Salacia reticulata (Kothala himbutu) revisited; a missed opportunity to treat diabetes and obesity?

In vitro and in silico analysis proving DPP4 inhibition and diabetes-associated gene network modulation by a polyherbal formulation: Nisakathakadi Kashaya

Dipeptidyl-peptidase IV (DPP4) inhibitors are an important class of anti-diabetic drugs recognised for their systemic biological actions. Polyherbal preparations like Ayurveda formulations are considered to be ideal sources for discovering novel DPP4 inhibitors owing to their rich phytochemical composition. The current study reports the DPP4 inhibitory potential of a clinically established Ayurvedic anti-diabetic formulation Nisakathakadi Kashaya (NK) using in vitro assay and substantiates it by identifying potential bioactives responsible for DPP4 inhibition using computational biology tools. NK showed a dose-dependent DPP4 inhibition with an IC50 of 2.06 μg GAE/mL, and the molecular docking and simulation studies showed three compounds, namely Terchebin, Locaracemoside B and 1,2,4,6 Tetra o Galloyl Beta D Glucose having stable interactions with DPP4 similar to the standard drug Vildagliptin. Further, for the reason that polyherbal formulations exert a network pharmacology mode of action, in silico analysis was carried out to identify the other putative phytochemical-protein networks modulated by NK. The complex pharmacological network of the formulation was explored further using a subnetwork of diabetes proteins and their relationship with diabetes-associated comorbidities. A number of key targets like TNFα, TGFβ1, SOD1, SOD2, AKT1, DPP4 and GLP1R were identified in the protein-protein interaction network that is vital to diabetic progression and complications. A combination of in vitro and in silico methods allowed us to prove the DPP4 inhibition potential of NK as well as provided insights into the possible pharmacological networking through which NK potentially exerts its systemic effect in diabetes management.Communicated by Ramaswamy H. Sarma.

The Effect of Salacia Reticulata Extract Biscuits on Blood Sugar Control of Type 2 Diabetes Mellitus Patients: A Two-Period, Two-Sequence, Crossover, Randomized, Triple-Blind, Placebo-Controlled, Clinical Trial

Background Traditional physicians in Sri Lanka and India use extracts from the plant Salacia reticulata,or Kothala Himbutu (KH) to treat diabetes. The effect of a KH biscuit, taken as a snack, on glycemic control was investigated in patients with type 2 diabetes. Methodology This triple-blind, randomized, placebo-controlled, two-period, two-sequence, crossover study was conducted in the Internal Medical Clinic, Teaching Hospital Anuradhapura. A research assistant opened computer-generated random numbers enclosed in a sealed envelope and performed treatment allocation. The group outcome was masked from the researchers, patients, and analysts. Both the placebo and the KH biscuit were identical. The primary outcome measure was HbA1c. Intention to treat analyses was used. Glycemic stability was assured in the run-in period, and patients with severe renal, liver, or heart disease were excluded. If patients needed insulin, they were withdrawn from the trial. Results From January 2014 to May 2016, 230 patients were screened, and 136 were randomized. Of them, 62 were allocated, 58 completed the placebo biscuit, 71 were allocated, and 69 completed the KH biscuit. After the washout period and crossover, 57 completed the KH and 65 completed the placebo biscuit. The baseline mean HbA1c level was 8.45% (68.9 mmol/mol) and 8.65% (71.0 mmol/mol) for the placebo-KH biscuit and KH-placebo biscuit groups. At the end of the trial, the HbA1c levels in the placebo-KH biscuit group and the KH-placebo biscuit group were 8.23% (66.4 mmol/mol) and 8.53% (69.3 mmol/mol), respectively. The unadjusted mean HbA1c reduced from the baseline with 0.10% (95% CI = -0.12, 0.32) after the placebo biscuit and 0.35% (95% CI = 0.10, 0.60) after the KH biscuit. After the placebo and KH biscuits, the HbA1c values were 8.46% (95% CI = 8.19, 8.73) (69 mmol/mol with 95% CI = 66, 72) and 8.19% (95% CI = 7.90, 8.48) (66 mmol/mol with 95% CI = 63, 69), respectively. The paired sample t-test shows that the reduction was not significant for placebo biscuits (p = 0.324), while it is significant for KH biscuits (p = 0.003). Analysis with multiple imputations confirmed a significant difference between the placebo and KH biscuit in reducing the HbA1c level. Conclusions KH biscuit taken as a snack reduces HbA1c by 0.25% compared to placebo without serious renal or liver adverse effects. The biscuit can be safely recommended as a snack to patients with type 2 diabetes.

