Inhibitory effect of silibinin on tumour necrosis factor-alpha and hydrogen peroxide production by human monocytes

Abstract

Silibinin is a chemically defined flavonoid and the main active component of silymarin, a polyphenolic complex from Silybum marianum, which has anti-inflammatory, hepatoprotective and anticarcinogenic properties. Monocytes obtained from healthy individuals were incubated with silibinin to evaluate cell viability, hydrogen peroxide (H2O2) release and tumour necrosis factor-alpha (TNF-) production by these cells. The duration of treatment and different silibinin concentrations had no significant effect on cell viability. Monocytes showed a dose-dependent inhibitory effect on H2O2 release by phorbol myristate acetate-stimulated monocytes in silibinin concentrations ranging from 6.25 to 50 mu g mL-1. Significant inhibition of TNF- production by lipopolysaccharide-stimulated monocytes was observed at concentrations of 12.5, 50 and 100 mu g mL-1 of silibinin. These results suggest that silibinin exerts antioxidant and anti-inflammatory properties on human monocytes through an inhibitory effect on H2O2 release and on TNF- production, respectively.