Gastroprotective Effects of the Aqueous Extract of Finger Citron Pickled Products against Ethanol-Induced Gastric Damage: In Vitro and In Vivo Studies

Finger citron pickled products (FCPP), as folk remedies, are famous in southern China for protecting gastric mucosa. However, the gastric mucosa protection of FCPP has not been reported yet, and its effective mechanism is unclear. In this study, the protective mechanism of FCPP aqueous extract on gastric mucosa was investigated in vitro and in vivo for the first time, using human gastric mucosa epithelial cells (GES-1) and acute alcoholic gastric ulcer rat model respectively. Furthermore, we also investigated the main substances in the aqueous extract that exert gastroprotective activity using a GES-1 scratch test and basic chemical composition analysis. FCPP aqueous extract was found to play a protective and reparative role in GES-1 by promoting the secretion of trefoil factor thyroid transcription factor 2 (TFF2) and inhibiting the secretion of tumor necrosis factor-α (TNF-α) in cells damaged by alcohol. The ulcer index of gastric tissue induced by alcohol was significantly decreased (p < 0.01) after pretreatment with FCPP aqueous extract, indicating that FCPP aqueous extract had a good protective effect on the stomach mucosa. Moreover, FCPP aqueous extract could increase superoxide dismutase (SOD) activity and inhibit malondialdehyde (MDA) content, exhibiting good antioxidant capacity. Aqueous extract of FCPP could also effectively inhibit the increase of cytokines TNF-α, interleukin-1β (IL-1β) and interleukin-6 (IL-6) in serum of rats, and promote the increase of anti-inflammatory cytokines interleukin-10 (IL-10) to some extent. Furthermore, FCPP aqueous extract could inhibit the expression of nuclear factor kappa-B (NF-κB/P65) protein, caspase-1 protein and IL-1β protein in the gastric tissue of rats, while promoting the expression of IκBα protein, indicating that the gastric mucosa protection effects of FCPP aqueous extract were mainly dependent on the NF-κB/caspase-1/IL-1β axis. The polysaccharides in FCPP aqueous extract might be the main components that exerted gastroprotective activity, as demonstrated by GES-1 cell scratch assay. This study confirmed that FCPP aqueous extract presented promising potential in protecting gastric mucosa and avoiding gastric ulcers, which could provide an experimental basis for further utilizing the medicinal value and developing new products of FCPP.