Influence of chalcone analogues on serum glucose levels in hyperglycemic rats

A Natural Chalcone Cardamonin Inhibited Transformation of Aryl Hydrocarbon Receptor Through Binding to the Receptor Competitively

SCOPE

Chalcones are widely present in most plants and have various health beneficial functions. This study investigates the suppressive effect of 13 natural and synthetic chalcones on transformation of aryl hydrocarbon receptor (AhR) induced by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and 3-methylcholanthrene (3-MC) in a cell-free system, Hepa-1c1c7 cells, and liver of ICR mice.

METHODS AND RESULTS

In the cell-free system, cardamonin dose-dependently inhibits AhR transformation. Chalcones with substitution on 2' and/or 6' position is important for the suppressive effect, while the substitution on 4' position is negatively for the effect. Moreover, cardamonin and 2'-hydroxychalcone competitively inhibit the binding of [3H]-3-MC to the AhR. In Hepa-1c1c7 cells, cardamonin inhibits AhR transformation and expression of cytochrome P4501A1 (CYP1A1) in a dose-dependent manner through suppressing TCDD-induced phosphorylation of both AhR and AhR nuclear translocator, heterodimerization of them, and nuclear translocation of AhR. In the liver of mice, oral administered cardamonin also inhibits 3-MC-induced AhR translocation and expression of CYP1A1.

CONCLUSION

Among used chalcones, a natural chalcone cardamonin competitively binds to AhR and suppresses its transformation. Thus, cardamonin is an effective food factor for suppression of the dioxin-caused biochemical alterations and toxicities.

Transition Metal-Catalyzed Transformations of Chalcones

Chalcones are a class of naturally occurring flavonoid compounds associated to a variety of biological and pharmacological properties. Several reviews have been published describing the synthesis and biological properties of a vast array of analogues. However, overviews on the reactivity of chalcones has only been explored in a few accounts. To fill this gap, a systematic survey on the most recent developments in the transition metal-catalyzed transformation of chalcones was performed. The chemistry of copper, palladium, zinc, iron, manganese, nickel, ruthenium, cobalt, rhodium, iridium, silver, indium, gold, titanium, platinum, among others, as versatile catalysts will be highlighted, covering the literature from year 2000 to 2023, in more than 380 publications.

Symbiotic Antidiabetic Effect of Lactobacillus casei and the Bioactive Extract of Cleome droserifolia (Forssk.) Del. on Mice with Type 2 Diabetes Induced by Alloxan

The consumption of probiotics protects pancreatic β-cells from oxidative damage, delaying the onset of type 2 diabetes mellitus (T2DM) and preventing microvascular and macrovascular complications. This study aimed to evaluate the antidiabetic activity of CDE fermented by Lactobacillus casei (ATCC 39539) (LC) in alloxan-induced diabetic rats. The oxidative stress identified by catalase (CAT), serum AST, ALT, ALP, creatinine, urea, and uric acid were measured. The chemical profiles of the plant extract and the fermented extract were studied using HPLC/MS. The potential of the compounds towards the binding pockets of aldose reductase and PPAR was discovered by molecular docking. A significant reduction in fasting blood glucose in alloxan-treated rats. The CAT showed a significant decrease in diabetic rats. Also, serum AST, ALT, ALP, creatinine, urea, and uric acid were significantly decreased in the mixture group. Mild histological changes of pancreatic and kidney tissues suggested that the mixture of probiotics and cleome possesses a marked anti-diabetic effect. Overall, the study suggests that the combination of Cleome droserifolia fermented by Lactobacillus casei exhibits significant antidiabetic activity (p-value=0.05), reduces oxidative stress, improves lipid profiles, and shows potential for the treatment of diabetes.

Signal transduction of the insulin secretion induced by the chalcone analogue, (E)-3-(phenyl)-1-(3,4,5-trimethoxyphenyl)prop-2-en-1-one, and its role in glucose and lipid metabolism