Pleiotropic effects of Salacia reticulata and Simvastatin on oxidative stress and insulin resistance in a rat model

BACKGROUND

The present study investigated the effects of Salacia reticulata and simvastatin on oxidative stress and insulin resistance in Sprague-Dawley (SD) rats. We compared the protective effect of a methanolic extract of Salacia reticulata (SR) with simvastatin (SVS) in rats fed a high-fat diet (HFD).

METHODS AND RESULTS

Male Sprague-Dawley rats were divided into the following five different groups: control (C), C+SR, HFD, HFD+SR, and HFD+SVS. High-fat diet fed rats showed hyperglycemia, hyperinsulinemia, hyperleptinemia, dyslipidemia, and hypoadiponectinemia after 90 days. Treatment of high-fat diet fed rats with SR/SVS significantly (p < 0.05) reduced high-fat diet induced increases in plasma triglycerides, total cholesterol, very-low-density lipoprotein (VLDL), low-density lipoprotein (LDL) and decreased high- density lipoprotein (HDL) accompanied by an increase in lipid peroxidation (LPO) and protein oxidation. In addition, a significant decrease in the activities of antioxidant enzymes and enzymes of the polyol pathway was observed in rats fed high-fat diet. SR was found to be more effective than SVS. Moreover, infiltration of inflammatory cells and fibrosis in the liver of high-fat diet fed rats by SR/SVS were also prevented.

CONCLUSIONS

The present study confirms that SR/SVS may be a new and promising remedial approach because of its beneficial effects on the pathophysiological processes of obesity and related metabolic disorders.

Targeting N-Terminal Human Maltase-Glucoamylase to Unravel Possible Inhibitors Using Molecular Docking, Molecular Dynamics Simulations, and Adaptive Steered Molecular Dynamics Simulations

There are multiple drugs for the treatment of type 2 diabetes, including traditional sulfonylureas biguanides, glinides, thiazolidinediones, α-glucosidase inhibitors, glucagon-like peptide-1 (GLP-1) receptor agonists, dipeptidyl peptidase IV (DPP-4) inhibitors, and sodium-glucose cotransporter 2 (SGLT2) inhibitors. α-Glucosidase inhibitors have been used to control postprandial glucose levels caused by type 2 diabetes since 1990. α-Glucosidases are rather crucial in the human metabolic system and are principally found in families 13 and 31. Maltase-glucoamylase (MGAM) belongs to glycoside hydrolase family 31. The main function of MGAM is to digest terminal starch products left after the enzymatic action of α-amylase; hence, MGAM becomes an efficient drug target for insulin resistance. In order to explore the conformational changes in the active pocket and unbinding pathway for NtMGAM, molecular dynamics (MD) simulations and adaptive steered molecular dynamics (ASMD) simulations were performed for two NtMGAM-inhibitor [de-O-sulfonated kotalanol (DSK) and acarbose] complexes. MD simulations indicated that DSK bound to NtMGAM may influence two domains (inserted loop 1 and inserted loop 2) by interfering with the spiralization of residue 497–499. The flexibility of inserted loop 1 and inserted loop 2 can influence the volume of the active pocket of NtMGAM, which can affect the binding progress for DSK to NtMGAM. ASMD simulations showed that compared to acarbose, DSK escaped from NtMGAM easily with lower energy. Asp542 is an important residue on the bottleneck of the active pocket of NtMGAM and could generate hydrogen bonds with DSK continuously. Our theoretical results may provide some useful clues for designing new α-glucosidase inhibitors to treat type 2 diabetes.

Novel Phytochemical Constituents and their Potential to Manage Diabetes

BACKGROUND

Diabetes is a chronic disease affecting a large population worldwide and stands as one of the major global health challenges to be tackled. According to World Health Organization, about 400 million are having diabetes worldwide and it is the seventh leading cause of deaths in 2016. Plant-based natural products have been in use from ancient times as ethnomedicine for the treatment of several diseases, including diabetes. As a result of that, there are several reports on plant-based natural products displaying antidiabetic activity. In the current review, such antidiabetic potential compounds reported from all plant sources along with their chemical structures are collected, presented and discussed. These kinds of reports are essential to pool the available information to one source, followed by statistical analysis and screening to check the efficacy of all known compounds in a comparative sense. This kind of analysis can give rise to a few potential compounds from hundreds, which can further be screened through in vitro and in vivo studies, and human trails leading to the drug development.

METHODS

Phytochemicals, along with their potential antidiabetic property, were classified according to their basic chemical skeleton. The chemical structures of all the compounds with antidiabetic activities were elucidated in the present review. In addition to this, the distribution and their other remarkable pharmacological activities of each species are also included.

