Oral application of Thuja occidentalis enhances immune parameters in rats and immunosuppressed mice

For the herbal immunomodulator Esberitox® containing an aqueous-ethanolic extract of a mixture of Thujae occiden-talis herba, Baptisiae tinctoriae radix, Echinaceae purpureae radix and Echinaceae pallidae radix, immunological activity has been proven in vitro and in vivo [1]. In comparative in vitro investigations on the activity profiles of the single drugs used for the preparation of the Esberitox® extract, it was shown that Thuja has its most striking activities in the activation of macrophages and CD4+ T-helper cells, resulting in an enhanced production of IL-2 [1,2].

The present study was undertaken in order to prove the dosage rationale for the Thuja component in the Esberitox® extract and to emphasize its significance in the herbal combination. Therefore the influence of different concentrations of Thuja extract on the cytokine production of spleen cells was investigated in immunosuppressed mice. G-CSF was quantified as marker cytokine for macrophage/monocyte-activation. Il-2 and IFNγ were determined in order to verify the postulated mode of action. In a second in vivo test system, the effect of peroral application of an ethanolic extract of Thujae occidentalis herba on the bronchus-associated lymphatic system was investigated in rats.

In immunosuppressed mice the treatment with the Thuja extract had a dose-dependent and statistically significant stimulatory effect on the production of G-CSF, IFNγ and Il-2 in spleen cells. In the second assay, Thuja induced an increase in the numbers of alveolar macrophages and stimulated dose-dependently the production of the effector substances NO₂ ^-, TNFα and IL-1. These results indicate that amounts of Thuja as used in Esberitox® enhance immune response after peroral application in vivo and confirm that Thuja essentially contributes to the immunostimulatory/-modulatory effects and pharmacodynamic profile of Esberitox®.

References: 1. Bodinet, K. (1999) Immunpharmakologische Untersuchungen an einem pflanzlichen Immunmodulator. Dissertation, Greifswald, EMAU Greifswald. 2. Gohla, S. et al. (1988) Leukemia 2: 528–533.