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Structural polymeric features that contribute to in vitro immunostimulatory activity of instant coffee

Ferreira, Sónia S., Passos, Cláudia P., Cepeda, Márcio R., Lopes, Guido R., Teixeira-Coelho, Maria, Madureira, Pedro, Nunes, Fernando M., Vilanova, Manuel, Coimbra, Manuel A.
Food chemistry 2018 v.242 pp. 548-554
B-lymphocytes, alpha-N-arabinofuranosidase, arabinogalactans, arabinose, chymotrypsin, dendritic cells, gel chromatography, hydrolysis, immunostimulants, in vitro studies, instant coffee, lymphocyte proliferation, macrophages, mice, spleen, ultrafiltration
An instant coffee fraction, rich in arabinogalactans, obtained by ultrafiltration, using 1 and 5kDa membranes, has previously shown in vitro stimulatory activity on BALB/c mice spleen B lymphocytes. The compounds inducing lymphocytic activation were shown to elute, mainly near the void volume by size-exclusion chromatography, using Bio-Gel P6 (1–6kDa). Treatment of the compounds with chymotrypsin, a digestive protease, did not affect the induced B lymphocyte activation. On the contrary, hydrolysis with an α-l-arabinofuranosidase, removing single terminally-linked arabinose residues, decreased the extent of B cell activation. The immunostimulatory activity of these compounds was also observed by in vitro experiments, using bone marrow-derived macrophages and dendritic cells as responders. Altogether, these results show the relevance of single arabinose residues, present at the non-reducing end of polymeric compounds, to the coffee stimulatory activity in cells mediating innate and acquired immunity.