Immunomodulatory effects of epicatechin-(2β→O→7, 4β→8)-ent-epicatechin isolated from Rhododendron spiciferum in vitro.

BACKGROUND

Many traditional Chinese medicines (TCMs) can act as either immunosuppresants or immunostimulants, properties that have lead to their increasing use as immunomodulators in the treatment of disease. Recently, our lab successfully identified a dimer epicatechin-(2β→O → 7, 4β→8)-ent-epicatechin (EEE) from the chloroform extract of Rhododendron spiciferum.

OBJECTIVE

To evaluate the immunomodulatory effects of EEE in vitro.

METHODS

Splenocytes, peritoneal macrophages and peripheral blood mononuclear cells from BALB/c mice were incubated with different concentrations of EEE.

RESULTS

EEE significantly stimulates splenocyte proliferation when administered either alone or in combination with concanavalin A (Con A), lipopolysaccharide (LPS), and Anti-CD3. EEE enhances the cytotoxicity of natural killer (NK) cells markedly and phagocytic function of macrophage. Moreover, we found that the levels of several helper T1 (Th1) cytokines, including interleukin-2 (IL-2), IL-12, interferon-γ (IFN-γ) and tumor necrosis factor-α (TNF-α) are significantly increased after EEE treatment, while the levels of Th2 cytokine IL-4 and IL-10 are significantly decreased. As a result, the ratio of Th1/Th2 is significantly increased in the presence of EEE. EEE also increased CD4 and CD8 cell populations.

CONCLUSIONS

These results indicate that EEE exhibits immunomodulatory activity and suggests that this compound could be developed as a novel immunotherapeutic agent for treating cancer and other immune-mediated diseases.