Anti-allergic effects and oedema inhibition caused by the extract of Drymis winteri

Abstract

Objective: To study the acute anti-inflammatory and anti-allergic properties of an extract of D. winteri.

Material and methods: Paw oedema induced in rats with various stimuli and anaphylactic shock in mice.

Results: The hydroalcoholic extract (HE) of D. winteri (Winteraceae) (30 to 100 mg/kg, p.o., 1 h prior) inhibited carrageenan (300 micrograms/paw) and dextran (100 micrograms/paw)-induced paw oedema formation in a dose-dependent manner, with mean ID50 values of 49 and < 30 mg/kg, respectively. The HE of D. winteri (30 to 100 mg/kg) also inhibited paw oedema induced by bradykinin (BK) (3 nmol), substance P (SP) (10 nmol) and PAF-acether (PAF) (10 nmol), in a dose-dependent manner, with mean ID50 values of 56, 63, and 58 mg/kg, respectively. However, the HE inhibited the rat paw oedema induced by prostaglandin E2 (PGE2) (10 nmol) (29 +/- 7 and 33 +/- 2% at 60 and 240 min) to a smaller extent, and had no effect on oedema elicited by histamine (100 nmol). In adrenalectomized animals, the inhibition by the HE of D. winteri (100 mg/kg, p.o., 1 h prior) of BK-elicited oedema (3 nmol/paw) was significantly smaller when compared with that observed in control animals. When assessed in rats actively sensitised to ovalbumin (OVO), the oedema caused by OVO (6 micrograms/paw) was significantly inhibited by HE of D. winteri (30 to 100 mg/kg, p.o.), with a mean ID50 of about 65 mg/kg. The HE of D. winteri (100 and 200 mg/kg, p.o.) significantly increased survival rate when assessed in anaphylactic shock in mice actively sensitised to the antigen. The protective effect was long-lasting, being observed for up to 15 h. Dexamethasone, used as positive control (0.5, 1 and 2 mg/kg) produced a long-lasting (up to 24 h) increase in the survival rate of the animals.

Conclusions: These results confirm and extend our previous studies, and demonstrate the clear oral anti-inflammatory and anti-allergic properties of the active principle(s) present in the barks of D. winteri, thus confirming its reported medicinal use in folk medicine for the management of airway diseases.