Castanea sativa Mill. leaf extracts contain ellagitannins with antibacterial and anti-inflammatory activity in H. pylori infection

Helicobacter pylori (H. pylori) infection is associated with gastritis and elevated risk of gastric cancer. Virulent strains cause the activation of NF-κB and the expression of IL-8 at mucosal level, leading to severe inflammation [1]. Polyphenols could adjuvate the pharmacological treatment through antibacterial and anti- inflammatory properties [2]. However, the role of ellagitannins in H. pylori-related gastritis has been poorly investigated.

The present research aimed at studying two genotyped varieties of Castanea sativa Mill. (Northern Italy), verdesa and venegon, in a human in vitro model of gastric epithelium (GES-1 cells) infected with H. pylori. The bioactivity was compared after in vitro simulated gastric digestion.

Ethanol:water (50:50) extracts were prepared from leaves and characterised for ellagitannin content. The high levels of polyphenols were partially maintained after gastric digestion (19 – 23%), similar to the ellagitannin castalagin (0.2 – 0.4% w/w of dry extract), measured by LC-MS analysis. In GES-1 cells infected by H. pylori, leaf extracts and castalagin inhibited IL-8 release (IC₅₀≈28 μg/mL and 11 μM, respectively). The anti-inflammatory mechanism was partly due to the impairment of NF-κB translocation (200 μg/mL), observed by immunofluorescence. Moreover, the extracts and pure compound reduced bacterial growth (MIC=200 μg/mL and 25 μM, respectively) and adhesion to cells. NGS analysis showed that castalagin downregulated proinflammatory genes (NF-κB, AP-1, ERK) and cell migration (Rho GTPase).

This investigation supported for the first time the role of ellagitannins from Castanea sativa Mill. leaf against H. pylori infection [3].

Publikationsverlauf

Artikel online veröffentlicht:
16. November 2023

• References

• 1 McColl K.E.. Clinical practice. Helicobacter pylori infection. N Engl J Med 2010; 362: 1597-1604
• 2 Guerra-Valle M.. et al. Plant-Based Polyphenols: Anti-Helicobacter pylori Effect and Improvement of Gut Microbiota. Antioxidants 2022; 11 (01) 109
• 3 Martinelli G., Piazza S., Fumagalli M., Pozzoli C., Maranta N., Giavarini F., Colombo L., Nicotra G., Vicentini S.F., Genova F.. et al. Ellagitannins from Castanea sativa Mill. Leaf Extracts Impair H. pylori Viability and Infection-Induced Inflammation in Human Gastric Epithelial Cells. Nutrients 2023; 15: 1504