Intestinal microbiology and metabolomics of streptozotocin-induced type 2 diabetes mice by polysaccharide from Cardamine violifolia

Phytochemical Analysis, Antioxidant, Enzyme Inhibitory, and Cytotoxicity Properties of Cardamine raphanifolia subsp. acris

In this work, the phytochemical profile of Cardamine raphanifolia subsp. acris extracts were analyzed, and the total phenolic/flavonoid content was evaluated using spectrophotometric methods. The highest phenolic content was found in butanol extracts (ButE), while the highest flavonoid content was detected in chloroform extracts (ChrE). GC-MS analysis identified 32 compounds, such as n-hexadecanoic acid in ethyl acetate (EtcE). The antioxidant activities of the extracts were confirmed through 2,2-diphenyl-1-picrylhydrazyl radical (DPPH) and ferric reducing antioxidant power (FRAP) assays, but their effectiveness was lower compared to gallic acid. In enzyme inhibition tests, the extracts demonstrated tyrosinase inhibitory effects ranging from 42.91% to 52.22% at 200 µg/mL. As elastase inhibitors, EtcE and ChrE showed the highest potential, whereas no collagenase inhibition was detected. Cytotoxicity analysis revealed that ButE did not have a cytotoxic effect on the human keratinocyte (HaCaT) cell line. These findings demonstrate that C. raphanifolia has the potential to serve as a source for developing skin health and antiaging agents.

Extraction, purification, chemical characterization, and in vitro hypoglycemic activity of polysaccharides derived from Rosa laevigata Michx

This study aimed to optimize the extraction process of polysaccharides from Rosa laevigata Michx. (RLMP) using an ultrasound-microwave-assisted method and investigate its in vitro hypoglycemic activity. Key factors affecting RLMP yield were identified using a Plackett-Burman design, followed by a Box-Behnken design and response-surface methodology, to determine the optimal extraction conditions. RLMP was purified using DEAE-52 cellulose, yielding two homogeneous fractions: RLMP-1 and RLMP-2. Monosaccharide composition was analyzed by gas chromatography, and structural characterization of RLMP, RLMP-1, and RLMP-2 was performed using FT-IR, SEM, and TEM. Methylation analysis and NMR were used to elucidate the sugar-chain structure of RLMP-1. In vitro hypoglycemic activity analysis showed that RLMP improved the glucose consumption and glycogen synthesis and enhanced the activities of pyruvate kinase and hexokinase in IR-HepG2 cells. Moreover, RLMP significantly increased the activities of antioxidant enzymes, such as CAT, SOD, and GSH-Px and decreased those of ROS and MDA. Western blotting analysis confirmed that RLMP enhances glucose and lipid metabolism and reduces oxidative stress by activating the PI3K/Akt/GLUT-4 signaling pathway, thereby exerting its hypoglycemic effect. These findings suggest that RLMP is a promising candidate for developing novel antioxidant agents or hypoglycemic drugs.

Functional Properties, Rheological Characteristics, Simulated Digestion, and Fermentation by Human Fecal Microbiota of Polysaccharide from Morchella importuna

Morchella importuna polysaccharide (MIP) has been proven to have obvious hypoglycemic effects on mice with type 2 diabetes (T2DM). This study looked at the functional and rheological characteristics of MIP, and investigated the effects of MIP on the human fecal microbiota through in vitro fermentation experiments. The outcomes demonstrate the excellent oil-holding capacity, emulsifying, foaming, and rheological characteristics of MIP. After salivary gastrointestinal digestion, the Mw of MIP decreased from 398.2 kDa and 21.5 kDa to 21.9 kDa and 11.7 kDa. By 16S rRNA sequencing of bacteria fermented in vitro, it was found that MIP did not improve the richness and diversity of intestinal microorganisms, but it may exert an anti-T2DM function by significantly increasing the relative abundance of Firmicutes and promoting Ruminococcaceae_UCG_014, Bacteroides, and Blautia proliferation. Escherichia-Shigella could also be inhibited to improve the intestinal microenvironment. In addition, the fermentation of MIP increased the total short-chain fatty acid (SCFA) concentration from 3.23 mmol/L to 39.12 mmol/L, and the propionic acid content increased significantly. In summary, MIP has excellent processing performance and is expected to exert potential anti-T2DM activity through the human intestinal microbiota, which has broad market prospects.

