Effect of NR-Salacia on post-prandial hyperglycemia: A randomized double blind, placebo-controlled, crossover study in healthy volunteers

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 If patients needed insulin, they were withdrawn from the trial.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.

Mutagenicity assessment of Salacia chinensis by bacterial reverse mutation assay using histidine dependent Salmonella typhimurium tester strains

Background and objective

Genotoxicity analysis is one of the most important non-clinical environmental safety investigations required for pharmaceutical and agrochemical product registration. Any medicinal product must undergo a risk evaluation to determine its mutagenicity and carcinogenicity.

Materials and methods

The Ames test is a commonly used in vitro test for determining a test chemical's mutagenic activity. Histidine-dependent Salmonella typhimurium strains with a defective gene that causes the bacteria to synthesis the necessary amino acid histidine for life were tested for mutagenic potential. In order to reveal pro-mutagens and mutagens, the mutagenic potential of both plate integration and pre-incubation techniques was examined in the presence and absence of metabolizing system. Salacia chinensis has been widely used in ayurveda to treat various ailments. However, the information of mutagenicity of Salacia chinensis is scarce as per available literature.

Results

The mutagenicity of a Salacia chinensis root extract was investigated utilizing the Ames assay with plate incorporation and pre-incubation protocols using the appropriate Salmonella typhimurium tester strains: TA98, TA100, TA1537, TA1535, and TA102 in the presence and absence of S9. The concentrations used were 0.3123, 0.625, 1.25, 2.5 and 5 mg/plate. The extract of Salacia chinensis root did not show any mutagenic effect in any of the Salmonella typhimurium strains at the concentrations tested in the absence or presence of metabolic activation.

Conclusion

The root of Salacia chinensis was hence confirmed to be non-mutagenic and at least according to the results of this genotoxicity evaluation can be regarded as being safe for human use.

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.

Dose-Dependent Suppression of Postprandial Hyperglycemia and Improvement of Blood Glucose Parameters by Salacia chinensis Extract: Two Randomized, Double-Blind, Placebo-Controlled Studies

The number of diabetes mellitus and borderline diabetes cases is increasing and poses a serious problem worldwide. Plants of the genus Salacia are known to have α-glucosidase inhibitory activity and to lower postprandial hyperglycemia. Two randomized, double-blind, placebo-controlled clinical trials were conducted to evaluate the efficacy of Salacia chinensis extract. Study 1 was a single-dose crossover study of 150, 300, or 600 mg of Salacia extract or placebo to determine the dose dependency of the effect on postprandial hyperglycemia. The duration of the washout period between each experimental day was a minimum of 6 days. Study 2 was a 12-week, multiple-dose, parallel-group study to evaluate the effects of 600 mg/day of Salacia extract on blood glucose parameters. In Study 1, Salacia induced significant dose-dependent suppression of postprandial blood glucose, insulin, and their incremental area under the curve values. The dose of 600 mg appeared to have the most significant effect. In Study 2, Salacia significantly improved several blood glucose-related parameters, such as hemoglobin A1c, and glucose tolerance after glucose challenge. These results suggest that S. chinensis extract may have beneficial effects in patients with diabetes.

Medicinal plants utilized in Thai Traditional Medicine for diabetes treatment: Ethnobotanical surveys, scientific evidence and phytochemicals

ETHNOPHARMACOLOGICAL RELEVANCE

Diabetes mellitus remains the most lethal metabolic disease of contemporaneous times and despite the therapeutic arsenal currently available, research on new antidiabetic agents remains a priority. In recent years, the revitalization of Thai Traditional Medicine (TTM) became a clear priority for the Thai government, and many efforts have been undertaken to accelerate research on herbal medicines and their use in medical services in various hospitals. Additionally, and particularly in rural areas, treatment of diabetes and associated symptomatology frequently relies on herbal preparations recommended by practitioners of TTM. In the current work, medicinal plants used in Thailand for treating diabetes, as well as their hypoglycaemic pharmacological evidences and potential therapeutic use for diabetes-related complications were reviewed.

