Inhibitory activity of cinnamon bark species and their combination effect with acarbose against intestinal α-glucosidase and pancreatic α-amylase

Identification of procyanidins as α-glucosidase inhibitors, pancreatic lipase inhibitors, and antioxidants from the bark of Cinnamomum cassia by multi-bioactivity-labeled molecular networking

This study examined the suppressive effects of 16 selected plant-based foods on α-glucosidase and pancreatic lipase and their antioxidant properties. Among these, the bark of Cinnamomum cassia (Cinnamon, WLN-FM 15) showed the highest inhibitory activity against α-glucosidase and the highest antioxidant activity. Additionally, WLN-FM 15 showed promising results in the other tests. To further identify the bioactive constituents of WLN-FM 15, a multi-bioactivity-labeled molecular networking approach was used through a combination of GNPS-based molecular networking, DPPH-HPLC, and affinity-based ultrafiltration-HPLC. A total of nine procyanidins were identified as antioxidants and inhibitors of α-glucosidase and pancreatic lipase in WLN-FM 15. Subsequently, procyanidins A1, A2, B1, and C1 were isolated, and their efficacy was confirmed through functional assays. In summary, WLN-FM 15 has the potential to serve as a functional food ingredient with the procyanidins as its bioactive constituents. These results also suggest that the multi-bioactivity-labeled molecular networking approach is reliable for identifying bioactive constituents in plant-based foods.

Identification and in vitro Characterization of Novel Antidiabetic Peptides Released Enzymatically from Peanut Protein

Bioactive peptides derived from proteins found in various foods provide significant health benefits, including regulating blood sugar levels by inhibiting carbohydrate-hydrolyzing enzymes. Hydrolysates of peanut protein were prepared using alcalase (AH) or trypsin (TH) to generate antidiabetic peptides with high activity against α-amylase (IC50 of 6.46 and 5.71 mg/mL) and α-glucosidase (IC50 of 6.30 and 5.57 mg/mL), as well as antiradical activity to scavenge DPPH• (IC50 of 4.18 and 3.12 mg/mL) and ABTS•+ (IC50 of 2.87 and 2.56 mg/mL), respectively. The bioactivities of hydrolysates were greatest in the ultrafiltration-generated F3 fraction (< 3 kDa). The most active fraction was TH-F3, which was purified by gel filtration chromatography to generate sub-fractions (SF). With IC50 values of 1.05 and 0.69 mg/mL, the F3-SF8 fraction was the most effective at inhibiting the activity of α-amylase and α-glucosidase, respectively. This fraction was further purified using RP-HPLC to generate sub-subfractions (SSF), the most active of which were F3-SF8-SSF9 and SSF10. The peptide sequences F3-SF8-SSF9 and SSF10 were determined using LC-MS/MS. Two novel antidiabetic peptides with the potential to inhibit α-amylase and α-glucosidase were identified, with the sequences Asp-Trp-Arg (476.22 Da, IC50 of 0.78, and 0.35 mg/mL) and Phe-Tyr (329.15 Da, IC50 of 0.91, and 0.41 mg/mL). These results suggest that peptides derived from peanut protein are attractive natural ingredients for diabetes management applications.

Screening of Multitarget Compounds against Acetaminophen Hepatic Toxicity Using In Silico, In Vitro, and In Vivo Approaches

Combination therapy and multitarget drugs have recently attracted much attention as promising tools to fight against many challenging diseases and, thus, represent a new research focus area. The aim of the current project was to screen multitarget compounds and to study their individual and combined effects on acetaminophen-induced liver injury. In this study, 2 of the best hepatoprotective multitargeting compounds were selected from a pool of 40 major compounds present in Curcuma longa and Cinnamomum zeylanicum by using molecular docking, ADMET profiling, and Pfizer's rule of five. The two selected compounds, quercetin and curcumin, showed a high binding affinity for the CYP2E1 enzyme, MAPK, and TLR4 receptors that contribute to liver injury. The candidates caused the decreased viability of cancer cell lines (HepG2 and Huh7) but showed no effect on a normal cell line (Vero). Examination of biochemical parameters (ALT, AST, ALP, and bilirubin) showed the hepatoprotective effect of the candidate drugs in comparison with the control group, which was confirmed by histological findings. Taken together, quercetin and curcumin not only satisfied the drug-like assessment criterion and proved to be multitargeting by preventing liver damage but also showed anticancer activities.

Prospective Nutraceutical Effects of Cinnamon Derivatives Against Insulin Resistance in Type II Diabetes Mellitus-Evidence From the Literature

Apart from advances in pharmaceutical antidiabetic agents, efforts are being made toward hypoglycemic agents derived from natural sources. Cinnamon has been reported to have significant benefits for human health, particularly as an anti-inflammatory, antidiabetic, and anti-hypertriglyceridemic agent. The phytochemicals in cinnamon can be extracted from different parts of plant by distillation and solvent extraction. These chemicals help in decreasing insulin resistance and can act against hyperglycemia and dyslipidemia, inflammation and oxidative stress, obesity, overweight, and abnormal glycation of proteins. Cinnamon has shown to improve all of these conditions in in vitro, animal, and/or human studies. However, the mechanism of action of active ingredients found in cinnamon remains unclear. The current review presents the outstanding ability of cinnamon derivatives to control diabetes by various pathways modulating insulin release and insulin receptor signaling. It was also found that the type and dosage of cinnamon as well as subject characteristics including drug interactions are likely to affect the response to cinnamon. Future research directions based on this review include the synergistic usage of various cinnamon derivatives in managing and/or preventing diabetes and possible other relevant chronic diseases.

Role of Fenugreek, Cinnamon, Curcuma longa, Berberine and Momordica charantia in Type 2 Diabetes Mellitus Treatment: A Review

Type 2 diabetes mellitus (T2DM) is a complex disease that has become a major global health concern. Given the efficacy of antidiabetic drugs, pharmacological therapy is considered the first-line treatment of T2DM; however, due to their potential side effects and high costs, new and cost-effective treatments with minimal side effects are needed. Medicinal plants have been used for centuries as part of traditional medicine to treat T2DM. Among these, fenugreek, cinnamon, Curcuma longa, berberine, and Momordica charantia have demonstrated different degrees of hypoglycemic activity in clinical studies and animal models. Therefore, the aim of this review is to synthesize the mechanisms of action of five medicinal plants, as well as the experimental and clinical evidence of their hypoglycemic activity from the published literature.

Relevance of Indian traditional tisanes in the management of type 2 diabetes mellitus: a review

Background

Tisanes are a potential source of phytochemicals to reduce disease risk conditions and are used to protect from non-communicable diseases, globally. A few tisanes have gained more popularity than others depending on their chemical composition based on the geographical origin of the used herb. Several Indian tisanes have been claimed to have traits beneficial to people with or at a high risk of type 2 diabetes mellitus. Under the concept, the literature was reviewed and compiled into a document to highlight the chemical uniqueness of popular Indian traditional tisanes to be more informative and potent as per modern medicine to overcome type 2 diabetes mellitus.

Methods

An extensive literature survey was conducted using computerized database search engines, such as Google Scholar, PubMed, ScienceDirect, and EMBASE (Excerpta Medica database) for herbs that have been described for hyperglycemia, and involved reaction mechanism, in-vivo studies as well as clinical efficacies published since 2001 onwards using certain keywords. Compiled survey data used to make this review and all findings on Indian traditional antidiabetic tisanes are tabulated here.

