[Pharmacological studies on leaf of Arctostaphylos uva-ursi (L.) Spreng. III. Combined effect of arbutin and indomethacin on immuno-inflammation].

A study was carried out to examine the combined effect of arbutin isolated from the leaves of Arctostaphylos uva-ursi (L.) Spreng. (Bearberry leaf) and indomethacin on Type IV allergic reaction-induced immuno-inflammation, carrageenin-induced edema and adjuvant-induced arthritis. Contact dermatitis caused by picryl chloride (PC-CD) and sheep red cell delayed type hypersensitivity (SRBC-DTH) was not inhibited by the oral application of arbutin at 2 divided doses immediately before and 16 h after the application, but arbutin at dose of 50 mg/kg 24 h after the application rapidly decreased the swelling of PC-CD. Arbutin (p.o.) plus indomethacin (s.c.) showed inhibitory effect on the swelling of PC-CD and SRBC-DTH stronger than that of indomethacin alone. When arbutin (p.o.) and indomethacin (s.c.) in a given portion were simultaneously administered, the inhibitory effect was more potent than that of indomethacin alone in both carrageenin-induced edema and adjuvant-induced arthritis. These results suggest that arbutin may increase the inhibitory action of indomethacin on PC-CD, SRBC-DTH, carrageenin-induced edema and adjuvant-induced arthritis, but further investigations are required to understand the mechanism involved.