Sônia Pereira Leite

Effect of Moringa oleifera lectin on development and mortality of Aedes aegypti larvae

Aedes aegypti larvae have developed tolerance to many insecticides used for mosquito control. Moringa oleifera seeds contain a water-soluble lectin (WSMoL) and this paper reports the effect of M. oleifera seed extracts (MoE(1-15)) and WSMoL on development and survival of A. aegypti larvae. WSMoL peptide from in-gel trypsin digestion is also described. MoE(1-15) showed hemagglutinating activity and WSMoL had similarity with flocculating proteins from M. oleifera seeds. MoE(1) and MoE(3) delayed larval development which stopped in the third instar (L3) in MoE(6) and MoE(15). Significant (p<0.0001) larval mortality was only detected in MoE(15). Native WSMoL showed larvicidal activity (LC(50) 0.197 mg mL(-1)) and heated lectin, without hemagglutinating activity, did not kill fourth instar (L4) larvae. Optical microscopy showed that live L4 from MoE(1) presented underlying epithelium, increased gut lumen and hypertrophic segments; dead L4 from WSMoL were absent of underlying epithelium, had increased gut lumen and hypertrophic segments. The presence of hemagglutinating activity in the extracts suggests that soluble lectin promotes the delay of larval development and mortality; furthermore, the absence of larvicidal activity in heat-denatured WSMoL strengthens the involvement of lectin in this activity mechanism.

Antimicrobial Activity of Indigofera suffruticosa

Various organic and aqueous extracts of leaves of Indigofera suffruticosa Mill (Fabaceae) obtained by infusion and maceration were screened for their antibacterial and antifungal activities. The extracts were tested against 5 different species of human pathogenic bacteria and 17 fungal strains by the agar-solid diffusion method. Most of the extracts were devoid of antifungal and antibacterial activities, except the aqueous extract of leaves of I. suffruticosa obtained by infusion, which showed strong inhibitory activity against the Gram-positive bacteria Staphylococcus aureus with a minimal inhibitory concentration (MIC) of 5000 µg ml−1. The MIC values to dermatophyte strains were 2500 µg ml−1 against Trichophyton rubrum (LM-09, LM-13) and Microsporum canis. This study suggests that aqueous extracts of leaves of I. suffruticosa obtained by infusion can be used in the treatment of skin diseases caused by dermatophytes.

Indigofera suffruticosa: an alternative anticancer therapy.

Indigofera suffruticosa Mill (Fabeceae) occurs in the Northeast countryside and has intensive popular use in the treatment of infectious, inflammatory and other processes. The main aim of the present work was to investigate the cytotoxic and antitumor effects of aqueous extracts of leaves of I. suffruticosa obtained by infusion and maceration as well as to evaluate the toxicological properties. Aqueous extracts did not exhibit cytotoxicity against HEp-2 (human epidermoid cancer cell) cell lines by MTT method. From the aqueous extract by infusion, the toxicological assay showed low order of toxicity. The antitumor effect of aqueous extracts by infusion (64.53%) and maceration (62.62%) against sarcoma 180 in mice at a dose of 50 mg kg−1 (intraperitoneally), based on low order of toxicity was comparable to the control group, which showed 100% development. Considering the low order of toxicity and that it is highly effective in inhibiting growth of solid tumors, the aqueous extracts of leaves of I. suffruticosa may be used as an alternative anticancer agent.

Preliminary study of the molluscicidal and larvicidal properties of some essential oils and phytochemicals from medicinal plants

This study aimed to evaluate the molluscicidal and larvicidal activity of some essential oils and phytochemicals from medicinal plants. Molluscicide and larvicidal activity were determined by, respectively, the lethality bioassays using Artemia salina Leach. Artemiidae and Aedes aegypti L. Culicidae larvae. Essential oils from Eugenia uniflora L. Myrtaceae, Laurus nobilis L. Lauraceae, Origanum vulgare L. Lamiaceae and the phytochemicals α-pinene and eugenol presented citotoxicity toward Artemia salina with CL50 values between 9.59 and 253.43 μL/mL. Essential oils from E. uniflora, M. piperita, O. vulgare and R. officinalis showed embryotoxicity on Aedes aegypti larvae with a viability inhibition between 40 and 100%. These results show the bioactivity of the assayed essential oils and phytochemicals and, partially, justify their insertion in further evaluation in order to establish a safe exploitation of their biological potentiality.

