Insecticidal and Repellent Activity of Siparuna guianensis Aubl. (Negramina) against Aedes aegypti and Culex quinquefasciatus

This study investigated the toxic effects of essential oils isolated from Siparuna guianensis against Aedes aegypti, Culex quinquefasciatus (eggs, larvae, pupae, and adult) and Aedes albopictus (C6/36) cells. The oviposition-deterring activity, egg viability, and repellence activity in the presence of different essential oils concentrations were determined. The essential oils showed high toxicity to all developmental stages of A. aegypti and C. quinquefasciatus. Furthermore, the oils also showed high repellent activity towards the adult stage of mosquitoes (0.025 to 0.550 μg/cm2 skin conferred 100% repellence up to 120 min) and in contact with cultured insect cells (C6/36) induced death possibly by necrosis. The results presented in this work show the potential of S. guianensis essential oils for the development of an alternative and effective method for the natural control of mosquitoes in homes and urban areas.     

Neuroprotective role of lipoic acid against acute toxicity of N-acetylaspartic acid

N-Acetylaspartic acid (NAA) accumulates in Canavan disease, a severe inherited neurometabolic disorder clinically characterized by mental retardation, hypotonia, macrocephaly, and seizures. The mechanisms of brain damage in this disease remain poorly understood. Recent studies developed by our research group showed that NAA induces oxidative stress in vitro and in vivo in cerebral cortex of rats. Lipoic acid is considered as an efficient antioxidant which can easily cross the blood–brain barrier. Considering the absence of specific treatment to Canavan disease, this study evaluates the possible prevention of the oxidative stress promoted by NAA in vivo by the antioxidant lipoic acid to preliminarily evaluate lipoic acid efficacy against pro-oxidative effects of NAA. Fourteen-day-old Wistar rats received an acute administration of 0.6 mmol NAA/g body weight with or without lipoic acid (40 mg/kg body weight). Catalase (CAT), glutathione peroxidase (GPx), and glucose 6-phosphate dehydrogenase activities, hydrogen peroxide content, thiobarbituric acid-reactive substances (TBA-RS), spontaneous chemiluminescence, protein carbonyl content, total antioxidant potential, and DNA–protein cross-links were assayed in the cerebral cortex of rats. CAT, GPx activities, and total antioxidant potential were significantly reduced, while hydrogen peroxide content, TBA-RS, spontaneous chemiluminescence, and protein carbonyl content were significantly enhanced by acute administration of NAA. Those effects were all prevented by lipoic acid pretreatment. Our results clearly show that lipoic acid may protect against the oxidative stress promoted by NAA. This could represent a new therapeutic approach to the patients affected by Canavan disease.     

Nutraceutical Effect of Trace Elements as Additional Injectable Doses to Modulate Oxidant and Antioxidant Status,and Improves the Quality of Lamb Meat

Our study aimed to evaluate whether zinc, copper, selenium, and manganese subcutaneous mineral application (trace elements) reduced mortality, improved performance, and modulated oxidant and antioxidant balance in lamb meat, thereby improving its quality. We divided the 110 newborn Lacaune lambs into two groups: non-treated (control), and treated (application of minerals) with three doses of 0.33 mL/kg of body weight mineral complex on days of life 1, 30, and 60. All animals were weighed on day of life 1, 30, 60, 90, and 150. At the end of the experiment, 12 animals were slaughtered for physical and chemical analysis of meat, oxidant, and antioxidant status, and for allometric analysis. Mineral-application animals had greater live-weight (P < 0.05) on days of life 60 and 90. There was an increase in fat thickness (P = 0.004); pH levels (P = 0.002) were lower in mineral-application animal meat than in that of the control group. Meat was paler (according to lightness (L color)) in the control group (P = 0.04). Weight loss from cooking was greater in control animals (P = 0.004). Shear strength values were lower in the meat of treated lambs (P = 0.008) suggesting that mineral application was associated with increased meat tenderness. In addition, catalase and superoxide dismutase activities were higher (P = 0.01) in mineral-treated animals, associated with a reduction in reactive oxygen species levels (P < 0.01), and lipid peroxidation products (P = 0.02). These data suggest that mineral application modulated oxidant and antioxidant status, reflecting better meat quality.