Plectranthus barbatus Andrews as anti-Helicobacter pylori agent with activity against adenocarcinoma gastric cells

Abstract Helicobacter pylori colonizes half of the World population and has been associated with gastric diseases including gastric cancer. In this scenario, Plectranthus barbatus is a wide-used medicinal plant in Brazil in the treatment of gastric injuries, however, no scientific report describe it against H. pylori. The aim of this study was to evaluate the ethyl acetate fraction (EAF) chemical profile from P. barbatus and its anti-H. pylori, immunomodulatory, antioxidant and cytotoxic activities. The substances identified by (-)-ESI-FT-ICR MS were plectrin, hydrolyzed abieatane, barbatusin, 3β-hydroxy-3-deoxibarbatusin, cyclobutatusin, luteolin, rosmarinic acid and coleoside B. The anti-H. pylori results presented a minimum inhibitory concentration (MIC) of 256 μg/mL and minimum bactericidal concentration (MBC) of 1024 μg/mL. Scanning electron microscopy evidenced H. pylori morphological changes in its surface induced by EAF. Molecular docking studies were conducted to investigate the binding mode of the proposed compounds at H. pylori Penicillin-Binding Protein active site. Antioxidant activities presented IC50 ranging from 26.64 ± 0.62–69.96 ± 1.25 μg/mL and the immunomodulatory activity was significant to IL-6 and NO with 28 % and 35 % of inhibition at 25 μg/mL. EAF showed significant cytotoxic activity with CI50 of 33.89 ± 0.32 μg/mL on gastric adenocarcinoma cells. These results indicate the potential of P. barbatus as candidate for H. pylori eradication and H. pylori induced related gastric disease prevention.