A Model-Based 13C-Sucrose Breath Test Diagnostic for Gut Function Disorders Characterized by a Loss of Sucrase-Isomaltase Enzymatic Activity

BACKGROUND

Environmental enteric dysfunction (EED) causes malnutrition in children in low-resource settings. Stable-isotope breath tests have been proposed as noninvasive tests of altered nutrient metabolism and absorption in EED, but uncertainty over interpreting the breath curves has limited their use. The activity of sucrose-isomaltase, the glucosidase enzyme responsible for sucrose hydrolysis, may be reduced in EED. We previously developed a mechanistic model describing the dynamics of the 13C-sucrose breath test (13C-SBT) as a function of underlying metabolic processes.

OBJECTIVES

This study aimed to determine which breath test curve dynamics are associated with sucrose hydrolysis and with the transport and metabolism of the fructose and glucose moieties and to propose and evaluate a model-based diagnostic for the loss of activity of sucrase-isomaltase.

METHODS

We applied the mechanistic model to 2 sets of exploratory 13C-SBT experiments in healthy adult participants. First, 19 participants received differently labeled sucrose tracers (U-13C fructose, U-13C glucose, and U-13C sucrose) in a crossover study. Second, 16 participants received a sucrose tracer accompanied by 0, 100, and 750 mg of Reducose, a sucrase-isomaltase inhibitor. We evaluated a model-based diagnostic distinguishing between inhibitor concentrations using receiver operator curves, comparing with conventional statistics.

RESULTS

Sucrose hydrolysis and the transport and metabolism of the fructose and glucose moieties were reflected in the same mechanistic process. The model distinguishes these processes from the fraction of tracer exhaled and an exponential metabolic process. The model-based diagnostic performed as well as the conventional summary statistics in distinguishing between no and low inhibition [area under the curve (AUC): 0.77 vs. 0.66-0.79] and for low vs. high inhibition (AUC 0.92 vs. 0.91-0.99).

CONCLUSIONS

Current summary approaches to interpreting 13C breath test curves may be limited to identifying only gross gut dysfunction. A mechanistic model-based approach improved interpretation of breath test curves characterizing sucrose metabolism.

Pharmacological and Pathological Effects of Mulberry Leaf Extract on the Treatment of Type 1 Diabetes Mellitus Mice

This study investigated the pharmacological and pathological effects of aqueous mulberry leaf extract on type 1 diabetes mellitus mice induced with an intraperitoneal injection of streptozotocin (STZ). Diabetic mice were randomized into six groups: control (normal group), model, metformin-treated mice, and high-dose, medium-dose, and low-dose mulberry. The mulberry-treated mice were divided into high-, medium-, and low-dose groups based on the various doses of aqueous mulberry leaf extract during gavage. The efficacy of the six-week intervention was evaluated by measuring levels of fasting plasma glucose, alkaline phosphatase, alanine aminotransferase, aspartate transaminase, blood urea nitrogen, gamma-glutamyl transferase, glucose, high-density lipoprotein cholesterol, lactate dehydrogenase, and low-density lipoprotein cholesterol and recording body weight. Results revealed that mulberry leaf extract exhibited an ideal hypoglycemic effect, and the high-dose group was the most affected. Histology analysis, glycogen staining and apoptosis detection were used to study the extract's effects on the liver, kidney, and pancreatic cells of diabetic mice, enabling the assessment of its effectiveness and complications on a clinical and theoretical basis. It was shown that a certain concentration of aqueous mulberry leaf extract repaired the islet cells of type 1 diabetes mellitus mice, promoting normal insulin secretion. Herein, it was confirmed that mulberry leaf could be used to develop new hypoglycemic drugs or functional health food with broad applicability.

Mulberry leaf extract improves intestinal barrier function and displays beneficial effects on colonic microbiota and microbial metabolism in weaned piglets

BACKGROUND

Mulberry leaf extract (MLE) extracted from mulberry leaves is rich in a variety of bioactive ingredients and can be used as feed additives of weaned piglets. The present study was conducted to evaluate the effects of dietary MLE supplementation on intestinal barrier function, colon microbial numbers and microbial metabolites of weaned piglets.

