Traditional medicinal herbs and food plants have the potential to inhibit key carbohydrate hydrolyzing enzymes in vitro and reduce postprandial blood glucose peaks in vivo

Antihyperglycemic potential of the Lavandula stoechas aqueous extract via inhibition of digestive enzymes and reduction of intestinal glucose absorption

BACKGROUND

Diabetes mellitus is a widespread metabolic disorder affecting global populations. Lavandula stoechas from Moroccan traditional medicine is used for its potential anti-diabetic effects.

OBJECTIVE

This study aims to evaluate the antihyperglycemic impact of the aqueous extract of L. stoechas (AqLs) and explore its mechanisms.

METHODS

The study employed a glucose tolerance test (OGTT) on normal and diabetic Wistar rats, administering AqLs at 150 mg/kg. In vitro, AqLs was tested against α-glucosidase and α-amylase activities, confirmed in vivo using normal and Allx-diabetic rats. The extract's impact on intestinal d-glucose absorption was assessed using the jejunum segment perfusion technique at 250 mg/kg in situ. Albino mice were used to assess toxicity.

RESULTS

AqLs significantly reduced postprandial hyperglycemia (P < 0.001) due to glucose overload. It inhibited pancreatic α-amylase (IC50: 0.485 mg/mL) and intestinal α-glucosidase (IC50: 168 µg/mL) in vitro. Oral AqLs at 150 mg/kg reduced hyperglycemia induced by sucrose and starch in normal and diabetic rats. It also lowered (P < 0.001) intestinal glucose absorption in situ at 250 mg/kg. Oral acute toxicity tests on Albino mice indicated no adverse effects at different doses.

CONCLUSION

to summarize, L. stoechas has evident antihyperglycemic effects attributed to inhibiting intestinal glucose absorption and key monosaccharide digestion enzymes like α-amylase and α-glucosidase.

Therapeutic effects of Salvia balansae on metabolic disorders and testicular dysfunction mediated by a high-fat diet in Wistar rats

Medicinal plants offer an important therapeutic resource in treatment of male infertility. We aim to evaluate the possible therapeutic effects of Salvia balansae on metabolic disorders and testicular dysfunction resulting from a high-fat diet (HFD). Antioxidant activity of aqueous extract of S. balansae leaves was evaluated using 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay, 2,2’-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS) assay and total antioxidant capacity (TAC) assay. Antidiabetic activity was determined by α-amylase inhibition. In vivo, HFD was administered in Wistar rats for 18 weeks and aqueous extract of S. balansae for the last 6 weeks (200 mg/Kg of body weight/day). At the term of experimentation, testosterone and some plasma parameters were analyzed and removed testes were subjected to a histomorphometric study. Our results show high levels of phenolic components in aqueous extract of S. balansae and significant antioxidant and antidiabetic activity. HFD increases body weight, causes type 2 diabetes, dyslipidemia, liver failure and inflammation. Also, HFD decreases testosterone and alters testis histological structure (seminiferous tubular degeneration, impaired spermatogenesis and interstitial fibrosis). Treatment of HFD rats with extract of S. balansae normalizes body weight and plasma parameters, increases testosterone and regenerates testicular structure and function. In summary, S. balansae could reduce metabolic complications induced by HFD and serve the basis for developing a new therapy for testicular dysfunction.

Phytochemical Composition, Antioxidant Activity, α-Glucosidase and Acetylcholinesterase Inhibitory Activity of Quinoa Extract and Its Fractions

