Study Of Active Insecticidal Constituents Of Veratrum Nigrum L.

Veratrum nigrum L.is a perennial traditional herbal plant of Liliaceae family.V.nigrum has a relative long history of application as a typical botanical insecticide in China,Europe and North America.To clarify the insecticidal components in V.nigrum,this study used different column chromatography to extract and isolate alkaloids from V.nigrum,and perform a series of bioassay to determine the insecticidal activity of extract,alkaloidal portion,non-alkaloidal portion and compounds.Determination of the indoor toxicity and control effect（field test）of 0.5%veratrine soluble liquid were also performed.The main results were as follows:1.Ten compounds were isolated from the roots of V.nigrum,and nine of them had been identified the structure.They are:（20R）-Jervine（L-1）,（20S）-Jervine（L-11）,Veratrosine（L-2）,O-acetyl Jervine（L-5）,3-angeloylzygadenine（L-7）,3-veratroylzygadenine（L-8）,（20R）-Veratramine（L-12）,（20S）-Veratramine（L-13）Dihydrojervine（L-16）.2.The results of indoor bioassay showed that the extract and alkaloidal portion of V.nigrum had a relative good biological activity against Tetranychus harti（Ewing）and Anaphothrips obscurus（Muller）,with LC₅₀ values of 2.37and 2.03 mg/mL（extract）,2.67 and0.28 mg/mL（alkaloidal portion）.The extract,alkaloidal and non-alkaloidal portion of V.nigrum had no potency against Aphis citricola von der Goot at the concentration of 140,40,40 mg/mL,respectively.Among the isolated compounds,L-7 had a notable activity against Anaphothrips obscurus（Muller）and Tetranychus harti（Ewing）,with LC50 values of 12.70μg/mL,0.82 mg/mL.At the concentration of 1 mg/mL,compounds,L-8,L-13 and L-14showed a notable activity against Anaphothrips obscurus（Muller）with 24 h mortality of89.71%,58.15%and 45.27%,respectively.L-8 had 24 h mortality of 67.42%against Tetranychus harti（Ewing）.Compounds L-5,L-13 and L-14 had 24 h mortality of 26.74%,18.15%and 15.56%at the dose of 0.053μg/head,respectively.The extract,alkaloidal portion,non-alkaloidal portion and compounds showed no potency against Mythimna separate and Plutella xylostella.3.The results of indoor toxicity and control effect of the agent of 0.5%veratrine soluble liquid showed that it had a good insecticidal activity against Tetranychus cinnabarinus and Thrips tabaci L.with LC₅₀ values of 8.16,41.12 mg/L.The results of the field test showed that 0.5%veratrine soluble liquid had a good control effect with 64.73%,80.25%,and81.41%,a,at the dose of 2250 g/hm²,after it was sprayed for 1,3,7 d,an equal control effect to 5.7%emamectin benzoate microemulsion at the dose of 225 g/hm².And the results showed that it had a good biological activity against Thrips tabaci L.with control effect of 57.71%,75.10%and 74.11%at the dose of 2250 g/hm²,after it was sprayed for 1,3,7 d.Above results indicated that the steroidal alkaloids of V.nigrum were the main active insecticidal ingredients.3-angeloylzygadenine（7）had a notable insecticidal activity against Tetranychus hani and Anaphothrips obscurus（Muller）.The results of indoor toxicity test and field test of 0.5%veratrine soluable liquid indicated that it had a relative good control effect against Tetranychus cinnabarinus and Thrips tabaci L.,and it is worth promoting the application.