RESULTS

MLE supplementation increased the villus height and the villus height/crypt depth ratio in jejunum and ileum (P < 0.05), increased the mRNA expression of ZO-1, Claudin-1 and MUC-2 in the ileal mucosa (P < 0.05), and decreased the serum level of lipopolysaccharide (P < 0.01). Meanwhile, MLE reduced the mRNA expression of tumor necrosis factor-α and interleukin-1β (P < 0.05) and increased secretory immunoglobulin A level in the ileal mucosa (P < 0.05). In addition, MLE increased the numbers of beneficial bacteria Bifidobacterium and Lactobacillus (P < 0.05) and decreased the number of potential pathogenic bacteria Escherichia coli (P < 0.05) in the colon. Correspondingly, MLE supplementation reduced the pH value of colonic digesta (P < 0.05) and altered the microbial fermentation pattern of the colon by increasing the concentrations of microbial metabolites derived from carbohydrates fermentation such as lactate, acetate, butyrate and total short-chain fatty acids (P < 0.05), and decreasing the concentrations of microbial metabolites derived from amino acid fermentation such as p-cresol, skatole, spermine, histamine and tryptamine (P < 0.05).

CONCLUSION

MLE supplementation improved intestinal barrier function and displayed beneficial effects on colon microbes and microbial metabolism in weaned piglets. © 2022 Society of Chemical Industry.

Mulberry Leaf (Morus alba L.) Extracts and Its Chlorogenic Acid Isomer Component Improve Glucolipotoxicity-Induced Hepatic Lipid Accumulation via Downregulating miR-34a and Decreased Inflammation

Mulberry leaf (Morus alba L.) is used as a traditional medicine and potential health food to treat various metabolic diseases, such as hypertension, diabetes, and hyperlipidemia. However, we sought the mechanisms by which functional components of mulberry leaves mediate diabetic steatohepatitis. We applied an in vitro model of HepG2 cells induced by glucolipotoxicity and evaluated the effects of MLE and its major components nCGA, Crp, and CGA. The results showed that MLE and nCGA reduced liver fat accumulation by inhibiting SREBP-1/FASN, SREBP-2/HMG-CoAR, and activating PPARα/CPT-1. Additionally, MLE and nCGA decreased inflammatory responses associated with NF-κB, TNF-α, and IL-6 to alleviate steatohepatitis. Furthermore, we showed that MLE and nCGA exerted anti-glucolipotoxicity effects by downregulating miR-34a, thus activating SIRT1/AMPK signaling, and subsequently suppressing hepatic lipid accumulation.

High Hydrostatic Pressure Extract of Mulberry Leaf Attenuated Obesity-Induced Inflammation in Rats

Low-grade inflammation might be a link between obesity and obesity-associated metabolic dysfunction, including diabetes, hepatic steatosis, and other health complications. This study investigated whether the supplementation of high hydrostatic pressure extract of mulberry (Morus alba L.) leaves (HML) to obese rats could counteract obesity-related inflammation. Three-week-old male Sprague-Dawley rats were separated into three groups as follows: (a) a normal diet, (b) 45% high-fat (HF) diet, and HF diet containing 0.4% HML (c) or 0.8% HML (d) (IACUC No. 17-033). After 14 weeks of HML supplementation, adipose tissue mass, mRNA expression of adipogenic genes, such as aP2, peroxisome proliferator-activated receptor γ (PPARγ), and sterol regulatory element binding protein 1c (SREBP1c), and macrophage recruitment were significantly decreased in HF-fed obese rats. Serum concentrations of nitric oxide and mRNA levels of arginase1 (Arg1), CD11c, and inducible nitric oxide synthase (iNOS) involved in adipose tissue macrophage M1 polarization were also significantly reduced by HML. Moreover, HML alleviated the serum and hepatic lipid profiles and reduced hepatic lipogenic gene expression of acetyl-CoA carboxylase (ACC), cluster of differentiation 36 (CD36), CPT1, fatty acid synthase (FAS), stearoyl-CoA desaturase (SCD1), and SREBP1c, and inflammation-associated genes, including IL1β, interleukin 6 (IL6), and tumor necrosis factor α (TNFα). Serum IL6 and TNFα levels were remarkedly suppressed in the 0.8% HML group. These results suggested that the favorable effect of HML on obesity-associated inflammation might be related in part to the decrease in adipose tissue and hepatic fat deposition and inflammation.

Safety evaluation of a beverage containing mulberry leaf extract

Mulberry leaf extract (MLE) has known as inhibits elevated postprandial blood glucose level in human. Then, we conducted a randomized, double-blind placebo-controlled parallel-group trial to evaluate safety when a green tea containing MLE is consumed 3 times a day, every day for 4 weeks. The participants (n = 48) were randomly allocated into 2 groups, an MLE beverage group and a control beverage group. The subjects were instructed to drink either a 500 mL green tea containing 550 mg MLE or a 500 mL green tea not containing MLE, 3 times a day, every day, for 4 weeks. No adverse reactions were observed over the 4 weeks trial, and no difference in the incidence of adverse events between the groups. These findings demonstrate that the consumption of a green tea containing 550 mg MLE 3 times a day for 4 weeks is safe for healthy adults.

