Influence of mulberry leaf extract on the blood glucose and breath hydrogen response to ingestion of 75 g sucrose by type 2 diabetic and control subjects

Evidence of traditional Chinese medicine for treating type 2 diabetes mellitus: from molecular mechanisms to clinical efficacy

CONTEXT

The global prevalence of type 2 diabetes mellitus (T2DM) has increased significantly in recent decades. Despite numerous studies and systematic reviews, there is a gap in comprehensive and up-to-date evaluations in this rapidly evolving field.

OBJECTIVE

This review provides a comprehensive and current overview of the efficacy of Traditional Chinese Medicine (TCM) in treating T2DM.

METHODS

A systematic review was conducted using PubMed, Web of Science, Wanfang Data, CNKI, and Medline databases, with a search timeframe extending up to November 2023. The search strategy involved a combination of subject terms and free words in English, including 'Diabetes,' 'Traditional Chinese Medicine,' 'TCM,' 'Hypoglycemic Effect,' 'Clinical Trial,' and 'Randomized Controlled Trial.' The studies were rigorously screened by two investigators, with a third investigator reviewing and approving the final selection based on inclusion and exclusion criteria.

RESULTS

A total of 108 relevant papers were systematically reviewed. The findings suggest that TCMs not only demonstrate clinical efficacy comparable to existing Western medications in managing hypoglycemia but also offer fewer adverse effects and a multitarget therapeutic approach. Five main biological mechanisms through which TCM treats diabetes were identified: improving glucose transport and utilization, improving glycogen metabolism, promoting GLP-1 release, protecting pancreatic islets from damage, and improving intestinal flora.

CONCLUSIONS

TCM has demonstrated significant protective effects against diabetes and presents a viable option for the prevention and treatment of T2DM. These findings support the further exploration and integration of TCM into broader diabetes management strategies.

A Novel Nutraceutical Supplement Lowers Postprandial Glucose and Insulin Levels upon a Carbohydrate-Rich Meal or Sucrose Drink Intake in Healthy Individuals-A Randomized, Placebo-Controlled, Crossover Feeding Study

BACKGROUND

Alkaloid- and polyphenol-rich white mulberry leaf and apple peel extracts have been shown to have potential glucose-lowering effects, benefitting the control of postprandial blood glucose levels. This study aimed to determine the effect of the combination of Malus domestica peel and Morus alba leaf extracts (GLUBLOCTM) on postprandial blood glucose and insulin-lowering effects in healthy adults after a carbohydrate-rich meal or sucrose drink intake.

METHODS

This study was designed as a randomized, crossover, single-blinded clinical trial. Out of 116 healthy participants, 85 subjects (aged 18-60 years) completed the day 1 and 5 crossover study. On day 1, subjects were supplemented with a placebo or GLUBLOCTM tablet 10 min before the carbohydrate-rich meal (300 g of tomato rice) or sucrose drink intake (75 g of sucrose dissolved in 300 mL water). On day 5, the treatments were crossed over, and the same diet was followed. Postprandial blood glucose and insulin levels were measured on days 1 and 5 (baseline 0, post-meal 30, 60, 90, and 120 min). Differences in iAUC, Cmax, and Tmax were determined between the placebo and GLUBLOCTM-treated cohorts.

RESULTS

Significant changes in total iAUC (0-120 min), Cmax, and Tmax of postprandial blood glucose and insulin levels were noticed upon GLUBLOCTM supplementation. The percentage reduction in the iAUC of blood glucose levels was 49.78% (iAUC0-60min) and 43.36% (iAUC0-120min), respectively, compared with the placebo in the sucrose drink intake study. Similarly, there was a 41.13% (iAUC0-60min) and 20.26% (iAUC0-120min) glucose-lowering effect compared with the placebo in the carbohydrate-rich meal intake study.

CONCLUSIONS

Premeal supplementation with GLUBLOCTM significantly reduced the postprandial surge in blood glucose and insulin levels after a carbohydrate-rich meal or sucrose drink intake over 120 min in healthy individuals. This study proves that GLUBLOCTM can manage steady postprandial blood glucose levels.

Effect of Low-Dose Mulberry Fruit Extract on Postprandial Glucose and Insulin Responses: A Randomized Pilot Trial in Individuals with Type 2 Diabetes

Adding mulberry fruit extract (MFE) to carbohydrate-rich meals can reduce postprandial glucose (PPG) and insulin (PPI) responses in healthy individuals. This pilot study assessed the acute postprandial effects of low doses of MFE in individuals with type 2 diabetes. In a randomized cross-over (within-subjects) design, 24 unmedicated adult males and females with type 2 diabetes (mean [SD] age 51.0 [9.3] yr, BMI 27.5 [3.9] kg/m2) consumed meals with 0 (control), 0.37, and 0.75 g of MFE added to ~50 g of available carbohydrates from rice. Primary and secondary outcomes were the PPG 2 hr positive incremental area under the curve and the corresponding PPI. Results were reported as mean differences from the control meal with 95% CI. Relative to control, 0.37 and 0.75 g of MFE reduced the mean 2 hr PPG by 8.2% (-20.8 to 6.6%) and 22.4% (-38.6 to -1.9%), respectively, and reduced PPI by 9.6% (-20.7 to 3.0%) and 17.5% (-27.9 to -5.7%). There were no indications of adverse events or gastrointestinal discomfort. MFE additions also led to dose-related reductions in glucose peak and glucose swing. At these levels, MFE appears to dose-dependently reduce acute PPG and PPI in individuals with type 2 diabetes and may be a feasible dietary approach to help attenuate glycemic exposures.

Hypoglycemic effects and associated mechanisms of resveratrol and related stilbenes in diet

Hyperglycemia has become a global health problem due to changes in diet and lifestyle. Most importantly, persistent hyperglycemia can eventually develop into type II diabetes. While the usage of current drugs is limited by their side effects, stilbenes derived from fruits and herbal/dietary plants are considered as important phytochemicals with potential hypoglycemic properties. Herein, the most common stilbenoids in consumed foods, i.e. resveratrol, pterostilbene, piceatannol, oxyresveratrol, and 2,3,5,4'-tetrahydroxystilbene-2-O-β-glucopyranoside (THSG), are reviewed in this paper. These stilbenes are found to regulate glucose homeostasis via (a) modulation of feeding behaviour and nutrition absorption; (b) restoration of insulin signalling by enhancing insulin production/insulin sensitivity; (c) improvement of gut permeability, gut microbial profile and resulting metabolomes; and (d) amelioration of circadian rhythm disruption. In this review, we have summarized the underlying mechanisms for the hypoglycemic effects of the five most common dietary stilbenoids listed above, providing a comprehensive framework for future study and applications.

Effect of mulberry fruit extract on post-prandial glycaemic and insulinemic responses to different rice types: a randomised trial in healthy adults

We previously reported that the addition of a specified mulberry fruit extract (MFE) to rice consistently reduces post-prandial glycaemic (PPG) and post-prandial insulinemic (PPI) responses. This research tested whether this effect generalises to a broad range of rice types, reflecting the wide variation in rice characteristics known to influence glycaemic responses. In a randomised, balanced, partial factorial crossover design, Sona Masoori (SM), Bora Saul (BS), Gobindobogh (Gb) and Banskati (Bn) rices were tested with and without 0·37 g MFE. Healthy, normal-weight Indian adults (N 120) each consumed four of the eight possible boiled rice meals, all containing about 50 g available carbohydrate. The primary outcome was the effect of MFE on PPG, expressed as the percentage change in the positive, incremental AUC over 2 h. The mean effect of MFE on PPG for all rice types combined was -11·4 % (P < 0·003). The reduction in PPG was in a qualitatively similar range for all rice types (-9·8 to -15·1 %), and this was statistically significant for Bn. MFE also reduced the corresponding PPI response to all rice types combined by a mean of 10·1 % (P < 0·001; range -6·1 to -13·4 %), and the reduction in PPI was statistically significant for SM, Gb and BS. In conclusion, addition of 0·37 g MFE modestly reduced PPG and PPI responses to rices in general, and the effects were statistically significant for specific rice types.

