RESUMO:Os antioxidantes podem ser de grande benefício para a melhoria da qualidade de vida, já que eles têm a capacidade de proteger um organismo dos danos causados pelos radicais livres, prevenindo ou adiando o início de várias doenças. Uma das técnicas atualmente utilizada para detectar a presença de compostos antioxidantes, é um método baseado na eliminação do radical livre estável 1,1-difenil-2-picrilhidrazil (DPPH•). Este método é considerado fácil, preciso, rápido, simples, e econômico, sendo adequado para a determinação da capacidade antioxidante de substâncias puras e misturas. O objetivo deste artigo de revisão é fornecer informações sobre esse método. A pesquisa foi realizada usando o termo radical DPPH•, capacidade antioxidante-DPPH• e método DPPH• em periódicos, tais como: Pubmed, Wiley Online Library, ACS Publications, SpringerLink e ScinceDirect até janeiro de 2014. Palavras-chave: Antioxidantes, método DPPH•, capacidade antioxidante.ABSTRACT: Determination in vitro of the antioxidant capacity of natural products by the DPPH•method: review study. Antioxidants can be of great benefit to improve the quality of life, since they have the ability to protect an organism from damage caused by free radicals, preventing or delaying the onset of various diseases. One of the techniques currently used to detect the presence of antioxidant compounds is a method based on the elimination of the stable free radical 1,1-diphenyl-2-picrylhydrazyl (DPPH•). This method is considered easy, accurate, rapid, simple and inexpensive, and it is suitable for the determination of the antioxidant capacity of pure substances and blends.

Schistosomiasis is a neglected tropical disease that affects hundreds of millions of people worldwide. Since the treatment of this disease currently relies on a single drug, praziquantel, new and safe schistosomicidal agents are urgently required. Nerolidol, a sesquiterpene present in the essential oils of several plants, is found in many foods and was approved by the U.S. Food and Drug Administration. In this study we analysed the in vitro antiparasitic effect of nerolidol on Schistosoma mansoni adult worms. Nerolidol at concentrations of 31.2 and 62.5 μM reduced the worm motor activity and caused the death of all male and female schistosomes, respectively. In addition, confocal laser scanning microscopy revealed morphological alterations on the tegument of worms such as disintegration, sloughing and erosion of the surface, and a correlation between viability and tegumental damage was observed. In conclusion, nerolidol may be a promising lead compound for the development of antischistosomal natural agents.

Praziquantel is currently the only drug available to treat schistosomiasis, a disease of enormous public health significance caused by a blood fluke of the genus Schistosoma. Diminazene, a drug approved by the FDA, has been successfully used to treat diseases caused by blood protozoan parasites. In this study, we evaluated the antiparasitic properties of diminazene against S. mansoni ex vivo and in mice harboring either chronic or early S. mansoni infection. In vitro, we monitored phenotypic and tegumental changes as well as the effects of the drug on pairing and egg production. In a mouse infected with either adult (chronic infection) or immature (early infection) worms, diminazene was administered intraperitoneally (10-100 mg/kg) or by oral gavage (100-400 mg/kg), and we studied the influence of drug on worm burden and egg production. Liver and spleen pathologies and serum aminotransferase levels were also analyzed. In vitro, EC50 and EC90 values revealed that diminazene is able to kill both immature and adult parasites, and its effect was time- and concentration-dependent. In addition, confocal laser scanning microscopy showed morphological alterations in the tegument of schistosomes. In an animal model, the influence of the drug on worm burden, egg production, hepatomegaly, and splenomegaly depended on the dosing regimen applied and route of administration. Diminazene also caused a significant reduction in aminotransferase levels. Comparatively, diminazene treatment was more effective in chronic infection than early infection. In tandem, our study revealed that diminazene possesses anthelmintic properties and it improves liver injury caused by Schistosoma eggs.

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Mauritia flexuosa L. (Arecaceae) is a popular Brazilian fruit known as "buriti" and belonging to the category of functional foods. This work reviewed the phytochemistry profile, nutritional and pharmacological activities of M. flexuosa. The main bioactive compounds reported to buriti were carotenoids, tocopherols, ascorbic acid, phenolic compounds, fiber, phytosterols, and mono-and poly-unsaturated fatty acids. These compounds were mainly related to antioxidant, hypolipemiant, photoprotector, antiaggregant, antithrombotic, anti-inflammatory, hypoglycemiant, antimicrobial, and antitumor activities. Furthermore, some compounds present in buriti fruit and its properties were tested in vitro and in vivo and showed biotechnology applications, especially for extraction of fiber, polysaccharides, pigments, antioxidants, and oil. Howerer, the buriti fruit shows great relevance to the development of new products in food, pharmaceutical and chemical industry, this fruit is still underexploited and it has need to expand its production chain and processing to encourage their consumption and utilization.