The antibacterial activity of various saturated and unsaturated fatty acids against several oral pathogens.

The antibacterial activity of various saturated fatty acids (SFA) and unsaturated fatty acids (USFA) against different oral pathogens which are implicated in the cause of dental caries, stomatitis, gingivitis, and periodontitis was examined. The saturated fatty acids Pa, StA and ArA, and the unsaturated w-7 fatty acids PLA and w-9 fatty acids OA showed either none to low antimicrobial activity against all of the 12 oral pathogenic strains used in this study. In contrast, the w-3 PUFAs, ALA, SDA, EPA and DHA, and the w-6 PUFAs, LA, GLA, and AA showed considerable antimicrobial activity against 8, 7, 6 and 5 strains, and 6, 10 and 5 strains, respectively. In particular, the w-3 and w-6 PUFAs showed strong antimicrobial activity against Porphyromonas gingivalis KCTC 381, the cause of periodontitis, and against Aggregatibacter segnis KCTC 5968, Fusobacterium nucleatum subsp. Polymorphum KCTC 5172 and Prevotella intermedia KCTC 25611, all organisms implicated in the cause of gingivitis. To date, no bacterial resistance to free fatty acids has been encountered and no resistance phenotype has emerged. Therefore, these results suggest that PUFAs may be useful in the development of therapeutic agents for oral diseases, and in particular, in the development of agents that have minimal side effects and against which there is no bacterial resistance.

Inhibition of oral pathogens and collagenase activity by seaweed extracts.

Fifty-seven species of common seaweed from the Coast of Korea were screened for antimicrobial (i.e. inhibition of Prevotella intermedia and Porphyromonas gingivalis growth) activity. As a source of bioactive compounds, seaweeds can produce many secondary metabolites with a variety of activities. Using the agar diffusion method, only 17 species (29.8%) showed inhibitory activity. Of these, methanol extracts of Enteromorpha linza, Sargassum sagamianum, and Ulva pertusa showed strong inhibitory effects against both P. intermedia and P. gingivalis. The MIC values of E. linza, S. sagamianum, and U. pertusa extracts against P. intermedia were 625, 78 and 625 Ag ml-1 and those against P. gingivalis were 312, 156 and 625 Ag ml-1, respectively. When these three species’ extracts were separated into five fractions according to their polarity, the main active agents were determined to be phenolic compounds. We then compared the antimicrobial activities of these phenolic compounds against various periodontal pathogens using a MIC test. Phenolic compound containing extracts at concentrations of 10 to 100 Ag ml-1 showed a moderate to significant inhibitory effect on collagenase 1, 2 and 3 activity.

In vitro antibacterial and anti-inflammatory properties of seaweed extracts against acne inducing bacteria, Propionibacterium acnes.

This study was conducted to evaluate the antimicrobial activities of common seaweeds from the coast of South Korea against the etiologic agents of acne vulgaris. Fifty-seven species of seaweed were screened for potential antimicrobial activity. Methanol extracts of 13 species (22.8%) showed inhibitory effects against Propionibacterium acnes. The aqueous extracts of only two species (3.5%) showed antimicrobial activity. When tested with the agar disk diffusion method, Ecklonia cava, E. kurome, Ishige sinicola, and Symphyocladia latiuscula had the strongest inhibitory effects. However, these four seaweed extracts showed no antibacterial activity against Staphylococcus epidermidis at 5 mg disk-1. The minimum inhibitory concentration (MIC) values of E. cava and E. kurome were both 0.31 mg ml-1 and the MIC values of I. sinicola and S. latiuscula were 0.26 and 0.21 mg ml-1, respectively. Among whole plants of E. cava and E. kurome, extracts of the pinnate blade had the highest inhibitory activity on bacterial growth. In cytotoxicity assays, methanol extracts of E. cava, E. kurome, and I. sinicola showed no effect on cell viability at concentrations of 200 μg ml-1. However, the methanol extracts of S. latiuscula reduced cell viability rates to 50% at the same concentration. Additionally, methanol extracts of E. cava, E. kurome, and I. sinicola potently inhibited the in vitro production of nitric oxide. These results suggest that the methanol extracts from these three species may be useful in the development of therapeutic agents for acne vulgaris. Further investigations to determine the bioactive compound are in progress.

Anti-inflammatory activities of methanol extracts from various seaweed species.

Thirty-seven species of common seaweeds from the coast of Korea were screened for anti-inflammatory activity Methanol extracts of the seaweeds were tested against mouse ear edema and erythema induced by phorbol myristate acetate. At 40 mg ml(-1) of extract, edema was strongly suppressed by the seaweeds Undaria pinnatifida and Ulva linza, with relative inhibition of 85 and 84%, respectively These two seaweeds also showed the greatest suppression of erythema, with inhibition of 78 and 70%, respectively IC50 values of U. pinnatifida were 10, 15, and 18 mg ml(-1) when inflammation symptoms of edema, erythema, and blood flow, respectively were measured. The IC50 of U. linza was 20, 26, and 31 mg ml(-1) when edema, erythema, and blood flow, respectively, were measured. A linear correlation among inhibition rates of edema, erythema, and blood flow was observed with high confidence.