Lucantoni L, Giusti F, Cristofaro M, Pasqualini L, Esposito F, Lupetti P, Habluetzel A
Department of Experimental Medicine and Public Health, University of Camerino, Camerino, Italy.
Tissue Cell. 2006 Dec;38(6):361-71. doi: 10.1016/j.tice.2006.08.005. Epub 2006 Nov 13.
Secondary metabolites of the neem tree (Azadirachta indica A. Juss., Meliaceae) exhibit a wide range of biological activities in insects. However, few studies have addressed the effects of neem extracts or compounds in arthropods of medical importance. In this study, a laboratory strain of Anopheles stephensi was used to assess the effects of a commercial formulation (Neem Azal) (NA)), containing azadirachtin A at 34%, on blood feeding, oviposition and oocyte ultrastructure. Oral administration of Neem Azal) to A. stephensi females through artificial blood meals did impair blood intake and oviposition in a concentration dependent manner. Similar results were obtained on females, which had consumed Neem Azal) in sucrose solution before taking a blood meal of plain blood. Neem treated females displayed a delay in oocyte development in both the phase of vitellogenesis and the phase of choriogenesis. The ultrastructural studies on ovaries from Neem Azal) treated females revealed distinct structural modifications indicative of: (i) a complete block of oogenesis, (ii) impairment of vitellogenesis and vitelline envelope formation, (iii) a severe degeneration of follicle cells. In agreement with results obtained in other insects, this study indicates that Neem Azal) impairs hormone control of oogenesis and exerts a cytotoxic effect on both follicular cells and oocytes of the Asian malaria vector A. stephensi.
印楝树（Azadirachta indica A. Juss.，楝科）的次生代谢产物在昆虫中表现出广泛的生物活性。然而，很少有研究探讨印楝提取物或化合物对具有医学重要性的节肢动物的影响。在本研究中，使用斯蒂芬斯按蚊的实验室品系来评估一种商业制剂（印楝素（Neem Azal）（NA）），其含有34%的印楝素A，对吸血、产卵和卵母细胞超微结构的影响。通过人工血餐对斯蒂芬斯按蚊雌蚊口服印楝素（Neem Azal）确实会以浓度依赖的方式损害血液摄入和产卵。对在取纯血餐之前在蔗糖溶液中摄入印楝素（Neem Azal）的雌蚊也获得了类似结果。经印楝处理的雌蚊在卵黄发生期和卵壳形成期的卵母细胞发育均出现延迟。对经印楝素（Neem Azal）处理的雌蚊卵巢的超微结构研究揭示了明显的结构改变，表明：（i）卵子发生完全受阻，（ii）卵黄发生和卵黄膜形成受损，（iii）卵泡细胞严重退化。与在其他昆虫中获得的结果一致，本研究表明印楝素（Neem Azal）损害卵子发生的激素控制，并对亚洲疟疾媒介斯蒂芬斯按蚊的卵泡细胞和卵母细胞产生细胞毒性作用。