Clinical potential and mechanistic insights of mulberry (Morus alba L.) leaves in managing type 2 diabetes mellitus: Focusing on gut microbiota, inflammation, and metabolism

ETHNOPHARMACOLOGICAL RELEVANCE

Natural herbs are gradually gaining recognition for their efficacy and safety in preventing diabetes and improving quality of life. Morus alba L. is a plant widely grown in Asia and is a traditional Chinese herb with a long history of use. Furthermore, several parts of Morus alba L. have been found to have significant health benefits. In particular, mulberry (Morus alba L.) leaves (ML) have been shown in human and animal studies to be promising hypoglycemic agents that can reduce or prevent glucolipid metabolism disorders caused by imbalances in the gut microbiota, inflammation, and oxidative stress and have demonstrated significant improvements in glucose metabolism-related markers, effectively lowering blood glucose, and reducing hyperglycemia-induced target organ damage.

AIM OF THE STUDY

This review briefly summarizes the methods for obtaining ML's bioactive components, elaborates on the clinical potential of the relevant components in managing type 2 diabetes mellitus (T2DM), and focuses on the therapeutic mechanisms of gut microbiota, inflammation, oxidative stress, and metabolism, to provide more inspiration and directions for future research in the field of traditional natural plants for the management of T2DM and its complications.

MATERIALS AND METHODS

Research on ML and its bioactive components was mainly performed using electronic databases, including PubMed, Google Scholar, and ScienceNet, to ensure the review's quality. In addition, master's and doctoral theses and ancient documents were consulted.

RESULTS

In clinical studies, we found that ML could effectively reduce blood glucose, glycated hemoglobin, and homeostasis model assessment of insulin resistance in T2DM patients. Furthermore, many in vitro and in vivo experiments have found that ML is involved in various pathways that regulate glucolipid metabolism and resist diabetes while alleviating liver and kidney damage.

CONCLUSIONS

As a potential natural anti-diabetic phytomedicine, an in-depth study of ML can provide new ideas and valuable references for applying traditional Chinese medicine to treat T2DM. While continuously exploring its clinical efficacy and therapeutic mechanism, the extraction method should be optimized to improve the efficacy of the bioactive components. in addition, further research on the dose-response relationship of drugs to determine the effective dose range is required.

A Randomized, Placebo-Controlled Crossover Study to Evaluate Postprandial Glucometabolic Effects of Mulberry Leaf Extract, Vitamin D, Chromium, and Fiber in People with Type 2 Diabetes

INTRODUCTION

Reducing postprandial (PP) hyperglycemia and PP glucose excursions is important for overall glycemic management. Although most therapeutic lifestyle interventions that reduce caloric intake would affect this, there is no particular nutritional intervention favored.

METHODS

We evaluated the effects of a novel natural food adjuvant combining mulberry leaf extract (MLE) with other bioactive ingredients, in people with type 2 diabetes (T2D) originating from Asia, on improving PP glucometabolic response in a randomized controlled exploratory crossover, two-center study (USA, Singapore). A 2-g blend of 250 mg MLE [containing 12.5 mg of 1-deoxynojirimycin (DNJ)], fiber (1.75 g), vitamin D₃ (0.75 μg), and chromium (75 μg), compared with a similar blend without the MLE, was sprinkled over a 350-kcal breakfast meal (55.4 g carbs) and PP blood glucose (primary exploratory endpoint), insulin, and incretin hormones (GLP-1, GIP) were evaluated in blood samples over 3 h. Changes in incremental areas under the concentration curve (iAUC) and maximum concentrations (C_max) were compared.

RESULTS

Thirty individuals (12 women, mean age 59 years, HbA1c 7.1%, BMI 26.5 kg/m²) were enrolled and the MLE-based blend relative to the blend without MLE significantly reduced glucose iAUC at 1 h (- 20%, p < 0.0001), 2 h (- 17%, p = 0.0001), and 3 h (- 15%, p = 0.0032) and C_max [mean (95% CI) difference - 0.8 (- 1.2, - 0.3) mmol/L, p = 0.0006]. A statistically significant reduction in 1 h insulin iAUC (- 24%, p = 0.0236) was observed, but this reduction was no longer present at either 2 h or 3 h. No difference in GLP-1 was seen, but GIP response (iAUC and C_max) was less with the MLE-based blend.

CONCLUSIONS

The observation of a significant glucose reduction paralleled with a significant lower insulin response supports a reduced gastrointestinal glucose absorption. These results support the use of a 2-g natural blend of MLE, fiber, vitamin D, and chromium in T2D as a convenient dietary adjuvant to improve PP glucometabolic response.

CLINICALTRIALS

gov identifier NCT04877366.

Dose-response efficacy of mulberry fruit extract for reducing post-prandial blood glucose and insulin responses: randomised trial evidence in healthy adults

Extracts of mulberry have been shown to reduce post-prandial glucose (PPG) and insulin (PPI) responses, but reliability of these effects and required doses and specifications are unclear. We previously found that 1·5 g of a specified mulberry fruit extract (MFE) significantly reduced PPG and PPI responses to 50 g carbohydrate as rice porridge, with no indications of intolerance. The trials reported here aimed to replicate that work and assess the efficacy of lower MFE doses, using boiled rice as the carbohydrate source. Two separate randomised controlled intervention studies were carried out with healthy Indian males and females aged 20-50 years (n 84 per trial), with PPG area under the curve over 2 h as the primary outcome. Trial 1 used doses of 0, 0·37, 0·75, 1·12 and 1·5 g MFE in boiled rice and 0 or 1·5 g MFE in rice porridge. Trial 2 used doses of 0, 0·04, 0·12, 0·37 g MFE in boiled rice. In trial 1, relative to control, all MFE doses significantly decreased PPG (-27·2 to -22·9 %; all P ≤ 0·02) and PPI (-34·6 to -14·0 %, all P < 0·01). Breath hydrogen was significantly increased only at 1·5 g MFE (in rice porridge), and self-reported gastrointestinal symptoms were uniformly low. In trial 2, only 0·37 g MFE significantly affected PPG (-20·4 %, P = 0·002) and PPI (-17·0 %, P < 0·001). Together, these trials show that MFE in doses as low as 0·37 g can reliably reduce PPG and PPI responses to a carbohydrate-rich meal, with no apparent adverse effects.

Effects of the timing of acute mulberry leaf extract intake on postprandial glucose metabolism in healthy adults: a randomised, placebo-controlled, double-blind study

BACKGROUND/OBJECTIVES

Glucose tolerance is controlled by the internal clock and is worse in the evening. From a chrononutrition perspective, diabetes prevention requires evaluating the antidiabetic effects of the timing of functional ingredients and nutrient intake. The purpose of this study was to investigate the timing effects of acute mulberry leaf extract (MLE) intake on postprandial glucose levels in young adults.

