The gastroprotective potential of silibinin against Helicobacter pylori infection and gastric tumor cells

Aims: Silibinin is the major component of flavonolignans complex mixture (Silymarin), which is obtained from Silybum marianum (L.) Gaertn. Despite several reports about silibinin, little is known about its effects on gastric diseases. Then, the present study aims to evaluate the silibinin effect against Helicobacter pylori infection, gastric tumor cells and immunomodulation. Main methods: The anti-H. pylori effect was performed on 43504 and 43629 strains by minimum inhibitory concentration (MIC) determination, observing morphological alterations by scanning electron microscopy and in silico evaluation by molecular docking. Immunomodulatory activity (Interleukins-6 and 10, TNF-alpha and NO inhibition) was determined in H. pylori-stimulated macrophages and the cytotoxic activity on gastric adenocarcinoma cells prior and after metabolization by S9 fraction. Key findings: Silibinin showed anti-H. pylori activity with MIC of 256 mu g/mL, promoted important morphological changes in the bacterial cell wall, as blebs and clusters, suggesting interaction with Penicillin Binding Protein (PBP) subunits. Immunomodulatory potential was observed at 50 mu g/mL with the inhibition of produced cytokines and NO by H. pylori-stimulated macrophages of 100% for TNF-alpha, 56.83% for IL-6, and 70.29% for IL-10 and 73.33% for NO. Moreover, silibinin demonstrated significant cytotoxic activity on adenocarcinoma cells (CI50: 60.17 +/- 0.95 mu g/mL) with a higher selectivity index (SI: 1.52) compared to cisplatin. After metabolization silibinin showed an increase of cytotoxicity with a CI50 six-fold decrease (10.46 +/- 0.25). Significance: The use of silibinin may become an important alternative tool in the prevention and treatment of H. pylori infection and, consequently, in gastric cancer.