Acetaminophen (APAP) used as an antipyretic and analgesic agent can cause acute liver injury (AILI) under overdose. Sanghuangporous vaninii is an edible fungus with abundant metabolites exhibits excellent hepatoprotective activities, but the effect for AILI is not yet fully understood. In this study, the polyphenol-rich extract from S. vaninii (PSV) was prepared, with a total phenolic content of 75.72% and 34 compounds. The data of hepatoprotection indicated that PSV obviously alleviated the hepatocellular injury induced by APAP in vivo and in vitro. The protective mechanism of PSV against APAP-induced AILI might be attributed to the activating NRF2/GPX4 pathway. Based on network pharmacology analysis, the active components of PSV such as caffeic acid, osmundacetone and hispolone played a key role in hepatoprotection of PSV. Consequently, this study highlights the protection of PSV on AILI, which provides new insight into bioactivities of S. vaninii.

In order to explore the flavor composition profiles of fresh and dried Stropharia rugosoannulata and the key components determining its good flavor, the aroma and flavor components of fresh and dried samples prepared by four different drying methods, namely hot air drying (HAD), vacuum freeze drying (VFD), microwave drying (MWD), natural drying (ND) were analyzed. A total of 118 aroma compounds were detected. After drying, the aroma richness was significantly improved (P < 0.05), and VFD could retain the aroma quality of fresh mushroom to a large extent. Meanwhile, 19 aroma components common to all samples were found to constitute the characteristic component profile of S. rugosoannulata, among which the number and content of aldehydes were dominant, especially for n-hexanal (green aroma). The total amounts of soluble sugar and free amino acids in the HAD sample were significantly higher than those in the fresh sample, and the loss of flavor nucleotides in the VFD sample was least. Therefore, the two drying methods had significant advantages in equivalent umami concentration (EUC) (P < 0.05). The comprehensive sensory score for flavor was in the decreasing order of VFD > HAD > ND > fresh sample > MWD. A partial least squares regression model was established based on the sensory scores and the component data. The R_X², R_Y² and Q² of the first three principal components were 79.4%, 98.9%, and 0.974, respectively. The loading information showed that the interaction between aroma and taste characteristics was obvious. Variable importance in projection scores showed that sweet amino acids, 1-octene-3-ol, butyl-2-octenal and EUC were crucial for the good characteristic flavor of S. rugosoannulata. This study will provide a theoretical basis for subsequent screening of sample pretreatment methods and the development of flavor related products.

Umami peptides from the enzymatic hydrolysate of Stropharia rugosoannulata were separated by ultrafiltration (UF) and gel filtration chromatography (GFC) combined with sensory evaluation and electronic tongue analysis. Fraction F3, with the strongest umami intensity, were identified by reversed-phase high performance liquid chromatography-tandem mass spectrometry (RP-HPLC-MS/MS). The identified peptides were synthesized and evaluated for their taste characteristics. The results showed that eight umami peptides were identified in fraction F3, namely ELWR, RLVDR, KPDNR, AHLRF, LDWDR, LAEWR, DDWWR and EGHKGW, and all of them possessed umami characteristics and umami-enhancing effects with thresholds ranging from 0.30 to 1.33 mmol/L and from 0.53 to 2.43 mmol/L, respectively. All peptides except LDWDR showed different degrees of umami improvement in monosodium glutamate (MSG) solution, ranging from 0.18% to 61.12%. ELWR, RLVDR, KPDNR, AHLRF and EGHKGW showed good umami-enhancing effects at low concentrations. The peak concentration of RLVDR and KPDNR for synergistic umami-enhancing effect was 5 mg/mL. LDWDR, LAEWR, DDWWR and EGHKGW reached the umami peak at 4 mg/mL. The amino acid composition and the spatial structure of umami peptides could affect their taste properties. The results of this study provide a theoretical basis for the development and utilization of umami peptides from S. rugosoannulata.

Protein-polysaccharide complexes of Agaricus bisporus, Stropharia rugosa and Morchella esculenta were prepared and their protein and polysaccharide contents as well as amino acid and monosaccharide composition were evaluated. The in vitro and in vivo lipid-lowering effects of the complexes on oleic acid-induced liver LO-2 cells and high-fat diet fed mice were investigated. The results showed that the protein contents of the three complexes were (55.56 ± 0.51)%, (52.41 ± 0.31)%, and (54.96 ± 0.47)%, respectively, and the polysaccharide contents were (21.98 ± 1.17)%, (31.95 ± 0.52)%, and (15.55 ± 0.78)%, respectively. In vitro cell experiments showed that all the complexes significantly inhibited the accumulation of lipid droplets in hepatocytes. Animal experiments showed that they significantly inhibited the increase in body mass, triglyceride (TG) and low-density lipoprotein cholesterol (LDL-C) levels, blocked the swelling of the swelling of hepatocytes, and inhibited hepatic lipid deposition in mice fed a high-fat diet. In the high-dose group, the hepatic lipid content of mice with hyperlipidemia was reduced from (30.59 ± 0.38)% to (13.74 ± 1.57)%, (9.68 ± 0.73)%, and (7.15 ± 0.39)%, respectively, by the complexes from A. bisporus, S. rugosa and M. esculenta, and the inhibition rates of hepatic lipid droplets by these complexes were (55.09 ± 5.12)%, (68.34 ± 2.37)% and (76.64 ± 1.28)%, respectively. In addition, the protein-polysaccharide complexes alleviated liver function damage caused by long-term high-fat diet. In summary, it can be concluded that A. bisporus, S. rugosa and M. esculenta protein-polysaccharide complexes can regulate lipid metabolism, alleviate liver injury and hyperlipidemia, which provides a reference for the development of functional products based on edible fungi.

The taste presentation and receptor perception mechanism of the salty peptide of Stropharia rugosoannulata were predicted and verified using peptide omics and molecular interaction techniques. The combination of aspartic acid (D) and glutamic acid (E), or peptide fragments composed of arginine (R), constitute the characteristic taste structural basis of salty peptides of S. rugosoannulata. The taste intensity of the salty peptide positively correlates with its concentration within a specific concentration range (0.25–1.0 mg/mL). The receptor more easily recognizes the first amino acid residue at the N-terminal of salty peptides and the aspartic acid residue in the peptides. GLU513, ASP707, and VAL508 are the critical amino acid residues for the receptor to recognize salty peptides. TRPV1 is specifically the receptor for recognizing salty peptides. Hydrogen bonds and electrostatic interactions are the main driving forces for the interactions between salty peptides and TRPV1 receptors. KSWDDFFTR has the most potent binding capacity with the receptor and has tremendous potential for application in sodium salt substitution. This study confirmed the taste receptor that specifically recognizes salty peptides, analyzed the receptor-peptide binding interaction, and provided a new idea for understanding the taste receptor perception of salty peptides.