SUBJECTS/METHODS

Twelve young adults underwent four trials. Blood samples were collected in a fasting state and at 30, 60, 120, and 180 min after eating a mixed meal. The study had a randomised, placebo-controlled, double-blind trial design involving: (1) morning placebo trial (08:00 h; MP trial), (2) evening placebo trial (18:00 h; EP trial), (3) morning MLE trial (08:00 h; MM trial), and (4) evening MLE trial (18:00 h; EM trial).

RESULTS

The incremental area under the blood glucose curve (iAUC) in the EM trials was significantly lower than that in the EP trials (P = 0.010). The postprandial glucose concentrations 120 min after the meal were significantly lower in the EM trials than those in the EP trials (P = 0.006). The postprandial insulin concentrations at 120 min were significantly lower in the MM trials than those in the MP trials (P = 0.034). Moreover, the postprandial insulin concentrations 180 min after the meal were significantly lower in the EM trials than those in the EP trials (P = 0.034).

CONCLUSIONS

MLE intake in the evening, but not in the morning, was effective in improving glucose tolerance.

TRIAL REGISTRATION

Clinical trial reference: UMIN 000045301; website of trial registry: https://center6.umin.ac.jp/cgi-open-bin/ctr/ctr_view.cgi?recptno=R000051340 .

The anti-obesity effect of mulberry leaf (Mori Folium) extracts was increased by bioconversion with Pectinex

Mulberry leaf (Mori Folium) extract (MLE) is known to have anti-obesity effects. In this study, the enhanced effects of MLE after bioconversion treatment using Pectinex (BMLE) on obesity were explored, and the underlying mechanisms were investigated using the active components, neochlorogenic acid (5-CQA) and cryptochlorogenic acid (4-CQA), whose amounts were increased by bioconversion of MLE. Both MLE and BMLE inhibited lipid accumulation in 3T3-L1 adipocytes without cytotoxicity and suppressed the expression of CCAAT/enhancer-binding protein alpha (C/EBPα). In addition, MLE and BMLE decreased high-fat diet-induced adipose tissue mass expansion. Notably, BMLE significantly increased antiadipogenic and anti-obesity effects compared to MLE in vitro and in vivo. The active ingredients increased by bioconversion, 5-CQA and 4-CQA, inhibited the protein levels of C/EBPα and the mRNA levels of stearoyl-CoA desaturase 1 (Scd1). These findings provide new insights into the therapeutic possibility of using bioconversion of MLE, by which upregulation of 5-CQA and 4-CQA potently inhibits adipogenesis.

The role of selected nutraceuticals in management of prediabetes and diabetes: An updated review of the literature

Dysglycemia is a disease state preceding the onset of diabetes and includes impaired fasting glycemia and impaired glucose tolerance. This review aimed to collect and analyze the literature reporting the results of clinical trials evaluating the effects of selected nutraceuticals on glycemia in humans. The results of the analyzed trials, generally, showed the positive effects of the nutraceuticals studied alone or in association with other supplements on fasting plasma glucose and post-prandial plasma glucose as primary outcomes, and their efficacy in improving insulin resistance as a secondary outcome. Some evidences, obtained from clinical trials, suggest a role for some nutraceuticals, and in particular Berberis, Banaba, Curcumin, and Guar gum, in the management of prediabetes and diabetes. However, contradictory results were found on the hypoglycemic effects of Morus, Ilex paraguariensis, Omega-3, Allium cepa, and Trigonella faenum graecum, whereby rigorous long-term clinical trials are needed to confirm these data. More studies are also needed for Eugenia jambolana, as well as for Ascophyllum nodosum and Fucus vesiculosus which glucose-lowering effects were observed when administered in combination, but not alone. Further trials are also needed for quercetin.

Metabolic Fate and Expectation of Health Benefits of [U-14C]-Sucrose Inhibited from Digestion Using Morus alba Leaf Extract

Morus alba leaf extract (MLE), a strong inhibitor of sucrase, suppresses blood glucose elevation following sucrose ingestion. To investigate that sucrose inhibited from digestion using MLE is utilized through gut microbiota, [U-¹⁴C]-sucrose solutions with or without MLE were administered orally to conventional and antibiotic-treated rats, and the excretion of ¹⁴CO₂ and H₂ produced by gut microbiota was measured for 24 h. After an administration of [U-¹⁴C]-sucrose to conventional rats, the unit excreted ¹⁴CO₂ peaked at 4 h, and the cumulative ¹⁴CO₂ excreted over 24 h was approximately 60% of the radioactivity administered. No H₂ was excreted. Following an administration of [U-¹⁴C]-sucrose and MLE in conventional rats, the unit excreted ¹⁴CO₂ peaked later, at 8 h, and was significantly lower (p<0.05). The cumulative ¹⁴CO₂ excreted over 24 h was equal in both groups, although there was a time lag of 2-3 h in rats given [U-¹⁴C]-sucrose and MLE. The amount of H₂ excreted by these rats peaked 8 h after administration. Following the administration of [U-¹⁴C]-sucrose and MLE to antibiotic-treated rats, the unit excreted ¹⁴CO₂ peaked lower, and the cumulative ¹⁴CO₂ excretion over 24 h was approximately 40%. In this group, H₂ was minimally excreted. H₂ and ¹⁴CO₂ produced by gut microbiota were excreted simultaneously. In conclusion, sucrose inhibited from digestion using MLE was fermented spontaneously by gut microbiota and was not excreted into feces. In addition, it confirmed that H₂ excretion could be used directly to indicate the degree of fermentation of nondigestible carbohydrates.

13C-sucrose breath test for the non-invasive assessment of environmental enteropathy in Zambian adults

Objectives

Environmental enteropathy (EE) is a subclinical disorder highly prevalent in tropical and disadvantaged populations and is thought to play a role in growth faltering in children, poor responses to oral vaccines, and micronutrient deficiencies. This study aims to evaluate the potential of a non-invasive breath test based on stable isotopes for evaluation of impaired digestion and absorption of sucrose in EE.

Methods

We optimized a ¹³C-sucrose breath test (¹³C-SBT) in 19 young adults in Glasgow, United Kingdom. In a further experiment (in 18 adults) we validated the ¹³C-SBT using Reducose, an intestinal glucosidase inhibitor. We then compared the ¹³C-SBT to intestinal mucosal morphometry, immunostaining for sucrose-isomaltase (SI) expression, and SI activity in 24 Zambian adults with EE.

Results

Fully labeled sucrose (0.3 mg/kg) provided clear breath enrichment signals over 2–3 h in both British and Zambian adults, more than fivefold higher than naturally enriched sucrose. Reducose dramatically impaired ¹³C-sucrose digestion, reducing 4 h ¹³CO₂ breath recovery by > 50%. Duodenal biopsies in Zambian adults confirmed the presence of EE, and SI immunostaining was present in 16/24 adults. The kinetics of ¹³CO₂ evolution were consistently faster in participants with detectable SI immunostaining. Although sucrase activity was strongly correlated with villus height (r = 0.72; P < 0.05) after adjustment for age, sex and body mass index, there were no correlations between ¹³C-SBT and villus height or measured sucrase activity in pinch biopsies.

Conclusion

A ¹³C-SBT was developed which was easy to perform, generated clear enrichment of ¹³CO₂ in breath samples, and clearly reports sucrase activity. Further work is needed to validate it and understand its applications in evaluating EE.

