Larvicidal property of the extracts of the seaweeds; Sargassum wightii, S. ilicifolium and Gelidiella acerosa vis-a-vis Anopheles stephensi, Aedes aegypti and Culex quinquefasciatus

Abstract

Toxicity potential of the 3-solvent extracts of Sargassum wightii, S. ilicifolium and Gelidiella acerosa – seaweeds against the 4th larval-stage of 3 mosquitos was evaluated. The ethyl acetate extracts of the brown seaweeds (S. wightii & S. ilicifolium) and the red seaweed (G. acerosa) exerted the highest larvicidal effect. The S. wightii-ethyl acetate extract (SW-EA) exerted the huge death-rates of Anopheles stephensi with the lethal concentrations of (μg/mL);3.98 - LC50 and 12.17- LC90 followed by 4.43 & 24.44 on Culex quinquefasciatus and 9.26 & 52.00 on Aedes aegypti, respectively. The S. ilicifolium - ethyl acetate (SI-EA) caused the deaths of Anopheles stephensi with the lethal (LC-50&LC-90) doses (μg/mL) of; 18.934 & 371.753, followed by 34.104 & 423.012 on Aedes aegypti, and 40.728 & 683.813 on Culex quinquefasciatus respectively. Corresponding values for the G. acerosa-ethyl acetate-extract (GA-EA) (that caused maximum death-toll of Anopheles stephensi were); 4.59& 15.91, followed by 14.18& 78.77 on Culex quinquefasciatus and 23.261& 354.903 for Aedes aegypti. The algal-analyses showed the common phytochemical - constituents, aliphatic amines, alkynes and alkenes - groups and predominantly the Phytol acetate, OCTADECANOIC ACID and n-Hexadecanoic acid. The generated data form important basis for further investigation towards antimalarial drug development.