A chalcone analogue, (E)-3-(phenyl)-1-(3,4,5-trimethoxyphenyl)prop-2-en-1-one (DMU 101), was synthesized using classic base catalysis and Claisen-Schmidt condensation, and then screened for its antidiabetic properties. The compound's effects on glucose and lipid metabolism were assayed in rats that were treated acutely and for a short time to elucidate its mechanism of action, evaluating glucose tolerance and lactate dehydrogenase activity in response to chalcone analogue administration. The chalcone's in vitro and ex vivo effects on glycogen, glucose, lipid and lipolysis were also investigated, as well as the mechanism by which it induces 45Ca2+ influx-mediated insulin secretion. The analogue (10 mg/kg) diminished glycemia, without inducing acute cell damage, increased glycogen content in the skeletal muscle and reduced serum triacylglycerol and total cholesterol, but did not alter high-density lipoprotein or low-density lipoprotein. Chalcone (10 μM) stimulated glucose uptake in the soleus muscle and did not modulate in vitro or ex vivo lipolysis. This analogue also increased insulin secretion by triggering calcium influx and blocking ATP-sensitive K+ channels and voltage-dependent calcium channels. However, it also modulated stored calcium via sarco/endoplasmic reticulum calcium ATPase (SERCA) and ryanodine receptor (RYR) activity. These findings indicate that this chalcone may induce cellular repolarization via a mechanism mediated by calcium-dependent potassium channels.

Novel hybrids of quinoline with pyrazolylchalcones as potential antimalarial agents: Synthesis, biological evaluation, molecular docking and ADME prediction

A novel series of pyrazolyl chalcones containing quinoline scaffold, 5 a-v has been synthesized by Claisen Schimdt condensation of aromatic acetophenone with 1-(4-methylquinolin-2-yl)-3-aryl-1H-pyrazole-4-carbaldehyde in quantitative yield. The compounds were characterized using IR, NMR, MS and elemental analysis. An E-configuration about CC ethylenic bond was determined using ¹H NMR spectroscopy. These compounds exhibited significant antimalarial potential against CQ-sensitive and CQ-resistant strain of Plasmodium falciparum. Structure activity relationship has also been established based on outcomes of in vitro schizont inhibition assay. Compound 5u, (Z)-3-(1-(4-methylquinolin-2-yl)-3-p-tolyl-1H-pyrazol-4-yl)-1-p-tolylprop-2-en-1-one, was found to be the most potent among the series of synthetic analogues. In vivo, it demonstrated significant parasitemia suppression of 78.01% at a dose of 200 mg/kg against P. berghei in infected mice without any mortality in 7 days. In silico molecular docking study revealed that this compound 5u bound to the active site of cysteine protease falcipain-2 enzyme. Furthermore, in silico ADME studies, were also performed and physicochemical qualifications of the title compounds were determined. The biological outcomes of newer heterocyclic compounds may pave the new paths for researchers in development of potential antimalarial agents.

Pharmacological Properties of Chalcones: A Review of Preclinical Including Molecular Mechanisms and Clinical Evidence

Chalcones are among the leading bioactive flavonoids with a therapeutic potential implicated to an array of bioactivities investigated by a series of preclinical and clinical studies. In this article, different scientific databases were searched to retrieve studies depicting the biological activities of chalcones and their derivatives. This review comprehensively describes preclinical studies on chalcones and their derivatives describing their immense significance as antidiabetic, anticancer, anti-inflammatory, antimicrobial, antioxidant, antiparasitic, psychoactive, and neuroprotective agents. Besides, clinical trials revealed their use in the treatment of chronic venous insufficiency, skin conditions, and cancer. Bioavailability studies on chalcones and derivatives indicate possible hindrance and improvement in relation to its nutraceutical and pharmaceutical applications. Multifaceted and complex underlying mechanisms of chalcone actions demonstrated their ability to modulate a number of cancer cell lines, to inhibit a number of pathological microorganisms and parasites, and to control a number of signaling molecules and cascades related to disease modification. Clinical studies on chalcones revealed general absence of adverse effects besides reducing the clinical signs and symptoms with decent bioavailability. Further studies are needed to elucidate their structure activity, toxicity concerns, cellular basis of mode of action, and interactions with other molecules.

Divergent Synthesis and Evaluation of the in vitro Cytotoxicity Profiles of 3,4-Ethylenedioxythiophenyl-2-propen-1-one Analogues

A new series of 3,4-ethylenedioxythiophene (EDOT)-appended propenones were prepared by condensation reaction and their in vitro cytotoxicity effects were evaluated against five human cancer cell lines. Preliminary structure-activity relationships of EDOT-incorporated 2-propenone derivatives were also established. The EDOT-appended enones demonstrated significant cytotoxicity against human cancer cell lines. The most active analogue, (E)-3-(2,3-dihydrothieno[3,4-b][1,4]dioxin-5-yl)-1-(3,4,5-trimethoxyphenyl)prop-2-en-1-one (3 p, GI₅₀ =110 nm), severely inhibited the clonogenic potential of cancer cells, and induced cell-cycle arrest in the G2/M phase and caused an accumulation of HCT116 colon cancer cells with >4 N DNA content. Also, 3 p exhibited weak inhibition of the enzymatic activity of human topoisomerase I. Molecular docking studies indicated preferential binding of the compounds to the ATP-binding pocket of the human checkpoint 2 kinase (Chk2) catalytic domain, thus, identifying a novel diaryl 2-propenone chemotype for the development of potent inhibitors of Chk2.