Results

Tisanes render oxidative stress, counter the damage by overexposure of free radicals to the body, affect enzymatic activities, enhance insulin secretion, etc. The active molecules of tisanes also act as anti-allergic, antibacterial, anti-inflammatory, antioxidant, antithrombotic, antiviral, antimutagenicity, anti-carcinogenicity, antiaging effects, etc. WHO also has a strategy to capitalize on the use of herbals to keep populations healthy through effective and affordable alternative means with robust quality assurance and strict adherence to the product specification.

Ethyl-acetate fraction from a cinnamon-cortex extract protects pancreatic β-cells from oxidative stress damage

Background: The pathogenesis of diabetes mellitus is mediated mainly by oxidative stress produced by damaged pancreatic β-cells. We identified that an ethyl-acetate fraction (EA) from a cinnamon-cortex extract (CCE) is rich in flavonoid, and showed no toxicity to β cells. Objective: In this study, we evaluated the pharmacologic activities of EA on pancreatic β cells using a model of oxidative stress induced by H₂O₂ or alloxan. Results: The results showed that EA could significantly reduce reactive oxygen (ROS) accumulation to improve the survival of cells. Western blot showed that EA treatment upregulated expression of nuclear factor erythroid 2 related factor 2, heme oxygenase-1, and gamma glutamylcysteine synthetase. The same model study found that EA also can protect β cells against the apoptosis induced by oxidative stress. Furthermore, EA can enhance insulin secretion in rat and mouse β cell lines treated or not with alloxan or H₂O₂. The expression of the insulin transcription factor PDX-1 increased in an EA concentration-dependent manner. At last, the major functional compounds of EA analysis showed that three compounds, cinnamyl alcohol, coumarin, and cinnamic acid, had similar effects as EA. Conclusions: In sum, our data suggested that EA fraction from CCE can protect β cells from oxidative stress, and increase insulin secretion to improve the function of β cells. This function might be due to these three compounds found in EA. Our findings provide a theoretical basis and functional molecules for the use of CCE against diabetes mellitus.

Combination therapy of bioactive compounds with acarbose: A proposal to control hyperglycemia in type 2 diabetes

Type 2 diabetes (T2D) is a chronic metabolic disease with a high impact on public health and social welfare. Hyperglycemia is a characteristic of T2D that leads to different complications. Acarbose (ACB) reduces hyperglycemia by inhibiting α-amylase (AMY) and α-glucosidase (GLU) enzymes. However, ACB causes low adherence to treatment by patients with diabetes due to its side effects. Consequently, reducing the side effects produced by ACB without compromising its efficacy is a challenge in treating T2D. Bioactive compounds (BC) are safe and could decrease the side effects compared to antidiabetic drugs such as ACB. Nevertheless, their efficacy alone concerning that drug is unknown. The scientific advances have been directed toward searching for new approaches, such as combination therapies between BC and ACB. This review analyzes the combined therapy of BC (extracts or isolates) with ACB in inhibiting AMY and GLU as a proposal to control hyperglycemia in T2D. PRACTICAL APPLICATION: Postprandial hyperglycemia is one most typical signs of type 2 diabetes, and it can have significant consequences, including cardiovascular problems. Acarbose has side effects that lead to the abandonment of treatment. Bioactive compounds in extracts or isolated forms have become a viable option for controlling hyperglycemia without side effects, but their administration alone is insufficient. The scientific advances of acarbose/bioactive compound combination therapy as a proposal for controlling hyperglycemia in T2D were analyzed. The findings suggested that bioactive compounds combined with acarbose are effective when they function synergistically or additively; however, they are not recommended in therapy when they have an antagonistic effect.

Dietary proanthocyanidins on gastrointestinal health and the interactions with gut microbiota

Many epidemiological and experimental studies have consistently reported the beneficial effects of dietary proanthocyanidins (PAC) on improving gastrointestinal physiological functions. This review aims to present a comprehensive perspective by focusing on structural properties, interactions and gastrointestinal protection of PAC. In brief, the main findings of this review are summarized as follows: (1) Structural features are critical factors in determining the bioavailability and subsequent pharmacology of PAC; (2) PAC and/or their bacterial metabolites can play a direct role in the gastrointestinal tract through their antioxidant, antibacterial, anti-inflammatory, and anti-proliferative properties; (3) PAC can reduce the digestion, absorption, and bioavailability of carbohydrates, proteins, and lipids by interacting with them or their according enzymes and transporters in the gastrointestinal tract; (4). PAC showed a prebiotic-like effect by interacting with the microflora in the intestinal tract, and the enhancement of PAC on a variety of probiotics, such as Bifidobacterium spp. and Lactobacillus spp. could be associated with potential benefits to human health. In conclusion, the potential effects of PAC in prevention and alleviation of gastrointestinal diseases are remarkable but clinical evidence is urgently needed.

Phytochemical Characterization and Evaluation of the Antioxidant and Anti-Enzymatic Activity of Five Common Spices: Focus on Their Essential Oils and Spent Material Extractives

The essential oil industry of aromatic herbs and spices is currently producing a significant amount of by-products, such as the spent plant materials remaining after steam or hydrodistillation, that are simply discarded. The aim of this study was to comparatively investigate the phytochemical composition, antioxidant and multi-enzymatic inhibitory potential of the essential oils and spent plant material extractives obtained from cinnamon, cumin, clove, laurel, and black pepper. The essential oils were characterized by the presence of several phytochemical markers (cinnamaldehyde, cuminaldehyde, eugenol, eucalyptol, α-terpinene, limonene, β-caryophyllene or β-pinene). On the other hand, the LC-HRMS/MS profiling of the spent material extracts allowed the annotation of species specific and non-specific metabolites, such as organic acids, phenolic acids, flavonoids, proanthocyanidins, hydrolysable tannins, fatty acids, or piperamides. All samples exhibited very strong antioxidant effects, with the clove essential oil displaying the strongest radical scavenging (525.78 and 936.44 mg TE/g in DPPH and ABTS assays), reducing (2848.28 and 1927.98 mg TE/g in CUPRAC and FRAP), and total antioxidant capacity (68.19 mmol TE/g). With respect to the anti-acetylcholinesterase (0.73-2.95 mg GALAE/g), anti-butyrylcholinesterase (0-3.41 mg GALAE/g), anti-tyrosinase (0-76.86 mg KAE/g), anti-amylase and anti-glucosidase (both 0-1.00 mmol ACAE/g) assays, the spice samples showed a modest activity. Overall, our study reports that, not only the volatile fractions of common spices, but also their spent plant materials remaining after hydrodistillation can be regarded as rich sources of bioactive molecules with antioxidant and multi-enzymatic inhibitory effects.

Herbal Infusions as a Valuable Functional Food

Herbal infusions are an underestimated and easy to intake a source of biologically active natural compounds (polyphenols), which, in the dissolved form, are more easily absorbed. Therefore, this study aimed to assess the potential of herbal infusions as a functional food to reduce postprandial hyperglycemia (inhibition of α-amylase and α-glucosidase) and to reduce the effects of increased blood glucose level (antioxidant effect-DPPH, CUPRAC, and Fe²⁺ chelating assays, as well as anti-inflammatory activity-inhibition of collagenase). We showed that polyphenols are present in the examined aqueous herbal infusions (including chlorogenic and gallic acids). Subsequently, our research has shown that herbal infusions containing cinnamon bark, mulberry leaves, and blackberry fruits most strongly inhibit glucose release from complex carbohydrates, and that all herbal infusions can, to different degrees, reduce the effects of elevated blood sugar. In conclusion, infusions prepared from herbal blends could be recommended to prevent type II diabetes.

