Antioxidant properties of different dietary supplements based on Agaricus blazei Murrill

In 2012, the market for nutraceuticals earned $90 billion worldwide and it is predicted to reach$33.6 billion in the next four years. Agaricus blazei Murrill mushroom is native to Brazil and widely cultivated due to nutritional and medicinal value [I ,2]. Its beneficial effects have long been recognized, becoming popular as ordinary food, increasing also its production and marketing as dietary supplements (3]. A. blazei is traditionally used to combat a variety of diseases such as cancer, diabetes, hepatitis and hypercholesterolemia [2]. The use of dietary supplements based on A. blazei has grown significantly, due to pharmacological studies reporting antioxidant, antitumor, anti-inflammatory, antimicrobial, immunostimulant, apoptotic and chemopreventive effects [2,3], attributed to ®-glucans and other bioactive compounds, such as steroids, tocopherols and phenolic compounds [4]. Herein, the antioxidant activity of A. blazei capsules enriched with fmits of Malpighia glabra L. (acerola), Solanum melongena L. (eggplant) and Euterpe oleracea Mart. (açai), calcium and chitosan, were evaluated though in vitro assays: DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging activity, reducing power, inhibition of G-carotene bleaching and inhibition of lipid peroxidation in brain homogenates by thiobarbituric acid reactive substances (TSARS) assay. Two capsules (daily recommended dose) were dissolved in 100 mL of distilled water in order to prepare a stock solution. Several dilutions were tested until determination of EC50 values (concentration responsible for 50% of antioxidant activity or 0.5 of absorbance in reducing power assay). Globally, all the tested formulations showed high antioxidant activity. A. blazei with acerola gave the highest DPPH scavenging activity (EC50=0.81±0.0 1 mg/mL) and reducing power (EC50=0.53±0.0 1 mg/mL). Nevertheless, A. blazei with ayai showed the highest activity in the lipophilic assays: f3 - carotene bleaching inhibition (EC50=0.55±0.02 mg/mL) and lipid peroxidation inhibition by TSARS assay (EC50=O. 14±0.01 mg/mL). The studied formulations might be useful as antioxidants-enriched supplements to prevent some of the diseases related to oxidative stress

The powerful in vitro bioactivity of Euterpe oleracea Mart. seeds and related phenolic compounds

The Euterpe oleracea Mart. (açaí) is a plant from the Amazon region, classified as "super fruit" because of its various functional properties. However, limited investigation has been performed on açaí by-products, such as seeds. Therefore, the aim of this work was to characterized the phenolic compounds of the aqueous extract of açaí seeds and further evaluate its bioactivity (antioxidant and cytotoxic activities. Only proanthocyanidins were detected, being a B-type (epi)catechin tetramer the most abundant; however, procyanidin trimmers were the most predominant form. Açaí seeds extract revealed a high antioxidant (EC50 ranging from 3.6 to 19.4 μg/mL) and cytotoxic activity, being more effective in the cervical carcinoma cell line (HeLa; GI50 = 18 μg/mL); it did not show toxicity for non-tumor cells. Açaí seeds are considered a waste and could have an added economic benefit, through the extraction of natural antioxidants, particularly proanthocyanidins, that could find applications in food and pharmaceutical industries.The authors are grateful to Foundation for Science and Technology (FCT, Portugal) for financial support to the research centre CIMO (strategic project PEst OE/AGR/UI0690/2011) and L. Barros researcher contract under “Programa Compromisso com Ciência - 2008”. The authors are also grateful to Jamil S. Oliveira by the initial discussions on the preparation of samples