Tussilagone inhibits allergic responses in OVA-induced allergic rhinitis guinea pigs and IgE-stimulated RBL-2H3 cells.

Farfarae Flos is the dried flower buds of Tussilago farfara L. which is widely used to treat allergic and inflammatory diseases in Chinese folk. Tussilagone (TSL), a sesquiterpene compound purified from Farfarae Flos, has been confirmed the main active component in the plant. However, its anti-allergic activity hasn't been reported yet. The purpose of this study is to investigate the anti-allergic effect of TSL in ovalbumin (OVA)-induced allergic rhinitis (AR) guinea pigs and immunoglobulin E (IgE)-stimulated RBL-2H3 cells. The AR symptoms such as nasal scratching, sneezing and runny nose were scored and the histological changes of nasal mucosa were observed by H&E staining. The levels of histamine, OVA-specific IgE, IL-6 and TNF-α in the serum were measured by ELISA. In IgE-stimulated RBL-2H3 cells, the phosphoryration of Lyn, Syk, Akt, NF-κB p65, ERK and p38 MAPK were investigated by western blot analysis. The results showed that intraperitoneal injection of TSL at doses of 25 and 50 mg/kg significantly alleviated the allergic symptoms and the histological changes of nasal mucosa in OVA-induced allergic rhinitis guinea pigs. Moreover, the levels of histamine, IgE and IL-6 in the serum decreased significantly (p < .05). In vitro, TSL suppressed the phosphorylation of Lyn, Syk, Akt, NF-κB p65, ERK and p38 MAPK in IgE-stimulated RBL-2H3 cells. These results indicate TSL has therapeutic effect on allergic rhinitis in guinea pigs. The anti-allergic mechanism may be through the inhibition of allergic and inflammatory related pathways in mast cells.