Beneficial effects of cinnamon and its extracts in the management of cardiovascular diseases and diabetes

Cardiovascular diseases (CVDs) and diabetes are the leading causes of death worldwide, which underlines the urgent necessity to develop new pharmacotherapies. Cinnamon has been an eminent component of spice and traditional Chinese medicine for thousands of years. Numerous lines of findings have elucidated that cinnamon has beneficial effects against CVDs in various ways, including endothelium protection, regulation of immune response, lowering blood lipids, antioxidative properties, anti-inflammatory properties, suppression of vascular smooth muscle cell (VSMC) growth and mobilization, repression of platelet activity and thrombosis and inhibition of angiogenesis. Furthermore, emerging evidence has established that cinnamon improves diabetes, a crucial risk factor for CVDs, by enhancing insulin sensitivity and insulin secretion; regulating the enzyme activity involved in glucose; regulating glucose metabolism in the liver, adipose tissue and muscle; ameliorating oxidative stress and inflammation to protect islet cells; and improving diabetes complications. In this review, we summarized the mechanisms by which cinnamon regulates CVDs and diabetes in order to provide a theoretical basis for the further clinical application of cinnamon.

Peppermint leaves hydrodistillation by-products: bioactive properties and incorporation into ice cream formulations

Distillation by-products of peppermint have not been considered for the valorization of bioactive compounds. In this study, by-products of peppermint after hydrodistillation, hydrosol and distilled leaves, were investigated followed by the most effective fraction was incorporated into ice cream formulations in order to improve the health promoting effects including antioxidant and α-glucosidase inhibition capacities of the ice creams. Distilled leaves of peppermint were subjected to sequential extraction by ethyl acetate and ethanol. HPLC analyses of eriocitrin and total phenolic analysis indicated that hydrosol contained significant amount of phenolics after 2 h hydrodistillation. Extending hydrodistillation from 1 to 2 h had insignificant effects on phenolic content. Distilled leaves of peppermint had extract yield of 7.39 and 7.19 g/100 mL in 1 and 2 h ethyl acetate extraction, respectively. The predominant phenolic of peppermint (eriocitrin) was 917.5 mg/L in hydrosol after 1 h distillation. Four h distillation of peppermint resulted in decrease in the amount of eriocitrin, however, hydrosol contained valuable amount of phenolics (840.1 mg/L). Hydrosols displayed higher antioxidant capacity in all tested methods than distilled leaves. Hydrosols, at equal amount of phenolics, had higher α-glucosidase inhibition capacity (5.92 µg/mL) than ethyl acetate extract (14.62 µg/mL) and ethanol extract (17.04 µg/mL) of deodorized leaves. Hydrosols were spray dried with the aid of maltodextrin in order to increase drying yield and incorporate the spray dried hydrosol (SDH) into ice cream formulations. Among others, ice cream incorporated with 0.5% of SDH was accepted by the panelists without damaging sensorial properties of ice cream.

A Review on Antidiabetic Activity of Centaurea spp.: A New Approach for Developing Herbal Remedies

Objective

Diabetes mellitus (DM) is a long-life metabolic disorder, characterized by high blood glucose levels. The hyperglycemic condition generally leads to irreversible nerve injury and vascular damage. Among different types of diabetes, type 2 is more common and has spread all over the world. Although various therapeutic approaches have been developed to control type 2 DM, regulating blood glucose levels has still remained a controversial challenge for patients. Also, most prescription drugs cause different side effects, such as gastrointestinal disorders. Thus, developing novel and efficient antidiabetic agents possessing fewer adverse effects is in high demand.

Method

The literature was comprehensively surveyed via search engines such as Google Scholar, PubMed, and Scopus using appropriate keywords.

Results

Medicinal plants, both extracts and isolated active components, have played a significant role in controlling the blood glucose levels. Good-to-excellent results documented in the literature have made them a precious origin for developing and designing drugs and supplements against DM. Centaurea spp. have been traditionally used for controlling high blood glucose levels. Also, the antidiabetic properties of different species of Centaurea have been confirmed in recent studies through in vitro assays as well as in vivo experiments.

Conclusion

Potent results encouraged us to review their efficacy to open a new horizon for development of herbal antidiabetic agents.

Diabetes medications as potential calorie restriction mimetics-a focus on the alpha-glucosidase inhibitor acarbose

The field of aging research has grown rapidly over the last half-century, with advancement of scientific technologies to interrogate mechanisms underlying the benefit of life-extending interventions like calorie restriction (CR). Coincident with this increase in knowledge has been the rise of obesity and type 2 diabetes (T2D), both associated with increased morbidity and mortality. Given the difficulty in practicing long-term CR, a search for compounds (CR mimetics) which could recapitulate the health and longevity benefits without requiring food intake reductions was proposed. Alpha-glucosidase inhibitors (AGIs) are compounds that function predominantly within the gastrointestinal tract to inhibit α-glucosidase and α-amylase enzymatic digestion of complex carbohydrates, delaying and decreasing monosaccharide uptake from the gut in the treatment of T2D. Acarbose, an AGI, has been shown in pre-clinical models to increase lifespan (greater longevity benefits in males), with decreased body weight gain independent of calorie intake reduction. The CR mimetic benefits of acarbose are further supported by clinical findings beyond T2D including the risk for other age-related diseases (e.g., cancer, cardiovascular). Open questions remain regarding the exclusivity of acarbose relative to other AGIs, potential off-target effects, and combination with other therapies for healthy aging and longevity extension. Given the promising results in pre-clinical models (even in the absence of T2D), a unique mechanism of action and multiple age-related reduced disease risks that have been reported with acarbose, support for clinical trials with acarbose focusing on aging-related outcomes and incorporating biological sex, age at treatment initiation, and T2D-dependence within the design is warranted.

Cinnamomum Species: Bridging Phytochemistry Knowledge, Pharmacological Properties and Toxicological Safety for Health Benefits

The genus Cinnamomum includes a number of plant species largely used as food, food additives and spices for a long time. Different traditional healing systems have used these plants as herbal remedies to cure diverse ailments. The aim of this comprehensive and updated review is to summarize the biodiversity of the genus Cinnamomum, its bioactive compounds, the mechanisms that underlie the pharmacological activities and molecular targets and toxicological safety. All the data in this review have been collected from databases and recent scientific literature including Web of Science, PubMed, ScienceDirect etc. The results showed that the bioactive compounds of Cinnamomum species possess antimicrobial, antidiabetic, antioxidant, anti-inflammatory, anticancer and neuroprotective effects. The preclinical (in vitro/in vivo) studies provided the possible molecular mechanisms of these action. As a novelty, recent clinical studies and toxicological data described in this paper support and confirm the pharmacological importance of the genus Cinnamomum. In conclusion, the obtained results from preclinical studies and clinical trials, as well as reduced side effects provide insights into future research of new drugs based on extracts and bioactive compounds from Cinnamomum plants.

