Structural Modification of Sanguinarine and Chelerythrine and Their <i>in Vitro</i> Acaricidal Activity against <i>Psoroptes cuniculi</i>
作者:Fang Miao、Xin-Juan Yang、Yan-Ni Ma、Feng Zheng、Xiao-Ping Song、Le Zhou
DOI:10.1248/cpb.c12-00618
日期:——
Sanguinarine (1) and chelerythrine (2) are two quaternary benzo[c]phenanthridine alkaloids (QBAs). Eighteen derivatives of 1 and 2 were synthesized by modification of C=N+ bond and evaluated for their in vitro acaricidal activity against Psoroptes cuniculi, a mange mite. A new method was developed to prepare 6-alkoxy dihydro derivatives of 1 and 2 (1a–e, 2a–e). Among all the compounds, only 6-alkoxy dihydrosanguinarines (1a–e) showed significant acaricidal activity at 5.0 mg/mL and 1a possessed the strongest activity (50% lethal concentrations (LC50)=339.70±0.75 mg/L, 50% lethal time (LT50)=6.53±0.04 h), comparable with a standard drug ivermectin (LC50=168.19±11.79 mg/L, LT50=16.54±0.11 h). The iminium moiety in 1 and 2 was proven to be the determinant for their acaricidal properties. 6-Alkoxy dihydro derivatives (1a–e, 2a–e) were prodrugs of 1 and 2. Compared with 7,8-dimethoxy groups, 7,8-methylenedioxy group was able to significantly improve the bioactivity. The present results suggested that QBAs are promising candidates or lead compounds for the development of new isoquinoline acaricidal agents.
血根碱(1)和白屈菜红碱(2)是两种季铵基苯并[c]菲啶生物碱(QBAs)。通过C=N+键的修饰合成了1和2的18个衍生物,并评估了它们对兔耳螨(Psoroptes cuniculi)的体外杀螨活性。开发了一种新方法制备1和2的6-烷氧基二氢衍生物(1a–e,2a–e)。在所有化合物中,只有6-烷氧基二氢血根碱(1a–e)在5.0 mg/mL浓度下显示出显著的杀螨活性,其中1a具有最强的活性(50%致死浓度(LC50)=339.70±0.75 mg/L,50%致死时间(LT50)=6.53±0.04 h),与标准药物伊维菌素(LC50=168.19±11.79 mg/L,LT50=16.54±0.11 h)相当。1和2中的亚胺基团被证实是其杀螨活性的决定因素。6-烷氧基二氢衍生物(1a–e,2a–e)是1和2的前药。与7,8-二甲氧基相比,7,8-甲基二氧基能显著提高生物活性。现有结果表明,QBAs是有前景的候选化合物或开发新型异喹啉杀螨剂的先导化合物。