Xiang Duan

Naturally Occurring Angiotensin I-Converting Enzyme Inhibitory Peptide from a Fertilized Egg and Its Inhibitory Mechanism

This study was performed to investigate the angiotensin I-converting enzyme (ACE) inhibitory activity of peptides derived from fertilized eggs and elucidate the inhibition mechanism of these peptides. During incubation, ACE inhibitory activity of the peptides remained stable before day 12 and then increased markedly on day 15. Two ACE inhibitory peptides, VGVIKAVDKKAGGAGKVT and HLFGPPGKKDPV, were purified from peptides on day 15 by consecutive chromatography. Because HLFGPPGKKDPV possessed a higher ACE inhibitory activity (IC50 = 125 μM), an antihypertensive effect of this peptide was further evaluated in vivo. The result showed that this peptide had an antihypertensive effect in spontaneously hypertensive rats (SHRs) at a dosage of 10 mg/kg. Furthermore, Lineweaver-Burk plots suggested that HLFGPPGKKDPV played as a non-competitive inhibitor against ACE, as supported by docking simulation. These data indicated that a fertilized egg has potential as antihypertensive components in functional foods and nutraceuticals.

Postfertilization changes in nutritional composition and protein conformation of hen egg.

Fertilized hen egg is traditionally considered as a dietary supplement in many Asian countries. This work aimed to obtain information on the effect of fertilization on total nutritional composition of egg contents and protein conformation. Chemical analysis showed that the lipid level in fertilized egg began to decrease after day 9. Fertilized egg before day 9 was higher in essential free amino acids (EFAA) and monounsaturated fatty acids (MUFA) contents but lower in cholesterol and polyunsaturated fatty acids (PUFA) than unfertilized counterparts. Fertilized egg proteins were characterized by an increase in hydrophobicity and a decrease in electrostatic interaction. Circular dichroism analysis showed that β-sheet decreased with increasing incubation time, whereas unordered structure increased. The findings observed in this work provide a crucial basis for understanding nutritional composition and protein conformation of fertilized egg, with the potential of being utilized as an EFAA/MUFA-rich, low-cholesterol dietary supplement.

Germinated Brown Rice Enhances Antioxidant Activities and Immune Functions in Aged Mice

ABSTRACT The present work was designed to obtain information on the effect of germinated brown rice (GBR) that has undergone different germination times (zero, one, two, three, and four days) on antioxidant activities and immune functions in aged mice. White rice (WR) was also investigated as a comparison. Chemical analysis of rice samples showed that the amounts of most nutritional and bioactive components increased significantly after two days of germination and were much higher in GBR and brown rice (BR) than in WR. Animal feeding experiments showed that dietary GBR and BR performed much better than WR in enhancing antioxidant activities and improving immune function in aged mice, and dietary GBR from three to four days of germination overall exhibited a better effect than GBR from zero to two days of germination.