Morus alba L. for Blood Sugar Management: A Systematic Review and Meta-Analysis

Introduction

Morus alba L. is used for blood sugar management in patients with diabetes mellitus. This review aimed to evaluate the effect of Morus alba on blood sugar management.

Methods

This review was conducted in accordance with the Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols (PRISMA-P). We searched PubMed, EMBASE, and four Korean medical databases (RISS, OASIS, NDSL, and KISS) using relevant keywords. Randomized controlled trials with any type of control intervention were included. The selection of studies, data extraction, and quality assessment were performed independently by two researchers.

Results

Our results showed that Morus alba can reduce postprandial glucose and insulin levels. However, it is insufficient to conclude that Morus alba is an effective intervention for lowering blood glucose levels. Therefore, more rigorous studies are needed to reveal the effect of MA on blood glucose levels.

Conclusion

The conclusion of this review provides evidence that Morus alba can control blood sugar level. This systematic review was registered with the International Prospective Register of Systematic Reviews (PROSPERO) (CRD42021255940).

Could Dietary Modification Independent of Energy Balance Influence the Underlying Pathophysiology of Type 2 Diabetes? Implications for Type 2 Diabetes Remission

High-quality clinical trial data demonstrate that remission is possible for people living with type 2 diabetes (T2D) if they lose a large amount of weight (≥ 10 kg). Durable remission appears predicated on the long-term maintenance of weight loss. Unfortunately, long-term follow-up data from lifestyle-based weight loss programmes show that, on average, most people regain at least some of the weight lost. In addition, restoration of a diminished first-phase insulin response also appears necessary for durable remission, and this becomes less likely as T2D progresses. A pragmatic approach to enhance the effects of weight loss on durable remission is to consider whether dietary components could help control blood glucose, independent of caloric balance. This manuscript reviews current evidence on weight-neutral effects of diet on blood glucose, including high-protein, low-carbohydrate, high-fibre and plant-based diets, with a particular focus on the effect of nutrition on the underlying pathophysiology of T2D, including the first-phase insulin response. The importance of mechanistic data in enhancing our understanding of dietary strategies in T2D remission is described, and suggestions are made for future advances in remission research.

Antidiabetic Phytochemicals From Medicinal Plants: Prospective Candidates for New Drug Discovery and Development

Diabetes, a chronic physiological dysfunction affecting people of different age groups and severely impairs the harmony of peoples' normal life worldwide. Despite the availability of insulin preparations and several synthetic oral antidiabetic drugs, there is a crucial need for the discovery and development of novel antidiabetic drugs because of the development of resistance and side effects of those drugs in long-term use. On the contrary, plants or herbal sources are getting popular day by day to the scientists, researchers, and pharmaceutical companies all over the world to search for potential bioactive compound(s) for the discovery and development of targeted novel antidiabetic drugs that may control diabetes with the least unwanted effects of conventional antidiabetic drugs. In this review, we have presented the prospective candidates comprised of either isolated phytochemical(s) and/or extract(s) containing bioactive phytoconstituents which have been reported in several in vitro, in vivo, and clinical studies possessing noteworthy antidiabetic potential. The mode of actions, attributed to antidiabetic activities of the reported phytochemicals and/or plant extracts have also been described to focus on the prospective phytochemicals and phytosources for further studies in the discovery and development of novel antidiabetic therapeutics.

A Narrative Review of Human Clinical Trials on the Impact of Phenolic-Rich Plant Extracts on Prediabetes and Its Subgroups

Phenolic-rich plant extracts have been demonstrated to improve glycemic control in individuals with prediabetes. However, there is increasing evidence that people with prediabetes are not a homogeneous group but exhibit different glycemic profiles leading to the existence of prediabetes subgroups. Prediabetes subgroups have been identified as: isolated impaired fasting glucose (IFG), isolated impaired glucose tolerance (IGT), and combined impaired fasting glucose and glucose intolerance (IFG/IGT). The present review investigates human clinical trials examining the hypoglycemic potential of phenolic-rich plant extracts in prediabetes and prediabetes subgroups. Artemisia princeps Pampanini, soy (Glycine max (L.) Merrill) leaf and Citrus junos Tanaka peel have been demonstrated to improve fasting glycemia and thus may be more useful for individuals with IFG with increasing hepatic insulin resistance. In contrast, white mulberry (Morus alba Linn.) leaf, persimmon (Diospyros kaki) leaf and Acacia. Mearnsii bark were shown to improve postprandial glycemia and hence may be preferably beneficial for individuals with IGT with increasing muscle insulin resistance. Elaeis guineensis leaf was observed to improve both fasting and postprandial glycemic measures depending on the dose. Current evidence remains scarce regarding the impact of the plant extracts on glycemic control in prediabetes subgroups and therefore warrants further study.

Ethanol extract of mulberry leaves partially restores the composition of intestinal microbiota and strengthens liver glycogen fragility in type 2 diabetic rats

BACKGROUND

Mulberry leaf as a traditional Chinese medicine is able to treat obesity, diabetes, and dyslipidemia. It is well known that diabetes leads to intestinal microbiota dysbiosis. It is also recently discovered that liver glycogen structure is impaired in diabetic animals. Since mulberry leaves are able to improve the diabetic conditions through reducing blood glucose level, it would be interesting to investigate whether they have any positive effects on intestinal microbiota and liver glycogen structure.

METHODS

In this study, we first determined the bioactive components of ethanol extract of mulberry leaves via high-performance liquid chromatography (HPLC) and liquid chromatography/mass spectrometry (LC/MS). Murine animal models were divided into three groups, normal Sprague-Dawley (SD) rats, high-fat diet (HFD) and streptozotocin (STZ) induced type 2 diabetic rats, and HFD/STZ-induced rats administered with ethanol extract of mulberry leaves (200 mg/kg/day). Composition of intestinal microbiota was analyzed via metagenomics by sequencing the V3-V4 region of 16S rDNAs. Liver glycogen structure was characterized through size exclusion chromatography (SEC). Both Student's t-test and Tukey's test were used for statistical analysis.

RESULTS

A group of type 2 diabetic rat models were successfully established. Intestinal microbiota analysis showed that ethanol extract of mulberry leaves could partially change intestinal microbiota back to normal conditions. In addition, liver glycogen was restored from fragile state to stable state through administration of ethanol extract of mulberry leaves.

CONCLUSIONS

This study confirms that the ethanol extract of mulberry leaves (MLE) ameliorates intestinal microbiota dysbiosis and strengthens liver glycogen fragility in diabetic rats. These finding can be helpful in discovering the novel therapeutic targets with the help of further investigations.

Efficacy and Safety of Mulberry Twig Alkaloids Tablet for the Treatment of Type 2 Diabetes: A Multicenter, Randomized, Double-Blind, Double-Dummy, and Parallel Controlled Clinical Trial

OBJECTIVE

This study aimed to evaluate the efficacy and safety of mulberry twig alkaloids (Sangzhi alkaloids [SZ-A]) in the treatment of type 2 diabetes (T2D).

RESEARCH DESIGN AND METHODS

This was a multicenter, randomized, double-blind, double-dummy, and parallel controlled noninferiority clinical trial that was conducted for 24 weeks. A total of 600 patients were randomly allocated to the SZ-A group (n = 360) or acarbose group (n = 240). The primary efficacy end point was the change of glycosylated hemoglobin (HbA_1c) compared with baseline. In addition, adverse events (AEs), severe AEs (SAEs), treatment-related AEs (TAEs), and gastrointestinal disorders (GDs) were monitored.

