title: Larvicidal activity of catechin isolated from Leucas aspera against Aedes aegypti, Anopheles stephensi, and Culex quinquefasciatus (Diptera: Culicidae).
abstract: Vector control is facing a threat due to the emergence of resistance to synthetic insecticides. Insecticides of plant origin my serve as an alternative biocontrol technique in the future. The aim of the present study was to evaluate the larvicidal activity of fractions and compounds from the whole-plant methanol extracts of Leucas aspera on the fourth-instar larvae of Aedes aegypti, Anopheles stephensi, and Culex quinquefasciatus. The larvae were exposed to fractions with concentrations ranging from 1.25, 2.25, 5, 10, and 20 ppm and isolated compounds. After 24 h exposure, larval mortality was assessed. Among the eight fractions, four from hexane extractions showed potent larvicidal activity against tested mosquito species at 20 ppm concentration. The isolated compound catechin showed pronounced larvicidal activity at very low concentrations. The LC50 and LC90 values of catechin were 3.05 and 8.25 ppm against Ae. aegypti, 3.44 and 8.89 ppm against An. stephensi, and 3.76 and 9.79 ppm against C. quinquefasciatus, respectively. The isolated compound was subjected to spectral analyses (GC-MS, FTIR, (1)H NMR, and (13)C NMR) to elucidate the structure and to compare with spectral data literature.
authors.affiliation: Department of Zoology, Presidency College (Autonomous), Chennai, 600 005, Tamil Nadu, India.
authors.forename: Devan
authors.initials: D
authors.lastname: Elumalai
authors.affiliation: Department of Zoology, University of Madras, Guindy campus, Chennai, 600 025, Tamil Nadu, India.
authors.forename: Maduraiveeran
authors.initials: M
authors.lastname: Hemavathi
authors.affiliation: Department of Zoology, Presidency College (Autonomous), Chennai, 600 005, Tamil Nadu, India.
authors.forename: Periaswamy
authors.initials: P
authors.lastname: Hemalatha
authors.affiliation: Department of Chemistry, Presidency College (Autonomous), Chennai, 600 005, Tamil Nadu, India.
authors.forename: Chandrasekar Vijayalakshmi
authors.initials: CV
authors.lastname: Deepaa
authors.affiliation: Department of Zoology, Presidency College (Autonomous), Chennai, 600 005, Tamil Nadu, India. pkkaleena@yahoo.co.in.
authors.forename: Patheri Kunyil
authors.initials: PK
authors.lastname: Kaleena
mesh_terms: D000330:Aedes; D000818:Animals; D000852:Anopheles; D002392:Catechin / Q000737:chemistry; D002849:Chromatography, Gas; D002855:Chromatography, Thin Layer; D003465:Culex; D007306:Insecticides / Q000737:chemistry; D019686:Lamiaceae / Q000737:chemistry*; D007814:Larva; D007928:Lethal Dose 50; D009682:Magnetic Resonance Spectroscopy; D010936:Plant Extracts / Q000737:chemistry; D021241:Spectrometry, Mass, Electrospray Ionization; D017550:Spectroscopy, Fourier Transform Infrared
chemical_list: D007306:Insecticides; D010936:Plant Extracts; D002392:Catechin
keywords: Aedes aegypti; Anopheles stephensi; Catechin; Culex quinquefasciatus; Larvicidal activity; Leucas aspera