis resupinata took the second, and Aconitumszechenyianum performed the worst. In systemic effects, the performance ofArtemisia argyi extracts was the best, LC50was177.495mg/mL, Hypecoumleptocarpum was second, and LC50was233.503mg/mL. Hypecoum leptocarpumshowed the best acaricidal activity among the five plants meanwhile with repellenteffects, contact effects and ovicidal effects against Tetranychus urticae.3. Ethanol and Soxhlet extraction method was the best extraction solvent and methodfor Hypecoum leptocarpum of acaricidal active composition. And the main acaricidalcomposition of Hypecoum leptocarpum distributed on fennel stems and leaves. Bymeasuring contact effect, finding that acaricidal activity of the ethanol extracts wasthe highest, and the corrected mortality of constant temperature oscillation method,Soxhlet extraction and ultrasonic extraction method was88.60%、95.16%and85.59%respectively after48h. Ethanol and methanol extracts of Hypecoum leptocarpum by48h-constant temperature oscillation method and Soxhlet extraction method hadstrong repellent effects on Tetranychus urticae with no significant difference. But theactivity of ethanol extracts by the ultrasonic extraction method was markedly higherthan that of extracts by other solvents. In systemic action, acaricidal activity ofethanol, ethyl acetate and petroleum extracts by Soxhlet extraction method andultrasonic extraction method was not difference significant, while showing distinctdifference in constant temperature oscillation method. In ovicidal action, ethanol andmethanol extracts had no significant difference in acaricidal activity markedly higherthan other solvent extracts. The three extraction methods had no significantdifference.4. The ethanol extract of Hypecoum leptocarpum by Soxhlet extraction method hadsignificant activating effect on the GSTs of Tetranychus urticae and the activity ofGSTs was2.59times as the CK after systemic treatment for12h. The activity of CarEof Tetranychus urticae was weakly activited, in4h, the enzyme activity of mite treatedwas1.139times as the CK. The activity of MFO of Tetranychus urticae firstlyincreased then decreased and finally increased, the activating effect was not obvious.The activity of AchE of Tetranychus urticae was significantly inhibited showing strongest inhibition after contact treatment for12hours and the activity of AchE ontreatment mites was inhibited by2.917times compared with the CK. These resultsindicate that main acaricidal mechanism of ethanol extracts of Hypecoumleptocarpum against Tetranychus urticae was inhibiting the activity of the AchE.5. From Hypecoum leptocarpum ethanol extracts,40compounds were isolated and28kinds were identified. Weak polar fraction mainly included alkanes and fatty acid ester.The advanced alkanes occupied56.92percent in total content of plant. Fatty acidesters including Isopropyl Palmitate, Hexadecanoic,ethyl ester,9,12-Octadecadienoicacid (Z,Z)-,methyl ester,9,12,15-Octadecatrienoic acid, ethyl ester with respectivecontent accounting for16.13%,6.42%,2.31%and12.09%in plant. In addition to thering three terpene ketone (Lup-20(29)-en-3-one) and acetic acid(A’-Neogammacer-22(29)-en-3-ol,acetate), Lup-20(29)-en-3-ol,acetate,(3.beta))accounted for1.73%,1.87%and1.18%in plant. In Polar fraction,15-Nonacosanol,advanced fatty acid (i-Hexadecanoic acid, Tetracosanoic acid, Hexacosanoic acid,Octacosanoic acid) had high relative richness and content in plant includingNonacosylalcohol-15,3(accounting for5.17percent) and advanced fatty acid(iso-hexadecenoic acid, tetracosanoic acid, hexacosanoic acid and n-octacosanoic acid)all with content more than1.9percent. The others were such as9,12-Octadecanoicacid, Octadecanoic acid, Eicosanoic acid, Docosanoic acid, alkyl esters (Methylhexadecadienoate, occupying4.54percent in plant) and2-Pentadecanone,6,10,14-trimethyl,etc. Main acaricidal active components of ethanolextracts of Hypecoum leptocarpum included fatty acids, fatty acids esters and threepentacyclic terpene an i-Hexadecanoic acid,2-Pentadecanone,6,10,14-trimethyl,Neophytadiene, Lup-20(29)-en-3-one,A’-Neogammacer-22(29)-en-3-ol,acetate werefirstly discovered in Papaveraceae family plants. |
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