| Botanical-derivated VFB was a kind of anti-viral agent mainly from Portulaca oleracea L. and Glycyrrhiza uralensis Fisch., which was developed by Research and Development Center of Biorational Pesticide, Northwest A&F University. The earlier research indicated VFB had good protection and treatment to viral disease in tobacco and capsicum and so on. VFB had the ability of inactivating TMV, inhibiting infectivity and multiplication of TMV. VFB also could remarkably increase the content of chlorophyll, total phenols, flavonoid and free amino acid, reduce the content of MDA, and increase the activity of POD, PPO and PAL. In this study, we took Nicotiana glutinosa and Nicotiana Tabacum, tobacco mosaic virus (TMV) as the host material and the experiment virus, optimized the formula, separated the active constituent of VFB and researched on physiological-biochemical changes of the host. The results were as follows:The components of VFB all had the activity of inactivating TMV in vitro in a certain extent, and had the lower activity of inhibiting infectivity and multiplication of TMV. When the extraction of VFB was compounded by four kinds of plants materials, its inhibition rate of necrotic local lesions was 51.52%. The inhibition rate of VFB formulation, which joined four adjuvants in extraction of VFB was 60.52%, and enhanced 11.84% compared with Virus A at the same time.The proportioning of four adjuvant of VFB formulation was optimized by orthogonal experiment. The results showed that the effect of adjuvant C was the highest. When the proportion of four adjuvants was: A 0.1mg/mL, B 0.2mg/mL, C 2.0μL/mLl, D 0.8mg/mL, the inhibition rate of VFB formulation was 73.60%, 13.08% and 21.92% higher than the original formulation and Virus A.The active ingredients of VFB were separated with bioassay-direction. Four active compounds(B1-0,B1-1,B1-5 and B1-6) were isolated. Chmical construction of 2 of them was identified with spectrum technology. They were (E)-2-(4-methoxyphenyl) ethanol and 2,3-dihydro-7-hydroxy-2-(4-hydroxyphenyl)chromen-4-one. The activities of inactivating TMV by four compounds were 54.66%, 60.89%, 50.38% and 48.38% at the concentrations of 1mg/mL, respectively.The effect of VFB treatment on the permeability of cell membrane of the leaf in Nicotiana tabacum was investigated. The results indicated that the treatment of VFB prevention could markedly inhibited the increase of the conductivity value after virus infection. During the experiment, its conductivity value changed smoothly and was remarkably lower than other treatment and disease control at the same time. The effect of VFB remediation was lower than that of VFB prevention and higher than that of Virus A remediation.The effect of VFB treatment on the activity of SOD, CAT,β-1,3-glucanase and chitinase was investigated. The results showed that VFB could remarkably increase the activity of SOD, CAT,β-1,3-glucanase and chitinase. These enzymes were related to the host's resistance against diseases.From the above discussion, we can indicate that the anti-virus activity of VFB was increased after formula optimization. Four active compounds(B1-0,B1-1,B1-5 and B1-6) were separated from VFB, its inhibition rate were 54.66%, 60.89%, 50.38% and 48.38% at the concentrations of 1mg/mL, respectively. VFB could remarkably increase the activity of SOD, CAT,β-1,3-glucanase and chitinase, induce the host resistance against disease, and strengthen its antiviral capability. |