This study is aimed to evaluate the chemical compositions and biological activities of quinoa, a novel and excellent food crop. Quinoa extract and its fractions were prepared by ethanol extraction and liquid-liquid extraction, including ethanol crude extract, and petroleum ether, chloroform, ethyl acetate (EAF), and n-butanol and water fractions. The total phenolic and flavonoid contents, antioxidant activities, α-glucosidase and acetylcholinesterase inhibitory abilities of the extract and fractions were further determined. Based on these foundations, the chemical composition of the EAF fraction exhibiting the strongest functional activity was analyzed by ultra-performance liquid chromatography-mass spectrometry. The results showed the EAF fraction had the highest phenolic and flavonoid contents, and the highest antioxidant activities, as well as the strongest α-glucosidase and acetylcholinesterase inhibitory abilities, which is even better than the positive control. The phytochemical composition of the EAF fraction indicated that 661 and 243 metabolites were identified in positive and negative ion modes, which were classified into superclass, class and subclass levels, respectively. Phenolic acids and flavonoids were the major bioactive compounds in the EAF fraction. This study found that quinoa, especially its ethyl acetate fraction, had the potential for the development of natural antioxidants, acetylcholinesterase inhibitors, and hypoglycemic agents.

Synthesis, Antioxidant, and Antidiabetic Activities of Ketone Derivatives of Succinimide

The prevalence of diabetes mellitus is persistently increasing globally creating a serious public health affliction. Diabetes mellitus is categorized into two major types designated as type I and Type II. Type I diabetes mellitus is characterized by complete lack of secretion of insulin, while Type II diabetes mellitus is the resistance of peripheral tissues to the action of insulin and inadequate compensatory secretion of insulin. Chronic hyperglycemia associated with diabetes causes failure of cardiovascular system, nervous system, kidneys, and eyes. At present, different types of drugs are used for the management of diabetes, but each of them is associated with more or less serious side effects. Therefore, we need to develop new therapeutic agents that have better efficacy and safety profile. In this study, three ketone derivatives of succinimides were synthesized based on Michael addition and characterized using NMR. All the synthesized compounds were checked for their in vitro α-amylase and α-glucosidase inhibitory activities. Further the synthesized compounds were also explored for their antioxidant activities, i.e, DPPH and ABTS assays. Based on the in vitro results, the synthesized compounds were further evaluated for in vivo antidiabetic activity. The synthesized compounds were (2-oxocyclohexyl)-1-phenylpyrrolidine-2,5-dione (BW1), benzyl-3-(2-oxocyclohexyl) pyrrolidine-2,5-dione (BW2), and (4-bromophenyl)-3-(2-oxocyclohexyl) pyrrolidine-2,5-dione (BW3). BW1 showed the highest inhibitory activity for DPPH causing 83.03 ± 0.48 at 500 μg/ml with IC50 value of 10.84 μg/ml and highest inhibitory activity for ABTS causing 78.35 ± 0.23 at 500 μg/ml with IC50 value of 9.40 μg/ml against ascorbic acid used as standard. BW1 also exhibited the highest activity against α-amylase and α-glucosidase inhibition causing 81.60 ± 0.00 at concentrations of 500 μg/ml with IC50 value of 13.90 μg/ml and 89.08 ± 1.04 at concentrations of 500 μg/ml with IC50 value of 10.49 μg/ml, respectively, against the standard drug acarbose.

Improvement of a Traditional Orphan Food Crop, Portulaca oleracea L. (Purslane) Using Genomics for Sustainable Food Security and Climate-Resilient Agriculture

Purslane (Portulaca oleracea L.) is a popular orphan crop used for its nutritional properties in various parts of the world. It is considered one of the richest terrestrial sources of omega-3 and omega-6-fatty acids (ω-3 and 6-FAs) suggesting its importance for human health. This ethnomedicinal plant is also an important part of traditional healing systems among the indigenous people. Many studies have indicated its tolerance against multiple stresses and found that it easily grows in a range of environmental gradients. It has also been considered one of the important biosaline crops for the future. Despite its huge nutritional, economic, and medicinal importance, it remains neglected to date. Most of the studies on purslane were focused on its ethnomedicinal, phytochemical, pharmacological, and stress-tolerance properties. Only a few studies have attempted genetic dissection of the traits governing these traits. Purslane being an important traditional food crop across the globe can be valorized for a sustainable food security in the future. Therefore, this review is an attempt to highlight the distribution, domestication, and cultivation of purslane and its importance as an important stress-tolerant food and a biosaline crop. Furthermore, identification of genes and their functions governing important traits and its potential for improvement using genomics tools for smart and biosaline agriculture has been discussed.

