Anti-anaphylactic and anti-inflammatory effects of ternatin, a flavonoid isolated from Egletes viscosa Less.

Ternatin, a tetramethoxy flavone isolated from Egletes viscosa Less (Compositae), was tested for its efficacy in modulating mouse passive cutaneous anaphylaxis (PCA) and rat carrageenan-induced pleurisy. Ternatin (12.5, 25 and 50 mg/kg, ip) caused a dose-dependent inhibition of IgG antibody-mediated 1.5-h homologous PCA as well as IgE antibody-mediated 48-h homologous PCA in 2-month old mice (N = 5 per group). The inhibitory activity of ternatin was more potent on IgE-mediated PCA (47-79%) than on IgG (45-59%). In the rat carrageenan pleurisy test, ternatin (25 and 50 mg/kg, ip) reduced the response to carrageenan at 5 h both by decreasing exudate volume (33-40%) and leukocyte number (60%) in 5-6-month old rats (N = 6 per group). In contrast, indomethacin (2 mg/kg, po), a known cyclooxygenase inhibitor, showed greater potency in the inhibition of exudate volume (57%) and leukocyte number (77%). These results show that ternatin has both anti-inflammatory and anti-anaphylactic properties and suggest that it may be a useful alternative to anti-allergic drugs of the disodium cromoglycate (DSCG) type for use in bronchial asthma.