Antibacterial characteristics of black currant fruit extracts

Background : Our group previously reported from high bactericidal potential of berry juices, especially from blackcurrant fruits. The present study observed different fractions from blackcurrant fruits (all-fruit juice: AFJ, squeezed juice: SJ, non-dialyzable juice material: NDFM, alcoholic fraction from beery skins: AFBS, aqueous fraction from beery skins: AQFBS) in their efficiency of suppressing various oral gram-positive and gram-negative bacteria. Methods : AFJ, SJ, NDFM, AFBS and AQFBS were prepared from freshly harvested blackcurrant fruits and incubated in direct contact (60s) to planktonic cultures of Fusobacterium nucleatum (F.n.), Agregatibacter 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 most efficient, causing total suppression of F.n., P.g. and S.g. and induced major reduction in A.a., S.g. and A.n.. Bactericidal efficiency was as follows: AFJ>SJ>EFBS>AQFBS>NDFM. Gram-negative bacteria were more susceptible to blackcurrant extracts compared to gram-positive species. AFJ was efficient as 0.2% CHX in suppressing F. n., P. g. and S. g.. Conclusions : All-fruit juice from blackcurrant shows strong bactericidal activity on F.n., A.a., P.g., S.g. and A.n.. Further research should aim on investigating the function of blackcurrant fruit extracts in controlling oral biofilm formation.