Mineral Content, Chemical Analysis, In Vitro Antidiabetic and Antioxidant Activities, and Antibacterial Power of Aqueous and Organic Extracts of Moroccan Leopoldia comosa (L.) Parl. Bulbs

Medicinal plants are a rich source of bioactive phytochemicals or bionutrients. Studies carried out during the past few decades have shown that these phytochemicals play an important role in preventing metabolic diseases such as cancer and diabetes. The present study was dedicated to the analysis of mineral and chemical composition and evaluation of antidiabetic, antioxidant, and antibacterial properties of aqueous and organic extracts of Leopoldia comosa, a plant with a long history of therapeutic and food use. Mineral content was determined using inductively coupled plasma atomic emission spectroscopy. Chemical composition was carried out by extraction of essential oils, preparation of aqueous and organic extracts, and qualitative and quantitative analysis. The biological study consisted of the evaluation of antidiabetic activity by inhibition of three enzymes, antioxidant activity by five tests, and antibacterial activity by the disc diffusion method. The correlation between chemical composition and antidiabetic and antioxidant properties was explored by PCA. The results showed that L. comosa contains high levels of Fe, K, P, Na, Cu, Mg, and Ca with values, respectively, in the order of 33552, 1843.14, 756.36, 439.65, 303.9, 272.37, and 20.55 mg/kg. Quantitative analysis showed that the diethyl ether extract had the highest content of polyphenols (129.75 ± 0.29 µg GAE/mg E), flavonoids (988.26 ± 0.18 µg QE/mg E), and tannins (30.22 ± 0.15 µg CE/mg E). All extracts of L. comosa possess inhibitory activity of alpha-amylase, alpha-glucosidase, and beta-galactosidase enzymes, mainly the decocted and the acetone extract. The antioxidant results showed that organic extracts are more active than aqueous extracts especially diethyl ether extract which was similarly found to have an antibacterial effect on Listeria innocua and Proteus mirabilis. PCA allowed us to deduce that phenolic compounds, flavonoids, and tannins are strongly correlated with antioxidant and antidiabetic activity. L. comosa may have potential remedy in the prevention of metabolic disease.

An integrated exploration of pharmacological potencies of Bischofia javanica (Blume) leaves through experimental and computational modeling

Bischofia javanica (Blume), an edible wild plant, has both prospective nutraceutical and therapeutic properties. Here, we intended to explore the pharmacological potentials of the methanol extract of B. javanica (MEBJ) through integrated approaches. Phytochemical screening revealed the presence of important phytoconstituents which were found to be safe during cytotoxicity analysis. The sedative potential of MEBJ (200 and 400 mg/kg) was determined by employing open field, hole cross, and thiopental sodium-induced sleeping time tests, where a significant reduction of the locomotor performance and an enhancement in the duration of sleeping have been observed, respectively. In addition, mice treated with MEBJ exhibited superior exploration during both elevated plus maze and hole board tests. In parallel, anti-diabetic potency was investigated via alpha-amylase inhibitory assay, where a dose-response increase in the percentage of inhibition has been marked. A similar response, such as an increased percentage of clot lysis, was observed during the thrombolytic test. Furthermore, molecular docking was performed with the identified compounds, demonstrated strong binding affinities to the target receptors of the experiments as mentioned above. Also, ADME/T and toxicological parameters verified the drug-like properties of the identified compounds. Collectively, these results indicate bioactivity of Bischofia javanica, which can be a potential candidate in the food and pharmaceutical industries.