High hydrostatic pressure extract of mulberry leaves ameliorates hypercholesterolemia via modulating hepatic microRNA-33 expression and AMPK activity in high cholesterol diet fed rats

Background

Mulberry leaf (Morus alba L.) contains multiple bioactive ingredients and has been used in the treatment of obesity, diabetes, inflammation, and atherosclerosis. High hydrostatic pressure (HHP) processing has been developed for the extraction of bioactive compounds from plants. However, the hypocholesterolemic effect of the HHP extract from mulberry leaves and its underlying mechanism have never been investigated.

Objective

The specific aim of the present study was to investigate the hypocholesterolemic property of a novel extract obtained from mulberry leaves under HHP in rats.

Design

Sprague–Dawley rats were divided into four groups and fed either a normal diet (NOR), a high cholesterol diet containing 1% cholesterol and 0.5% cholic acid (HC), an HC diet containing 0.5% mulberry leaf extract (ML), or a 1% mulberry leaf extract (MH) for 4 weeks.

Results

High hydrostatic pressure extract of mulberry leaves significantly reduced the HC-increased serum levels of triglyceride (TG), cholesterol (TC) and low-density lipoprotein cholesterol (LDL-C), and hepatic contents of TG and TC. The HHP extraction from mulberry leaves also increased the HC-decreased fecal TC and bile acid levels without changing body weight, food intake, liver weight, and serum activities of alanine transaminase (ALT) and aspartate transaminase (AST) (P < 0.05). The mulberry leaf extract significantly enhanced the expression of hepatic genes such as cholesterol 7 alpha-hydroxylase (CYP7A1), liver X receptor alpha (LXRα), and ATP-binding cassette transporters, ABCG5/ABCG8, involved in hepatic bile acid synthesis and cholesterol efflux (P < 0.05). In addition, the HHP extraction of mulberry leaves significantly suppressed hepatic microRNA(miR)-33 expression and increased adenosine monophosphate-activated protein kinase (AMPK) activity.

Conclusion

These results suggest that the HHP extract of mulberry leaves lowers serum cholesterol levels by partially increasing hepatic bile acid synthesis and fecal cholesterol excretion through the modulation of miR-33 expression and AMPK activation in the liver.

Potential probiotics Lactobacillus casei K11 combined with plant extracts reduce markers of type 2 diabetes mellitus in mice

AIMS

Probiotics and plant extracts have been used to prevent the development of type 2 diabetes mellitus (T2DM). The study aimed to explore the effect of the interaction between potential probiotics and bitter gourd extract (BGE) or mulberry leaf extract (MLE) on T2DM.

METHODS AND RESULTS

Potential probiotics were tested for their gastrointestinal tract viability and growth situation combined with BGE and MLE in vitro. The diabetes model was constructed in C57BL/6 mice, and the potential effect and mechanism of regulating blood glucose were verified. Hematoxylin-eosin staining (HE), gas chromatography (GC), ELISA, and RT-PCR were also used for analysis. The results showed that Lactobacillus casei K11 had outstanding gastrointestinal tract viability and growth situation with plant extracts. Administration of L. casei K11 combined with BGE and MLE significantly reduced blood glucose levels and ameliorated insulin resistance in diabetic mice than the administration of Lactobacillus paracasei J5 combined with BGE and MLE. Moreover, in L. casei K11 combined with BGE and MLE groups, lipid metabolism, oxidative stress, and proinflammatory cytokine levels were regulated. Furthermore, the results indicated that L. casei K11 combined with BGE and MLE improved free fatty acid receptor 2 (FFAR2) upregulation, glucagon-like peptide-1 (GLP-1) secretion, and short-chain fatty acid (SCFA) levels.

CONCLUSIONS

These findings showed that L. casei K11 combined with BGE and MLE modified the SCFA-FFAR2-GLP-1 pathway to improve T2DM.

SIGNIFICANCE AND IMPACT OF THE STUDY

This study identified a new modality for evaluating interactions between potential probiotics and plant extracts. Our findings revealed that L. casei K11 combined with BGE and MLE significantly promoted the SCFA-FFAR2-GLP-1 pathway to inhibit T2DM.

