The effects of eugenol, a major component of clove, on anaphylaxis wer
e evaluated in rats. Eugenol inhibited compound 48/80-induced systemic
anaphylaxis 100% with a dose of 10 mu g g(-1) body weight (BW). While
serum levels of histamine were markedly elevated after compound 48/80
injection in all groups of rats, rats injected with eugenol showed a
significant reduction in serum histamine levels. Eugenol also inhibite
d passive cutaneous anaphylaxis activated by anti-dinitrophenyl (DNP)
IgE. Eugenol dose-dependently inhibited histamine release from the rat
peritoneal mast cells (RPMC) activated by compound 48/80 or anti-DNP
IgE. The morphological examination clearly showed that eugenol prevent
ed the anaphylactic degranulation of RPMC. Moreover, Eugenol (10 mu g
ml(-1)) had a significant inhibitory effect on anti-DNP IgE-induced tu
mor necrosis factor-alpha production. These degranulation. (C) 1997 It
alian Pharmacological Society.