Evaluation of In Vitro Antioxidant and Antidiabetic Activities of Aristolochia longa Extracts

Oxidative stress plays a major role in diabetic physiopathology; hence, the interest of using natural antioxidants as therapeutic tools exists. The aim of this study was the evaluation of in vitro antioxidant activity and inhibitory potential of organic extracts from Aristolochia longa roots against key enzymes linked to hyperglycemia. Antioxidant activity was performed using 2,2′-diphenyl-1-picrylhydrazyl (DPPH) and 2,2-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS) radicals and ferric reducing/antioxidant power (FRAP) methods. The α-Glucosidase and β-Galactosidase inhibitory activities were investigated using an in vitro model. Moreover, phytochemical analysis of tested extracts was carried out. The aqueous fraction of this herb exhibited the highest antioxidant activity for both DPPH and ABTS methods, IC₅₀=125.40±2.40 μg/mL and IC₅₀=65.23±2.49 μg/mL, respectively. However, the ethyl acetate fraction possessed the strongest inhibitory effect towards α-Glucosidase (IC₅₀=1.112±0.026 mg/mL). Furthermore, the result showed high levels of phenolic content. The results showed that this plant could be a significant source of medically important natural compounds.

Antidiabetic Effects of the Ethanolic Root Extract of Uvaria chamae P. Beauv (Annonaceae) in Alloxan-Induced Diabetic Rats: A Potential Alternative Treatment for Diabetes Mellitus

Diabetes mellitus has been a menace to mankind from time immemorial. However, a natural product such as U. chamae P. Beauv (Annonaceae) offers alternative treatment for diabetes mellitus. The study aimed at evaluating antidiabetic activity of the ethanolic root extract of U. chamae in alloxan-induced diabetic rats. Diabetes was induced in Sprague Dawley rats after overnight fast with 150 mg/kg alloxan intraperitoneally. After 72 h, those with plasma glucose levels >200 mg/dl were classified as diabetic. Five diabetic rats in each group were treated daily for 14 days orally with 100, 250, and 400 mg/kg of the extract, glibenclamide (71 µg/kg) and pioglitazone (429 µg/kg), respectively, while another group was untreated. Control received 0.5 ml of Acacia senegal. Effects of extract on glucose, other biochemical, and hematological parameters were evaluated. α-amylase and α-glucosidase inhibitory activities of extract and its fractions were also evaluated. Percentage inhibition and IC₅₀ values were determined. Diabetic control was achieved on the 7th day of the study with 100, 250, and 400 mg/kg of the extract showing glucose reduction of 72.14%, 78.75%, and 87.71%, respectively. The HDL-cholesterol levels of diabetic rats treated with extracts were significantly increased. Extract and its fractions caused α-amylase and α-glucosidase inhibition. Histologically, pancreas of diabetic rats treated with extract showed regenerated islet cells which were not seen in rats treated with glibenclamide and pioglitazone. This study showed that U. chamae has antidiabetic activity which may be through α-amylase and α-glucosidase inhibition and regeneration of pancreatic beta cells. Also, it may reduce the risk of cardiovascular disease by increasing HDL-cholesterol levels.

Inhibition of α-Glucosidase, Intestinal Glucose Absorption, and Antidiabetic Properties by Caralluma europaea

Many medicinal plants around the world are used for therapeutic purposes against several diseases, including diabetes mellitus. Due to their composition of natural substances that are effective and do not represent side effects for users, unlike synthetic drugs, in this study, we investigated the inhibitory effect of Caralluma europaea (CE) on α-glucosidase activity in vitro; then the kinetics of the enzyme were studied with increasing concentrations of sucrose in order to determine the inhibition type of the enzyme. In addition, this effect of Caralluma europaea (CE) was confirmed in vivo using rats as an experimental animal model. Among the five fractions of CE, only the ethyl acetate fraction of C. europaea (EACe) induced a significant inhibition of α-glucosidase and its inhibition mode was competitive. The in vivo studies were conducted on mice and rats using glucose and sucrose as a substrate, respectively, to determine the oral glucose tolerance test (OGTT). The results obtained showed that the EACe and the aqueous extract of C. europaea (AECe) have significantly reduced the postprandial hyperglycemia after sucrose and glucose loading in normal and diabetic rats. AECe, also, significantly decreased intestinal glucose absorption, in situ. The results obtained showed that Caralluma europaea has a significant antihyperglycemic activity, which could be due to the inhibition of α-glucosidase activity and enteric absorption of glucose.

