Polysaccharides (PMM) from Meretrix meretrix Linnaeus exhibit a variety of biological activities; however, conventional purification methods are costly, time consuming and introducing toxic agents. This paper aimed to develop a green and efficient method for the deproteinization of PMM by copper ion chelating aerogel (CCA) adsorption. First, CCA was successfully prepared by copper ion chelating composite aerogel (CA). Then, CCA adsorption was applied to remove protein mixed in PMM. The optimal parameter conditions of this deproteinization method were screened, using the deproteinization rate ( D r %), polysaccharide recovery rate ( R r %) and selectivity coefficient ( K c ) as evaluation indicators , by single factor experiment. The optimal conditions were obtained as follows: CCA dose of 1.4%, pH value of 5.0 and adsorption temperature of 30 °C. Under these conditions, equivalent D r % (93.31 ± 1.33%), higher R r % (93.34 ± 1.08%) and K c (14.01 ± 0.46) were achieved compared with the latest reported deproteinization report. Finally, the effect of deproteinization between CCA adsorption and Sevag method, which is the most classical deproteinization method, were compared to verify the practicability of CCA adsorption. As a result, CCA adsorption not only showed much higher R r % as well as K c , but also would not cause any reagent contamination and environment pressure. In conclusion, CCA adsorption would be a green and highly efficient method with great potential in large-scale environmentally sustainable deproteinization of polysaccharides in the future.
Na Li,Kaiyue Liu,Yue Zhang,Zhenzhen Hui,Ping Wang,Shuyang Sun,Chao Du
This study aimed to identify novel peptides with α-glucosidase inhibitory activity from Meretrix meretrix Linnaeus hydrolysates (MMLHs) following simulated gastrointestinal digestion (SGD) and to elucidate their inhibitory mechanisms. The molecular weight distribution of MMLHs progressively decreased during SGD, with hydrolysates from the intestinal digestion phase (MMLHs-I) exhibiting the strongest α-glucosidase inhibition (IC 50 : 0.14 ± 0.02 mg/mL). A total of 127 peptides were identified in MMLHs-I, among which 58 were unique compared to those from the gastric digestion phase. In silico screening and molecular docking identified six novel peptides—FAGDDAPR, VPLF, YRRL, WDH, PPLA, and WSG—with significant α-glucosidase inhibitory activity, displaying IC 50 values of 0.90, 1.30, 1.90, 1.20, 1.00, and 1.80 mg/mL, respectively. Among them, FAGDDAPR and PPLA exhibited the highest bioactivity. Kinetic analysis and fluorescence quenching assays demonstrated that both peptides acted as mixed-type inhibitors, forming stable complexes with α-glucosidase. Their inhibitory effects were primarily driven by hydrogen bonding and hydrophobic interactions, which hindered substrate binding and induced conformational changes in the enzyme. These findings suggest that peptides derived from MMLHs through gastrointestinal digestion possess potential antidiabetic properties, highlighting their promise as functional food ingredients for mitigating hyperglycemic damage.
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