The impact of Zataria multiflora Boiss extract on in vitro and in vivo Th1/Th2 cytokine (IFN-γ/IL4) balance.

BACKGROUND

Anti-inflammatory, anti-oxidant and effect of Zataria multiflora on Th1/Th2 balance were previously described. Different therapeutic effects of this plant have been described in Iranian traditional medicine. To evaluate the immune modulatory effects of Zataria multiflora on Th1/Th2 balance, which may be implicated in inflammatory disorders, in vitro and in vivo studies were carried out.

METHODS

The effects of three concentrations of the extract, dexamethasone, and saline on interleukin 4 (IL-4) and interferon γ (IFN-γ) gene expression were evaluated in phytohemagglutinin (PHA) stimulated and non-stimulated human peripheral blood mononuclear cells (hPBMCs). RNA was extracted from the hPBMCs to make cDNA for real time PCR relative quantification. Furthermore, the effect of the extract on serum level of IL-4 and IFN-γ was assessed in ovalbumin (OA) sensitized guinea pigs (n=6 for each group).

RESULTS

Dexamethasone showed significant inhibitory effect on both IFN-γ and IL-4 gene expression and serum level of the cytokines and significantly enhanced IFN-γ/IL-4 ratio (p<0.05-p<0.001). The extract inhibited IL-4 and enhance IFN-γ gene expression and IFN-γ/IL-4 ratio too (p<0.05-p<0.001). In sensitized animals also serum level of IL-4 were significantly decreased after treatment with both dexamethasone and extract, but serum level of IFN-γ and IFN-γ/IL-4 ratio were significantly increased due to extract treatment (p<0.01 for medium and p<0.001 for high concentration).

CONCLUSIONS

These results indicated consistent in vitro and in vivo data for selective immune modulatory effect of the extract of Zataria multiflora which increased IFN-γ, decreased IL-4, and enhanced the ratio of IFN-γ to IL-4 (Th1/Th2 balance). Therefore, the extract of Zataria multiflora may have therapeutic value in inflammatory responses such as allergy, autoimmunity and infectious diseases associated with Th1/Th2 imbalance.