In Vitro Inhibition of α-Amylase and α-Glucosidase by Extracts from Psiadia punctulata and Meriandra bengalensis

BACKGROUND

This research assessed the in vitro antidiabetic activity and phytochemical constituents of the traditionally used medicinal plants, Psiadia punctulata and Meriandra bengalensis.

METHOD

The leaves of both plants were subjected to cold extraction method using 70% ethanol and hot Soxhlet extraction using n-hexane, chloroform, methanol, and distilled water. The extracts were studied for their effect on glucose transport across yeast cells and inhibition of α-amylase and α-glucosidase enzyme activities. Thin-layer chromatographic analysis of ethanol extract was also undertaken.

RESULTS

The results of yeast glucose uptake assay revealed that extracts from both plants had a maximum increase in glucose uptake at the 25mM glucose concentration with a maximum dose of 2000μg/ml plant extract. The ethanol extract of P. punctulata and aqueous extract of M. bengalensis showed a high activity of 68% and 96%, respectively, at 25mM and 2000μg/ml of glucose and extract concentration. P. punctulata exerted peak inhibition activity of α-amylase of 37.5 ± 3% mg/dl (IC50 = 0.523 mg/dl) for methanol and distilled water extract at 0.5 mg/dl, respectively. M. bengalensis methanol extract exhibited the highest inhibition activity of 38 ± 8 % mg/dl (IC50 = 0.543 mg/dl) at 0.5 mg/dl. In the α-glucosidase inhibition assay, the methanolic extract of P. punctulata exhibited the highest inhibitory activity of 17.29 ± 9% mg/dl (IC50 = 0.761 mg/dl) at 0.5mg/dl. The chloroform extract of M. bengalensis had the highest inhibitory activity of 30 ± 5% mg/dl (IC50 = 0.6mg/dl) at 0.5 mg/dL. Phytochemical analysis of the different extracts of P. punctulata and M. bengalensis revealed the presence of flavonoids, alkaloids, tannins, saponins, phytosterols, and carbohydrates. Thin-layer chromatography analysis of ethanolic extract of both plants indicated presence of 15 and 17 spots for P. punctulata and M. bengalensis respectively.

CONCLUSION

P. punctulata and M. bengalensis extracts have moderate inhibitory activity against pancreatic α-amylase and relatively low inhibitory activities against α-glucosidase. The observed effects may be associated with the presence of flavonoids, saponins, and alkaloids. Additional in vivo analysis, toxicological studies, isolation, and structural characterization of the phytomolecules identified in this study and molecular docking studies should be undertaken.

The role of endemic plants in Mauritian traditional medicine - Potential therapeutic benefits or placebo effect?

ETHNOPHARMACOLOGICAL RELEVANCE

The Mauritian endemic flora has been recorded to be used as medicines for nearly 300 years. Despite acceptance of these endemic plants among the local population, proper documentation of their therapeutic uses is scarce. This review aims at summarising documented traditional uses of Mauritian endemic species with existing scientific data of their alleged bioactivities, in a view to appeal for more stringent validations for their ethnomedicinal uses.

MATERIAL AND METHODS

A comprehensive bibliographic investigation was carried out by analysing published books on ethnopharmacology and international peer-reviewed papers via scientific databases namely ScienceDirect and PubMed. The keywords "Mauritius endemic plants" and "Mauritius endemic medicinal plants" were used and articles published from 1980 to 2016 were considered. 675 works of which 12 articles were filtered which documented the ethnomedicinal uses and 22 articles reported the biological activities of Mauritian endemic plants. Only materials published in English or French language were included in the review. Available data on the usage of Mauritian endemic plants in traditional medicine and scientific investigation were related.

