Saucerneol D Suppresses the Growth of Helicobacter pylori and Their Virulence Factors

Helicobacter pylori infects the human stomach and causes various gastrointestinal diseases. Saucerneol D is a type of lignan, which is a polyphenol compound that exists naturally in plants, and it is abundant in flaxseed, sesame seeds, whole grains, vegetables, and fruits. Saucerneol D is found in Saurus chinensis extract and has been reported to exert a variety of effects, such as antioxidant and anti-inflammatory abilities. However, its antibacterial effect against H. pylori has not been reported; therefore, we analyzed the effect of saucerneol D on H. pylori in the present study. Changes in the expression of pathogenic factors and gene transcription in H. pylori were observed after treatment with saucerneol D using Western blotting and RT-PCR. It was confirmed that saucerneol D suppressed the growth of H. pylori by decreasing the expression of the genes dnaN and polA, which are required for bacterial replication. Saucerneol D also reduced the secretion of the major pathogenic toxin protein, CagA, by downregulating the expression of type IV secretion system-composing proteins. Furthermore, saucerneol D reduced ammonia production by inhibiting the expression of urease proteins, which are essential for the survival of H. pylori in the acidic gastric environment. Additionally, saucerneol D decreased the expression of flaB, potentially reducing motility. Finally, it was confirmed that the expression of the sabA gene, associated with cell adhesion, was reduced. These results suggest that saucerneol D inhibits the growth of H. pylori and the expression of several pathogenic factors, indicating that saucerneol D has an antimicrobial effect against H. pylori.