Anti-inflammatory properties of kefir and its polysaccharide extract

Kefir is a fermented beverage originating form the Caucasian regions composed of a number of bacteria and yeasts living together in polysaccharide grains secreted by them. Kefir can be considered a probiotic source as it presents anti-bacterial, anti-mycotic, anti-neoplasic and immunomodulatory properties. Aiming to appraise a possible anti-inflammatory effect of kefir we conducted cotton-induced granuloma and paw oedema assays in rats, the latter using carrageenan, dextran and histamine as stimuli. Kefir samples were thawed and continuously cultured during 15 days both in a molasses solution (50 g/l) and in cow's milk. A polysaccharide extract isolated from the grains (kefiran) was also tested in cotton-pellet experiments. The results showed significant inhibition in the formation of granuloma tissue for all the test groups, as compared to the blank group. Kefir suspensions in molasses presented an inhibition of 41 +/- 3% for the inflammatory process, fermented milk prepared from kefir showed 44 +/- 6% inhibition and kefiran extract 34 +/- 15%. Rat paw oedema also showed significant decreases with the mediators. Dextran-induced oedema was completely inhibited at 1 h after input, with a 76% inhibition after 2 h. Carrageenan stimulus was inhibited 62% after the 3rd hour, and histamine by 52% after the 2nd hour. These results points to the existence of anti-inflammatory prebiotic compounds present in symbiotic cultures of kefir growing in both aqueous and milky suspensions.