1,2,3,5,6-Pentathiepane (lenthionine) is a cyclic polysulphur compound that contributes to the distinctive flavour of shiitake mushrooms (Lentinula edodes) and inhibits platelet aggregation. However, its volatile hydrophobic characteristics present a challenge for its use in food applications. In this study, lenthionine was complexed with α-cyclodextrin (α-CD) to enhance its stability and bioavailability. The inclusion ratio of lenthionine with α-CD was 1:2. The formation of a stable inclusion complex was confirmed through diffusion order spectroscopy (DOSY) and proton nuclear magnetic resonance (¹H NMR) analyses. The inclusion of lenthionine in α-CD markedly suppressed its release. In vivo experiments demonstrated that the lenthionine/α-CD inclusion complex exhibited a more rapid and pronounced inhibitory effect on platelet aggregation than lenthionine alone. These findings indicate that inclusion of lenthionine in α-CD simultaneously mitigates its flavour and enhances its bioavailability, thereby expanding its potential for application in functional foods and pharmaceuticals.

Cardiovascular diseases, which are frequently associated with thrombosis and platelet aggregation, are a significant global health concern. The inhibition of platelet aggregation is a crucial strategy for the prevention of thrombotic disorders. Our previous studies have demonstrated that lenthionine, a cyclic polysulphur compound derived from shiitake mushrooms, possesses platelet anti-aggregatory properties. However, the underlying mechanism of action remains unclear. This study aimed to elucidate the inhibitory effects of lenthionine on platelet aggregation and αIIbβ3 activation. Lenthionine inhibits platelet aggregation induced by various types of agonists. Flow cytometry and scanning electron microscopy revealed that lenthionine suppresses platelet activation and morphological changes. Moreover, lenthionine did not affect the phosphorylation/dephosphorylation of myosin light chain (MLC), cofilin, and talin, but significantly inhibited the dephosphorylation of α-actinin. Our findings suggest that lenthionine may inhibit αIIbβ3 activation by potentially inhibiting the activity of protein disulfide isomerase (PDI), which is crucial for αIIbβ3 activation.

The objective of this study is to evaluate the suppressive effect of buckwheat-albumin hydrolysate on postprandial hyperglycemia and identify the peptide responsible to the function. Buckwheat-albumin hydrolysate was prepared by using digestive enzymes and was orally administered to rats together with soluble starch. The blood was taken from the tail vein up to 90 min after oral administration to measure blood-glucose and plasma-insulin levels. The peptide with α-amylase inhibitory activity was purified from the buckwheat-hydrolysate by gel-filtration chromatography, α-amylase affinity chromatography, and high performance liquid chromatography (HPLC). The amino-acid sequence of the peptide was identified by a protein sequencer and was compared with that in the buckwheat-genome database. Buckwheat-albumin hydrolysate significantly suppressed the elevation of blood glucose level 15 min after starch administration. The amino-acid sequence of the peptide with α-amylase inhibitory activity was YVEPDCGNLGCCYHC in the parental protein of molecular mass 17.8 kDa and theoretical pI 4.77. The amino-acid sequence, molecular weight, and pI of the parental protein in buckwheat albumin were different from those of α-amylase inhibitor in wheat albumin. This study suggests that the novel α-amylase inhibitor identified in buckwheat albumin is a potential candidate for a functional food material to suppress postprandial blood glucose elevation.