RESULTS AND DISCUSSION

We documented 87 taxa of Mauritian endemic plants for their medicinal value. Endemic plants are either used as part of complex herbal formulations or singly, and are prescribed by herbalists to mitigate a myriad of diseases from metabolic disorders, dermatological pathologies, arthritis to sexually transmissible diseases. However, these species have undergone a limited consistent evaluation to validate their purported ethnomedicinal claims. As the World Health Organization Traditional Medicine Strategy 2014-2023 emphasises on moving traditional medicine into mainstream medicine on an equally trusted footage, the re-evaluation and modernization of Mauritius cultural heritage become necessary.

CONCLUSIONS

With a consumer-driven 'return to nature', scientific validation and valorization of the herbal remedies, including efficacy and safety are, therefore, important. This review reports the scarcity of research on validating the efficacy and safety of medicinal endemic plants. This calls for the use of optimised methodologies to investigate the claims of therapeutic effects resulting from the use of these traditional medicines.

Effects of Aphloia theiformis on key enzymes related to diabetes mellitus

CONTEXT

Aphloia theiformis (Vahl.) Benn. (Flacourtiaceae) (AT) is traditionally used for the management of diabetes mellitus (DM), but there is no scientific data regarding activity against enzymes linked to this condition.

OBJECTIVE

To evaluate the kinetics of AT on key enzymes inhibition related to DM, and establish the antioxidant profile of AT.

MATERIALS AND METHODS

Dried powdered AT leaves were used to prepare crude methanol extract (70% v/v) (CME). Kinetics of CME (5000 to 156.25 μg/mL) on α-amylase, α-glucosidase, and lipase inhibition were studied. CME was partitioned using solvents of increasing polarity and kinetics of enzyme inhibition of each fraction (1000-31.25 μg/mL) was evaluated. Potent fractions were combined to assess any synergistic effect. Total phenol, flavonoid, tannin, anthocyanin contents, and antioxidant capacity of AT was evaluated using standard spectrophotometric methods.

RESULTS

CME, ethyl acetate, and n-butanol fractions showed potent inhibitory activities against the enzymes with IC50 ranging from 22.94-939.97 μg/mL. Significant (p < 0.05) reduction in IC50 (15.72 and 157.03 μg/mL against α-amylase and lipase, respectively) was observed when ethyl acetate and n-butanol fractions were combined; showing synergism. The extracts showed noncompetitive inhibition against α-amylase and α-glucosidase. Ethyl acetate, n-butanol fractions, and CME showed highest antioxidant capacities (0.44-1.41 μg GAE/mg sample), and phenol content (211.74-675.53 μg GAE/mg sample).

CONCLUSION

This study supports the use of AT in the management of DM and provides the rationale for bioactivity guided isolation and characterization of compounds from the ethyl acetate and n-butanol fractions.

Evaluation of cytogenotoxicity, antioxidant and hypoglycemiant activities of isolate compounds from Mansoa hirsuta D.C. (Bignoniaceae)

Mansoa hirsuta (Bignoniaceae) is a native plant from caatinga in Brazilian semiarid. This plant has been locally used as antimicrobial and hypoglycemiant agents, but their action mechanisms and toxicity remain largely unknown. Therefore, we evaluated the composition and antioxidant, cytoprotective and hypoglycemiant effects of raw extract, fractions and compounds from leaves of M. hirsuta. The cytogenotoxic effects of ursolic and oleanolic acids, the main phytotherapic components of this plant, were assessed. The raw extract and fractions presented steroids, saponins, flavonols, flavanonols, flavanones, xanthones, phenols, tannins, anthocyanins, anthocyanidins and flavonoids. The ethyl acetate fraction inhibited efficiently the cascade of lipid peroxidation while the hydroalcoholic fraction was richer in total phenols and more efficient in capturing 2,2-diphenyl-1-picrylhydrazyl (·DPPH) and 2,2'-azino-bis (3-ethylbenzthiazoline-6-sulfonic acid) (ABTS·+) radicals. The isolated fraction of M. hirsuta also inhibited the α-amylase activity. Cytotoxic effects were absent in both raw extract and fractions while ursolic+oleanolic acids were efficient in protecting cells after exposure to hydrogen peroxide. Moreover, this mixture of acid shad no significant interference on the mitotic index and frequency of nuclear and/or chromosomal abnormalities in Allium cepa test. Therefore, M. hirsuta represents a potential source of phytochemicals against inflammatory and oxidative pathologies, including diabetes.

