Larvicidal properties of Eugenia uniflora leaves

Abstract

Eugenia uniflora is used ethnomedicinally in Nigeria for diseases including malaria and in Brazil the leaves are spread on the floor for its insect-repellent activity. Search for plants useful in the control of vector of Dengue fever, necessitated investigation of the activity of E. uniflora leaf against fourth instars larvae of Aedes aegyptii, using bioactivity guided fractionation. Larvicidal activity (LC50 2.74 and 2.18 mg/ml at 24 and 48 h) of the leaf methanolic extract, comparable (p > 0.05) to Endosulphan (LC50 0.93 and 0.90 mg/ml at 24 and 48 h), was concentrated in the nhexane partition fraction (LC50 2.58 and 1.87 mg/ml at 24 and 48 h). Vacuum liquid chromatography of n-hexane fraction gave fifth and sixth bulked fractions with significantly (p < 0.05) higher larvicidal activities. Column chromatography of these combined fractions yielded first and third subfractions with LC50 1.01 and 1.17 mg/ml at 24 h, respectively and activities that were similar (p > 0.05) to that of Endosulphan and better than their mother fractions. The results established the larvicidal activity of E. uniflora leaf and encouraged further development of these fractions as alternative larvicide in the control of Dengue fever, especially among the rural populations of Africa.