RESULTS

After treatment for 24 weeks, the change in HbA_1c was -0.93% (95% CI -1.03 to -0.83) (-10.2 mmol/mol [-11.3 to -9.1]) and -0.87% (-0.99 to -0.76) (-9.5 mmol/mol [-10.8 to -8.3]) in the SZ-A and acarbose groups, respectively, and the least squares mean difference was -0.05% (95% CI -0.18 to 0.07) (-0.5 mmol/mol [-2.0 to 0.8]) between the two groups, with no significant difference on the basis of covariance analysis (P > 0.05). The incidence of TAEs and GDs was significantly lower in the SZ-A group than the acarbose group (P < 0.01), but no differences for AEs or SAEs between the two groups were observed (P > 0.05).

CONCLUSIONS

SZ-A exhibited equivalent hypoglycemic effects to acarbose in patients with T2D. Nevertheless, the incidence of TAEs and GDs was lower following SZ-A treatment than acarbose treatment, suggesting good safety.

Mulberry leaf extract improves glycaemic response and insulaemic response to sucrose in healthy subjects: results of a randomized, double blind, placebo-controlled study

Background

There are many benefits of maintaining healthy blood glucose levels, and studies have shown that lifestyle changes such as changes to diet can successfully restore normoglycaemia in participants with dysglycaemia. Significant health-related lifestyle changes are often difficult to implement and functional ingredients that can reduce glycaemic and insulaemic responses may help at risk populations. The aim of this study was to investigate whether a mulberry leaf extract could lower the glycaemic and insulinaemic responses to 75 g sucrose in healthy individuals.

Methods

A double-blind, randomised, placebo-controlled, crossover design trial was conducted by the Oxford Brookes Centre for Nutrition and Health. Thirty-eight participants were recruited into the trial and, after an overnight fast, were given 75 g sucrose + white mulberry leaf extract, or 75 g sucrose alone. Capillary blood samples were collected at 15-min intervals in the first hour and at 30-min intervals over the second hour to determine glucose and plasma insulin levels. Data analysis was conducted using a paired samples T test or a Wilcoxon signed rank test.

Results

The addition of mulberry leaf extract to sucrose resulted in a significantly lower glycaemic response and insulinaemic response compared to a matched placebo (sucrose alone). The change in blood glucose measurements were significantly lower at 15 min (p < 0.001), 30 min (p < 0.001), 45 min (p = 0.008), and 120 min (p < 0.001) and plasma insulin measurements were significantly lower at 15 min (p < 0.001), 30 min (p < 0.001), 45 min (p < 0.001), 60 min (p = 0.001) and 120 min (p < 0.001). The glucose iAUC (− 42%, p = 0.001), insulin iAUC (− 40%, p < 0.001), peak glucose (− 40.0%, p < 0.001) and peak insulin (− 41%, p < 0.001) from baseline were significantly lower for white mulberry leaf extract compared with the placebo. White mulberry leaf extract was well tolerated and there were no reported adverse events.

Conclusions

Mulberry leaf extract can be used as part of lifestyle changes that may lead to healthy blood glucose levels.

Trial registration: ISRCTN99601810 (23 October 2020, retrospectively registered)

The effect of 8 plant extracts and combinations on post-prandial blood glucose and insulin responses in healthy adults: a randomized controlled trial

BACKGROUND

Lower post-prandial glucose (PPG) and insulin (PPI) responses to foods are associated with reduced diabetes risk and progression. Several plant extracts have been proposed to reduce PPG or PPI by inhibiting enzymes or transporters involved in carbohydrate digestion and uptake. This study evaluates a range of such extracts, consumed with a carbohydrate load, for their effects on PPG, PPI and indicators of (gastrointestinal) tolerance.

METHODS

Interventions were extracts of mulberry fruit (MFE, 1.5 g), mulberry leaf (MLE, 1.0 g), white bean (WBE, 3.0 g), apple (AE, 2.0 g), elderberry (EE, 2.0 g), turmeric (TE, 0.18 g), AE + TE, and EE + TE. Each of these 8 individual extracts or combinations were added to a rice porridge containing ~ 50 g available carbohydrate (control). In a within-subject (randomised, balanced incomplete block) design, individual subjects received the control and a subset of 4 of the 8 extracts or combinations. Participants were 72 apparently healthy adults (mean [SD] age 31.2 [5.5] yr, body mass index 22.1 [2.0] kg/m2). The primary outcome was the percentage change in 2-h PPG (positive incremental area under the curve) relative to control. Secondary measures were the 2-h PPI response, 7-h breath hydrogen, measures of gastrointestinal discomfort, and urine glucose.

RESULTS

In the 65 subjects who completed the control and at least one intervention treatment, additions of AE, MFE and MLE produced statistically significant reductions in PPG vs control (p < 0.05; mean effect - 24.1 to - 38.1%). All extracts and combinations except TE and WBE significantly reduced PPI (p < 0.01; mean effect - 17.3% to - 30.4%). Rises in breath hydrogen > 10 ppm were infrequent, but statistically more frequent than control only for MLE (p = 0.02). Scores for gastrointestinal discomfort were extremely low and not different from control for any treatment, and no glucosuria was observed.

CONCLUSIONS

Additions of AE, MFE and MLE to rice robustly reduced PPG and PPI. EE significantly reduced only PPI, while TE and WBE showed no significant efficacy for PPG or PPI. Breath hydrogen responses to MLE suggest possible carbohydrate malabsorption at the dose used, but there were no explicit indications of intolerance to any of the extracts.

TRIAL REGISTRATION

ClinicalTrials.gov identifier NCT04258501. Registered 6 February 2020 - Retrospectively registered.

Comparison Among Garlic, Berberine, Resveratrol,Hibiscus sabdariffa, GenusZizyphus, Hesperidin, Red Beetroot,Catha edulis,Portulaca oleracea, and Mulberry Leaves in the Treatment of Hypertension and Type 2 DM: A Comprehensive Review

Diabetes mellitus (DM) and hypertension are 2 of the most prevalent diseases with poor impact on health status worldwide. In most cases, they coexist with other metabolic disorders as well as cardiac, micro- and macrovascular complications. Many plants are known for their hypotensive, cardioprotective, and/or antidiabetic activities. Their active ingredients either identified and isolated or still utilized as herbal preparations of certain plant parts. The use of medicinal plants comprises the main basis for most of the traditional medicine (TM) systems and procedures. As conventional medicines seem insufficient to control such progressive diseases, herbal agents from TM could be used as adjuvant with good impact on disease control and progression as well as other concomitant health conditions. The aim of this study is to compare the efficacy of 10 different herbal medicines of botanical origin or herbal preparations in the management of hypertension and its cardiovascular complications and type 2 DM along with various coexisting health disorders. These herbal medicines are garlic, berberine, resveratrol, Hibiscus sabdariffa, Zizyphus ( oxyphylla, mucronate, jujube, rugosa), hesperidin, red beetroot, Catha edulis, mulberry leaves, and Portulaca oleracea.

