The Study of a Novel Paeoniflorin-Converting Enzyme from Cunninghamella blakesleeana.

Paeoniflorin is a glycoside compound found in Paeonia lactiflora Pall that is used in traditional herbal medicine and shows various protective effects on the cardio-cerebral vascular system. It has been reported that the pharmacological effects of paeoniflorin might be generated by its metabolites. However, the bioavailability of paeoniflorin by oral administration is low, which greatly limits its clinical application. In this paper, a paeoniflorin-converting enzyme gene (G6046, GenBank accession numbers: OP856858) from Cunninghamella blakesleeana (AS 3.970) was identified by comparative analysis between MS analysis and transcriptomics. The expression, purification, enzyme activity, and structure of the conversion products produced by this paeoniflorin-converting enzyme were studied. The optimal conditions for the enzymatic activity were found to be pH 9, 45 °C, resulting in a specific enzyme activity of 14.56 U/mg. The products were separated and purified by high-performance counter-current chromatography (HPCCC). Two main components were isolated and identified, 2-amino-2-p-hydroxymethyl-methyl alcohol-benzoate (tirs-benzoate) and 1-benzoyloxy-2,3-propanediol (1-benzoyloxypropane-2,3-diol), via UPLC-Q-TOF-MS and NMR. Additionally, paeoniflorin demonstrated the ability to metabolize into benzoic acid via G6046 enzyme, which might exert antidepressant effects through the blood-brain barrier into the brain.

Molecular dynamics simulation integrating the inhibition kinetics of hydroxysafflor yellow A on α-glucosidase.

Inhibition of α-glucosidase has attracted the attention of researchers due to its connection to type-2 diabetes. Hydroxysafflor yellow A (HSYA) extracted from Carthamus tinctorius L. is a natural antioxidant used in traditional Chinese medicine. In this study, the effect of HSYA on α-glucosidase was evaluated using inhibitory kinetics based on the antioxidant properties of HSYA and by performing computational simulation integration methods. HSYA reversibly inhibited α-glucosidase in a competitive inhibition manner and the evaluated kinetic parameters were IC50 = 1.1 ± 0.22 mM and Ki = 1.04 ± 0.23 mM, respectively. The results of spectrofluorimetry showed that the inner hydrophobic regions of α-glucosidase, which are mostly in the active site, were exposed to the surface with increasing HSYA concentrations, indicating that the inactivation of α-glucosidase by HSYA was accompanied by regional unfolding. The molecular dynamics simulations indicated that the four rings of HSYA interact with four residues such as G217, A278, H279, and G280 at the entrance of the active site. Our study provides insight into the inhibition of α-glucosidase and the accompanying structural changes by HSYA. Based on its α-glucosidase-inhibiting effect and its potential as a natural antioxidant, HSYA is a potential agent for treating α-glucosidase-associated type-2 diabetes.

Amelioration of Intestinal Barrier Dysfunction by Berberine in the Treatment of Nonalcoholic Fatty Liver Disease in Rats.

OBJECTIVE: To investigate the effect of berberine (BBR) on intestinal barrier function in nonalcoholic fat liver disease (NAFLD) in rats. MATERIALS AND METHODS: Rats were divided into three groups: normal diet group (control group [CON group]), high-fat diet feeding group (HFD group), and HFD with BBR group. After 8 weeks of HFD feeding, rats in the BBR group were given BBR intragastrically at a dose of 150 mg/kg daily for 4 weeks. The same volume of normal saline was given to the CON and HFD groups. Liver index was detected, and Sudan black B staining was used to study fatty degeneration, also the expression level of occluding and intestinal flora was analyzed. RESULTS: BBR administration significantly reduced HFD-induced increase in body weight (CON group: 379.83 ± 61.51 g, HFD group: 485.24 ± 50.15 g, and BBR group: 428.60 ± 37.37 g). It obviously alleviated the HFD-induced liver fatty degeneration and histopathological changes of intestinal mucosa according to liver index low-density lipoprotein-cholesterol, high-density lipoprotein-cholesterol, and total cholesterol (P < 0.05). The triglyceride, alanine transaminase, and aspartate aminotransferase levels were greatly elevated after BBR treatment (P < 0.05); while endotoxin, intestinal fatty acid-binding protein, and tumor necrosis factor-α were significantly reduced (P < 0.05). Moreover, we found that BBR could obviously elevate the level of occludin and decrease the level of Faecalibacterium prausnitzii and upregulate the level of bacteroides. CONCLUSION: BBR provides significant protection in NAFLD through ameliorating intestinal barrier function. SUMMARY: Berberine (BBR), an alkaloid that can be isolated from many plants, has been medically used for its wide range of antimicrobial and anti-inflammatory effectsThis is a study of BBR on liver function and intestinal barrier function in nonalcoholic fat liver disease (NAFLD)BBR treatment for NAFLD could significantly restore the liver function and provide significant protection in NAFLD through ameliorating intestinal barrier function. Abbreviations used: BBR: Berberine, NAFLD: Nonalcoholic fat liver disease, ALT: Alanine transaminase, AST: Aspartate aminotransferase, TG: Triglyceride, I-FABP: Intestinal-fatty acid-binding protein, IBD: Inflammatory bowel disease.