UPLC-MS-Based Metabolomics Profiling for α-Glucosidase Inhibiting Property of Parkia speciosa Pods

Parkia speciosa is a food plant that grows indigenously in Southeast Asia. A great deal of interest has been paid to this plant due to its traditional uses in the treatment of several diseases. The pods contain many beneficial secondary metabolites with potential applications in medicine and cosmetics. However, studies on their phytochemical properties are still lacking. Therefore, the present study was undertaken to profile the bioactive compounds of P. speciosa pods collected from six different regions of Malaysia through ultra-high-performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UHPLC-QTOF-MS) and α-glucosidase inhibitory potential. This study applied metabolomics to elucidate the differences between P. speciosa populations found naturally in the different locations and to characterize potential α-glucosidase inhibitors from P. speciosa pods. P. speciosa collected from different regions of Malaysia showed good α-glucosidase inhibitory activity, with a median inhibitory concentration (IC₅₀) of 0.45–0.76 μg/mL. The samples from the northern and northeastern parts of Peninsular Malaysia showed the highest activity. Using UHPLC-QTOF-MS/MS analysis, 25 metabolites were identified in the pods of P. speciosa. The findings unveiled that the pods of P. speciosa collected from different locations exhibit different levels of α-glucosidase inhibitory activity. The pods are a natural source of potent antidiabetic bioactive compounds.

Assessment of Antihyperglycemic Effect and Acute Toxicity of the Aqueous Scorzonera undulata Extract in Rats

AIM

The current study was carried out in order to assess the antihyperglycemic effect of Scorzonera undulata (S. undulata). Backgroud: Scorzonera undulata subsp. deliciosa (DC.) Maire is used in the Moroccan pharmacopeia for managing diabetes.

OBJECTIVE

The objective of the study was to evaluate the anithyperglycemic activity in normal and streptozotocin (STZ)-induced diabetic rats as well as the acute toxicity of the aqueous extract of the roots of Scorzonera undulata (S. undulata).

METHODS

This study investigated the effects of the root aqueous extract of Scorzonera undulata (AERSU) at a dose of 20 mg/kg on blood glucose levels in normal and streptozotocin(STZ)-induced diabetic rats and the acute toxicity of AERSU was examined. Histopathological examination, preliminary phytochemical investigation, determination of glycogen content and evaluation of α-amylase were also performed.

RESULTS

Both single and repeated oral doses of AERSU (20 mg/kg) produced a significant reduction in blood glucose levels in normal and diabetic rats. Furthermore, repeated oral administration of AERSU during 15 days increased the glycogen content in the liver in both normal and diabetic rats, inhibited α- amylase activity and improved the histological architecture of the liver and pancreas in treated diabetic rats and ameliorated some biochemical parameters such as ALT and AST. In addition, the preliminary phytochemical investigation showed the richness of the roots of S. undulata in certain phytochemicals particularly in polyphenols.

CONCLUSION

AERSU exhibits an evident antihyperglycemic activity. This pharmacological effect may be due to the protection of surviving pancreatic β cells and hepatocytes, effect of α-amylase and the improvement of glycogen storage in the liver. The dose used in this study seems to be free of any toxicity.

Enzyme reaction-guided identification of active components from the flowers of Sophora japonica var. violacea

The flower of S. japonica is a favorite food and used as traditional medicine. In the present study, a facile and effective method based on the changes in the composition before and after the enzyme reaction was established to screen the active compounds from complex natural products. The separation of an active compound from the ethanolic extracts of Sophora japonica var. violacea, which exhibited the α-amylase inhibitory activity is presented as an example. The analysis of HPLC showed that one component was reduced by 25% after the enzyme reaction. The potential active compound was isolated via LH-20 gel permeation chromatography and identified as kaempferol 3-O-α-l-rhamnopyranosyl-(1 → 6)-β-d-galactopyranosyl-7-O-α-l-rhamnopyranoside by ¹H and ¹³C NMR. The in vitro test indicated that the compound had the α-amylase inhibitory activity, and the IC₅₀ was 88.56 ± 0.60 μg mL^-1. The molecular docking study of this compound showed that the compound enfolded in the active sites of α-amylase completely and interacted with the amino acid residues through hydrogen bonds, van der Waals force and hydrophobic interactions.

Herb-drug interactions: a mechanistic approach

In India, traditional herbal medicines have been an essential part of therapy for the last centuries. However, a large portion of the general populace is using these therapies in combination with allopathy lacking a proper understanding of possible interactions (synergistic or antagonistic) between the herbal product and the allopathic drug. This is based on the assumption that herbal drugs are relatively safe, i.e. without side effects. We have established a comprehensive understanding of the possible herb-drug interactions and identified interaction patterns between the most common herbs and drugs currently in use in the Indian market. For this purpose, we listed common interactors (herbs and allopathic drugs) using available scientific literature. Drugs were then categorized into therapeutic classes and aligned to produce a recognizable pattern present only if interactions were observed between a drug class and herb in the scientific literature. Interestingly, the top three categories (with highest interactors), antibiotics, oral hypoglycemics, and anticonvulsants, displayed synergistic interactions only. Another major interactor category was CYP450 enzymes, a natural component of our metabolism. Both activation and inhibition of CYP450 enzymes were observed. As many allopathic drugs are known CYP substrates, inhibitors or inducers, ingestion of an interacting herb could result in interaction with the co-administered drug. This information is largely unavailable for the Indian population and should be studied in greater detail to avoid such interactions. Although this information is not absolute, the systematic literature review proves the existence of herb-drug interactions in the literature and studies where no interaction was detected are equally important.

Anti-hyperglycemic and ameliorative effect of concentrated hot water-infusion of Phragmanthera incana leaves on type 2 diabetes and indices of complications in diabetic rats

Objectives

This study investigated the anti-hyperglycemic effects of concentrated hot water infusion of Phragmanthra incana leaves as well as its ameliorative effect on indices related to diabetic complications in a type 2 diabetes model of rats.

Methods

Type 2 diabetes was induced by feeding 10% fructose solution ad libitum for two weeks followed by an intraperitoneal injection of streptozotocin (40 mg/kg body weight (b.w.)). Concentrated plant infusion was administered orally at a dose of 150 and 300 mg/kg b.w. to two type 2 diabetes rat groups. Diabetic rats without treatment served as a negative control while the group administered with metformin was served as a positive control. The intervention lasted for 4 weeks when a single oral dose was given daily for 5 days a week. Body weight and blood glucose were determined every week. An oral glucose tolerance test was performed in the last week of treatment. The rats were sacrificed after 4 weeks of intervention, and the blood and organs were harvested for further analysis.

Results

Both dosages of the plant infusion significantly improved body weight, pancreatic β-cell function (HOMA-β), insulin secretion and reduced blood glucose, insulin resistance (HOMA-IR) with concomitant reduction in the elevated level of serum α-amylase activity, fructosamine, uric acid, urea, and liver function enzymes. The liver glycogen content was significantly improved while the activity of liver glucose-6-phosphatase was significantly reduced.

Conclusion

The results demonstrate the anti-hyperglycemic ability of P. incana and its ability to delay the onset of diabetic complications which can be exploited for the anti-diabetic drug discovery.

