Non-starch polysaccharides from nutmeg: Preparation process and bioactivity.

This study was for the preparation of bioactive non-starch polysaccharides from nutmeg (NEP), addressing the high content of lipids and starch in nutmeg. First, lipids were removed by 3 times defatted with petroleum ether. Then, the optimal extraction process was 170 min at 82 °C with a liquid solid ratio of 15: 1 mL/g. Finally, the removal of starch was confirmed through enzymatic hydrolysis with α-amylase and amyloglucosidase, supported by I2-KI reagent, HPLC, and IR analysis. The yield of NEP was 3.09 %. Compared with non-enzymatic hydrolysis polysaccharides (NNP), total sugar and uronic acid contents were increased by 13.8 % and 18.5 %, respectively. The molecular weight decreased from 1.031 × 106 to 6.31 × 105 Da, exhibiting a porous sheet-like morphology and β-glycosidic bonds. NEP had superior activity, with an IC50 value of 0.47 mg/mL for ABTS radical scavenging, compared to 1.20 mg/mL for NNP, and its total reducing capacity was nearly double that of NNP. 100 μg/mL of NEP stimulated RAW264.7 macrophages to release 12.14 μM of nitric oxide, exceeding the 9.13 μM induced by lipopolysaccharide. These results indicate the antioxidant and immunomodulatory efficacy of NEP, highlighting its potential as an active ingredient in foods or pharmaceuticals.