The anti-inflammatory properties of marine microalgae in LPS-induced macrophages

Inflammatory diseases such as inflammatory bowel disease (IBD) have become one of the leading causes of health issue throughout the world, having a considerable influence on healthcare costs. Moreover, patients with IBD are at higher risk for developing colorectal cancer than the general population. Until date, there is no known cure for IBD. Existing treatments are not effective and emphasize the need for a new biologic approach to improve IBD symptoms. Inflammation is mediated by cytokines produced by stimulated immune cells such as macrophages. There are both pro-inflammatory cytokines such as Tumor necrosis factor-α (TNFα) and anti-inflammatory cytokines such as Interleukin (IL)-10. Targeting cytokines often reduce the disease processes by influencing immune cells, tissue healing and inflammatory aspects of the diseases.

With the emerging developments in natural product, notable success has been achieved in discovering natural products and their synthetic structural analogs with anti-inflammatory activity. Marine microalgae have been identified as an underexplored reservoir of unique anti-inflammatory compounds. These include polyphenols, sulfated polysaccharides, terpenes, fatty acids and proteins. Consumption of these marine algae could provide defense against the pathophysiology of many chronic inflammatory diseases such as IBD. With further investigation, microalgae have the potential to be used as therapeutics with profound anti-inflammatory activity with reduced side effects.

In this study, the anti-inflammatory potential of microalgae was assessed in lipopolysaccharide (LPS)-stimulated murine RAW264.7 macrophages. Extraction from the microalgae was prepared using solid-liquid of ethyl acetate or Ethanol:H₂O (70:30%). We have found that the ethyl acetate extract was the most effective in reducing inflammation. From this extract, we isolated and identified the active fraction using a series of chromatographic steps and various instrumentations analytical methods.

The results showed that pretreatment of RAW 264.7 cells with the crude extract from microalgae significantly inhibited the secretion of TNFα by 50-60% (p < 0.001). Furthermore, the fractions extracts effectively inhibited the LPS-induced TNFα similar to the effect obtained by the crude extract. Interestedly, some fraction contained omega 3 and omega 7 that are known to have anti-inflammatory properties.

Our findings suggest that the microalgae might become a natural source for new anti-inflammatory treatment and lead to a promising route of treatment for chronic inflammation-linked diseases. Further research will be required in order to understand the mechanism of action of these compounds.