Oviposition and Embryotoxicity of Indigofera suffruticosa on Early Development of Aedes aegypti (Diptera: Culicidae)

Aqueous extract of Indigofera suffruticosa leaves obtained by infusion was used to evaluate the oviposition, its effect on development of eggs and larvae, and morphological changes in larvae of Aedes aegypti. The bioassays were carried out with aqueous extract in different concentrations on eggs, larvae, and female mosquitoes, and the morphological changes were observed in midgut of larvae. The extract showed repellent activity on A. aegypti mosquitoes, reducing significantly the egg laying by females with control substrate (343 (185–406)) compared with the treated substrate (88 (13–210)). No eclosion of A. aegypti eggs at different concentrations studied was observed. The controleclodedin 35%. At concentration of 250 μg/mL, 93.3% of larvae remained in the second instar of development and at concentrations of 500, 750, and 1000 μg/mL the inhibitory effect was lower with percentages of 20%, 53.3%, and 46.6%, respectively. Morphological changes like disruption on the peritrophic envelope (PE), discontinued underlying epithelium, increased gut lumen, and segments with hypertrophic aspects were observed in anterior region of medium midgut of larvae of A. aegypti. The results showed repellent activity, specific embryotoxicity, and general growth retardation in A. aegypti by medium containing aqueous extract of I. suffruticosa leaves.

Indigofera suffruticosa Mill (Fabaceae): Hepatic Responses in Mice Bearing Sarcoma 180

Indigofera suffruticosa es una planta utilizada para tratar procesos infecciosos e inflamatorios. Este trabajo tiene como objetivo evaluar los cambios histopatologicos en el tejido del higado de ratones con sarcoma 180 despues del tratamiento subcronica con el extracto acuoso obtenido por infusion y maceracion de las hojas de Indigofera suffruticosa. Los ratones machos fueron divididos en cuatro grupos de seis animales: pacientes G1 , G2 y G3 con Sarcoma 180 y G4 sin Sarcoma. G1 y G2 fueron tratados con infusion de maceracion respectivamente (50mg/kg.ip); Controles G3 y G4 recibieron solucion salina (15 ml/kg.ip). El analisis histopatologico y morfometrico de tejido hepatico despues de un tratamiento subcronico con extractos acuosos por infusion y la maceracion de los grupos G1, G2 y G4 fueron similares y no mostraron areas degradadas o la infiltracion de leucocitos en comparacion a G3, que muestra una marcada destruccion de la arquitectura del higado. Los resultados mostraron que despues de un tratamiento subcronico con el extracto acuoso de hojas de Indigofera suffruticosa obtenidos por infusion y la maceracion, se conservo la arquitectura hepatica, lo que sugiere su uso como una alternativa de agente hepatoprotector.

Screening Fitoquímico e Avaliação da Toxicidade de Croton heliotropiifolius Kunth (Euphorbiacea) frente à Artemia salina Leach

A especie Croton heliotropiifolius Kunth e utilizada no tratamento de desconfortos gastricos, vomitos, disenteria e antitermico. Este trabalho foi desenvolvido a fim de realizar um screening fitoquimico dos extratos metanolicos do caule, flores e folhas da especie C. heliotropiifolius , e avaliar a toxicidade frente a Artemia salina . Os extratos do caule, flores e folhas apresentaram rendimentos de 22,7 %; 31,4 %; 14,2 %, respectivamente. Foi identificada a presenca de compostos quimicos, tais como flavonoides nas folhas e flores, cumarinas no caule e em menor concentracao nas flores. Alcaloides e saponinas estao ausentes no material estudado. Os extratos metanolicos apresentaram alta toxicidade com valores de CL50 Artemia salina . Este estudo pode contribuir para o aprofundamento dos conhecimentos relativos a composicao quimica e toxicidade desta especie.