A polyether sponge constituent which is antioxidant, anti-inflammatory and increases prostaglandin concentrations at the inflamed site.

Granuloma formation was studied in rats following s.c. implantation of polyether sponges soaked in carrageenin. Sponges, which had been boiled in ethanol, produced larger granulomata and more exudate than unboiled sponges, but prostaglandin (PG) concentrations were lower in exudates from boiled sponges. Sub-cutaneous injection of the ethanolic sponge extract inhibited the delayed phase of carrageenin-induced rat hind paw oedema. A counter irritant action was ruled out by the demonstration that local administration of the extract also inhibited hind paw oedema. Ultra-violet spectrophotometry of the anti-inflammatory extract indicated that the main constituent was probably a phenolic material, commonly used as an antioxidant in the manufacture of polymers. The antioxidant nature of the extract was confirmed by its inhibition of the autoxidation of adrenaline. The results are discussed in the light of recent reports on the anti-inflammatory properties of phenolic antioxidants and their effects on the PG biosynthetic pathway.