Cinnamon Shows Antidiabetic Properties that Are Species-Specific: Effects on Enzyme Activity Inhibition and Starch Digestion

Despite considerable research the evidence around the antidiabetic properties of cinnamon remains equivocal, and this may be due to varietal differences which is an aspect that is understudied. This study systematically compared the anti-hyperglycaemic properties of the four major commercial cinnamon types used around the world (Chinese; Cinnamomum cassia [CC], Indonesian; C. burmanii [IC], Vietnamese; C. loureirii [VC], and Ceylon; C. zeylanicum [SC]). LC-MS analysis showed distinct diffrences in the phytochemical profiles of cinnamon with SC showing the lowest coumarin concentration. CC and IC had the highest polyphenol levels and antioxidant potential, and all four types differed significantly in their content (P < 0.001). All cinnamon types showed potent species-specific effects on starch digestion enzyme activity inhibition (P < 0.001), CC was most effective against α-amylase and all four strongly inhibited α-glucosidase compared to acarbose. Cinnamon significantly reduced starch breakdown during oral (P = 0.006) and gastric (P = 0.029) phases of gastro-intestinal digestion with IC and SC showing consistent effects. No effects of cinnamon were seen in the intestinal phase. IC, VC and SC showed the greatest potential to inhibit formation of advanced glycation endproducts (AGEs) during digestion. In conclusion, cinnamon demonstrates anti-hyperglycaemic properties, however effects are species-specific with best overall properties seen for Ceylon cinnamon.

Influence of gallic and tannic acid on therapeutic properties of acarbose in vitro and in vivo in Drosophila melanogaster

Background

In this study, gallic acid (GA) and its polymeric form-tannic acid (TA) which are two phenolic acids found abundantly distributed in plant food sources were investigated for their influence on therapeutic properties of acarbose (AC) in vitro and in vivo in Drosophila melanogaster.

Methods

Combinations of AC and GA or TA were assessed for their alpha-glucosidase and alpha-amylase inhibitory effects as markers of anti-hyperglycemic properties, as well as their free radicals scavenging, Fe²⁺ chelating and malondialdehyde (MDA) inhibitory effects (in vitro). Furthermore, wild type D. melanogaster cultures were raised on diets containing AC, GA, TA and their various combinations for seven days. Thereafter, flies were homogenized and glucose concentrations, alpha-glucosidase and alpha-amylase activities, as well as reactive oxygen species (ROS) and total thiol levels were determined.

Results

The results showed that GA and TA up to 5 mg/ml significantly (p < 0.05) increased the enzymes' inhibitory effects and antioxidant properties of AC in vitro. Also, there was significant reduction in glucose concentration, enzyme activities and ROS level in D. melanogaster fed diets supplemented with phenolic acids and acarbose.

Conclusions

These bioactive compounds–drug interactions provide useful information on improving the therapeutic properties of acarbose especially in its use as an antidiabetic drug.

Pharmacological properties and their medicinal uses of Cinnamomum: a review

OBJECTIVES

Cinnamomum (Family Lauraceae) is traditionally used for flavouring food and in pharmaceutical preparations against various ailments. Detailed literature on the ethnobotanical and pharmacological properties of Cinnamomum is segregated and not present in well-documented form. In the present review, we have been trying to gather its detailed medicinal as well as pharmacological properties. The ethnobotanical and pharmacological properties of Cinnamomum were collected by searching several scientific databases, that is PubMed, Elsevier, Google Scholar, Science Direct and Scopus.

KEY FINDINGS

The plant extracts have been reported to possess astringent, warming stimulant, carminative, blood purifier, digestive, antiseptic, antifungal, antiviral, antibacterial, antioxidant, anti-inflammatory and immunomodulatory properties and also help to reduce cholesterol and blood sugar levels. A wide range of phytochemical compounds including aldehydes, acetate, alcohol, terpinenes, flavonoids, alkaloids, anthraquinones, coumarins, phenols, saponins, tannins, carboxylic acid, hydrocarbons, camphene, spathulenol, fatty acids, actinodaphnine, butanolides, lignans, steroids, propenoids and kaempferol glycosides are found in various parts of plant.

SUMMARY

This review provides detailed information about history, traditional uses, phytochemistry and clinical impacts of cinnamon as a spice and medicine. So we recommend further study on the clinical, medicinal, purification and identification of the most effective antibacterial activity of cinnamon to cure various infectious diseases.

Biological and Chemical Insights of Beech (Fagus sylvatica L.) Bark: A Source of Bioactive Compounds with Functional Properties

The present study aimed, on the one hand, to improve the yield of microwave assisted extraction (MAE) of polyphenols from beech bark by using a design of experiments (DoE) approach. On the other hand, beech bark extracts (BBE) were characterized in terms of their phytochemical profile and evaluated for biological potential (antioxidant, antibacterial, antifungal, antimutagen, anti-α-glucosidase, and anti-tyrosinase). The extraction time varies with the amount of extracted total phenolic content (TPC). The microwave power favors TPC extraction but in different proportions. The optimum conditions which gave the highest TPC (76.57 mg GAE/g dry plant material) were reached when the microwave power was 300 W, extraction time was 4 min, and the solvent was an ethanol–water (50:50) mixture. The practical value of TPC after a controlled experiment was 76.49 mg GAE/g plant material. The identified compounds were vanillic acid, gallic acid, epicatechin, catechin, protocatechuic acid, chlorogenic acid, ferulic acid, and isoquercitrin. The antioxidant potential of BBEs was demonstrated by in vitro experiments. The BBEs were active against Staphylococcus aureus, Pseudomonas aeruginosa, Salmonella typhimurium, Escherichia coli, and Candida species. All extracts were antimutagenic and expressed an inhibition on α-glucosidase and tyrosinase activity. Regarding antimutagen activity, the assayed extracts may be considered to have low or no antimutagen effects.

Antioxidant and Glycemic Regulatory Properties Potential of Different Maturity Stages of Leaf of Ceylon Cinnamon (Cinnamomum zeylanicum Blume) In Vitro

Dichloromethane:methanol (1:1, v/v) extracts of different maturity stages (immature, partly mature, and mature) of authenticated leaves of Ceylon cinnamon (CC) were used in this study. Antioxidant properties [total polyphenolic content (TPC) and total flavonoid content (TFC), 1, 1-diphenyl-2-picryl-hydrazyl (DPPH), 2-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid (ABTS)), oxygen radical absorbance capacity (ORAC), and ferric reducing antioxidant power (FRAP)] and glycemic regulatory properties [antiamylase (AA); antiglucosidase (AG)] were evaluated using 96-well microplate based bio assays in vitro (TPC, TFC, DPPH, ABTS, ORAC n=4 each; FRAP, AA, AG n=3 each). Results clearly revealed significant differences (p<0.05) among different maturity stages of leaf of CC for both antioxidant and glycemic regulatory properties (except AG activity). The mean antioxidant and glycemic regulatory activities of immature, partly mature, and mature leaves ranged from TPC: 0.68 ± 0.02-22.35 ± 0.21 mg gallic acid equivalents/g of sample (GS); TFC: 0.85 ± 0.01-4.68 ± 0.06 mg quercetin equivalents/GS; DPPH: 0.42 ± 0.01-27.09 ± 0.65 mg Trolox equivalents (TE)/GS; ABTS: 3.57 ± 0.10-43.91 ± 1.46 TE/GS; ORAC: 0.71 ± 0.01-18.70 ± 0.26 TE/G, FRAP: 0.31 ± 0.02-69.16 ± 0.52 TE/GS; and AA: 18.05 ± 0.24-36.62 ± 4.00% inhibition at 2.5 mg/mL. Mature leaf had the highest antioxidant and AA activities for all the assays investigated. In contrast, immature leaf had the lowest. The order of potency for antioxidant and AA activities was mature leaf > partly mature leaf > immature leaf. This is the first study to report on antioxidant and glycemic regulatory properties of different maturity stages of leaf of Ceylon cinnamon and highlights its potential use in management of oxidative stress-associated chronic diseases including diabetes mellitus.