Mulberry leaves extract ameliorates alcohol-induced liver damages through reduction of acetaldehyde toxicity and inhibition of apoptosis caused by oxidative stress signals

Mulberry leaves (Morus alba L.), which are traditional Chinese herbs, exert several biological functions, such as antioxidant, anti-inflammation, antidiabetic, and antitumor. Alcohol intake increases inflammation and oxidative stress, and this increase causes liver injury and leads to liver steatosis, cirrhosis, and hepatocellular carcinoma, which are major health problems worldwide. Previous report indicated that mulberry leaf extract (MLE) exited hepatoprotection effects against chronic alcohol-induced liver damages. In this present study, we investigated the effects of MLE on acute alcohol and liver injury induced by its metabolized compound called acetaldehyde (ACE) by using in vivo and in vitro models. Administration of MLE reversed acute alcohol-induced liver damages, increased acetaldehyde (ACE) level, and decreased aldehyde dehydrogenase activity in a dose-dependent manner. Acute alcohol exposure-induced leukocyte infiltration and pro-inflammation factors, including cyclooxygenase-2 (COX-2), tumor necrosis factor-α (TNF-α), and interleukin-6 (IL-6), were blocked by MLE in proportion to MLE concentration. MLE prevented alcohol-induced liver apoptosis via enhanced caveolin-1 expression and attenuated EGFR/STAT3/iNOS pathway using immunohistochemical analysis. ACE induced proteins, such as iNOS, COX-2, TNF-α, and IL-6, and inhibited superoxide dismutase expression, whereas co-treated with MLE reversed these proteins expression. MLE also recovered alcohol-induced apoptosis in cultured Hep G2 cells. Overall, our findings indicated that MLE ameliorated acute alcohol-induced liver damages by reducing ACE toxicity and inhibiting apoptosis caused by oxidative stress signals. Our results implied that MLE might be a potential agent for treating alcohol liver disease.

Anti-adipogenic effect of mulberry leaf ethanol extract in 3T3-L1 adipocytes

BACKGROUND/OBJECTIVES

Adipogenesis is part of the cell differentiation process in which undifferentiated fibroblasts (pre-adipocytes) become mature adipocytes with the accumulation of lipid droplets and subsequent cell morphological changes. Several transcription factors and food components have been suggested to be involved in adipogenesis. The aim of this study was to determine whether mulberry leaf ethanol extract (MLEE) affects adipogenesis in 3T3-L1 adipocytes.

MATERIALS/METHODS

The 3T3-L1 adipocytes were treated with different doses of MLEE for 8 days starting 2 days post-confluence. Cell viability, fat accumulation, and adipogenesis-related factors including CCAAT-enhancer-binding protein alpha (C/EBPα), peroxisome proliferator-activated receptor gamma (PPARγ), PPARγ coactivator 1 alpha (PGC-1α), fatty acid synthase (FAS), and adiponectin were analyzed.

RESULTS

Results showed that MLEE treatments at 10, 25, 50, and 100 µg/ml had no effect on cell morphology and viability. Without evident toxicity, all MLEE treated cells had lower fat accumulation compared with control as shown by lower absorbances of Oil Red O stain. MLEE at 50 and 100 µg/ml significantly reduced protein levels of PPARγ, PGC-1α, FAS, and adiponectin in differentiated adipocytes. Furthermore, protein level of C/EBPα was significantly decreased by the treatment of 100 µg/ml MLEE.

CONCLUSION

These results demonstrate that MLEE treatment has an anti-adipogenic effect in differentiated adipocytes without toxicity, suggesting its potential as an anti-obesity therapeutic.

Effects of mulberry leaf extract rich in 1-deoxynojirimycin on blood lipid profiles in humans

Mulberry leaves are rich in 1-deoxynojirimycin (DNJ), an inhibitor of α-glucosidase. We previously showed that DNJ-rich mulberry leaf extract suppressed elevation of postprandial blood glucose in humans. The objective of this study was to evaluate the effects of DNJ-rich mulberry leaf extract on plasma lipid profiles in humans. An open-label, single-group study was conducted in 10 subjects with initial serum triglyceride (TG) level ≥200 mg/dl. Subjects ingested capsules containing DNJ-rich mulberry leaf extract at 12 mg three times daily before meals for 12 weeks. Our findings showed a modest decrease in serum TG level and beneficial changes in the lipoprotein profile following 12-week administration of DNJ-rich mulberry leaf extract. No significant changes in hematological or biochemical parameters were observed during the study period; no adverse events associated with DNJ-rich mulberry leaf extract occurred.