Antibacterial characteristics of black currant fruit extracts.

BACKGROUND: Our group previously reported on the high bactericidal potential of berry juices, particularly those derived from blackcurrant fruits. In the present study, we tested the efficiency of various juice fractions from blackcurrant fruits (all-fruit juice: AFJ, squeezed juice: SJ, non-dialyzable juice material: NDFM, alcoholic fraction from berry skins: AFBS, aqueous fraction from berry skins: AQFBS) in their efficiency to suppress various oral gram-positive and gram-negative bacteria. METHODS: AFJ, SJ, NDFM, AFBS, and AQFBS were prepared from freshly harvested blackcurrant fruits. These fractions were used for direct contact tests with planktonic cultures of Fusobacterium nucleatum (F.n.), Aggregatibacter actinomycetemcomitans (A.a.), Porphyromonas gingivalis (P.g.), Streptococcus gordonii (S.g.), Streptococcus mutans (S.m.), Streptococcus sobrinus (S.s.), Actinomyces naeslundii (A.n.), and Enterococcus faecalis (E.f.). RESULTS: AFJ was the most efficient fraction, causing complete suppression of F.n., P.g., and S.g., and inducing a major reduction in A.a., A.n., and E.f. colony count. Bactericidal efficiency of the juices presents as follows: AFJ> AFBS > SJ> AQFBS> NDFM. Gram-negative bacteria were more susceptible to blackcurrant extracts compared to gram-positive species. AFJ efficiency was similar to 0.2% chlorhexidine solution in suppressing F. n., P. g., and S. g. CONCLUSIONS: All-fruit juice from blackcurrant shows a strong bactericidal activity on F.n., A.a., P.g., S.g., and A.n. Further research should investigate the potential of blackcurrant fruit extracts in controlling oral biofilm formation.