Study on the effect of licochalcone A on intestinal flora in type 2 diabetes mellitus mice based on 16S rRNA technology

Licorice, has a long history in China where it has various uses, including as a medicine, and is often widely consumed as a food ingredient. Licorice is rich in various active components, including polysaccharides, triterpenoids, alkaloids, and nucleosides, among which licochalcone A (LicA) is an active component with multiple physiological effects. Previous studies from our research group have shown that LicA can significantly improve glucose and lipid metabolism and related complications in Type 2 diabetes mellitus (T2DM) mice. However, research on the mechanism of LicA in T2DM mice based on intestinal flora has not been carried out in depth. Therefore, in this study, LicA was taken as the research object and the effects of LicA on glucose and lipid metabolism and intestinal flora in T2DM mice induced by streptozotocin (STZ)/high-fat feed (HFD) were explored. The results indicated that LicA could reduce serum TC, TG, and LDL-C levels, increase HDL-C levels, reduce blood glucose, and improve insulin resistance and glucose tolerance. LicA also alleviated pathological damage to the liver. The results also showed that LicA significantly affected the intestinal microbiota composition and increased the α diversity index. β Diversity analysis showed that after the intervention of LicA, the composition of intestinal flora was significantly different from that in the T2DM model group. Correlation analysis showed that the changes in glucose and lipid metabolism parameters in mice were significantly correlated with the relative abundance of Firmicutes, Bacteroidetes, Helicobacter, and Lachnospiraceae (p < 0.01). Analysis of key bacteria showed that LicA could significantly promote the growth of beneficial bacteria, such as Bifidobacterium, Turicibacter, Blautia, and Faecococcus, and inhibit the growth of harmful bacteria, such as Enterococcus, Dorea, and Arachnococcus. In conclusion, it was confirmed that LicA reversed the imbalanced intestinal flora, and increased the richness and diversity of the species in T2DM mice.

Antidiabetic Effect of Millet Bran Polysaccharides Partially Mediated via Changes in Gut Microbiome

Diabetes is a type of metabolic disease associated with changes in the intestinal flora. In this study, the regulatory effect of millet bran on intestinal microbiota in a model of type 2 diabetes (T2DM) was investigated in an effort to develop new approaches to prevent and treat diabetes and its complications in patients. The effect of purified millet bran polysaccharide (MBP) with three different intragastric doses (400 mg/kg, 200 mg/kg, and 100 mg/kg) combined with a high-fat diet was determined in a streptozotocin (STZ)-induced model of T2DM. By analyzing the changes in indicators, weight, fasting blood sugar, and other bio-physiological parameters, the changes in gut microbiota were analyzed via high-throughput sequencing to establish the effect of MBP on the intestinal flora. The results showed that MBP alleviated symptoms of high-fat diet-induced T2DM. A high dosage of MBP enhanced the hypoglycemic effects compared with low and medium dosages. During gavage, the fasting blood glucose (FBG) levels of rats in the MBP group were significantly reduced (p < 0.05). The glucose tolerance of rats in the MBP group was significantly improved (p < 0.05). In diabetic mice, MBP significantly increased the activities of CAT, SOD, and GSH-Px. The inflammatory symptoms of liver cells and islet cells in the MBP group were alleviated, and the anti-inflammatory effect was partially correlated with the dose of MBP. After 4 weeks of treatment with MBP, the indices of blood lipid in the MBP group were significantly improved compared with those of the DM group (p < 0.05). Treatment with MBP (400 mg/kg) increases the levels of beneficial bacteria and decreases harmful bacteria in the intestinal tract of rats, thus altering the intestinal microbial community and antidiabetic effect on mice with T2DM by modulating gut microbiota. The findings suggest that MBP is a potential pharmaceutical supplement for preventing and treating diabetes.