Correlations between Microbiota Bioactivity and Bioavailability of Functional Compounds: A Mini-Review

Numerous studies have demonstrated the role of the microbiota in supporting the physiological functions, owing to its metabolomic component. The presence of biocomponents generally leads to the correction of the microbial pattern correlated with the reduction of oxidative pressure. This study aims to present the main processes that correlate the bioavailability and bioactivity of some functional components through the action of the human microbiota. The use of probiotics and prebiotics is an innovative manner involving alternatives that increase the bioavailability of certain natural or metabolic components has been proposed. Probiotic strains (Saccharomyces cerevisiae or Lactobacillus (L.) plantarum) may represent an intermediary for increasing the antioxidant bioactivity, and they may be administered in the form of a biomass enriched with functional compounds, such as phenolic acids. The limiting effect of gastrointestinal transit is, in several cases, the key to the biopharmaceutical value of new products (or supplements). The identification of newer ways of formulating supplements also involves the compatibility of different types of products, the testing of bioaccessibility, and the elimination of biotransformations.

The structure-activity relationship review of the main bioactive constituents of Morus genus plants

Abstract

Morus genus plants are mainly distributed in the temperate to tropical areas over the world and include 17 species and two subspecies. Due to their excellent pharmacological activity, security in food additives and high value in the national economy, Morus genus plants have drawn more and more attention in recent years. In the light of the references published over the last few decades, flavonoids, benzofurans, stilbenes, and Diels–Alder adducts have been reported to be the main bioactive constituents of Morus genus plants. This review summarizes the compounds with excellent bioactivities isolated from Morus genus plants as well as their structure–activity relationships (SARs), which might be useful for the further research and development of Morus genus plants.

Graphic abstract

The aromatic heterocycles with excellent bioactivities isolated from Morus genus plants as well as their structure–activity relationships (SARs) were summarized.

An Overview of Disease Burden, Mechanism, Traditional and Non-traditional Management of Type 2 Diabetes

Diabetes is a major global health problem leading to high morbidity, mortality, and economic burden. Diabetes is connected to complex social, environmental, and behavioral factors and requires multisectoral evidence-based strategies to reduce its incidence and prevalence. Here we attempt to connect existing diabetes data with the underlying mechanism of the disease, while touching disease processes and traditional management approaches for diabetes and its complications. The major objective of this manuscript is to examine the effect of nontraditional treatment modalities, e.g. non-pharmaceutical interventions, supplements, alternative and integrative therapies etc., on diabetes. We performed an extensive literature search and review using electronic databases (PubMed and Google Scholar) to examine recent and historical diabetes statistics, the underlying mechanism of the disease, traditional treatments, remission possibility, and finally, the role of alternative therapies and supplements in its management. We found that there is no sufficient evidence to make most of the alternative therapies the first line of management and prevention approach for diabetes. Long-term and large-scale studies are needed to evaluate the safety and efficacy of alternative medicine. We feel that this review could urge other health researchers to plan comprehensive studies to examine the role of alternative or newly-identified therapies in diabetes. Also, this information can be useful for diverse health professionals and policymakers in developing and implementing evidence-based strategies.

1-Deoxynojirimycin improves high fat diet-induced nonalcoholic steatohepatitis by restoring gut dysbiosis

Non-alcoholic steatohepatitis (NASH) is associated with chronic inflammation and gut bacterial dysbiosis. Studies show that 1-deoxynojirimycin (DNJ) may improve NASH, yet the role of gut microbiota in protective effect of DNJ on NASH remains to be known. In present study, we aimed to examine how DNJ ameliorated high-fat diet (HFD)-induced mouse NASH through the regulation of gut microbiota dysbiosis. C57BL/6 J mice fed with HFD were treated with DNJ (0.1 mg/mL, in drinking water) for 4 months. The results by using histochemical staining and qPCR confirmed that DNJ remarkably modulated glucose intolerance and hyperlipidemia, attenuated hepatic steatosis and systemic chronic inflammation in HFD-induced mice. Moreover, DNJ greatly reshaped the structure of disbalanced intestinal flora, as indicated by the enhanced bacterial richness and diversity, the decreased Firmicutes-to-Bacteroidetess ratio and the increased Akkermansia level. The prediction algorithm suggests that DNJ may extensively dampen the bacterial motility and bacterial energy metabolism. Consistently, the altered gut microbiota was closely correlated with metabolic biomarkers of mice with NASH. Based on our studies, DNJ could alleviate the progress of HFD-induced NASH by rebuilding the gut microbial community structure, suggesting that DNJ may serve as a functional food to prevent or treat NASH clinically.

Effects of unaltered and bioconverted mulberry leaf extracts on cellular glucose uptake and antidiabetic action in animals

Background

Mulberry is a Korean medicinal herb that shows effective prevention and treatment of obesity and diabetes. Bioconversion is the process of producing active ingredients from natural products using microorganisms or enzymes.

Methods

In this study, we prepared bioconverted mulberry leaf extract (BMLE) with Viscozyme L, which we tested in insulin-sensitive cells (i.e., skeletal muscle cells and adipocytes) and insulin-secreting pancreatic β-cells, as well as obese diabetic mice induced by co-administration of streptozotocin (100 mg/kg, IP) and nicotinamide (240 mg/kg, IP) and feeding high-fat diet, as compared to unaltered mulberry leaf extract (MLE).

Results

BMLE increased the glucose uptake in C2C12 myotubes and 3 T3-L1 adipocytes and increased glucose-stimulated insulin secretion in HIT-T15 pancreatic β-cells. The fasting blood glucose levels in diabetic mice treated with BMLE or MLE (300 and 600 mg/kg, PO, 7 weeks) were significantly lower than those of the vehicle-treated group. At the same concentration, BMLE-treated mice showed better glucose tolerance than MLE-treated mice. Moreover, the blood concentration of glycated hemoglobin (HbA_1C) in mice treated with BMLE was lower than that in the MLE group at the same concentration. Plasma insulin levels in mice treated with BMLE or MLE tended to increase compared to the vehicle-treated group. Treatment with BMLE yielded significant improvements in insulin resistance and insulin sensitivity.

Conclusion

These results indicate that in the management of diabetic condition, BMLE is superior to unaltered MLE due to at least, in part, high concentrations of maker compounds (trans-caffeic acid and syringaldehyde) in BMLE.

Electronic supplementary material

The online version of this article (10.1186/s12906-019-2460-5) contains supplementary material, which is available to authorized users.

Mulberry leaves and their potential effects against cardiometabolic risks: a review of chemical compositions, biological properties and clinical efficacy

CONTEXT

Cardiometabolic risks are regarded as the crucial factors associated with type 2 diabetes (T2DM) and cardiovascular diseases (CVD). Regarding an increased attention to medicinal plants in the current healthcare system, the effects of mulberry (Morus spp., Moraceae) leaves on cardiometabolic risks have been consecutively considered in scientific research.

OBJECTIVE

The present review compiles and summarizes the chemical compositions, biological properties and clinical efficacy of mulberry leaves that are related to the amelioration of cardiometabolic risks.

METHODS

Published English literature from the PubMed, Science Direct and Google Scholar databases was searched by using 'mulberry leaves' 'Morus spp.', 'hyperglycemia', 'hyperlipidemia', 'obesity', 'hypertension', 'oxidative stress', 'atherosclerosis' and 'cardiovascular diseases' as the keywords. The relevant articles published over the past two decades were identified and reviewed.

RESULTS

Mulberry leaves contain numerous chemical constituents. 1-Deoxynojirimycin (DNJ), phenolics and flavonoids are the prominent functional compounds. Preclinical and clinical studies showed that mulberry leaves possessed various beneficial effects against cardiometabolic risks, including antihyperglycaemic, antihyperlipidaemic, antiobesity, antihypertensive, antioxidative, anti-inflammatory, anti-atherosclerotic and cardioprotective effects.

