Gas chromatography mass spectrometry analysis and larvicidal activity of leaf essential oil extract of Leucas aspera against dengue, malaria and filariasis vectors

Background Insect-transmitted diseases cause high morbidity but they also include deadly diseases that cause high mortality rates among infected individuals. Several mosquito species including Aedes aegypti , Anopheles stephensi , and Culex quinquefasciatus are vectors. Ae . aegypti , a vector of yellow fever, dengue, and chikungunya is widely distributed in the tropical and subtropical zones. An . stephensi is the primary vector of malaria in India and other west Asian countries. C . quinquefasciatus is a vector of lymphatic filariasis and it is widely distributed tropical diseases with around 120 million people infected worldwide. Results In the view of an increasing interest in developing plant-derived insecticides as an alternative to chemical insecticides, this study was undertaken to assess the larvicidal potential of essential oil extracted from Leucas aspera leaves against three medically important species of mosquito vectors, Ae . aegypti , An . stephensi , and C . quinquefasciatus . The oil extract was found to be potent against Ae . Aegypti LC 50 and LC 90 (lethal concentration LC) value of 15.59 ppm and 46.77 ppm when compared to An . stephensi (17.10 ppm and 51.20 ppm) and C . quinquefasciatus with LC 50 and LC 90 (16.19 ppm and 47.79 ppm) respectively. Gas chromatography mass spectrometry analysis of the essential oil extract of L . aspera was done to identify the major phytocompounds. Conclusion The results showed that the oil extract of L . aspera and its effective constituents can be considered as potent source for the production of natural larvicides.