Larvicidal activity of <i>Ocimum gratissimum </i>and <i>Solenostemon monostachyus</i> leaves on <i>Anopheles gambiae</i>

Abstract

This study presents larvicidal activity of <i>Ocimum gratissimum </i>and <i>Solenostemon monostachyus </i>leaves’ extracts on <i>Anopheles gambiae</i>. Leaves contain alkaloids, saponins, phenolics, tannins, essential oils, lectins, glycosides and phytic acid. Larvicidal activity was determined by subjecting <i>Anopheles gambiae </i>larvae to different concentrations (12.5, 23.50, 100 and 200 ppm) of acetone and aqueous extracts of leaves using <i>in vitro </i>method at room temperature for 72 h exposure. Mortalities were respectively 85% and 45% for acetone and aqueous leaves’ extracts of <i>O. gratissimum </i>and 100% and 50% for acetone and aqueous leaves’ extracts of <i>S</i>. <i>monostachyus. </i>LC50 were respectively 52 ppm and 232 ppm for acetone and aqueous leaves’ extracts of <i>O.gratissimum </i>and 28 ppm and 200 ppm for acetone and aqueous leaves’ extracts of <i>S</i>. <i>monostachyus. </i>Leaves of <i>S</i>. <i>monostachyus </i>exhibited higher

toxicity than leaves of <i>O. gratissimum</i>. Acetone extracts were more potent than aqueous extracts and tested significant at P< 0.05. Lethal activities were found to be dose dependent.