Vaccinium dunalianum Wight, usually processed as a traditional folk tea beverage, is widely distributed in the southwest of China. The present study aimed to investigate the antioxidant, α-glucosidase and pancreatic lipase inhibitory activities of V.dunalianum extract and isolate the bioactive components. In this study, the crude extract (CE) from the buds of V. dunalianum was prepared by the ultrasound-assisted extraction method in 70% methanol and then purified with macroporous resin D101 to obtain the purified extract (PM). Five fractions (Fr. A–E) were further obtained by MPLC column (RP-C18). Bioactivity assays revealed that Fr. B with 40% methanol and Fr. D with 80% methanol had better antioxidant with 0.48 ± 0.03 and 0.62 ± 0.01 nM Trolox equivalent (TE)/mg extract for DPPH, 0.87 ± 0.02 and 1.58 ± 0.02 nM TE/mg extract for FRAP, 14.42 ± 0.41 and 19.25 ± 0.23 nM TE/mg extract for ABTS, and enzyme inhibitory effects with IC₅₀ values of 95.21 ± 2.21 and 74.55 ± 3.85 for α-glucosidase, and 142.53 ± 11.45 and 128.76 ± 13.85 µg/mL for pancreatic lipase. Multivariate analysis indicated that the TPC and TFC were positively related to the antioxidant activities. Further phytochemical purification led to the isolation of ten compounds (1–10). 6-O-Caffeoylarbutin (7) showed significant inhibitory effects on α-glucosidase and pancreatic lipase enzymes with values of 38.38 ± 1.84 and 97.56 ± 7.53 µg/mL, and had the highest antioxidant capacity compared to the other compounds.

Flammulina velutipes is an edible mushroom widely cultivated in China. As a by-product of Flammulina velutipes, the roots are rich in high-quality dietary fiber (DF). In order to obtain high-quality soluble dietary fiber (SDF), steam explosion (SE) is used as an effective modification method to improve the extraction rate and avoid the loss of active substances. Mounting evidence shows that SDF alleviates lipid metabolism disorders. However, it is not well understood how the influence of SDF with SE pretreatment could benefit lipid metabolism. In this study, we extracted a soluble dietary fiber from Flammulina velutipes root with an SE treatment, named SE-SDF, using enzymatic assisted extraction. The physicochemical and structural properties of the SE-SDF were investigated, and its hypolipidemic effects were also analyzed using oleic-acid-induced HepG2 cells. In addition, the anti-obesity and hypolipidemic effects of SE-SDF were investigated using a high-fat diet (HFD) mouse model. The results indicate that SE treatment (1.0 MPa, 105 s) increased the SDF content to 8.73 ± 0.23%. The SE-SDF was primarily composed of glucose, galactose, and mannose. In HFD-fed mice, SE-SDF significantly reduced weight gain and improved lipid profiles, while restoring liver function and reducing injury. This work provides an effective method for the processing of fungi waste and adds to its economic value. In future studies, the structural characteristics and the anti-obesity and gut microbiota regulation mechanisms of SE-SDF will be explored in depth, supporting its high-value utilization in healthcare products.

Hyperlipidemia is a chronic metabolic disorder driven by impaired lipid homeostasis. In this study, the steam explosion (SE)-assisted extraction was applied to obtain soluble dietary fiber (SDF) from ginger peel residue. Based on single-factor and orthogonal optimization experiments, SE treatment at a material-to-cavity ratio of 2:5 and a pressure of 1.5 MPa for 300 s achieved an SDF extraction yield of 8.20%, representing a 210.60% increase. Structural and physicochemical analyses showed that both SDF and SE-SDF were mainly composed of glucose, galactose and mannose. SE treatment generated a looser and more porous structure and significantly improved the thermal stability, water holding capacity (WHC) and swelling capacity (SC) of SE-SDF increasing by 38.89% and 30.77%, respectively (p < 0.05). In oleic acid/palmitic acid (OA/PA)-stimulated HepG2 cells, both SDF and SE-SDF reduced triglyceride (TG) and total cholesterol (TC) levels in a dose-dependent manner, with SE-SDF showing a stronger hypolipidemic activity. Zebrafish experiments further confirmed that 200 µg/mL SE-SDF significantly reduced TG and TC levels by 30.58% and 24.89%, respectively, and decreased lipid deposition in the caudal vasculature and liver by 65.59% and 33.86%, respectively. These findings indicate that SE-SDF from ginger peel residue is a promising functional food ingredient for hyperlipidemia prevention.