Background Vector control is facing a threat due to the emergence
September 7, 2017
Background Vector control is facing a threat due to the emergence of resistance to synthetic insecticides. (log probit analysis) and compared with Malathion. The chemical nature of the active substance was also evaluated following ultraviolet-visual (UV-Vis) and infrared (IR) analysis. Results In a 72 hour bioassay experiment with the aqueous extract, the highest mortality was recorded in 0.5% extract. When the mortality of different solvent extracts was compared, the maximum (p < 0.05) mortality was recorded at a concentration of 50 ppm of chloroform:methanol extract (1:1, v/v). The larvicidal activity was lower 501925-31-1 when compared with the chemical insecticide, Malathion (p < 0.05). Results of regression analysis revealed that the mortality rate (Y) was positively correlated with the period of exposure (X) and the log probit analysis (95% confidence level) recorded lowest value (5.97 ppm) at 72 hours of exposure. Phytochemical analysis of the chlororm:methanol extract reported the presence of many bioactive phytochemicals. Two toxic compounds were detected having Rf = 0.82 (70% and 73.33% mortality in 24 and 48 hours, respectively) and Rf = 0.95 (40% and 50% mortality in 24 and 48 hours, respectively). IR analysis provided preliminary information about the steroidal nature of the active ingredient. Conclusion S. villosum offers promise as potential bio control agent against S. aegypti particularly in its markedly larvicidal effect. The extract or isolated bioactive phytochemical could be used in stagnant water bodies for the control of mosquitoes acting as vector for many communicable diseases. Background Mosquitoes transmit several public health problems, such as malaria, filariasis, dengue and Japanese encephalitis, causing millions of deaths every year . Stegomyia aegypti (= Aedes aegypti) is a vector for an arbovirus responsible for dengue fever, dengue haemorrhagic fever and dengue shock syndrome, and with unusual manifestations such as central nervous system involvement [2,3]. About two-fifths of the world’s populations are at risk of catching dengue [4-6]. Mosquitoes in the larval stage are attractive targets for pesticides because they breed in water and, thus, are easy to deal with them in this habitat. The use of conventional chemical pesticides has resulted in the development 501925-31-1 of resistance [7,8], undesirable effects on non-target organisms and fostered environmental and human health concerns . The use of herbal products is one of the best alternatives for mosquito control. The search for herbal preparations that do not produce any 501925-31-1 adverse effects in the non-target organisms and are easily biodegradable remains a top research issue for scientists associated with alternative vector control . Solanum villosum (Solanaceae: Solanales), commonly known as red-fruit nightshade, is widely 501925-31-1 distributed in many parts of India. This is an Ayurvedic herb with multiple medicinal properties . The objective of the present study was to examine the larvicidal activity of aqueous, polar and non-polar solvent extracts of the green berries of this plant against the larvae of S. aegypti mosquitoes and to gather preliminary information about the nature of the Mouse monoclonal to BECN1 active ingredient responsible for larval mortality. Methods Test mosquitoes The present study was conducted at Burdwan (23 16′ N, 87 54′ E), West Bengal, India, during June-August 2006. Larvae of S. aegypti were obtained from a laboratory colony maintained in the Mosquito Research Unit, Department of Zoology, The University of Burdwan. The colony was kept free from exposure to pathogens, insecticides or repellents and maintained at 25C30C. The larvae were fed on a powdered mixture of dog biscuits and dried yeast powder at a ratio of 3:1. The adult colony was provided with 10% sucrose solution and 10% multivitamin syrup, and was periodically blood-fed on restrained rats. Preparation of aqueous extracts Fresh, mature, green berries of S. villosum were randomly harvested during the study period from plants growing on the outskirts of Burdwan. All the berries were initially rinsed with distilled water and dried on a paper towel. The crude extracts were prepared by grinding the plant material in a mortar and pestle and passing the ground material through Whatman No 1 filter paper. Required 501925-31-1 concentrations of aqueous extracts were prepared by mixing the crude extract with a suitable amount of sterilized distilled water. Preparation of plant extracts in different solvent systems We harvested 25 g of fresh, mature berries, which were rinsed with distilled water and dried in a shed. The dried berries were put in a Soxhlet apparatus and the plant extracts were prepared using five solvents, namely petroleum ether, benzene, chloroform:methanol (1:1, v/v), acetone and absolute alcohol, applying one after another (extraction period 72.