Y C Kuo1, H C Meng, W J Tsai. 1. Laboratory of Biochemistry, National Research Institute of Chinese Medicine, Taipei, Taiwan, ROC.
Abstract
OBJECTIVE AND DESIGN: This study was designed to elucidate action mechanisms of four anthraquinones identified from Polygonum hypoleucum Ohwi (P. hypoleucum Ohwi) on primary human T lymphocytes. MATERIAL AND METHODS: The cells were isolated from peripheral blood. TREATMENT: T cells were treated with 5 to 60 microM of four anthraquinones with or without phytohemagglutinin (PHA; 5 microg/ml) for 3 days. Effects of 4 anthraquinones on T lymphocyte proliferation, production and gene expression of inflammatory cytokines and intracellular free Ca2+ concentration ([Ca2+]i) were determined. Data were assessed with Student's t-test. RESULTS: On a percentage basis, emodin had the highest suppressing activity on T lymphocyte proliferation with an IC50 of 11.2 +/- 0.6 microM. Emodin decreased cytokine production, IL-2 mRNA expression, and [Ca2+]i in activated T cells. CONCLUSIONS: We hypothesize that the inhibitory mechanisms of emodin on activated T cells proliferation are related to the impairment of cytokine production, IL-2 mRNA level and [Ca2+]i in the cells.
OBJECTIVE AND DESIGN: This study was designed to elucidate action mechanisms of four anthraquinones identified from Polygonum hypoleucum Ohwi (P. hypoleucum Ohwi) on primary human T lymphocytes. MATERIAL AND METHODS: The cells were isolated from peripheral blood. TREATMENT: T cells were treated with 5 to 60 microM of four anthraquinones with or without phytohemagglutinin (PHA; 5 microg/ml) for 3 days. Effects of 4 anthraquinones on T lymphocyte proliferation, production and gene expression of inflammatory cytokines and intracellular free Ca2+ concentration ([Ca2+]i) were determined. Data were assessed with Student's t-test. RESULTS: On a percentage basis, emodin had the highest suppressing activity on T lymphocyte proliferation with an IC50 of 11.2 +/- 0.6 microM. Emodin decreased cytokine production, IL-2 mRNA expression, and [Ca2+]i in activated T cells. CONCLUSIONS: We hypothesize that the inhibitory mechanisms of emodin on activated T cells proliferation are related to the impairment of cytokine production, IL-2 mRNA level and [Ca2+]i in the cells.