α-Glucosidase Inhibitory Activity of Cycloartane-Type Triterpenes Isolated from Indonesian Stingless Bee Propolis and Their Structure-Activity Relationship

This study reports on the antioxidant activity and α-glucosidase inhibitory activity of five cycloartane-type triterpenes isolated from Indonesian stingless bee (Tetragonula sapiens Cockerell) propolis and their structure–activity relationships. The structure of the triterpenes was determined to include mangiferolic acid (1), Cycloartenol (2), ambonic acid (3), mangiferonic acid (4), and ambolic acid (5). The inhibitory test results of all isolated triterpenes against α-glucosidase showed a high potential for inhibitory activity with an IC₅₀ range between 2.46 and 10.72 µM. Among the compounds tested, mangiferonic acid (4) was the strongest α-glucosidase inhibitor with IC₅₀ 2.46 µM compared to the standard (–)-epicatechin (1991.1 µM), and also had antioxidant activities with IC₅₀ values of 37.74 ± 6.55 µM. The study on the structure–activity relationships among the compounds showed that the ketone group at C-3 and the double bonds at C-24 and C-25 are needed to increase the α-glucosidase inhibitory activity. The carboxylic group at C-26 is also more important for increasing the inhibitory activity compared with the methyl group. This study provides an approach to help consider the structural requirements of cycloartane-type triterpenes from propolis as α-glucosidase inhibitors. An understanding of these requirements is deemed necessary to find a new type of α-glucosidase inhibitor from the cycloartane-type triterpenes or to improve those inhibitors that are known to help in the treatment of diabetes.

Raffia palm (Raphia hookeri G. Mann & H. Wendl) wine modulates glucose homeostasis by enhancing insulin secretion and inhibiting redox imbalance in a rat model of diabetes induced by high fructose diet and streptozotocin

ETHNOPHARMACOLOGICAL RELEVANCE

Raffia palm (Raphia hookeri) wine (RPW) is amongst the natural products from plants, utilized singly or in combination with other medicinal plants for the treatment of several ailments including Diabetes Mellitus (DM). However, there is a scientific dearth on its antidiabetic activity.

AIM

The antidiabetic effect of RPW and its possible mechanism of actions were investigated in diabetic rats.

METHODS

Four groups of male SD rats were first supplied with 10% fructose solution ad libitum for 2 weeks instead of drinking water followed by an intraperitonial injection of streptozotocin (40 mg/kg) to induce diabetes. Two diabetic groups were administered RPW at 150 and 300 mg/kg bodyweight (BW) respectively; a group was administered with metformin, while the other one was served as a negative control. Two groups of normal rats were administered with water and RPW (300 mg/kg BW) and served as normal control and normal toxicology group, respectively.

RESULTS

Five weeks treatment of RPW led to significant (p < 0.05) increase in serum insulin and HDL-c levels with concomitant reduction in blood glucose, fructosamine, ALT, uric acid, triglycerides and LDL-c levels in diabetic rats. Rats treated with RPW had elevated levels of GSH, SOD, catalase, ATPase and α-amylase activities, while reduced NO level and myeloperoxidase activity was observed in their serum and pancreatic tissues. RPW also improved pancreatic β-cell function and restored β- and acinar cells morphology, and capillary networks. The activities of glycogen phosphorylase, fructose 1,6 biphosphatase, glucose-6-phosphatase, and acetylcholinesterase were also inhibited in RPW-treated diabetic rats, with concomitant down regulation of Nrf2 gene expression.

CONCLUSION

The data of this study suggest that RPW modulates glucose homeostasis by enhancing insulin secretion as well as inhibiting redox imbalance in diabetic rats, which may be attributed to the synergetic effects of its phytochemical constituents as identified by GC-MS analysis.

Isolation and characterization of resveratrol oligomers from the stem bark of Hopea ponga (Dennst.) Mabb. And their antidiabetic effect by modulation of digestive enzymes, protein glycation and glucose uptake in L6 myocytes

ETHNOPHARMACOLOGICAL RELEVANCE

Hopea ponga (Dennst.) Mabb. Is used in traditional herbal formulations for diabetes complications. The aim of this study is to evaluate the antidiabetic effect of extracts and compounds from H. ponga.

MATERIALS AND METHODS

Silica gel column chromatography was performed to identify various chemical components of the plant extract. Different extracts of H. ponga and isolated compounds were screened for their antidiabetic effect by modulation of digestive enzymes and protein glycation. The effect of glucose uptake by the compounds and the pathways through which the compounds mediate the glucose uptake potential were confirmed by fluorescent microscopy, flow cytometry and western blot analysis.

RESULTS

Acetone and ethanol extracts of the stem bark of Hopea ponga (Dennst.) Mabb. Afforded six resveratrol oligomers namely, E-resveratrol (1), (-)-ε-viniferin (2), (-)-α-viniferin (3), trihydroxyphenanthrene glucoside (THPG) (4), vaticaphenol A (5), (-)-hopeaphenol (6), along with four phytosterols. The structures were determined on the basis of spectroscopic analyses including nuclear magnetic resonance (NMR) spectroscopy and high resolution mass spectrometry (HRMS) data. Compounds 1-5 and 7-10 were tested for their α-glucosidase, α-amylase and glycation inhibitiory activities. All the resveratrol oligomers (1-5) showed prominent α-glucosidase inhibition with IC₅₀ values, 12.56 ± 1.00, 23.98 ± 1.11, 7.17 ± 1.10, 31.74 ± 0.42 and 16.95 ± 0.39 μM, respectively. Molecular docking studies also supported the observed α-glucosidase inhibition. Compound 3 displayed IC₅₀ values of 4.85 ± 0.06 and 27.10 ± 0.04 μM in α-amylase and glycation inhibitory assays activity. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay revealed that the compounds 3 and 4 were found to be less toxic at a concentration of 100 μM (<10%) and 25 μM (<20%), respectively. The effect of glucose uptake performed by 2-(N-(7-Nitrobenz-2-oxa-1,3-diazol-4-yl)amino)-2-deoxyglucose (2-NBDG) in L6 myoblast were measured by fluorescent microscopy and flow cytometry. The compounds 3 and 4 showed 2-NBDG uptake of 49.6% and 38.8% respectively. By examining the molecular pathway through which the compounds elicit their glucose uptake potential, it was observed that both the compounds mainly act via AMPK pathway.

CONCLUSION

This is the first report on the isolation of compounds from H. ponga. Altogether, the results of this study reveal the antidiabetic effects of H. ponga extracts and isolated compounds promoting traditional use of this plant in the treatment of diabetes.

