| Myrsine stolonifera(Koidz.) E. Walker belongs to Myrsine, Myrsinaceae, in China. Tested with Plutella xyllostella L. The insecticidal ingredients of M. stolonifera were isolated with activity-guided fractionation with two or three instars larvae of Plutella xylostella and adults of Musca domestica as target insects, and identified with nuclear magnetic resonance (NMR) and mass spectrometry (MS) spectras. The insecticidal menacnisms were also preliminarily researched and basised on the development and utilization of this plant in the future. The main results are as follows:1. Insecticidal activities of methanol extracts of roots, stems and leaves (5mg/g) from M. stolonifera on imago of M. domestica were assayed with stomach poisonous method and the results indicated that the corrected mortality of stem methanol extracts on tested insect was over 50% at 48 h after treatment, while the corrected mortality of methanol extracts from stems (5 mg/mL) from M stolonifera on three instar larvae of P. xyllostella with leaf-dip method reached 23.70%at 72 h after treatment. The root methanol extracts (5mg/mL) showed the strongest growth inhibitory rate of 34.77% at 24 h after treatment, nevertheless, the "selective"and "non-selective" activities of the stems methanol extracts (5 mg/mL) on tested insect were the strongest at 48 h after treatment, which of the antifeedant ratios were 44.84% and 37.46% respectively.2. The methanol extracts from M. stolonifera were primarily isolated with D101 macroporous resin and the insecticidal activities of fractions were aso further researched. The results indicated that insecticidal activities of 95% ethanol fractions (2mg/g) from the root and stem methanol extracts of M. stolonifera on imago of M. domestica were the strongest, which of the corrected mortalities were over 85% at 36 h after treatment. The stomach toxicities of frations on the three instar larvae of P. xylostella were demonstrated, which of the 50% ethanol fractions from leaves methanol extracts displayed the best effect with the corrected mortalities of 57.13%.The antifeedant actives of 70% and 50% ethanol fractions from leaves methanol extracts, and 95% and 70% ethanol fractions from the root and stem methanol extracts were all over 90% at 72 h after treatment. Furthermore, the growth inhibition activities of 50% and 70% ethanol fractions from leaves methanol extracts surpassed 100% at 72 h after treatment.3. The insecticidal mechanism of 95% ethanol fractions from the root and stem methanol extracts on the three instar larvae of P. xylostella were further studied. The results indicated that the inhibition activities of fraction on CarE, GSTs, MFO and AChE in the three instar larvae of P. xylostella were stronger than those in the control at 48,12,24, and 36 h after treatment, respectively.4.8 insecticidal activity ingredients of M. stolonifera was isolated with activity-guided fractionation and identified with nuclear magnetic resonance (NMR) and mass spectrometry (MS) spectras. as 4 flavonoids, quercetin-7-O-a-D-glucoside, kaempferol-3-O-glucopyranoside-rhamnose-glucopyranoside, quer-cetin-3-O- glucopyranoside- rhamnose-glucopyranoside, (-)-epicatechin,1 phenolic acids,3,5-dimethoxy-benzylalcohol-4-O-(3-D-glucopyranoside,3 phenylpropanoids,2,6-dimethoxy-4-hydroxyphenol-1-O-β-D-glucopyranoside, syringin, (+)-lyoniresinol 3a-O-β-D-glucopyrano-side.5. Insecticidal activities of 8 compounds isolated from M. stolonifera were evaluated with stomach poisonous method against M. domestica. The results indicated that syringin,2,6-dimethoxy-4-hydroxyphenol-1-O-O-β-glu, kaempferol-3-O-glu-rha-glu and quercetin-3-O-glu-rha-glu had strong insecticidal activies angainst M. domestica and good toxicity of kaempferol-3-O-glu- rha-glu and quercetin-3-O-glu-rha-glu were demonstrated with LC50 value of 0.75 mg/ g and 1.81 mg/g at 36 h after treatment.6. The effects of 2 high active compounds on enzyme activities of M. domestica adult were tested. The results indicated that kaempferol-3-O-glu-rha-glu and quercetin-3-O-glu-rha-glu could certainly inhibit the activities of CarE, GSTs, MFO and AChE in tested insect, meanwhile, which of the MFO and AChE were significantly higher than those in the control.7. The cell toxicities of 3 compounds on Spodoptera litura (Fabricius) SL cell were studied with MTT assay and found that syringin (100μg/mL) had strong activities on tested cell with the inhibition rate of 40.34%, which were less than that of rotenone (100μg/mL) with 62.47% inhibitory rates. The effect of syringin (50μg/mL) on mitochondrial potential was the strongest, which of the Rhodamine123 fluorescent intensity reached 25.19 and higher than that of rotenone (50μg/mL) with Rhodamine123 fluorescent intensity of 22.36. The active oxygen of syringin (50μg/mL) on tested S. lituraSL cell was the strongest with DCF fluorescent intensity of 27.07, which was almost equaled with rotenone (50μg/mL) with DCF fluorescent intensity of 26.04.Insecticidal activities and mechanism of the methanol extracts of M. stoloniferawere investigated and 8 compounds, including quercetin-7-O-α-D-glucoside, kaempferol-3-O-glucopyranoside-rhamnose-glucopyranoside, quer-cetin-3-O-glucopyranoside-rhamnose-glucopyranoside, (-)-epicatechin,3,5-dimethoxy-benzylalcohol-4-O-β-D-glucopyranoside,2,6-dimethoxy-4-hydroxyphenol-1-O-β-D-glucopyranoside, syringin, (+)-lyoniresinol 3α-O-β-D-glucopyrano-side, were isolated from M. stolonifera for the first time. Strong insecticidal, inhibitory activities and cell toxicities of 7-hydroxycoumarin, apigenin, chrysoeriol, eriodictyol and qucercetin. The strong insecticidal active of syringin was demonstrated and the insecticidal mechanism should be further researched. |
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