Walnut Meal Extracts Rich In Polyphenols Mitigate Insulin Resistance and Modulate Gut Microbiota in High Fat Diet-Fed Rats.

Walnut kernel is a traditional Chinese herb recorded in the Chinese Pharmacopoeia with the efficacies of invigorating kidney, tonifying lung, and relaxing bowel. However, the potential mechanisms were unclear. This article aims to uncover the interdict mechanisms of walnut meal extracts (WMP) on high-fat diet (HFD) induced metabolic disorders in rats and reveal how the WMP benefits are associated with changes in the intestinal flora. Sprague-Dawley (SD) rats were fed a standard chow diet or an HFD for 18 weeks. After 6 weeks, the HFD rats were supplemented with 750 mg WMP/kg body weight or the vehicle for 12 weeks. The structure of gut microbiota was assessed by analyzing 16S rDNA sequences. WMP suppressed the weight gain and visceral obesity. WMP treatment also improved lipid profiles and increased antioxidative activities. WMP fully reversed hepatic steatosis with the upregulation of adipocytokines involved in lipid catabolism (e.g., adiponectin, PPAR-γ, visfatin, CEBPα) and the increased activities of lipoprotein lipase and hormone-sensitive lipase, which were associated with glucose tolerance improvement and insulin resistance (IR) mitigation. As revealed by 16S rDNA sequencing, WMP restored the diversity of intestinal flora reduced by HFD. WMP dramatically reduced the abundance of Gram-negative bacteria, especially Fusobacterium varium and Bacteroides vulgatus, and sharply increased the abundance of Lactobacillus animalis decreased by HFD. Our findings demonstrated that WMP suppressed the weight gain and adiposity in HFD-fed rats and fully reversed HFD induced IR and hepatic steatosis while dramatically reducing the abundance of Fusobacteriaceae and Enterobacteriaceae, underscoring the gut-liver axis as a primary target of walnut polyphenols.

Diaphragma juglandis extracts modifies the gut microbiota during prevention of type 2 diabetes in rats.

ETHNOPHARMACOLOGICAL RELEVANCE: The diaphragma juglandis (DJ) comes from the wooden septum in the core of Juglans regia L, also known as the walnut septum. In Iranian traditional medicine, walnut distraction wood was widely used in the treatment of diabetes. However, there is a lack of research data on the mechanism of DJ against diabetes. AIM OF THE STUDY: To explore the protective effect of diaphragma juglandis extract (DJE) on type 2 diabetic rats and the hypoglycemic mechanism of DJE. MATERIAL AND METHODS: Supplemented DJE and fed a high-fat diet for five weeks, and then injected low-dose STZ, successfully induced type 2 diabetic rats. Collected rat serum, liver, pancreas and feces to determine the biochemical parameters of serum and liver, analyze the pathological damages of pancreas and liver, and measure the changes of gut microbes in feces. RESULTS: DJE could inhibit the metabolic abnormalities of T2DM by improving insulin resistance, abnormal lipid metabolism, liver damage, oxidative stress, and reducing inflammation. DJE significantly held fasting blood glucose, glycosylated serum protein, serum low density lipoprotein, high density lipoprotein, oral glucose tolerance test, nitric oxide, superoxide dismutase and catalase, serum and liver triglycerides, total cholesterol, aspartate aminotransferase, alanine aminotransferase, malondialdehyde, lipopolysaccharide, fasting insulin and tumor necrosis factor-α and prevented the pathological damage of pancreas and liver. The 16SrRNA gene sequencing results showed that DJE intercepted the disorders of the fecal gut microbes, mainly including Lactobacillaceae, Rikenella, Pygmaiobacter, Oscillospiraceae and Klebsiella. Spearman correlation analysis showed that the changes of gut microbes were closely relative with biochemical parameters. CONCLUSION: DJE might prevent type 2 diabetes and its complications and hold up the disorders of gut microbes.

Glycolipid metabolism and liver transcriptomic analysis of the therapeutic effects of pressed degreased walnut meal extracts on type 2 diabetes mellitus rats.