α-Glucosidase Inhibitory Effect of Fermented Fruit Juice of Morinda Citrifolia L and Combination Effect with Acarbose

Fermented fruit juice of M.citrifoliais supposed to be the future nutraceutical beverage due to its antidiabetic and antioxidant activities. The purposes of this study were to characterize the fermented juice microbiologically and chemically and to evaluate itsα-glucosidase inhibition and radical scavenging activities in vitro. The fruit of M.citrifolia was fermented and the fruit juice was obtained and evaluated for its radical scavenging activity based on a DPPH assay. It's in vitroanti diabetic activity on α-glucosidase inhibition was investigated, including its combined effect with acarbose by a Chou-Talalay method. The inhibition mode was evaluated by Line weaver-Burk plots. The juice was identified for its microbiome with 16S sequencing method and pictured with SEM. The bioactive compounds were analysed with LC-MS. The main microbiome was yeast and tentatively identified as Candida. The yeast was not able to grow in the normal growth medium for yeast, such as sabouroud agar. The TPC of the juice was 1,193 μg GAE/ml. The main compounds identified by an LC-MS were short-chain fatty acids (α-ketoglutaric acid and malic acid). The fermented fruit juice showed good α-glucosidase inhibitory and antioxidant activities with IC50 of 28.99 and 14.09μgGAE/ml, respectively. The kinetic study showed a non-competitive inhibition on α-glucosidase. The combination of the juice with acarbose at higher concentrations produced an additive effect on α-glucosidase. However, at lower concentrations, an antagonistic effect was observed. The fermented fruit juice of M.citrifoliais a good beverage with strong antidiabetic and antioxidant effects.

Screening of Musa balbisiana Colla. seeds for antidiabetic properties and isolation of apiforol, a potential lead, with antidiabetic activity

BACKGROUND

'Phytonutrients' have been reported to exert an incredible impact on the healthcare system and offer medical benefits including the prevention or treatment of lifestyle-associated diseases. We chose one of the most common and important plant families, Musaceae, for our present study and explored its antidiabetic potential.

RESULTS

Seeds of the edible fruits of Musa balbisiana Colla. were investigated for their antidiabetic potential. After estimating the proximate composition, the seeds were extracted with various solvents and evaluated for antidiabetic potential in terms of the inhibition of digestive enzymes, antiglycation activity and in vitro glucose uptake. The acetone extract demonstrated the highest inhibition of α-amylase and α-glucosidase enzymes with IC₅₀ values of 36.67 ± 0.367 and 100.61 ± 0.707 µg mL^-1 , respectively. The extract also exhibited significant glycation inhibition with an IC₅₀ value of 86.48 ± 0.751 µg mL^-1 . Furthermore, a major phytochemical, apiforol, was isolated from the acetone extract for the first time, which demonstrated promising α-glucosidase inhibition (IC₅₀  = 48.25 ± 0.255 µmol L^-1 ), antiglycation property (IC₅₀  = 114.23 ± 0.567 µmol L^-1 ) and enhanced glucose uptake in L6 myoblasts. In molecular docking studies, apiforol efficiently bonded to the active sites of α-glucosidase enzyme 3A4A.

CONCLUSIONS

As dietary intervention is one of the effective strategies for addressing diabetes, special attention is always given to natural food bio-actives or agro-products for better human health. The results of our study suggest that Musa balbisiana has significant potential as an ingredient in health food formulations by reducing postprandial hyperglycaemia. © 2018 Society of Chemical Industry.

Antihyperglycemic activities of twig extract of indigenous cinnamon (Cinnamomum osmophloeum) on high-fat diet and streptozotocin-induced hyperglycemic rats

BACKGROUND

Cinnamomum osmophloeum (indigenous cinnamon) is an endemic species in Taiwan and its twigs contain abundant A-type proanthocyanidins. C. osmophloeum twig extracts (CoTEs) were found to have α-glucosidase and α-amylase inhibitory activities in vitro. The aim of this study is to further investigate the antihyperglycemic activity of CoTEs in hyperglycemic rats.

RESULTS

Hyperglycemic rats were divided into three groups and were treated orally with high-dosage CoTEs (HCO, 150 mg kg^-1 ), low-dosage CoTEs (LCO, 30 mg kg^-1 ) and positive control (PC, 30 mg kg^-1 pioglitazone). The HCO group showed improved glucose tolerance in an oral glucose tolerance test after 1 month of treatment, contributed by the inhibition of intestinal disaccharidases, amylase, and lipase. Compared with the PC group, both the HCO and LCO groups had decreased weight of visceral fats and lower atherogenic index; while their low-density lipoprotein-cholesterol, food intake, feed efficiency, and biochemical parameters remained unchanged compared with the NC group. Furthermore, the HCO group had decreased weight gain and the LCO group had decreased serum leptin level.

CONCLUSION

These results suggest that CoTE has potential antihyperglycemic activities for treating hyperglycemia without weight gain. © 2018 Society of Chemical Industry.

Screening of Chemical Composition, in vitro Antioxidant, α-Amylase and α-Glucosidase Inhibitory Activities of the Leaf Essential Oils of Cinnamomum wightii from Different Populations

Cnnamomum wightii is an endemic species of the Western Ghats, India and is used in Ayurveda and Siddha systems of medicine. Its bark and leaves are adulterated with commercial cinnamon in southern India. Despite its medicinal and commercial importance, the species remains underexplored. The objective of the present work was to screen the chemical composition, in vitro antioxidant, α-amylase and α-glucosidase inhibitory activities of the leaf essential oil of C. wightii collected from different populations. GC-FID and GC-MS analyses of the leaf essential oils from seven accessions enabled the identification of a total of 70 constituents, of which only 16 compounds were present in all samples. Eleven major constituents (> 5%) were identified, of which only linalool and spathulenol were present in all accessions as major constituents. Among seven accessions, essential oil from Parson's valley, Nilgiris exhibited better antioxidant activity with IC50 values of 2.552 ± 0.13 and 3.485 ± 0.09 mg/mL for ABTS and DPPH respectively. The essential oil from Korakundah, Nilgiris showed better hypoglycemic activity with IC50 values of 1.617 ± 0.02 and 1.146 ± 0.02 mg/mL for α-amylase and α-glucosidase inhibitory activities respectively. The leaf essential oils of C. wightii may be used in nutraceutical products focusing diabetes mellitus as the moderate inhibition of the metabolic enzymes has the advantage of slow release of glucose.

The effect of cinnamon on polycystic ovary syndrome in a mouse model

BACKGROUND

Polycystic ovary syndrome (PCOS) is the most prevalent cause of anovulatory infertility and hyperandrogenism. Evidence favors insulin resistance and compensatory hyperinsulinemia as the predominant, perhaps primary, defects in PCOS. The use of insulin-sensitizing drugs has been shown to improve both the reproductive and the metabolic aspects of PCOS. Cinnamon has been found to have insulin sensitizing effect and improve menstrual cyclicity in women with PCOS. The aim of this study was to determine the effect and mechanism of cinnamon on PCOS using a dehydroepiandrosterone (DHEA) induced PCOS mouse model.

METHODS

Prepubertal C57BL/6 mice (age 25 days) were raised to developed into control group, DHEA group and DHEA plus cinnamon group for 20 days. The stages of the estrous cycle were determined based on vaginal cytology; metabolic characteristics were examined by intraperitoneal glucose tolerance test and insulin tolerance test, the serum levels of hormones (testosterone, insulin, LH, FSH, IGF-1, IGFBP-1) were checked using enzyme-linked immunosorbent assay (ELISA) method, the ovarian morphology was observed by stained with hematoxylin and eosin. IGF-1 and IGFBP-1 expression in ovary were detected by immunohistochemical stain.