α-glucosidase and glycation inhibitory effects of costus speciosus leaves

BACKGROUND

Hyperglycaemia is a salient feature of poorly controlled diabetes mellitus. Rate of protein glycation is increased with hyperglycaemia leading to long term complications of diabetes. One approach of controlling blood glucose in diabetes targets at reducing the postprandial spikes of blood glucose. The objectives of this study were to assess the in vitro inhibitory effects of Costus speciosus (COS) leaves on α-amylase and α-glucosidase activities, fructosamine formation, protein glycation and glycation-induced protein cross-linking.

METHODS

Methanol extracts of COS leaves were used. Inhibitory effects on enzyme activities were measured using porcine pancreatic α-amylase and α-glucosidase from Saccharomyces cerevisiae in the presence of COS extract. Percentage inhibition of the enzymes and the IC50 values were determined. In vitro protein glycation inhibitory effect of COS leaves on early and late glycation products were measured using bovine serum albumin or chicken egg lysozyme with fructose. Nitroblue tetrazolium was used to assess the relative concentration of fructosamine and polyacrylamide gel electrophoresis was used to assess the degree of glycation and protein cross-linking in the reaction mixtures.

RESULTS

α-Glucosidase inhibitory activity was detected in COS leaves with a IC50 of 67.5 μg/ml which was significantly lower than the IC50 value of Acarbose (p < 0.01). Amylase inhibitory effects occurred at a comparatively higher concentration of extract with a IC50 of 5.88 mg/ml which was significantly higher than the IC50 value of Acarbose (p < 0.01). COS (250 μg/ml) demonstrated inhibitory effects on fructosamine formation and glycation induced protein cross-linking which were in par with 1 mg/ml aminoguanidine were detected.

CONCLUSION

Methanol extracts of COS leaves demonstrated in vitro inhibitory activities on α-glucosidase, fructosamine formation, glycation and glycation induced protein cross-linking. These findings provide scientific evidence to support the use of COS leaves for hypoglycemic effects with an added advantage in slowing down protein glycation.

Ethnopharmacological uses of Antidesma madagascariense Lam. (Euphorbiaceae)

Antidesma madagascariense Lam. is an indigenous plant of the Mascarene Islands which has interestingly shined as a promising traditional medicinal plant. The ethnobotanical uses of this plant were geared toward the treatment and management of dysentery, albumin in the urine, jaundice, fever, diabetes, skin infections, rheumatic and body aches among others. Preliminary screening of this plant coupled with a plethora of in vitro and in vivo tests have furnished scientists with documented findings that have appraised its traditional use in the treatment and management of infectious diseases. The presence of antidesmin, a commonly characterized component of Antidesma species, might justify the medicinal virtues of this plant. The present monograph aims at providing the botanical description, traditional uses and latest findings documented on A. madagascariense. Nonetheless, continued research on this plant needs to be completed in order to rationalize the use of this promising plant as a potential source of beneficial constituents for the treatment and management of human diseases and hence set up promising optimism for drug development.