Walnut meal (WM) is rich in polyphenols which exhibit multiple therapeutic effects. The purpose of this study was to investigate the therapeutic effects of walnut meal extracts (WMP) on glycolipid metabolism and liver transcriptomics in T2DM rats. A T2DM rat model was established by using a high-fat diet combined with streptozotocin. A 5-week WMP therapy showed the effects of decreasing water intake, excretion, fasting blood glucose, fasting insulin, and insulin resistance, increasing ß-cell function and insulin sensitivity index; meanwhile regulating dysfunctional lipid metabolism and reducing inflammation; improving body weight, oral glucose tolerance test and insulin sensitivity; and increasing the activities of SOD and CAT while decreasing the MDA levels in the liver and serum of T2DM rats. Moreover, 10 key differentially expressed genes were identified by RNA-seq, including Gck, RT1-Ba, Fasn, Slc13a3, Cd74, Jun, Cyp4a1, Myh7b, Plin3, and Got1, and they were highly potentially related to glycolipid metabolism. Our results suggested that WMP exhibited the anti-diabetic effect and could regulate glycolipid metabolism in T2DM rats. This finding might assist in identifying potential therapeutic targets for T2DM prevention and intervention.

Optimization of simultaneous microwave/ultrasonic-assisted extraction of phenolic compounds from walnut flour using response surface methodology.

CONTEXT: Walnut is a traditional food as well as a traditional medicine recorded in the Chinese Pharmacopoeia; however, the large amounts of walnut flour (WF) generated in walnut oil production have not been well utilized. OBJECTIVE: This study maximized the total polyphenolic yield (TPY) from the walnut flour (WF) by optimizing simultaneous ultrasound/microwave-assisted hydroalcoholic extraction (SUMAE). MATERIALS AND METHODS: Response surface methodology was used to optimize the processing parameters for the TPY, including microwave power (20-140 W), ultrasonic power (75-525 W), extraction temperature (25-55 °C), and time (0.5-9.5 min). The polyphenol components were analysed by LC-MS. RESULTS: A second-order polynomial model satisfactorily fit the experimental TPY data (R2 = 0.9932, P < 0.0001 and Radj2 = 0.9868). The optimized quick extraction conditions were microwave power 294.38 W, ultrasonic power 93.5 W, temperature 43.38 °C and time 4.33 min, with a maximum TPY of 34.91 mg GAE/g, which was a rapid extraction. The major phenolic components in the WF extracts were glansreginin A, ellagic acid, and gallic acid with peak areas of 22.15%, 14.99% and 10.96%, respectively, which might be used as functional components for health food, cosmetics and medicines. DISCUSSION AND CONCLUSION: The results indicated that walnut flour, a waste product from the oil industry, was a rich source of polyphenolic compounds and thus could be used as a high-value functional food ingredient.

Comparison of laxative and antioxidant activities of raw, processed and fermented Polygoni Multiflori radix.

AIM: To observe the anti-oxidative activity and adverse laxative effect of raw, traditional processed and fermented products of Polygoni Multiflori Radix (PMR), and furthermore, to evaluate the fermentation method used in the processing procedure of PMR. METHODS: In vitro ferric reducing antioxidant power (FRAP) assay was carried out to evaluate the anti-oxidative activity. Modulation of normal defecation and effect on gastrointestinal motility in mice were carried out to investigate their adverse laxative effect. RESULTS: Fermented PMR induced less severe laxative adverse effect than Polygoni Multiflori Radix Praeparata (PMRP). PMR fermented with Rhizopus sp. (FB) could modulate the defecation significantly. The gastrointestinal motility was inhibited by PMRP and PMR fermented with Rhizopus oryzae (FA). FA and FB showed better antioxidant activity than PMRP in 50% and 95% ethanol group. Contents of 2, 3, 5, 4'-tetrahydroxy-stilbene-2-O-ß-D-glucoside (TSG) were reduced significantly after traditional processing but maintained after fermentation. Emodin and physcion were increased after traditional processing and fermented with Rhizopus oryzae. CONCLUSION: All processing procedure, including fermentation, might reduce its anti-oxidative activity. However, most of the processed products could lessen the adverse effect on gastrointestinal tract compared to PMR. Fermentation with Rhizopus oryzae was considered as a promising processing method of PMR.