RESULTS

Cinnamon restores the cyclicity and ovary morphology in PCOS mice model induced by DHEA. There are significant differences of serum level of total testosterone (0.033 ± 0.009 ng/ml), among control group, DHEA and cinnamon group (0.052 ± 0.011 ng/ml), and DHEA group (0.079 ± 0.015 ng/ml); There was an increasing tendency of serum FSH level from DHEA group (5.02 ± 0.31 ng/ml), DHEA and cinnamon group (5.81 ± 0.51 ng/ml), to control group (7.13 ± 0.74 ng/ml); and there was a decreasing trend of serum LH level from DHEA group (3.75 ± 0.57 ng/ml), DHEA and cinnamon group (1.35 ± 0.61 ng/ml), or control group (0.69 ± 0.34 ng/ml); serum insulin level is significantly higher in DHEA treated mice (1.61 ± 0.31 ng/ml) than control group (0.93 ± 0.19 ng/ml), or DHEA and cinnamon effect (1.27 ± 0.23 ng/ml) (p < 0.05). The DHEA group also has a higher serum IGF-1 level (0.35 ± 0.06 ng/ml) than control group (0.17 ± 0.04 ng/ml) or DHEA and cinnamon group (0.21 ± 0.05 ng/ml) (p < 0.05). While DHEA group has a lower IGFBP-1 level (5.5 ± 1.6 ng/ml) than control group (15.8 ± 2.1 ng/ml) or DHEA and cinnamon group (10.3 ± 2.5 ng/ml) (p < 0.05). Cinnamon also attenuates DHEA induced a higher IGF-1 and lower IGFBP-1 expression in ovary by immunohistochemistry.

CONCLUSIONS

These preliminary data suggest that cinnamon supplementation improves insulin resistance and may be a potential therapeutic agent for the treatment of PCOS.

Medicinal Plants with Multiple Effects on Diabetes Mellitus and Its Complications: a Systematic Review

PURPOSE OF REVIEW

This systematic review describes evidence concerning medicinal plants that, in addition to exerting hypoglycemic effects, decrease accompanying complications such as nephropathy, neuropathy, retinopathy, hypertension, and/or hyperlipidemia among individuals with diabetes mellitus (DM).

RECENT FINDINGS

Studies on the antidiabetic mechanisms of medicinal plants have shown that most of them produce hypoglycemic activity by stimulating insulin secretion, augmenting peroxisome proliferator-activated receptors (PPARs), inhibiting α-amylase or α-glucosidase, glucagon-like peptide-1 (GLP-1) secretion, advanced glycation end product (AGE) formation, free radical scavenging plus antioxidant activity (against reactive oxygen or nitrogen species (ROS/RNS)), up-regulating or elevating translocation of glucose transporter type 4 (GLUT-4), and preventing development of insulin resistance. Not only are medicinal plants effective in DM, but many of them also possess a variety of effects on other disease states, including the complications of DM. Such plants may be appropriate alternatives or adjuncts to available antidiabetic medications.

Phytotherapy in the Management of Diabetes: A Review

Phytotherapy has long been a source of medicinal products and over the years there have been many attempts to use herbal medicines for the treatment of diabetes. Several medicinal plants and their preparations have been demonstrated to act at key points of glucidic metabolism. The most common mechanisms of action found include the inhibition of α-glucosidase and of AGE formation, the increase of GLUT-4 and PPARs expression and antioxidant activity. Despite the large amount of literature available, the actual clinical effectiveness of medicinal plants in controlling diabetes-related symptoms remains controversial and there is a crucial need for stronger evidence-based data. In this review, an overview of the medicinal plants, which use in the management of diabetes is supported by authoritative monographs, is provided. References to some species which are currently under increasing clinical investigation are also reported.

Pentacyclic triterpenes as α-glucosidase and α-amylase inhibitors: Structure-activity relationships and the synergism with acarbose

In this paper, the inhibition of α-amylase and α-glucosidase by nine pentacyclic triterpenes was determined. For α-amylase inhibitory activity, the IC₅₀ values of ursolic acid, corosolic acid, and oleanolic acid were 22.6±2.4μM, 31.2±3.4μM, and 94.1±6.7μM, respectively. For α-glucosidase inhibition, the IC₅₀ values of ursolic acid, corosolic acid, betulinic acid, and oleanolic acid were 12.1±1.0μM, 17.2±0.9μM, 14.9±1.9μM, and 35.6±2.6μM, respectively. The combination of corosolic acid and oleanolic acid with acarbose showed synergistic inhibition against α-amylase. The combination of the tested triterpenes with acarbose mainly exhibited additive inhibition against α-glucosidase. Kinetic studies revealed that corosolic acid and oleanolic acid showed non-competitive inhibition and acarbose showed mixed-type inhibition against α-amylase. The results provide valuable implications for the triterpenes (ursolic acid, corosolic acid, and oleanolic acid) alone or in combination with acarbose as a therapeutic agent for the treatment of diabetes mellitus.

Antiamylase, Anticholinesterases, Antiglycation, and Glycation Reversing Potential of Bark and Leaf of Ceylon Cinnamon (Cinnamomum zeylanicum Blume) In Vitro

Ethanol (95%) and dichloromethane : methanol (DCM : M, 1 : 1 v/v) bark extracts (BEs) and leaf extracts (LEs) of authenticated Ceylon cinnamon (CC) were studied for antiamylase, antiglucosidase, anticholinesterases, and antiglycation and glycation reversing potential in bovine serum albumin- (BSA-) glucose and BSA-methylglyoxal models in vitro. Further, total proanthocyanidins (TP) were quantified. Results showed significant differences (p < 0.05) between bark and leaf extracts for the studied biological activities (except antiglucosidase) and TP. BEs showed significantly high (p < 0.05) activities for antiamylase (IC₅₀: 214 ± 2–215 ± 10 μg/mL), antibutyrylcholinesterase (IC₅₀: 26.62 ± 1.66–36.09 ± 0.83 μg/mL), and glycation reversing in BSA-glucose model (EC₅₀: 94.33 ± 1.81–107.16 ± 3.95 μg/mL) compared to LEs. In contrast, glycation reversing in BSA-methylglyoxal (EC₅₀: ethanol: 122.15 ± 6.01 μg/mL) and antiglycation in both BSA-glucose (IC₅₀: ethanol: 15.22 ± 0.47 μg/mL) and BSA-methylglyoxal models (IC₅₀: DCM : M: 278.29 ± 8.55 μg/mL) were significantly high (p < 0.05) in leaf. Compared to the reference drugs used some of the biological activities were significantly (p < 0.05) high (BEs: BChE inhibition and ethanol leaf: BSA-glucose mediated antiglycation), some were comparable (BEs: BSA-glucose mediated antiglycation), and some were moderate (BEs and LEs: antiamylase, AChE inhibition, and BSA-MGO mediated antiglycation; DCM : M leaf: BSA-glucose mediated antiglycation). TP were significantly high (p < 0.05) in BEs compared to LEs (BEs and LEs: 1097.90 ± 73.01–1381.53 ± 45.93 and 309.52 ± 2.81–434.24 ± 14.12 mg cyanidin equivalents/g extract, resp.). In conclusion, both bark and leaf of CC possess antidiabetic properties and thus may be useful in managing diabetes and its complications.