Abstract
In this work, biological effects of the water extract of Moringa oleifera seeds (WEMOS) were assessed on eggs and 3rd instar larvae of Aedes aegypti and on its toxicity upon laboratory animals (Daphnia magna, mice and rats). Crude WEMOS showed a LC50 value of 1260microg/mL, causing 99.2 +/- 2.9% larvae mortality within 24 h at 5200microg/mL, though this larvicidal activity has been lost completely at 80 masculineC/10 min. WEMOS did not demonstrate capacity to prevent egg hatching. After extensive dialyses of the crude WEMOS into watersoluble dialyzable (DF) and nondyalizable (NDF) fractions, only DF maintained its efficacy to kill larvae. Acute toxicity evaluations on daphnids (EC50 of 188.7microg/mL) and mice (LD50 of 446.5 mg/kg body weight) pointed out to low toxicity. Despite the thymus hypertrophy, WEMOS revealed to be harmless in orally and subacutelytreated rats. In conclusion, WEMOS has thermostable bioactive compounds against Ae. aegypti larvae with apparent molecular mass lower than 12 kDa and moderately toxic potential.
Highlights
Dengue is an important human viral disease transmitted by Aedes aegypti Linnaeus, 1762 (Diptera: Culicidae) that is gradually becoming endemic in several Central and South American countries (Gubler 1998)
The aim of this work was to assess the activity of the water extract of M. oleifera seeds (WEMOS) upon egg hatching and larval development of Ae. aegypti and its toxicity on Daphnia magna Straus, 1820 (Cladocera: Crustacea) and laboratory mammals
water extract of Moringa oleifera seeds (WEMOS) is expressed as soluble solids based on the proportion 1 seed: 10 mL (Gerdes 1997)
Summary
Dengue is an important human viral disease transmitted by Aedes aegypti Linnaeus, 1762 (Diptera: Culicidae) that is gradually becoming endemic in several Central and South American countries (Gubler 1998). The Northeast region of Brazil has been suffering successive dengue epidemics, and official reports have demonstrated that the State of Ceará has been one of the most affected states at that region. From 1986 to 2008, a total of 243,619 cases were reported and until last December, 178 out of 185 municipalities were infested (SESA 2008). The selective pressure of conventional insecticides, such as organochloranes, carbamates, pyrethroids and organophosphorates, is enhancing resistance of mosquito populations at an alarming rate, resulting in widespread resurgence, undesirable effects on non-target organisms and environmental and human health concerns (Brown 1986, Mazzari and Georghiou 1995). This, increases the demand for new products that be environmentally safe, target-specific and degradable
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