Larvicidal activity of 94 extracts from ten plant species of northeastern of Brazil against Aedes aegypti L. (Diptera: Culicidae)

Abstract

In an effort to find effective and affordable ways to control of Aedes aegypti L. (Diptera: Culicidae), the larvicidal activities of 94 extracts from ten plant species belonging to eight families [Guettarda grazielae and Spermacoce verticillata (Rubiaceae), Coccoloba mollis and Triplaris americana (Polygonaceae), Eschweilera ovata (Lecytidaceae), Merremia aegyptia (Convolvulaceae), Ouratea nitida (Ochnnaceae), Protium heptaphyllum (Burseraceae), Rourea doniana (Connaraceae), and Tovomita brevistaminea (Guttiferae)], widely found in the northeast of Brazil, were initially screened at 250 microg/mL. Nineteen of the 94 extracts from six plant species (C. mollis, G. grazielae, M. aegyptia, R. doniana, S. verticillata, and T. americana) showed significant activity (>75% mortality) against the fourth instar larvae. Some of these extracts showed 100% mosquito larvae mortality, with LD(50) values lower 200 microg/mL. When compared to synthetic insecticide Temephos (LD(50) 8.7 microg/mL), two of them, hexane (LD(50) 12.1 microg/mL) and ethyl acetate (LD(50) 51.6 microg/mL) extracts from stems of R. doniana and G. grazielae, respectively, were the most effective. The isolation and purification of these extracts are in progress and evaluation of these compounds will be needed to identify the active component.

Phytochemical and antifungal activity of anthraquinones and root and leaf extracts of Coccoloba mollis on phytopathogens

“…There are few published studies of this plant in the scientific literature. Hexane extracts of stem, bark and leaves of C. mollis have demonstrated larvicidal activity against Aedes aegypti, showing potential in the control of this vector of tropical diseases (Oliveira et al, 2010). In another study testing the ethanolic extracts of the leaves and roots of C. mollis, the results showed that both extracts induced the DNA damage at a concentration of 20 µg/mL, but neither showed genotoxicity at any of the concentrations tested, based on the micronucleus test (Tsuboy et al, 2007).…”

Chemical Constituents, Larvicidal Effects and Radical Scavenging Activity of Tetracera breyniana Schltdl. (Dilleniaceae)

“…As shown in Table 1, when compared to synthetic insecticide Temephos (LD 50 8.7 μg/mL), only hexane fraction from stem (LD 50 72.08 g/mL; 95% CL 60.92-82.47) was effective. All others were inactive (LD 50 > 280 g/mL; results not shown in Table 1) (Oliveira et al, 2010). The isolation and purification of this extract and evaluation of these compounds will be needed to identify the active component.…”

“…Since there is no vaccine currently available for dengue and DHF prevention, the eradication of the mosquito adults and larvae, which is primarily relied on applications of synthetic insecticides or larvicides, is the most commonly adopted strategy for reducing morbidity (WHO, 2008). According to the literature, the organophosphate temephos is one of the most employed commercial insecticides for the control of this vector (Macoris et al, 2007;Garcez et al, 2009;Oliveira et al, 2010). However, these chemicals can affect non target population and may increase mosquito resistance to insecticides.…”

“…The blood supply for the females was performed using the species pigeons Columbia livia. Larvicidal assays were performed following the recommendations of the WHO (1981) with some modifications (Oliveira et al, 2010). Initially all samples were screened at 250 μg/mL.…”

“…According to World Health Organization (WHO) estimates, 0.5 million people with dengue hemorrhagic fever (DHF) require hospitalization each year and approximately 2.5% of these individuals die from DHF (WHO, 2008). Annually, there may be over 50-100 million dengue infections in tropical and subtropical areas (Renjana and Thoppil, 2013), and so these diseases have emerged as a major international health problem and a notable increase in dengue cases (77.7%) has been reported by Brazilian health authorities (Oliveira et al, 2010).…”