Anti-inflammatory effects of dulse (Palmaria palmata) resulting from the simultaneous water-extraction of phycobiliproteins and chlorophyll a

•Water extraction of extracted from lyophilized dulse leaves contained phycobiliproteins and chlorophyll a.•The thermolysin-digested water extract showed anti-inflammatory activity in vitro and in vivo.•Decapeptide derived from phycoerythrin β-chain and chlorophyll a decomposition products showed anti-inflammatory activity.•The anti-inflammatory activity would be caused by phycobiliprotein and chlorophyll a decomposition products.

The use of dulse (Palmaria palmata) as a source of edible anti-inflammatory products was evaluated in this study. Phycobiliproteins and chlorophyll a were simultaneously extracted from lyophilized dulse leaves via water-extraction, and subjected to thermolysin digestion to produce thermolysin-digested water-extract (d-DWE). d-DWE significantly reduced tumor necrosis factor-α, interleukin-6, and nitric oxide in LPS-stimulated murine macrophages (RAW 264.7 cells), and orally administered d-DWE mitigated acute inflammation in carrageenan-induced paw edema of mice. Mass spectrometry revealed d-DWE contained peptide LRDGEIILRY (derived from phycoerythrin β-chain) and chlorophyll a decomposition products, and they individually reduced the secretion of the proinflammatory mediators in LPS-stimulated RAW 264.7 cells. These results indicate the anti-inflammatory activity could be from a combined effect of phycobiliprotein and chlorophyll a decomposition products prepared from the water-extract of dulse. Thus, inexpensive and safe water-extraction method is effective for the extraction of anti-inflammatory components from dulse.

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