Differential neuritogenic activities of two edible brown macroalgae, Undaria pinnatifida and Saccharina japonica.

Undaria pinnatifida (Harvey) Suringar and Saccharina japonica Areschoug are two common seaweeds, and both are known to have numerous pharmacological properties that include neuroprotective effects. In a previous study, we found that the ethanol extracts of U. pinnatifida (UPE) and S. japonica (SJE) had neurite promoting activities on developing hippocampal neurons. In the present study, we studied and compared the effects of UPE and SJE on neuronal maturation. Both UPE and SJE promoted neurite outgrowth in a dose-dependent manner with optimal concentrations of 5 and 15 µg/mL, respectively. Initial neuronal differentiation was significantly promoted by UPE and SJE. Subsequently, treatment with both increased indices of axonal and dendritic cytoarchitecture, such as, the numbers and lengths of primary processes, although only UPE had a significant effect on branching frequencies. In addition, UPE and SJE showed no evidence of cytotoxicity, rather they protected neurons from naturally occurring death in vitro. These results indicate that UPE and SJE promote axodendritic maturation and neuronal survival and suggest that these algal extracts, especially UPE, have beneficial effects on the nervous system.

Antimicrobial activities of stearidonic and gamma-linolenic acids from the green seaweed Enteromorpha linza against several oral pathogenic bacteria.

BACKGROUND: We found that the edible green seaweed Enteromorpha linza displayed potent antimicrobial activity against Prevotella intermedia and Porphyromonas gingivalis. To elucidate the active component of E. linza, isolation procedures were performed. RESULTS: The main active compound was isolated by polarity fractionation, Sephadex LH-20 gel chromatography, and reverse-phase high-performance liquid chromatography (RP-HPLC). The active compounds were eluted at isocratic 95% acetonitrile by RP-HPLC and identified as unsaturated fatty acids, stearidonic acid (SA, C18:4 n-3) and gamma-linolenic acid (GLA, C18:3 n-6) by gas chromatography-mass spectrometry, 1H nuclear magnetic resonance (NMR) spectroscopy, and 13C NMR spectroscopy. The yields of SA and GLA from dried seaweed tissue were 6.33 × 10-3% and 6.47 × 10-3%, respectively. The minimal inhibitory concentration values of SA and GLA were 39.06 µg/mL against P. intermedia and 9.76 µg/mL against P. gingivalis, respectively. SA and GLA were also active against several other oral pathogens, including Aggregatibacter actinomycetemcomitans, Candida albicans, Fusobacterium nucleatum subsp. vincenti, and Streptococcus mutans, at micromolar concentrations. CONCLUSIONS: These data suggest that the E. linza extracts SA and GLA are useful antimicrobial agents for the prevention and/or treatment of periodontitis.