ABSTRACT
The potent antioxidant and anti-hypertension activities have evidenced gastric enzymatic hydrolysates from flounder fish and their derived peptides. However, peptide composition and functional effect in various enzymatic hydrolysates differ by enzyme types, hydrolyzed times temperatures, etc. Therefore, we determined potential anti-hypertensive effect of hydrolysates produced from flounder fish using commercial enzymes such as Protamex, Flavourzyme, and Kojizyme which are common food grade proteases and characterized on its derived peptides. In this study, Protamex-mediated hydrolysate showed a more potent anti-hypertension effect than other commercial enzymes. Protamex-mediated hydrolysate was fractionated into three ranges of molecular weight (above 10 kDa (FPH-I), 5-10 kDa (FPH-II), and below 5 kDa (FPH-III)). The FPH-III exhibited the strongest anti-hypertensive effect, and it was revealed that three active peptides, valine-phenylalanine-serine-glycinetryptophan-alanine-alanine (VFSGWAA), leucine-histidine-phenylalanine (LHF) and tryptophan-proline-tryptophan (WPW) were contained. The activities were confirmed via angiotensin-converting enzyme (ACE) inhibition and molecular docking simulation. Among the three peptides, LHF and WPW have a molecular structure stability against the gastrointestinal digestion. LHF showed a significant anti-hypertension effect at 9 h after oral administration in spontaneously hypertensive rats (SHRs). Therefore, we suggest that Protamex-mediated hydrolysate would be an excellent anti-hypertensive agent due to the existence of stabilized functional peptides, including LHF and WPW.
ABSTRACT
The immune system is specifically sensitive to oxidative stress induced by ionizing radiation because of its rapid proliferative activity. For this reason, an instructive immune system is one of the best ways to minimize side effects, such immunodeficiency, of gamma radiation. Over the past few decades, several natural plants with antioxidant and immunomodulatory properties have been identified as adjuncts for nontoxic and successful radiotherapy. Hizikia fusiforme extract (HFE) containing plentiful dietary fiber and fucoidan is known for its instructive antioxidant capacity, immunomodulation abilities, and immune activation. In this study, we determined whether HFE protects radiosensitive immune cells from gamma radiation-induced damage. C57BL/6 mice were irradiated with gamma-ray. The effect of HFE on the ionizing radiation damage of immune cells was then evaluated with an MTT assay, 3H-thymidine incorporation assay, and PI staining. We found that HFE stimulated the proliferation of gamma-ray irradiated immune cells without cytotoxic effects. We also observed that HFE not only decreased DNA damage but also reduced gamma radiation-induced apoptosis of the immune cells. Our results suggest that HFE can protect immune cells from gamma-ray damage and may serve as an effective, non-toxic radioprotective agent.