RESULTS

The scrutiny of literature led to the identification of 44 plants with antidiabetic compounds (70) and other pharmacological activities. For the sake of information, the distribution of each species in the world is given. Many plant derivatives may exert anti-diabetic properties by improving or mimicking insulin production or action. Different classes of compounds including sulfur compounds (1-4), alkaloids (5-11), phenolic compounds (12-17), tannins (18-23), phenylpropanoids (24-27), xanthanoids (28-31), amino acid (32), stilbenoid (33), benzofuran (34), coumarin (35), flavonoids (36-49) and terpenoids (50-70) were found to be potential active compounds for antidiabetic activity. Of the 70 listed compounds, majorly 17 compounds are obtained from triterpenoids, 13 from flavonoids and 7 from alkaloids. Among all the 44 plant species, the maximum number (7) of compounds were isolated from Lagerstroemia speciosa followed by Momordica charantia (6) and S. oblonga with 5 compounds.

CONCLUSION

This is the first paper to summarize the established chemical structures of phytochemicals that have been successfully screened for antidiabetic potential and their mechanisms of inhibition. The reported compounds could be considered as potential lead molecules for the treatment of type-2 diabetes. Further, molecular and clinical trials are required to select and establish therapeutic drug candidates.

Sweet Selenium: Synthesis and Properties of Selenium-Containing Sugars and Derivatives

In the last decades, organoselenium compounds gained interest due to their important biological features. However, the lack of solubility, which characterizes most of them, makes their actual clinical exploitability a hard to reach goal. Selenosugars, with their intrinsic polarity, do not suffer from this issue and as a result, they can be conceived as a useful alternative. The aim of this review is to provide basic knowledge of the synthetic aspects of selenosugars, selenonium salts, selenoglycosides, and selenonucleotides. Their biological properties will be briefly detailed. Of course, it will not be a comprehensive dissertation but an analysis of what the authors think is the cream of the crop of this interesting research topic.

Herbal Teas and their Health Benefits: A Scoping Review

Herbal teas are used as therapeutic vehicles in many forms of traditional medicine and are a popular global beverage. The purpose of this scoping review was to examine the evidence relating to the clinical efficacy and safety of herbal teas, and to identify the main research themes and gaps in knowledge to inform further work. A scoping review methodology was followed that set out the research question and described the sourcing, selection and analysis of studies. Overall, a total of 145 research publications were retrieved from global bibliographic databases, and after applying exclusion criteria, 21 remained. These studies looked at herbal tea use in female health, diabetes, heart disease and weight loss, with plant species including lavender, chamomile, fenugreek, stinging nettle, spearmint, hibiscus, yerba maté, echinacea and combinations of herbs. Observational studies explored associations between herbal tea consumption and cancer risk, liver health, and the risks linked to the consumption of environmental contaminants in the plant material. Despite plant materials being the basis for drug discovery, and the popularity of herbal teas, the number of articles exploring clinical efficacy and safety is small. In this review we discuss how herbal teas may be beneficial in some areas of clinical and preventative health, and what further research is required to understand whether regular consumption can contribute to healthy living more generally.

Salacia Extract Improves Postprandial Glucose and Insulin Response: A Randomized Double-Blind, Placebo Controlled, Crossover Study in Healthy Volunteers

Thirty-five healthy subjects were randomly assigned to different doses of Salacia chinensis extract (200 mg, 300 mg, and 500 mg SCE) capsules and compared with placebo. It is a placebo controlled randomized crossover design study. Subjects were given oral sucrose solution along with capsules and plasma glucose and insulin responses were analyzed. Blood samples were collected at 0, 30, 60, 90, 120, and 180 minutes after administration. AUC insulin significantly lowered after ingestion of SCE. No significant adverse events were observed. Reducing glucose and insulin is very important in reducing postprandial hyperglycemia.

The availability and validity of safety information of over the counter herbal products for use in diabetes in Sri Lanka: A cross sectional study

AIMS

There is an increase of over-the-counter (OTC) herbal products for use in diabetes mellitus. The aim of this study is to evaluate the safety information provided with OTC herbal remedies intended for diabetic patients in Sri Lanka and to assess the completeness of the information provided.

METHODS

Inclusion criteria consisted of OTC herbal remedies meant for use in diabetes. They were bought from local Sri Lankan supermarkets and non-ayurvedic pharmacies and product information regarding the risk of hypoglycemia, precautions for use, adverse events, dose, and interactions were assessed using a scoring system. The accuracy of the information was then compared against published data.

RESULTS

11 products fulfilled the inclusion criteria. Five products contained a single constituent and five contained more than one. None had complete and accurate safety information according to our criteria. None specifically warned against the risk of hypoglycemia. 9 out of 11 products (81.8%) carried ≤3 items of the five essential factual information we expected. Hypoglycemic coma, gastrointestinal symptoms, hepatotoxicity, carcinogenesis, and interactions causing elevated drug levels of Carbamazepine were some of the safety information that was missing.

CONCLUSIONS

Key safety information was absent in most products. Regulation of sale, provision of key safety information and adverse event reporting should be a priority.