Preventive effect of a pectic polysaccharide of the common cranberry Vaccinium oxycoccos L. on acetic acid-induced colitis in mice.

OBJECTIVE

To study isolation and chemical characterization of pectin derived from the common cranberry Vaccinium oxycoccos L. (oxycoccusan OP) and the testing of its preventive effect on experimental colitis.

METHODS

Mice were administrated orally with OP two days prior to a rectal injection of 5% acetic acid and examined for colonic damage 24 h later. Colonic inflammation was characterized by macroscopical injury and enhanced levels of myeloperoxidase activity measured spectrophotometrically with o-phenylene diamine as the substrate. The mucus contents of the colon were determined by the Alcian blue dye binding method. Vascular permeability was estimated using 4% Evans blue passage after i.p. injection of 0.05 mol/L acetic acid.

RESULTS

In the mice treated with OP, colonic macroscopic scores (1.1+/-0.4 vs 2.7, P<0.01) and the total square area of damage (10+/-2 vs 21+/-7, P<0.01) were significantly reduced when compared with the vehicle-treated colitis group. OP was shown to decrease the tissue myeloperoxidase activity in colons (42+/-11 vs 112+/-40, P<0.01) and enhance the amount of mucus of colitis mice (0.9+/-0.1 vs 0.4+/-0.1, P<0.01). The level of colonic malondialdehyde was noted to decrease in OP-pretreated mice (3.6+/-0.7 vs 5.1+/-0.8, P<0.01). OP was found to decrease the inflammatory status of mice as was determined by reduction of vascular permeability (161+/-34 vs 241+/-21, P<0.01). Adhesion of peritoneal neutrophils and macrophages was also shown to decrease after administration of OP (141+/-50 vs 235+/-37, P<0.05).

CONCLUSIONS

Thus, a preventive effect of pectin from the common cranberry, namely oxycoccusan OP, on acetic acid-induced colitis in mice was detected. A reduction of neutrophil infiltration and antioxidant action may be implicated in the protective effect of oxycoccusan.