Fu-Ling, a Chinese herbal drug, modulates cytokine secretion by human peripheral blood monocytes

Fu-Ling, the sclederma of Poria cocos (Schw.) Wolf, has long been used as a sedative and diuretic in traditional Chinese herbal medicine. Our study demonstrated that the substances extracted from Fu-Ling by 50% hot ethanol significantly augmented the secretion of interleukins IL-1 beta and IL-6 6 h after in vitro cultivation of human peripheral blood monocytes. The augmented effect was dose dependent. Tumour necrosis factor-alpha (TNF-alpha) secretion was also increased as the cells were treated with 0.4 mg/ml or higher doses of Fu-Ling extract. By contrast, Fu-Ling extract significantly suppressed the secretion of transforming growth factor-beta (TGF-beta) 3 h after the in vitro drug treatment. The suppressive effect was shown at doses as low as 0.2 mg/ml of Fu-Ling extract. Since Fu-Ling extract enhanced the secretion of immune stimulators (IL-1 beta, IL-6 and TNF-alpha) but suppressed the secretion of an immune suppressor (TGF-beta), the substance in 50% hot ethanol extract of Fu-Ling might have potentiated the immune response. Fu-Ling extract was further fractionated by reverse-phase column chromatography and high-performance liquid chromatography (HPLC). The components showing activity in modulating the cytokine secretion were relatively high in hydrophobicity.