title: Immuno-suppressive effects of aqueous extract of soapnut Sapindus emarginatus on the larvae and pupae of vector mosquito, Aedes aegypti.
abstract: We recently reported the presence of potent anti-mosquito activity in aqueous kernel extract of the soapnut, Sapindus emarginatus, and demonstrated its impact on marker enzymes in larvae and pupae of the vector mosquito, Aedes aegypti. As a sequel to these findings, the present study elucidates immunotoxicity of this extract with respect to hemocyte-mediated cellular immune responses in fourth instar larvae and pupae as well as cuticular melanization reaction in the larvae of A. aegypti. The exposure of these two developmental stages of the mosquito to the soapnut extract at a lethal threshold concentration neither affected hemocyte viability tested up to 3h in vitro nor did it influence the hemocyte count. By contrast, exposure of the mosquito larvae and pupae to this extract significantly reduced the ability of their hemocytes to bind yeast cells, an important early event in the process of non-self recognition by immune cells. Consequently, the phagocytic activity of these hemocytes against yeast cells was also found to be adversely affected upon exposure of larvae and pupae to the extract. Besides, a perceptible initial delay in melanization reaction at the injured site of the cuticle in the extract-exposed larvae was observed. All these findings demonstrate, for the first time, the immuno-suppressive potential of a botanical biocide in the vector mosquito.
authors.affiliation: Laboratory of Pathobiology, Department of Zoology, University of Madras, Guindy Campus, Chennai 600025, India.
authors.forename: Arunagirinathan
authors.initials: A
authors.lastname: Koodalingam
authors.forename: Periasamy
authors.initials: P
authors.lastname: Mullainadhan
authors.forename: Munusamy
authors.initials: M
authors.lastname: Arumugam
mesh_terms: D000330:Aedes / Q000187:drug effects* / Q000276:immunology; D000818:Animals; D006434:Hemocytes / Q000187:drug effects / Q000276:immunology; D007113:Immunity, Innate / Q000187:drug effects; D007166:Immunosuppressive Agents / Q000302:isolation & purification / Q000494:pharmacology*; D007306:Insecticides / Q000302:isolation & purification / Q000494:pharmacology*; D007814:Larva / Q000187:drug effects / Q000276:immunology; D010587:Phagocytosis / Q000187:drug effects; D010936:Plant Extracts / Q000302:isolation & purification / Q000494:pharmacology*; D011679:Pupa / Q000187:drug effects / Q000276:immunology; D032127:Sapindus / Q000737:chemistry*
chemical_list: D007166:Immunosuppressive Agents; D007306:Insecticides; D010936:Plant Extracts