阿维菌素B2聚硅氧烷微球的制备及生物活性评价

Preparation and biological activity evaluation of avermectin B2 polysiloxane microspheres

[目的]为了利用阿维菌素B1(AVMB1)发酵过程中产生的20%~30%低活性阿维菌素B2(AVMB2)化合物,针对AVMB2易光解和残效期短的缺点,制备防紫外光降解的控释AVMB2聚硅氧烷微球。[方法]以甲基三甲氧基硅烷为前体,通过“溶胶-凝胶”法制备聚硅氧烷微球(PSQ)包埋AVMB2(AVMB2@PSQ),对载药微球的组成和形貌进行了FTIR、TGA、SEM、DLS表征以及缓释和抗紫外光解性能分析,并采用浸渍法评价了载药微球对松材线虫的室内生物活性。[结果]AVMB2成功包埋在PSQ中,形成平均粒径为1.1μm、载药率为32.74%的中空结构光滑球形的AVMB2@PSQ微球;12 h溶出率为55.492%,明显优于AVMB2溶出率87.862%;紫外光照射6 h降解率为39.074%,优于AVMB2降解率69.986%;对松材线虫48 h的半致死剂量(LC50)为19.743 mg/L,比AVMB2的LC50值37.992 mg/L高1.9倍。[结论]AVMB2@PSQ微球具有优异的缓释和防紫外光降解性能以及提高AVMB2对松材线虫的毒杀活性,为阿维菌素B2应用于防治松材线虫病农业生产提供了参考。

[Aims] In order to make full use of low-activity avermectin B2 produced in the fermentation process of avermectin B1 by account of 20%-30%, a controlled-release avermectin B2 polysiloxane microspheres(PSQ) with anti-ultraviolet degradation were prepared, in response to its drawbacks of easy photolysis and short residual efficacy.[Methods] AVMB2@PSQ was prepared by 'sol-gel' method using methyltrimethoxysilane as precursor, its composition and morphology were characterized by FTIR, TGA, SEM, DLS, its sustained release and anti-ultraviolet photolysis properties were studied, and its laboratory activity against Bursaphelenchus xylophilus was determined by immersion method. [Results] AVMB2 was successfully embedded in PSQ. The AVMB2@PSQ microspheres with smooth spherical hollow structure having an average particle size of 1.1 μm were formed, and the pesticide loading rate was 32.74%. The dissolution rate of 12 h was 55.492%, which was significantly better than that of AVMB2(87.862%). The degradation rate was 39.074% under UV irradiation for 6 h, which was better than that of AVMB2(69.986%). The median lethal dose(LC_(50)) for B. xylophilus at 48 h was 19.743 mg/L, which was 1.9 times better than that of AVMB2(37.992 mg/L). [Conclusions] AVMB2@PSQ microspheres with excellent sustained release and anti-ultraviolet degradation properties can improve the activity of AVMB2 against B. xylophilus. It provides a reference for the application of abamectin B2 in agricultural production to control pine wilt disease.