CONCLUSIONS

Mulberry leaves could be a promising therapeutic option for modulating cardiometabolic risks. However, further investigations should be performed to substantiate the potential of mulberry leaves in practical uses.

Effect of different planting areas on the chemical compositions and hypoglycemic and antioxidant activities of mulberry leaf extracts in Southern China

Guangdong, Guangxi and Chongqing are emerging sericulture areas in China where the production of mulberry leaves is huge. In order to identity high quality mulberry leaves that are suitable for healthy products to expand planting, 24 samples from three regions (Guangdong, Guangxi, Chongqing) in the south of China were quantified for two alkaloids (1-deoxynojirimycin and fagomine) and five phenols (chlorogenic acid, rutin, isoquercitrin, etc.) using high-performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS). Additionally, the total phenolic and total flavonoid contents, antioxidant and glycosidase inhibitory activities (hypoglycemic activity) were tested using different assays (DPPH, ABTS, FRAP) to comprehensively evaluate the quality of the mulberry leaves. The contents of DNJ and fagomine ranged from 0.401±0.003 to 5.309±0.036 mg/g and from 0.279±0.031 to 2.300±0.060 mg/g, respectively. The main phenolic constituents were chlorogenic acid, rutin and isoquercitrin, with chlorogenic acid present in the highest concentrations, ranging from 3.104±0.191 to 10.050±0.143 mg/g. The antioxidant activity exhibited a tendency as follows: Guangxi > Guangdong > Chongqing, except for two samples from Chongqing, which showed the highest antioxidant activity. Based on our study, mulberry leaves from Guangdong and Guangxi could be future sources of natural hypoglycemic and antioxidant products.

Mulberry leaf extract decreases digestion and absorption of starch in healthy subjects-A randomized, placebo-controlled, crossover study

PURPOSE

Mulberry (Morus alba L.) leaf tea has recently received much attention as a dietary supplement due to the wide range of putative health benefits, such as antidiabetic effects. Nevertheless, data evaluating its influence on carbohydrate metabolism in humans are scarce. The present study aims to investigate the effect of mulberry leaf extract supplementation on starch digestion and absorption in humans.

MATERIALS AND METHODS

The study comprised of 25 healthy subjects, aged 19-27 years. In all subjects, a starch ¹³C breath test was performed twice in a crossover and single blind design. Subjects were initially randomized to ingest naturally ¹³C-abundant cornflakes (50g cornflakes+100ml low fat milk) either with the mulberry leaf extract (36mg of active component-1-deoxynojirimycin) or the placebo and each subject received the opposite preparation one week later.

RESULTS

The cumulative percentage dose recovery was lower for the mulberry leaf extract test than for the placebo test (median [quartile distribution]: 13.9% [9.9-17.4] vs. 17.2% [13.3-20.6]; p=0.015). A significant decrease was detectable from minute 120 after the ingestion.

CONCLUSIONS

A single dose of mulberry leaf extract taken with a test meal decreases starch digestion and absorption. These findings could possibly be translated into everyday practice for improvement of postprandial glycemic control.

Natural Health Products and Diabetes: A Practical Review

The prevalence of natural health product (NHP) use in Canada is extensive. Patients with chronic diseases, including diabetes, use NHPs at a higher rate than the general population. Many NHPs exert hypoglycemic effects, among other effects relevant to diabetes management. To provide a practical, clinical review of NHPs with such effects targeted to pharmacists, a literature search was performed to collect data on the efficacy and safety profiles of 10 commonly used NHPs that exert antidiabetic properties. The following NHPs are included in this clinical review: alpha-lipoic acid, chromium, magnesium, bitter melon, cinnamon, fenugreek, gymnema, milk thistle, Reishi mushroom and white mulberry. Given the potential of NHPs to additively cause hypoglycemia when used concurrently with conventional medications, pharmacists should be up to date with current evidence around NHPs that may affect diabetes care to prevent adverse reactions and interactions. In addition, effective and respectful communication with patients around NHP use and collaboration with various health-care providers are essential in the patient care process.

A novel botanical formula prevents diabetes by improving insulin resistance

Background

Type 2 diabetes mellitus (T2DM) is a major risk factor for cardiovascular disease, and the prevalence has increased significantly in recent decades to epidemic proportions in China. Individually, fenugreek (Trigonella foenum graecum) seed, mulberry (Morus alba L.) leaf and American ginseng (Panax quinquefolius) root can improve glycemia in various animal models and humans with impaired glucose metabolism and T2DM. The aim of this study was to design an optimized botanical formula containing these herbal extracts as a nutritional strategy for the prevention of insulin resistance and T2DM.

Methods

Cell-free α-amylase and α-glucosidase enzyme assays were used to determine inhibitory potential of extracts. Glucose uptake was examined in differentiated human adipocytes using radiolabeled 2-deoxyglucose. Male Sprague Dawley rats were divided and glycemia balanced into 5 groups: two controls (naïve and model) and three doses of the botanical test formula containing standardized fenugreek seed, mulberry leaf and American ginseng extracts (42.33, 84.66 and 169.33 mg/kg BW). Insulin resistance and T2DM was induced by feeding animals a high fat diet and with an alloxan injection. Glucose tolerance was examined by measuring serum glucose levels following an oral glucose load.

Results

Fenugreek seed and mulberry leaf dose dependently inhibited α-amylase (IC50 = 73.2 μg/mL) and α-glucosidase (IC50 = 111.8 ng/mL), respectively. All three botanical extracts improved insulin sensitivity and glucose uptake in human adipocytes, which lead to the design of an optimized botanical test formula. In a rat model of insulin resistance and T2DM, the optimized botanical test formula improved fasting serum glucose levels, fasting insulin resistance and the development of impaired glucose tolerance. The reduction in epididymal adipose tissue GLUT4 and PDK1 expression induced by high fat diet and alloxan was blunted by the botanical test formula.

Conclusions

A novel botanical formula containing standardized extracts of mulberry leaf, fenugreek seed and American ginseng at a ratio of 1:1.3:3.4 prevented the development of insulin resistance, impaired glucose tolerance and T2DM. Given the rising need for effective non-drug targeting of insulin resistance and progression to T2DM, complementary and alternative nutritional strategies without intolerable side effects could have meaningful impact on metabolic health and diabetes risks.

Impact of mulberry leaf extract on type 2 diabetes (Mul-DM): A randomized, placebo-controlled pilot study

AIMS

Mulberry leaves have been used anecdotally in Asia to treat many disease states, including glucose abnormalities. Animal and human studies illustrate potential benefit of mulberry leaf extract (MLE) in type 2 diabetes mellitus (DM2). The purpose of this study is to evaluate the glycemic and safety effects of MLE in patients with DM2.

MATERIALS & METHODS

This randomized, double-blind, placebo-controlled pilot study evaluated MLE (1000mg standardized) versus matching placebo given three times daily with meals. Patients (n=24) were included if they had DM2 on single or combination oral therapy with a stable hemoglobin A1C (A1C). A 2-week placebo run-in (baseline) was followed by initiation of randomized medication for 3 months. Primary endpoints were change in A1C and self-monitoring blood glucoses (SMBG). Safety was also evaluated.

RESULTS

Of 24 patients enrolled, 17 patients completed the study. Post-prandial SMBG was significantly decreased at 3 months in the MLE group versus baseline (16.1%; p<0.05). This improvement in post-prandial SMBG persisted when compared to placebo (18.2%; p<0.05). A1C decreased from 7.30% at baseline to 6.94% in the MLE group but did not reach statistical significance (p=0.079). There was no difference in A1C between MLE and placebo. A significant 15% increase occurred in serum creatinine when the MLE group was compared to baseline or placebo (p<0.05 for both). There was no significant effect on weight, fasting SMBG, blood pressure, hypoglycemia, or other safety evaluation markers.

