Peptides are rarely reported from Chinese Baijiu (Chinese liquor) because they are often present in very low concentrations in the complex matrix. A tetrapeptide, Ala-Lys-Arg-Ala (AKRA), was recently identified by high-performance liquid chromatography and quadrupole-time-of-flight-mass spectrometry (HPLC-Q-TOF-MS) from sesame flavor-type Baijiu at a concentration of 8.497 ± 0.753 μg/L (P > 0.05), and this tetrapeptide showed preventive effects against 2,2'-azobis(2-methylpropanimidamidine) dihydrochloride (AAPH)-induced oxidative stress in HepG2 cells. The cellular antioxidant activity assay results showed that AKRA protected AAPH-induced oxidative stress in HepG2 cells in a concentration-dependent manner. Pretreatment of the cells for 2 h with AKRA (0.38-1.50 mg/mL) caused strong intracellular reactive oxygen species (ROS) scavenging activities and prevented a decrease in reduced glutathione (GSH) and increases in oxidized glutathione (GSSG) and malondialdehyde (MDA). In addition, AKRA treatment prevented significant decreases in glutathione peroxidase (GSH-Px), superoxide dismutase (SOD), and catalase (CAT) induced by AAPH. Thus, AKRA treatment ameliorated AAPH-induced oxidative stress in HepG2 cells. This study will be important for the design and regulation of functional Baijiu production.
Owing to their minimal side effects
and effective protection from
oxidative stress, inflammation, and malignant growth, natural polysaccharides
(NPs) are a potential adjuvant therapy for several diseases caused
by intestinal barrier injury (IBI). More studies are accumulating
on the protective effects of NPs with respect to IBI, but the underlying
mechanisms remain unclear. Thus, this review aims to represent current
studies that investigate the protective effects of NPs on IBI by directly
maintaining intestinal epithelial barrier integrity (inhibiting oxidative
stress, regulating inflammatory cytokine expression, and increasing
tight junction protein expression) and indirectly regulating intestinal
immunity and microbiota. Furthermore, the mechanisms underlying IBI
development are briefly introduced, and the structure–activity
relationships of polysaccharides with intestinal barrier protection
effects are discussed. Potential developments and challenges associated
with NPs exhibiting protective effects against IBI have also been
highlighted to guide the application of NPs in the treatment of intestinal
diseases caused by IBI.
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