Effect of natural compounds on human macrophage activation

Tumor-associated macrophages (TAMs) of M2 phenotype promote tumor proliferation and relate to poor prognosis in patients with gliobrastoma. We screened natural compounds possessing inhibitory effect on M2 polarization in human monocyte-derived macrophages. Among 130 purified natural compounds, some natural compounds such as glycyrrhizin, medicarpin and solasodine significantly inhibited the expression of CD163, one of the phenotypic markers of M2 macrophages, as well as suppressed the secretion of IL-10, one of the anti-inflammatory cytokine preferentially produced by M2 macrophages, thus suggesting that glycyrrhizin, medicarpin and solasodine suppress macrophage polarization towards M2 phenotype. Therefore, glycyrrhizin, medicarpin and solasodine may be potentially useful new strategy for the prevention and therapy of tumor.