Abstract

ABDALA-DIAZ, RT et al. Effect of Porphyridium cruentum polysaccharides on the activity of murine macrophage cell line RAW 264.7. Cienc. mar [online]. 2010, vol.36, n.4, pp.345-353. ISSN 0185-3880.

Red algae are considered an important source of polysaccharides with potential immunomodulatory properties. Polysaccharides from the cell wall of the red alga Porphyridium cruentum can compose more than 50% of its biomass; however, little is known regarding its biochemical composition and phage-modulatory properties. Consequently, this study aimed to evaluate the effect of P. cruentum polysaccharides on tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and nitric oxide (NO) production. Polysaccharides from P. cruentum were extracted and purified by N-cetylpyridinium bromide precipitation and characterized by Fourier transform infrared spectroscopy. The effect on the activity of murine macrophage cell line RAW 264.7 was examined by quantification of TNF-a, IL-6, and NO production using enzyme-linked immunosorbent assays. The results showed that the polysaccharides from P. cruentum induced TNF-a and IL-6 cytokine accumulation. The production of TNF-α was significantly higher than that in the control (bacterial lipopolysaccharide, LPS) when the concentration of polysaccharides was higher than 6.25 µg mL^-1. The addition of polysaccharide levels above 25 µg mL^-1 produced IL-6 levels ranging from 3.4 to 4 ng mL^-1, which were comparable to the production of IL-6 induced by 50 ng mL^-1 of LPS (3.3 ± 0.3). In contrast to IL-6 and TNF-α, NO production was only detected when polysaccharide concentrations were higher than 25 µg mL^-1. These results indicate for the first time that polysaccharides from P. cruentum are strong cytokine inducers.

Keywords : red microalga; Porphyridium cruentum; immunomodulator; macrophages; FTIR spectroscopy.