Abstract: The blue berry(Vaccinium corymbosum) fruit contains bioactive polyphenols with reported anti-bacterial properties.This study sought to investigate the anti-bacterial,cartilage-protecting and anti-inflammatory effects of a polyphenolic-enriched blue berry extract using a plate inhibition test,a minimum inhibitory concentration(MIC)test,and an in vitro bovine nasal explant cell culture model.Results showed that not only gram-positive Bacillus subtilis and gram-negative Escherichia coli were inhibited but a multiply antibiotic resistant bacterium Proteus mirabilis was also susceptive to blue berry extract.Gelatin zymography test showed the protease activity was significantly decreased in bovine nasal explant cell culture samples after blue berry extract addition,which was infected with antibiotic resistant bacterium Proteus mirabilis. This confirmed the release inhibition of glycosaminoglycan(GAG),which was a signal of inflammatory,was in according with protease inhibition by blue berry extract.

Key words: blue berry, polyphenols, anti-bacterial, anti-inflammatory, Proteus mirabilis