Guarana powder polysaccharides: characterisation and evaluation of the antioxidant activity of a pectic fraction.

Guarana is a fruit from the Amazon whose seeds are used to produce guarana powder. Guarana powder is consumed by the population mainly for its stimulant activity. It has been shown that guarana seeds contain low-molar-mass compounds; however, no data have been reported concerning the polysaccharides. In this work, the polysaccharides present in guarana powder were investigated. A pectic fraction and a xylan were isolated and characterised. Antioxidant activity tests were performed with a methanolic extract and the pectic fraction at concentrations of 0.1-10 mg/ml. The methanolic extract exhibited a strong capacity for scavenging DPPH radicals (90.9% at 10 mg/ml). At the same concentration, the polysaccharide showed a DPPH(·)-scavenging activity of 68.4%. At a higher concentration, the methanolic extract and the polysaccharide exhibited similar hydroxyl radical-scavenging effects (~70%). The results suggest that the polysaccharides present in guarana can contribute to the possible biological effects of guarana powder.

Characterization and antineoplasic effect of extracts obtained from Pleurotus sajor-caju fruiting bodies.

Fungi of the Pleurotus genus present a great industrial interest due to their possibility of producing pharmacological compounds, pigments, aromas, organic acids, polysaccharides, enzymes, vitamins, amino acids, etc. Among the therapeutic products, we can highlight those with antineoplasic activity, attributed to the fungi cell wall components. Based on this, the objective of this work was to study the antineoplasic capacity of the polysaccharidic fractions obtained from Pleurotus sajor-caju fruiting bodies. Female Swiss mice were inoculated with the Ehrlich ascitic tumor (5 x 10(6) cells/animal) in ascitic form. The polysaccharidic fractions were administered intraperitoneally, during a 6-day period. Fractions FI and FII presented a lower volume of ascitic liquid (3.1 and 1.8 mL, respectively) and a higher reduction in the number of neoplasic cells present in the ascitic liquid (86.2% and 85%, respectively), when compared to the positive control (group inoculated with the tumor but without treatment). These fractions were characterized in terms of monosaccharide composition. Glucose was the major component detected, followed by galactose and mannose. The anomeric carbon configuration of the beta-glucan was confirmed by the (13)C NMR (delta 103.7). Substituted and free C3 and C6 were also detected. Protein bands were confirmed through infrared analysis.