Isolation of Two Anti-inflammatory and One Pro-inflammatory Polyunsaturated Fatty Acids from the Brown Seaweed Undaria pinnatifida

Two anti-inflammatory ω-3 polyunsaturated fatty acids (PUFAs) of stearidonic acid (SA) and eicosapentaenoic acid (EPA) and one pro-inflammatory ω-6 PUFA of arachidonic acid (AA) were isolated from the edible brown seaweed Undaria pinnatifida. SA was active against mouse ear inflammation induced by phorbol myristate acetate, with IC₅₀ values of 160, 314, and 235 μg per ear for edema, erythema, and blood flow, respectively. EPA was also active against edema, erythema, and blood flow, with IC₅₀ values of 230, 462, and 236 μg per ear, respectively. Although AA at low concentrations showed anti-inflammatory activities when measured 10 h later, AA doses of more than 243 μg per ear induced inflammatory symptoms 1 h later. Mature thalli generally had larger amounts of PUFAs than young thalli. The algal blade contained more ω-3 PUFAs than were found in other parts, while the holdfast contained extremely high amounts of AA. Late-season thalli showed increased amounts of PUFAs, especially AA.

Keywords: Anti-inflammation; arachidonic acid; eicosapentaenoic acid; Phaeophyta; stearidonic acid; Undaria pinnatifida