Evaluation of larvicidal activity of Piper longum leaf against the dengue vector, Aedes aegypti, malarial vector, Anopheles stephensi and filariasis vector, Culex quinquefasciatus

Abstract

Vector-borne diseases impose enormous menace worldwide including India. The principal strategies for combating diseases are vector control including the use of ovicide and larvicide against mosquitoes. The present study assessed the role of larvicidal and ovicidal properties of dried leaf extract of Piper longum and also determined their toxicity against three important 3rd instar mosquito larvae, viz., Aedes aegypti, Anopheles stephensi and Culex quinquefasciatus. The plant extracts with different concentrations caused a significant mortality as assayed by WHO (2005) procedure. The aqueous extract of P. longum (PLWE) showed the highest larval mortality on 24 h post treatment. PLWE showed ovicidal activity with the mean percent hatchability of egg(s) raft of three vectors on 48 h post treatment. The initial phytochemical screening of PLWE showed terpenoids, alkaloids etc. and gas chromatography–mass spectroscopy (GC–MS) analysis showed chemical constituents such as Eugenol, n-Hexadecanoic acid, Phytol, Oleic Acid, 4-Chromanol, 2,4-Di‑tert‑butylphenol, Tetradecanoic acid etc. Further, the study of histopathology showed alterations in the midgut epithelium with PLWE treatment causing larval death. Thus, our data suggest that the PLWE is the promising larvicidal activity to control the disease vectors and to our knowledge, larvicidal properties of PLWE are the first report so far. Further in-depth study is needed to establish mechanism of action of larvicidal activity of plant extract at molecular level.