Triterpene derivative: A potential signaling pathway for the fern-9(11)-ene-2α,3β-diol on insulin secretion in pancreatic islet

AIM

Triterpenes and their derivatives influence on carbohydrate metabolism. In vivo and in vitro treatment investigated the effect of the natural triterpene fern-9(11)-ene-2α,3β-diol (1), isolated from Croton heterodoxus, and a derivative triterpene (2) on glucose homeostasis.

MAIN METHODS

The antidiabetic effect of the crude extract from C. heterodoxus leaves, the natural triterpene (1) as well as the derivative triterpene (2) were assayed on glucose tolerance. The effect and the mechanism of action on in vivo treatment with triterpene 2 on glycaemia and insulin secretion were studied. In addition, in vitro studies investigated the mechanism of triterpene 2 on glucose uptake and calcium influx on insulin secretion in pancreatic islets.

KEY FINDINGS

The results show the extract slightly reduced the glycaemia when compared with hyperglycemic group. However, the presence of the substituent electron-withdrawing 4-nitrobenzoyl group in the A-ring of triterpene 2 powered the serum glucose lowering compared to triterpene 1. In addition, in vivo treatment with triterpene 2 significantly increased the insulin secretion induced by glucose and stimulated the glucose uptake and calcium influx in pancreatic islet. The effect of triterpene on calcium influx was completely inhibited by diazoxide, nifedipine and stearoylcarnitine treatment.

SIGNIFICANCE

The stimulatory effect of triterpene 2 on glucose uptake, calcium influx, regulation of potassium (K(+)-ATP) and calcium (L-VDCCs) channels activity as well as the pathway of PKC highlights the mechanism of action of the compound in pancreatic islets on insulin secretion and glucose homeostasis. In addition, this compound did not induce toxicity in this experimental condition.

Hypoglycemic Effect of the Methanol flower Extract of Piper Claussenianum and the Major Constituent 2',6'-dihydroxy-4'-methoxychalcone in Streptozotocin Diabetic Rats

Piper claussenianum inflorescences crude methanol extract was tested for hypoglycemic effect in streptozotocin-induced diabetic rats. The blood glucose levels of rats treated with methanol extract were reduced from 318.4±28.1 mg/dl before treatment to 174.2±38.3 mg/dl after 12 days of treatment (P<0.05). Phytochemical studies were carried out on inflorescences methanol crude extract in order to investigate the possible metabolites responsible for the pharmacological properties of the extract. After chromatographic procedures, three flavonoids were isolated and characterized. The major compound 2’,6’-dihydroxy-4’-methoxychalcone was also tested. Rats that received the chalcone content also displayed a reduction in blood glucose levels from 277.4±7.7 mg/dl before treatment to 158.8±9.2 mg/dl after 12 days of treatment (P<0.05). The results suggest this chalcone is one of the metabolite responsible for the blood glucose levels reduction in rats with streptozotocin-induced diabetes. The inflorescence crude extract of P. claussenianum was found to be composed mainly by flavonoids and may be a potential natural source of compounds with hypoglycemic properties.

Chalcones and their therapeutic targets for the management of diabetes: structural and pharmacological perspectives

Diabetes Mellitus (DM) is the fastest growing metabolic disorder affecting about 387 million people across the globe and is estimated to affect 592 million people by year 2030. The search for newer anti-diabetic agents is the foremost need to control the accelerating diabetic population. Several natural and (semi) synthetic chalcones deserve the credit of being potential candidates that act by modulating the therapeutic targets PPAR-γ, DPP-4, α-glucosidase, PTP1B, aldose reductase, and stimulate insulin secretion and tissue sensitivity. In this review, a comprehensive study (from January 1977 to October 2014) of anti-diabetic chalcones, their molecular targets, structure activity relationships (SARs), mechanism of actions (MOAs) and patents have been described. The compounds which showed promising activity and have a well-defined MOAs, SARs must be considered as prototype for the design and development of potential anti-diabetic agents. They should be evaluated critically at all clinical stages to ensure their therapeutic and toxicological profile to meet the demand of diabetics.

