Selective extraction and quantitative analysis of pyrroloquinoline quinone from food.

Pyrroloquinoline quinone (PQQ) is a bioactive compound that has attracted significant attention due to its potential health benefits. In this study, we developed a new magnetic molecularly imprinted nanoparticle (MMIN) for the selective extraction and determination of PQQ from food samples. The MMIN was synthesized using a surface molecular imprinting technique with PQQ as the template molecule, FeO nanoparticles as the magnetic core, and methacrylic acid as the functional monomer.

A new α-amylase inhibitory peptide from Gynura medica extract.

In this study, we discovered a novel peptide, Gymepeptide A, with α-amylase inhibitory activity in the water extract of Gynura medica. The structure of Gymepeptide A was determined as CGDREETR using HR-MS, H NMR, C NMR, and 2D-NMR techniques. Notably, Gymepeptide A possesses a rare double arginine residue structure and exhibits strong α-amylase inhibitory activity.