Larvicidal activity of marine algae, Sargassum swartzii and Chondria dasyphylla, against malaria vector Anopheles stephensi

The objective of this study was to evaluate larvicidal activity of native marine algae against main malaria vector Anopheles stephensi. The total 70% methanol (MeOH) extract and partition fractions of chloroform (CHCl3), ethylacetate (EtOAc), and MeOH from two algae, Sargassum swartzii and Chondria dasyphylla were investigated for larvicidal activities against late III and early IV instar larvae of malaria vector An. stephensi. Among all the fractions tested against larvae, EtOAc fraction of S. swartzii and C. dasyphylla, showed mortality rate of 96 and 95%, respectively. Probit analysis of logarithmic concentration from regression line exhibited the LC50 and LC90 values of 11.75 and 53.47 ppm respectively for S. swartzii and 10.62 and 56.39 ppm respectively for C. dasyphylla. This is the first report of larvicidal activities of two native algae against An. stephensi. We propose that the larvicidal activity of EtOAc fraction is related to the presence of semi- polar compounds. Further isolation and purification could lead to identify more potent compounds.