Bio-efficacy of insecticidal molecule emodin against dengue, filariasis, and malaria vectors

Emodin, a chemical isolated from Aspergillus terreus, was studied using chromatographic and spectroscopic methods and compound purity (96%) was assessed by TLC. Furthermore, high larvicidal activity against Aedes aegypti-AeA (LC50 5.08 and LC90 8.23 mg.L− 1), Culex quinquefasciatus-CuQ (7.13 and 12.01 mg.L− 1), and Anopheles stephensi-AnS larvae (6.40 and 15.24 mg.L− 1) was recorded. The first isolated fraction showed higher pupicidal activity against AeA (0.349 and 0.872 mg.L− 1). Most emodin-treated larvae (ETL) involutate variations in acetylcholine esterase, α and β-carboxylesterases, and phosphatase activities in the 4th instar, indicating intrinsic differences in their biochemical changes. ETL had numerous altered tissues, including muscle, gastric caeca, hindgut, midgut, nerve ganglia, and midgut epithelium. Acute toxicity of emodin against brine shrimp Artemia nauplii (154.0 and 184.5 mg.L− 1) and the zebrafish Danio rerio (less toxicity observed) was evaluated. In docking studies, Emodin interacted well with odorant-binding-proteins of AeA, AnS, and CuQ with docking scores of -8.89, -6.53, and − 8.09 kcal/mole, respectively. Therefore, A. terreus is likely to be effective against mosquito larvicides.