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The inhibition mechanism of two homoisoflavonoids from Ophiopogon japonicus including methylophiopogonanone A (MO-A) and methylophiopogonanone B (MO-B) on tyrosinase (Tyr) was studied by multiple spectroscopic techniques and molecular docking.

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A biomacromolecule, named as β-galactoglucofurannan (SVPS2), was isolated from the cultivated parts of Sanghuangporus vaninii under the forest. Its primary and advanced structure was analyzed by a series of techniques including GC-MS, methylation, NMR, MALS as well as AFM. The results indicated that SVPS2 was a kind of 1, 5-linked β-Glucofurannan consisting of β-glucose, β-galactose and α-fucose with 23.4 KDa. It exhibited a single-stranded chain with an average height of 0.72 nm in saline solution. The immunostimulation test indicated SVPS2 could facilitate the initiation of the immune reaction and promote the secretion of cytokines in vitro. Moreover, SVPS2 could mediate the apoptosis of HT-29 cells by blocking them in S phase. Western blot assay revealed an upregulation of Bax, Cytochrome c and cleaved caspase-3 by SVPS2, accompanied by a downregulation of Bcl-2. These results collectively demonstrate that antitumor mechanism of SVPS2 may be associated with enhancing immune response and inducing apoptosis of tumor cells in vitro. Therefore, SVPS2 might be utilized as a promising therapeutic agent against colon cancer and functional food with immunomodulatory activity.

Dietary carbohydrates are unexploited in the by-products of economically valuable Phyllostachys pracecox bamboo shoots. A residue-derived polysaccharide (PBSR1) was aqueously extracted from the processing waste of this bamboo shoot species. Its primary structure and advanced conformation were elucidated by a combined analysis of spectroscopy, chromatography, 2D nuclear magnetic resonance, laser light scattering and atomic microscopy. The results indicated PBSR1 was a triple-helix galactan consisting of →6)-β-D-Galp and →3)-β-D-Galp in linear with an 863 KD molecular weight (Mw). The relationship between the radius of gyration (Rg) and intrinsic viscosity ([η]) on Mw were established as Rg = 1.95 × 10−2Mw0.52±0.03 (nm) and [η] = 9.04 × 10−1Mw0.56±0.02 (mL/g) for PBSR1 in saline solution at 25 °C, which indicated it adopted a triple-helix chain shape with a height of 1.60 ± 0.12 nm supported by a red shift of λmax in Congo red analysis. The thermodynamic test (TG) displayed that it had excellent thermal stability for the food industry. Further, those unique structure features furnish PBSR1 on antioxidation with EC50 of 0.65 mg/mL on DPPH· and an ORAC value of 329.46 ± 12.1 μmol TE/g. It also possessed pronounced immunostimulation by up-regulating pro-inflammatory signals including NO, IL-6, TNF-α and IL-1β in murine cells. Our studies provided substantial data for the high-valued application of residues and a better understanding of the structure–function relationship of polysaccharide.