Exploring gastroprotective effect and mechanisms of epigallocatechin gallate-impregnated black garlic in acidic ethanol-induced gastric ulcer model mice

Background: Peptic ulcers, particularly gastric ulcers (GUs), are multifactorial disorders with unclear mechanisms. Black garlic (BG) has shown gastroprotective effects. This study evaluated the effects of BG and epigallocatechin gallate-impregnated BG (EG) in acidic ethanol (AE)-induced GU model mice. Mice were pretreated with BG or EG (50–200 mg/kg) for 7 days before ulcer induction. Oral acute toxicity evaluations for BG and EG were also conducted. Results: Oral acute toxicity evaluations showed elevated serum renal function indices at 5 g/kg of BG and 10 g/kg of EG but without histopathological liver or kidney damage. Both BG and EG pretreatments reduced ulcer indices, with EG offering stronger and significant protection. EG pretreatments also showed higher gastric mucosal accumulations. They significantly decreased AE-induced malondialdehyde levels and restored glutathione, superoxide dismutase, and catalase. AE-induced serum levels of tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), interleukin-1 beta (IL-1β), as well as gastric transcript levels of TNF-α, IL-6, IL-1β, cyclooxygenase-2, inducible nitric oxide synthase, and myeloperoxidase, were suppressed. EG further reduced AE-induced phosphorylations of extracellular signal-regulated kinase, c-jun-N-terminal kinase, p38, nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), and inhibitor of κB. Conclusion: EG2 showed stronger gastroprotective activity than BG by modulating oxidative stress, inflammatory response, and mitogen-activated protein kinase (MAPK)/NF-κB signaling pathways. This study supports the application of EG as a value-added functional food ingredient for GU prevention.