RESUMO
In this research, we evaluated the aphicidal effect of the ethanolic extract of stems and bark of Ficus petiolaris Kunth (Moraceae), in laboratory bioassays in an artificial diet against apterous adult females of Melanaphis sacchari Zehntner (Hemiptera: Aphididae). The extract was evaluated at different concentrations (500, 1,000, 1,500, 2,000, and 2,500 ppm), and the highest percentage of mortality (82%) was found at 2,500 ppm after 72 h. The positive control imidacloprid (Confial®) at 1% eliminated 100% of the aphids, and the negative control (artificial diet) only presented mortality of 4%. The chemical fractionation of the stem and bark extract of F. petiolaris yielded five fractions of FpR1-5, which were each evaluated at 250, 500, 750, and 1,000 ppm. FpR2 had the strongest aphicidal effect, with 89% mortality at 72 h at 1,000 ppm. The pure xanthotoxin compound extracted from this fraction was even more effective, with 91% aphid mortality after 72 h at 100 ppm. The lethal concentration (LC50) of xanthotoxin was 58.7 ppm (72 h). Our results indicate that the extract of F. petiolaris showed toxic activity against this aphid, and its xanthotoxin compound showed strong aphicidal activity at low concentrations.
Assuntos
Afídeos , Ficus , Sorghum , Animais , Feminino , Metoxaleno , Extratos Vegetais/farmacologiaRESUMO
ABSTRACT: The insecticidal activity of a Ricinus communis leaf hexane extract and its fractions against adult yellow sugarcane aphids (Sipha flava) was evaluated using a contact bioassay after fumigation. The n-hexane extract at 10,000 ppm achieved the highest mortality (80%); the positive control had 100% mortality and the negative control had only 4% mortality over the 72-h experiment time. Chemical fractionation of the hexane extract of R. communis leaves produced multiple fractions, and 10,000 ppm of the F4 fraction resulted in 92% aphid mortality at 72 h. Gas chromatography-mass spectrometry of the F4 fraction revealed linoleic acid as the major compound (84.5%). The R. communis n-hexane extract and linoleic acid could be used for integrated pest control as an ecologically friendly alternative to synthetic chemical insecticides.
Assuntos
Afídeos , Ricinus/química , Animais , Ácido Linoleico , Folhas de Planta/químicaRESUMO
This study investigates updated information in different search engines on the distribution, phytochemistry, pharmacology, and toxicology of Brugmansia suaveolens (Solanaceae) using the extracts or chemical compounds at present. This plant has been used in traditional medicine in different cultures as a hallucinatory, analgesic, aphrodisiac, nematicide, sleep inducer, and muscle relaxant, as well as a treatment for rheumatism, asthma, and inflammation. The flowers, fruits, stems, and roots of the plant are used, and different chemical compounds have been identified, such as alkaloids, volatile compounds (mainly terpenes), coumarins, flavonoids, steroids, and hydrocarbons. The concentration of the different compounds varies according to the biotic and abiotic factors to which the plant is exposed. The toxic effect of the plant is mainly attributed to atropine and scopolamine, their averages in the flowers are 0.79 ± 0.03 and 0.72 ± 0.05 mg/g of dry plant, respectively. Pharmacological studies have shown that an aqueous extract exhibits the antinociceptive effect, at doses of 100 and 300 mg/kg i.p. in mice. On the other hand, the ethanolic extract at 1000 mg/L, showed a nematocidal activity in vitro of 64% against Meloidogyne incognita in 72 h. Likewise, it showed a 100% larvicidal activity at 12.5 mg/L against Ancylostoma spp. In another study, the lethal activity of shrimp in brine from an ethanolic extract showed an LC50 of 106 µg/mL at double serial concentrations of 1000-0 (µg/mL). Although there are pharmacological and phytochemical studies in the plant, they are still scarce, which has potential for the examination of the biological activity of the more than one hundred compounds that have been reported, many of which have not been evaluated.
