996 Floral research doi: 10.1016/S2222-1808(16)61171-4 ©2016 by the Asian Pacific Journal of Tropical Disease. All rights reserved. Chemical characterization and insecticidal activity of Calotropis gigantea L. flower extract against Tribolium castaneum (Herbst) Muhammad Rowshanul Habib, Muhammad Rezaul Karim * Department of Biochemistry and Molecular Biology, University of Rajshahi, Rajshahi-6205, Bangladesh Asian Pac J Trop Dis 2016; 6(12): 996-999 Asian Pacific Journal of Tropical Disease journal homepage: www.elsevier.com/locate/apjtd *Corresponding author: Muhammad Rezaul Karim, Department of Biochemistry and Molecular Biology, University of Rajshahi, Rajshahi-6205, Bangladesh. Tel: +88-0721-750590 Fax: +88-0721-750064 E-mail: rezaplazad@yahoo.com Foundation Project: Supported by the University Grant Commission (UGC), Bangladesh (662-5/52/UGC research grant/science/2015). The journal implements double-blind peer review practiced by specially invited international editorial board members. 1. Introduction Most of the chemicals that are used as insecticides in agricultural sector for crop protection, have undesirable effects on living beings particularly animals and human. These chemicals are considered as one of the reasons of environmental pollution. Therefore, the development of environment-friendly insecticides is an urgent need. In recent years, bioinsecticides have drawn a special attention of researchers as a viable pest control strategy[1-3]. Plant extracts and phytochemicals have already been recognized as antifeedants, repellents, growth inhibitors or as insecticides. The trend to utilize botanical pest control agents led to the study of the efficacy of many plant extracts as insecticides[4,5]. A common and most destructive pest, Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae), is found throughout the world. This species has been found associated with a wide range of commodities including grain, flour, peas, beans, cacao, nuts, dried fruits and spices[6]. This pest attacks the germ part (embryo portion) of the grain and their presence in stored foods directly affects both the quantity and quality of the commodity[7]. Currently, there are different kinds of preventive and curative control measures to get protection from this pest and chemical pesticides are one of them. But the use of chemical pesticides has serious drawbacks such as direct toxicity to beneficial insects, fishes and human due to their effects on non-target organisms[8,9]. However, few plant materials that are locally available in Bangladesh, have been investigated to determine their efficacy against Tribolium castaneum (T. castaneum). We have already demonstrated the insecticidal activity of root bark of Calotropis gigantea L. against T. castaneum (Herbst)[10]. As a continuation, the chemical constituents present in ethyl acetate extract of Calotropis gigantea L. flower (EECF) were determined in this study and the insecticidal activity of EECF was tested against the T. castaneum of different larval and adult stages. 2. Materials and methods 2.1. Plant material For this study, the plant materials (flower’s petal) were collected from ARTICLE INFO ABSTRACT Objective: To test the insecticidal activity of ethyl acetate extract of Calotropis gigantea L. flower (designated as EECF) against stored grain pest Tribolium castaneum (Herbst) of different larval and adult stages. Methods: Residual film method was used here to study the toxicity of EECF against Tribolium castaneum and gas chromatography-mass spectrometer analysis was also performed to characterize the chemicals of EECF. Results: In residual film bioassay, EECF showed lowest LD 50 (0.134 mg/cm 2 ) against 1st instar larvae of Tribolium castaneum and this finding ultimately revealed that the insect of initial stage was more susceptible than other stages. From the results of this study, it was found that with the increasing of age, Tribolium castaneum showed some extent of resistance against the toxicity of EECF. Moreover, chemical profiles of EECF identified by gas chromatography-mass spectrometer analysis were also found to consistent with its insecticidal activity. Conclusions: So, the overall results suggested that extracts of Calotropis gigantea L. flower have potential insecticidal effect which might be used in pest control. Contents lists available at ScienceDirect Article history: Received 1 Aug 2016 Received in revised form 15 Aug, 2nd revised form 7 Sep, 3rd revised form 8 Sep 2016 Accepted 24 Sep 2016 Available online 26 Oct 2016 Keywords: Calotropis gigantea Flower Insecticidal Tribolium castaneum