Antihyperglycemic and antihyperlipidemic activities of 2-(4-[(2-hydroxybenzyl) amino]-phenyl amino-methyl)-phenol in STZ induced diabetic rats

Oral administration of 2-(4-[(2-hydroxybenzyl) amino]-phenyl amino-methyl)-phenol (HBPMP) (30 mg/kg) to Streptozotocin (STZ) rats produced significant antidiabetic activity after 6 h of HBPMP administration. Treatment of the STZ rats with HBPMP (30 mg/kg/day) for 30 days resulted in a significant decrease in their Fasting Blood Glucose (FBG), Serum Total Cholesterol (TC), Low Density Lipoprotein-Cholesterol (LDL-C), Very Low Density Lipoprotein-Cholesterol (VLDL-C) and triglycerides (TG) along with an increase in serum High Density Lipoprotein-Cholesterol (HDL-C) levels. Activities of Serum Aspartate transaminase (AST), Alanine transaminase (ALT) and Alkaline phosphatase (ALP) and levels of blood urea and creatinine were improved to near normal levels in the treated STZ rats indicating the protective role of the HBPMP against liver and kidney damage and its non-toxic property. In conclusion, HBPMP possesses antihyperglycemic and antihyperlipidemic activities.

Cytotoxic 3,4,5-trimethoxychalcones as mitotic arresters and cell migration inhibitors

Based on classical colchicine site ligands and a computational model of the colchicine binding site on beta tubulin, two classes of chalcone derivatives were designed, synthesized and evaluated for inhibition of tubulin assembly and toxicity in human cancer cell lines. Docking studies suggested that the chalcone scaffold could fit the colchicine site on tubulin in an orientation similar to that of the natural product. In particular, a 3,4,5-trimethoxyphenyl ring adjacent to the carbonyl group appeared to benefit the ligand-tubulin interaction, occupying the same subcavity as the corresponding moiety in colchicine. Consistent with modeling predictions, several 3,4,5-trimethoxychalcones showed improved cytotoxicity to murine acute lymphoblastic leukemia cells compared with a previously described parent compound, and inhibited tubulin assembly in vitro as potently as colchicine. The most potent chalcones inhibited the growth of human leukemia cell lines at nanomolar concentrations, caused microtubule destabilization and mitotic arrest in human cervical cancer cells, and inhibited human breast cancer cell migration in scratch wound and Boyden chamber assays.

Influence of the traditional Brazilian drink Ilex paraguariensis tea on glucose homeostasis

In this study we examined the acute in vivo effect and short- and long-term in vitro effects of samples from native and commercial Ilex paraguariensis on glucose homeostasis. Also, the potential effect of I. paraguariensis on serum insulin secretion was investigated. The chemical identification and quantification of methyl xanthines and polyphenols in CH₂Cl₂, EtOAc and n-BuOH fractions of native I. paraguariensis as well as infusions of green and roasted I. paraguariensis from a commercial source was verified by high-performance liquid chromatography. The results for the serum glucose-lowering indicated that both fractions and both infusions were able to improve significantly the oral glucose tolerance curve. Additionally, both the EtOAc and n-BuOH fractions induced-insulin secretion, but EtOAc induced an early (at 15 min) and late (at 60 min) biphasic peak of insulin secretion similar to glipizide stimulatory effect. Both fractions increased liver glycogen content compared with fasted normal rats. Also, EtOAc and n-BuOH fractions inhibited in vitro disaccharidases activities after an acute treatment. The maximum inhibitory effect of the EtOAc and n-BuOH fractions on maltase activity (at 5 min) was around 35%. The evident reduction of protein glycation by glucose or fructose with EtOAc and n-BuOH fractions increased from 7 to 28 days of in vitro incubation. Inhibition of bovine serum albumin glycation by glucose and fructose, by around 50% and 90%, respectively, was observed. Additionally, the green and roasted mate infusions reduced the formation of AGEs in a characteristic long-term effect. In conclusion, this study shows that I. paraguariensis has an anti-hyperglycemic potential role able to improve the diabetic status and is probably a source of multiple hypoglycemic compounds.

Synthesis, biological evaluation, and molecular modeling of chalcone derivatives as potent inhibitors of Mycobacterium tuberculosis protein tyrosine phosphatases (PtpA and PtpB)

Tuberculosis (TB) is a major infectious disease caused by Mycobacterium tuberculosis (Mtb). According to the World Health Organization (WHO), about 1.8 million people die from TB and 10 million new cases are recorded each year. Recently, a new series of naphthylchalcones has been identified as inhibitors of Mtb protein tyrosine phosphatases (PTPs). In this work, 100 chalcones were designed, synthesized, and investigated for their inhibitory properties against MtbPtps. Structure-activity relationships (SAR) were developed, leading to the discovery of new potent inhibitors with IC(50) values in the low-micromolar range. Kinetic studies revealed competitive inhibition and high selectivity toward the Mtb enzymes. Molecular modeling investigations were carried out with the aim of revealing the most relevant structural requirements underlying the binding affinity and selectivity of this series of inhibitors as potential anti-TB drugs.