Biologic propensities and phytochemical profile of Vangueria madagascariensis J. F. Gmelin (Rubiaceae): an underutilized native medicinal food plant from Africa

Vangueria madagascariensis (VM), consumed for its sweet-sour fruits, is used as a biomedicine for the management of diabetes and bacterial infections in Africa. The study aims to assess the potential of VM on α -amylase, α -glucosidase, glucose movement, and antimicrobial activity. The antioxidant properties were determined by measuring the FRAP, iron chelating activity, and abilities to scavenge DPPH, HOCl, (∙) OH, and NO radicals. Leaf decoction, leaf methanol, and unripe fruit methanol extracts were observed to significantly inhibit α -amylase. Active extracts against α -glucosidase were unripe fruit methanol, unripe fruit decoction, leaf decoction, and ripe fruit methanol, which were significantly lower than acarbose. Kinetic studies revealed a mixed noncompetitive type of inhibition. Leaf methanolic extract was active against S. aureus and E. coli. Total phenolic content showed a strong significant positive correlation (r = 0.88) with FRAP. Methanolic leaf extract showed a more efficient NO scavenging potential and was significantly lower than ascorbic acid. Concerning (∙) OH-mediated DNA degradation, only the methanol extracts of leaf, unripe fruit, and ripe fruit had IC50 values which were significantly lower than α -tocopherol. Given the dearth of information on the biologic propensities of VM, this study has established valuable primary information which has opened new perspectives for further pharmacological research.

Inhibitory Potential of Five Traditionally Used Native Antidiabetic Medicinal Plants on α -Amylase, α -Glucosidase, Glucose Entrapment, and Amylolysis Kinetics In Vitro

Five traditionally used antidiabetic native medicinal plants of Mauritius, namely, Stillingia lineata (SL), Faujasiopsis flexuosa (FF), Erythroxylum laurifolium (EL), Elaeodendron orientale (EO), and Antidesma madagascariensis (AM), were studied for possible α-amylase and α-glucosidase inhibitory property, glucose entrapment, and amylolysis kinetics in vitro. Only methanolic extracts of EL, EO, and AM (7472.92 ± 5.99, 1745.58 ± 31.66, and 2222.96 ± 13.69 μg/mL, resp.) were found to significantly (P < 0.05) inhibit α-amylase and were comparable to acarbose. EL, EO, AM, and SL extracts (5000 μg/mL) were found to significantly (P < 0.05) inhibit α-glucosidase (between 87.41 ± 3.31 and 96.87 ± 1.37% inhibition). Enzyme kinetic studies showed an uncompetitive and mixed type of inhibition. Extracts showed significant (P < 0.05) glucose entrapment capacities (8 to 29% glucose diffusion retardation index (GDRI)), with SL being more active (29% GDRI) and showing concentration-dependent activity (29, 26, 21, 14, and 5%, resp.). Amylolysis kinetic studies showed that methanolic extracts were more potent inhibitors of α-amylase compared to aqueous extracts and possessed glucose entrapment properties. Our findings tend to provide justification for the hypoglycaemic action of these medicinal plants which has opened novel avenues for the development of new phytopharmaceuticals geared towards diabetes management.

Potential for improved glycemic control with dietary Momordica charantia in patients with insulin resistance and pre-diabetes

Bitter Melon (Momordica charantia) is a widely used traditional remedy for hyperglycemia. While the medicinal properties of this plant have been studied extensively using in vitro and animal models, the clinical efficacy and safety in humans is largely unknown. This review discusses the benefits and limitations of bitter melon supplementation in the context of epidemic levels of insulin resistance and pre-diabetes throughout the world.

Traditional Indian medicines used for the management of diabetes mellitus

Plants have always been a source of drugs for humans since time immemorial. The Indian traditional system of medicine is replete with the use of plants for the management of diabetic conditions. According to the World Health Organization, up to 90% of population in developing countries use plants and its products as traditional medicine for primary health care. There are about 800 plants which have been reported to show antidiabetic potential. The present review is aimed at providing in-depth information about the antidiabetic potential and bioactive compounds present in Ficus religiosa, Pterocarpus marsupium, Gymnema sylvestre, Allium sativum, Eugenia jambolana, Momordica charantia, and Trigonella foenum-graecum. The review provides a starting point for future studies aimed at isolation, purification, and characterization of bioactive antidiabetic compounds present in these plants.