CONCLUSIONS

These results suggest that mulberry leaf extract may be a useful complementary mealtime glucose option for patients with DM2. ClinicalTrials.gov Identifier NCT00795704.

Mulberry-extract improves glucose tolerance and decreases insulin concentrations in normoglycaemic adults: Results of a randomised double-blind placebo-controlled study

BACKGROUND

High sugar and refined carbohydrate intake is associated with weight gain, increased incidence of diabetes and is linked with increased cardiovascular mortality. Reducing the health impact of poor quality carbohydrate intake is a public health priority. Reducose, a proprietary mulberry leaf extract (ME), may reduce blood glucose responses following dietary carbohydrate intake by reducing absorption of glucose from the gut.

METHODS

A double-blind, randomised, repeat measure, phase 2 crossover design was used to study the glycaemic and insulinaemic response to one reference product and three test products at the Functional Food Centre, Oxford Brooks University, UK. Participants; 37 adults aged 19-59 years with a BMI ≥ 20kg/m2 and ≤ 30kg/m2. The objective was to determine the effect of three doses of mulberry-extract (Reducose) versus placebo on blood glucose and insulin responses when co-administered with 50g maltodextrin in normoglycaemic healthy adults. We also report the gastrointestinal tolerability of the mulberry extract.

RESULTS

Thirty-seven participants completed the study: The difference in the positive Incremental Area Under the Curve (pIAUC) (glucose (mmol / L x h)) for half, normal and double dose ME compared with placebo was -6.1% (-18.2%, 5.9%; p = 0.316), -14.0% (-26.0%, -2.0%; p = 0.022) and -22.0% (-33.9%, -10.0%; p<0.001) respectively. The difference in the pIAUC (insulin (mIU / L x h)) for half, normal and double dose ME compared with placebo was -9.7% (-25.8%, 6.3%; p = 0.234), -23.8% (-39.9%, -7.8%; p = 0.004) and -24.7% (-40.8%, -8.6%; p = 0.003) respectively. There were no statistically significant differences between any of the 4 groups in the odds of experiencing one or more gastrointestinal symptoms (nausea, abdominal cramping, distension or flatulence).

CONCLUSIONS

Mulberry leaf extract significantly reduces total blood glucose rise after ingestion of maltodextrin over 120 minutes. The pattern of effect demonstrates a classical dose response curve with significant effects over placebo. Importantly, total insulin rises were also significantly suppressed over the same time-period. There were no statistically significant differences between any of the treatment groups (including placebo) in the odds of experiencing one or more gastrointestinal symptoms. Mulberry extract may have multiple modes of action and further studies are necessary to evaluate ME as a potential target for the prevention of type 2 diabetes and the regulation of dysglycaemia.

Phase 1 and Pharmacokinetic Drug-Drug Interaction Study of Metformin, Losartan, and Linagliptin Coadministered With DW1029M in Healthy Volunteers

We investigated botanical drug-pharmaceutical drug interactions between DW1029M (a botanical extract of Morus alba linne root bark and Puerariae radix) and metformin, losartan, and linagliptin in the steady state. Three studies were conducted as randomized, open-label, 2-period, 2-treatment, multiple-dose, 2-way crossover designs. Eligible subjects received metformin (500 mg twice daily), losartan (50 mg once daily), or linagliptin (5 mg once daily) with DW1029M (300 mg × 2T twice daily) every 12 hours on days 1 through 6 and a single dose on the morning of day 7. Coadministration of DW1029M with metformin, losartan, or linagliptin had no clinically relevant effects based on the area under the plasma concentration-time curve (AUC_τ ) geometric least-squares mean ratio (GMR) - AUC_τ GMR, 89.7; 90% confidence interval (CI), 81.0-99.4 for metformin; AUC_τ GMR, 96.2; 90%CI, 86.3-107.1 for losartan; and AUC_τ GMR, 89.7; 90%CI, 83.2-96.6 for linagliptin. In addition, coadministration of DW1029M did not have any clinically meaningful effect on the maximum plasma concentration (C_max,ss ) - C_max,ss GMR, 87.3; 90%CI, 76.2-100.0 for metformin; C_max,ss GMR, 90.5; 90%CI, 78.3-104.6 for losartan; and C_max,ss GMR, 81.4; 90%CI, 69.5-95.3 for linagliptin. Coadministration of DW1029M with metformin, losartan, or linagliptin was well tolerated.

New potential phytotherapeutics obtained from white mulberry (Morus alba L.) leaves

The present work demonstrates the profound and unique phyto-pharmacological and nutritional profile of white mulberry (Morus alba L.) leaves which containing considerable amounts of easy digestive proteins, carbohydrates, micro- and macronutrients, polyphenols, free amino acids, organic acids. The wide range of significant biopharmaceutical activities of the aqueous and polar organic solvents extracts from mulberry leaves - including antidiabetic, antibacterial, anticancer, cardiovascular, hypolipidemic, antioxidant, antiatherogenic, and anti-inflammatory - have been critically discussed. The main objective was to demonstrate the results of recently published study on the components of white mulberry leaves exhibiting their biological activity in the various pathological and health human ailments. In addition, we intend to drawn the attention of researchers and public health workers for the extended exploration of this deciduous plant leaves as the source of potential indigenous nutraceuticals and functional food products to enable development of alternative prevention and treatment protocols offered in therapy of the common non-communicable diseases and malignances.

Mulberry extract to modULate Blood glucosE Responses in noRmoglYcaemic adults (MULBERRY): study protocol for a randomised controlled trial

BACKGROUND

Worldwide sugar consumption has tripled during the last fifty years. High sugar intake is associated with weight gain and increased incidence of diabetes and has been linked with increased cardiovascular mortality. Reducing the health impact of dietary sugar and poor quality carbohydrate intake is a public health priority. IminoNorm®, a proprietary mulberry leaf extract (ME), may reduce blood glucose responses following dietary sugar and carbohydrate intake by reducing absorption of glucose from the gut. Previous research has shown that ME can reduce blood glucose and improve insulin responses in healthy subjects and also in subjects with raised fasting blood glucose levels. Mulberry leaf has an excellent safety profile. This pilot study will test a novel, safe, water soluble product in normoglycaemic adults in the UK to determine if it can reduce glucose absorption without increasing plasma insulin concentration.

METHODS/DESIGN

The trial will be a double-blind, individually randomised, four-arm single-dose crossover design to test the effect of three doses of ME in order to determine efficacy, dose response relationship and gastrointestinal side effects with respect to placebo. A total of 40 subjects will participate in this study and attend for four visits receiving each of the four interventions in random order.

DISCUSSION

We aim to test the evidence that mulberry leaf extract can reduce blood glucose without a disproportionate increase in blood insulin responses in healthy individuals in a high-quality research study based in the UK. It is hoped that this will lead to further randomised controlled trials and an effective dietary supplement to lower blood glucose concentrations.

TRIAL REGISTRATION

ISRCTN

ISRCTN14597438 (21 April 2015).

Mulberry and mulberry wine extract increase the number of mitochondria during brown adipogenesis

Mulberry extract (ME) has been shown to possess beneficial effects towards obesity, but its mechanism is still unclear.