Valorization of Sea Buckthorn ( Hippophae rhamnocaides L.) Leaves: Polyphenol-Rich Extract Targeting Helicobacter pylori Virulence and Gastric Mucosal Homeostasis

Sea buckthorn (Hippophae rhamnoides L.) leaves are rich in polyphenols and exhibit potent activity against Helicobacter pylori. This study found that its extract demonstrates a dual mechanism of action, inhibiting bacterial virulence while protecting the gastric mucosa. For multidrug-resistant strains, the minimum inhibitory concentration (MIC) range of this extract was 0.08–0.64 mg/mL. At 0.32 mg/mL, it significantly suppressed H. pylori motility and urease activity by 72% and 56%, respectively. In an infected mouse model, the extract lowered gastric pro-inflammatory cytokines (TNF-α, IL-1β, IL-6) and promoted mucosal protection. Multiomics analysis reveals enhanced mucosal immunity and increased abundance of beneficial gastric microbiota (Ligilactobacillus and Akkermansia). As an agricultural byproduct, sea buckthorn leaf extract holds promise as a dietary supplement for managing H. pylori-associated gastropathy.