Phloridzin reduces blood glucose levels and improves lipids metabolism in streptozotocin-induced diabetic rats

Phloridzin is the specific and competitive inhibition of sodium/glucose cotransporters in the intestine (SGLT1) and kidney (SGLT2). This property which could be useful in the management of postprandial hyperglycemia in diabetes and related disorders. Phloridzin is one of the dihydrochalcones typically contained in apples and in apple-derived products. The effect of phloridzin orally doses 5, 10, 20 and 40 mg/kg body weight on diabetes was tested in a streptozotocin-induced rat model of diabetes type 1. From beneficial effect of this compound is significant reduction of blood glucose levels and improve dyslipidemia in diabetic rats. As a well-known consequence of becoming diabetic, urine volume and water intake were significantly increased. Administration of phloridzin reduced urine volume and water intake in a dose-dependent manner. Phloretin decreases of food consumption, as well as a marked lowering in the weight. In conclusion, this compound could be proposed as an antihyperglycemic and antihyperlipidemic agent in diabetes and potential therapeutic in obesity.

Hypoglycemic activity of a novel anthocyanin-rich formulation from lowbush blueberry, Vaccinium angustifolium Aiton

Blueberry fruits are known as a rich source of anthocyanin components. In this study we demonstrate that anthocyanins from blueberry have the potency to alleviate symptoms of hyperglycemia in diabetic C57b1/6J mice. The anti-diabetic activity of different anthocyanin-related extracts was evaluated using the pharmaceutically acceptable self-microemulsifying drug delivery system: Labrasol. Treatment by gavage (500 mg/kg body wt) with a phenolic-rich extract and an anthocyanin-enriched fraction formulated with Labrasol lowered elevated blood glucose levels by 33 and 51%, respectively. The hypoglycemic activities of these formulae were comparable to that of the known anti-diabetic drug metformin (27% at 300 mg/kg). The extracts were not significantly hypoglycemic when administered without Labrasol, demonstrating its bio-enhancing effect, most likely due to increasing the bioavailability of the administered preparations. The phenolic-rich extract contained 287.0+/-9.7 mg/g anthocyanins, while the anthocyanin-enriched fraction contained 595+/-20.0 mg/g (cyanidin-3-glucoside equivalents), as measured by HPLC and pH differential analysis methods. The greater hypoglycemic activity of the anthocyanin-enriched fraction compared to the initial phenolic-rich extract suggested that the activity was due to the anthocyanin components. Treatment by gavage (300 mg/kg) with the pure anthocyanins, delphinidin-3-O-glucoside and malvidin-3-O-glucoside, formulated with Labrasol, showed that malvidin-3-O-glucoside was significantly hypoglycemic while delphinidin-3-O-glucoside was not.

Mechanism of action of the stimulatory effect of apigenin-6-C-(2''-O-alpha-l-rhamnopyranosyl)-beta-L-fucopyranoside on 14C-glucose uptake

There has been a growing interest in hypoglycemic agents from natural products, particularly those derived from plants. Flavonoids are naturally occurring phenolic compounds with a broad range of biological activities and the beneficial effects of flavonoids have been studied in relation to diabetes mellitus, either through their capacity to avoid glucose absorption or to improve glucose tolerance. The purpose of this study was to investigate the mechanism of action of the stimulatory effect of apigenin-6-C-(2''-O-alpha-L-rhamnopyranosyl)-beta-L-fucopyranoside (1), isolated from Averrhoa carambola L. (Oxalidaceae) leaves, on (14)C-glucose uptake. This compound (1) was found to have an acute effect on blood glucose lowering in diabetic rats and stimulated glucose-induced insulin secretion after oral treatment in hyperglycemic rats. A significant stimulatory effect of compound 1 on (14)C-glucose uptake was observed at 50 and 100 microM. The effect of compound 1 on glucose uptake was completely nullified by wortmannin, an inhibitor of phosphatidylinositol 3-kinase (PI3K), RO318220, an inhibitor of protein kinase C (PKC), PD98059, a specific inhibitor of mitogen-activated protein kinase (MEK), cycloheximide, an inhibitor of protein synthesis, and colchicine, a microtubule-depolymerizing agent. Compound 1 (100 microM) and insulin (10 nM) did not show any synergistic effect on glucose uptake. These results suggest that the flavonoid may have a dual target of action, as an insulin-secretagogue and also as an insulin-mimetic agent.