MATERIALS AND METHODS

Ethnopharmacological information on the plant materials used in TTM for diabetes treatment was collected through literature search in a range of scientific databases using the search terms: diabetes, folk medicine, Thailand medicinal plants, traditional medicine. Information regarding scientific evidence on the antidiabetic effects of surveyed species was obtained considering not only the most common taxonomic designation, but also taxonomic synonyms, and including the keywords 'diabetes' and 'hypoglycaemic effect'.

RESULTS

A total of 183 species known to be used for diabetes management in TTM were reviewed, with 30% of them still lacking experimental evidences to support claims regarding the mechanisms and phytochemicals underlying their antidiabetic properties. Moreover, a total of 46 bioactives displaying effective antidiabetic effects have been isolated from 24 species, their underlying mechanism(s) of action being fully or partially disclosed.

CONCLUSIONS

We deliver the most extensive survey dealing with the ethnomedicinal knowledge of Thai medicinal plants utilized on diabetes management. We are certain that the current review will spark further research on Thai plants for the development of new standardized phytomedicines through drug discovery programmes.

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.

Use of household ingredients as complementary medicines for perceived hypoglycemic benefit among Sri Lankan diabetic patients; a cross-sectional survey

Background:

Biologic based therapies are frequently used as complementary medicines in diabetes. The aim of this study was to identify the commonly used herbal remedies and their preparations in Sri Lankan patients with Type 2 diabetes.

Methods:

This is a descriptive, cross-sectional study on 220 diabetic patients using herbal remedies for perceived glycemic benefit.

Results:

All the patients used their regular conventional medications together with herbal remedies. The most commonly used medication was metformin (91.4%). Ivy gourd (Coccinia grandis) was the most commonly used herbal remedy (32%), followed by crepe ginger (Costus speciosus) (25%) and bitter gourd (Momordica charantia) (20%). Herbal remedies used less frequently were finger millet (Eleusine corocana) (5%), anguna leaves (Wattakaka volubilis) (5%), goat weed (Scoparia dulcis) (4%), Salacia reticulata (4%), fenugreek (Trigonella foenum-graecum) (3%) and tree turmeric (Coscinium fenestratum) (0.5%). None of the patients used commercially available over-the-counter herbal products. The common preparations were salads (72.8%), curries (12.8%), herbal tea (6%), and herbal porridges (6%).

Conclusion:

The practice of using household ingredients as complementary medicines is common in Sri Lanka. Few herbal remedies and their methods of preparation have limited evidence for efficacy. In view of the frequent use by diabetic patients each needs to be documented for reference and scientifically explored about their hypoglycemic potential.

Anti-diabetic and Anti-hyperlipidemic Effects and Safety of Salacia reticulata and Related Species

Extracts of Salacia reticulata Wight (Hypocrataceae) roots, stems, and leaves have been used in Asia for hundreds of years for the folkloric treatment of diabetes and other health problems. Constituents that have been identified as exhibiting anti-diabetic effects include salacinol, kotalanol, ponkorinol, salaprinol, and their corresponding de-0-sulfonated compounds. Mangiferin, kotalagenin 16-acetate and various proanthocyanidin oligomers have also been isolated. Studies indicate that Salacia extracts modulate multiple targets that influence carbohydrate and lipid metabolism including α-glucosidase, aldose reductase, pancreatic lipase, peroxisomal proliferator-activated receptor-α, glucose transporter-4 mediated glucose uptake, and angiotensin II type 1 receptor. Furthermore, Salacia extracts exhibit free radical scavenging, antioxidant and hepatoprotectant activities. In human studies, Salacia extracts have been shown to decrease plasma glucose and insulin levels, decrease HbA1c, and modulate serum lipid levels with no adverse effects being reported. Similar results have been demonstrated in rat and mouse models as well as in vitro systems. Safety of S. reticulata and other Salacia species as S. oblonga and S. chinensis in rats and mice indicate that extracts are exceedingly safe. No clinical studies have examined the effects of Salacia extracts on human weight loss, although weight loss and decreases in weight gain have been demonstrated in animal models. Because of the large number of pharmacologically active compounds, it is difficult to establish standards for extracts.