Ethanol Extract of Hedyotis diffusa Willd Affects Immune Responses in Normal Balb/c Mice In Vivo

Abstract

Numerous clinical anticancer drugs are obtained from natural plants and Hedyotis diffusa Willd (EEHDW) has been used as a major component in Traditional Chinese medicine formulas since a long time. Ethanol extracts of EEHDW have been shown to possess various biological activities including anticancer function in vitro. Our earlier studies have shown that EEHDW affects immune responses in WEHI-3-generated leukemia mice, but EEHDW has not been reported to affect immune responses in a normal mouse model. Herein, we investigated whether EEHDW could affect immune responses on normal murine cells in vivo. Normal BALB/c mice were orally treated with or without EEHDW at 0, 16, 32, and 64 mg/kg or 32 mg/kg by i.p. for 3 weeks, then were weighed, and blood, liver and spleen samples were collected for further experiments. Results indicated that EEHDW did not significantly affect body and liver weight but significantly increased the spleen weight by i.p. treatment when compared to control groups. Flow cytometric assays indicated that EEHDW promoted CD11b levels at 16, 32 and 64 mg/kg oral treatment, CD19 levels at 16, 32, 64 mg/kg oral treatment and i.p. treatment, and Mac-3 levels at 16, 32 and 64 mg/kg oral treatment, however, it did not significantly affect the levels of CD3. Oral treatment with 16 and 32 mg/kg of EEHDW significantly decreased macrophage phagocytosis from PBMC; 32 mg/kg of EEHDW by i.p. treatment significantly increased phagocytosis activity of macrophages obtain from the peritoneal cavity. EEHDW at 32 mg/kg by i.p. treatment led to an increase of NK cell activities compared to oil control groups. EEHDW at 32 mg/kg of EEHDW by i.p. treatment increased B- and T-cell proliferation. Based on these observations, EEHDW seems to have promoted immune responses in this murine model.

Keywords: Natural killer cells; ethanol extract of Hedyotis diffusa Willd; macrophage; normal BALB/c mice; phagocytosis.