In vitro effects of cinnamic acid derivatives on protein tyrosine phosphatase 1B

Exploring the Antiviral Potential of Esters of Cinnamic Acids with Quercetin

Severe acute respiratory syndrome-related Coronavirus 2 (SARS-CoV-2) has infected more than 762 million people to date and has caused approximately 7 million deaths all around the world, involving more than 187 countries. Although currently available vaccines show high efficacy in preventing severe respiratory complications in infected patients, the high number of mutations in the S proteins of the current variants is responsible for the high level of immune evasion and transmissibility of the virus and the reduced effectiveness of acquired immunity. In this scenario, the development of safe and effective drugs of synthetic or natural origin to suppress viral replication and treat acute forms of COVID-19 remains a valid therapeutic challenge. Given the successful history of flavonoids-based drug discovery, we developed esters of substituted cinnamic acids with quercetin to evaluate their in vitro activity against a broad spectrum of Coronaviruses. Interestingly, two derivatives, the 3,4-methylenedioxy 6 and the ester of acid 7, have proved to be effective in reducing OC43-induced cytopathogenicity, showing interesting EC50s profiles. The ester of synaptic acid 7 in particular, which is not endowed with relevant cytotoxicity under any of the tested conditions, turned out to be active against OC43 and SARS-CoV-2, showing a promising EC50. Therefore, said compound was selected as the lead object of further analysis. When tested in a yield reduction, assay 7 produced a significant dose-dependent reduction in viral titer. However, the compound was not virucidal, as exposure to high concentrations of it did not affect viral infectivity, nor did it affect hCoV-OC43 penetration into pre-treated host cells. Additional studies on the action mechanism have suggested that our derivative may inhibit viral endocytosis by reducing viral attachment to host cells.

Ferulic, Sinapic, 3,4-Dimethoxycinnamic Acid and Indomethacin Derivatives with Antioxidant, Anti-Inflammatory and Hypolipidemic Functionality

A series of thiomorpholine and cinnamyl alcohol derivatives, conjugated with cinnamic acid-containing moieties, such as ferulic acid, sinapic acid and 3,4-dimethoxycinnamic acid, were synthesized and tested for their antioxidant, anti-inflammatory and hypolipidemic properties. An indomethacin ester with 2,6-di-tert-butyl-4-(hydroxymethyl)phenol was also prepared for reasons of comparison. The majority of the compounds demonstrated considerable antioxidant capacity and radical scavenging activity, reaching up to levels similar to the well-known antioxidant trolox. Some of them had an increased anti-inflammatory effect on the reduction of carrageenan-induced rat paw edema (range 17-72% at 150 μmol/kg), having comparable activity to the NSAIDs (non-steroidal anti-inflammatory drugs) used as reference. They had moderate activity in soybean lipoxygenase inhibition. All the tested compounds exhibited a significant decrease in lipidemic indices in Triton-induced hyperlipidemia in rats, whilst the most active triglycerides and total cholesterol decreased by 72.5% and 76%, respectively, at 150 μmol/kg (i.p.), slightly better than that of simvastatin, a well-known hypocholesterolemic drug, but with negligible triglyceride-lowering effect. Since our designed compounds seem to exhibit multiple pharmacological activities, they may be of use in occasions involving inflammation, oxidative stress, lipidemic deregulation and degenerative conditions.

Supramolecular Pd@methioine-EDTA-chitosan nanocomposite: an effective and recyclable bio-based and eco-friendly catalyst for the green Heck cross-coupling reaction under mild conditions

Supramolecular palladium(ii) supported on modified chitosan by dl-methionine using an ethylenediaminetetraacetic acid linker (Pd@MET-EDTA-CS) was designed and prepared through a simple procedure. The structure of this novel supramolecular nanocomposite was characterized by different spectroscopic, microscopic and analytical techniques including FTIR, EDX, XRD, FESEM, TGA, DRS, TEM, AA, and BET. The obtained bio-based nanomaterial was successfully investigated, as a highly efficient and green heterogeneous catalyst, in the Heck cross-coupling reaction (HCR) for the synthesis of various valuable biologically active cinnamic acid ester derivatives from the corresponding aryl halides using several acrylates. Indeed, aryl halides containing I or Br survived very well under optimized conditions to afford the corresponding products compared to the substrates with Cl. The prepared Pd@MET-EDTA-CS nanocatalyst promoted the HCR in high to excellent yields and short reaction times with minimum Pd loading (0.0027 mol%) on its structure as well as without any leaching occurring during the process. The recovery of the catalyst was performed by simple filtration and the catalytic activity remained approximately constant after five runs for the model reaction.

Exploring the Gallic and Cinnamic Acids Chimeric Derivatives as Anticancer Agents over HeLa Cell Line: An in silico and in vitro Study

Cervical cancer is one of the most aggressive and important cancer types in the female population, due to its low survival rate. Actually, the search for new bioactive compounds, like gallic and cinnamic acid, is one of the most employed options to finding a treatment. In the present study, 134 phenolic compounds with cytotoxic activity over HeLa cell line were used to generate a descriptive ( R 2 ${{R}^{2}}$ =0.76) and predictive ( Q 2 ${{Q}^{2}}$ =0.69 and Q e x t 2 ${{Q}_{{\rm e}{\rm x}{\rm t}}^{2}}$ =0.62) QSAR model. Structural, electronic, steric, and hydrophobic features are represented as different molecular descriptors in our QSAR model. From this model, nine gallate-cinnamate ester derivatives (N1-N9) were designed and synthesized. Furthermore, in vitro cytotoxic activity was evaluated against HeLa and non-tumorigenic cells. Derivatives N6, N5, N1, and N9 were the most active molecules with IC_50ExpHeLa values from 7.26 to 11.95 μM. Finally, the binding of the synthesized compounds to the colchicine binding site on tubulin was evaluated by molecular docking as a possible action mechanism. N1, N5 and N6 can be considered as templates for the design of new cervical anticancer compounds.

Synthesis of activity evaluation of flavonoid derivatives as ɑ-glucosidase inhibitors

Six flavonoid derivatives were synthesized and tested for anti-α-glucosidase activities. All derivatives were confirmed using NMR and HRMS and exhibited excellent inhibitory effects on α-glucosidase. Derivative four exhibited the highest anti-α-glucosidase activity (IC50: 15.71 ± 0.21 μM). Structure-activity relationship results showed that bromine group would be the most beneficial group to anti-α-glucosidase activity. Inhibitory mechnism and inhibition kinetics results showed derivative four was a reversible and mixed-type inhibitor. Molecular docking revealed that derivative four was tightly bind to the amino acid residues of active pocket of α-glucosidase and formed hydrogen bond, π-π stacking, and Pi-Donor hydrogen with α-glucosidase. Moreover, the physicochemical parameters of all derivatives were assessed using SwissADME software. This results also showed that the hybridization of flavonoid and phenylpropionic acid would be a useful strategy for the development of α-glucosidase inhibitors.

Novel cinnamic acid magnolol derivatives as potent α-glucosidase and α-amylase inhibitors: Synthesis, in vitro and in silico studies

In this study, twenty novel cinnamic acid magnolol derivatives were synthesized, and screened for their anti-hyperglycemic potential. All synthesized compounds exhibited good to moderate α-glucosidase and α-amylase inhibitory activities with IC₅₀ values: 5.11 ± 1.46-90.26 ± 1.85 µM and 4.27 ± 1.51-49.28 ± 2.54 µM as compared to the standard acarbose (IC₅₀: 255.44 ± 1.89 μM and 80.33 ± 2.95 μM, respectively). Compound 6j showed the strongest inhibitory activity against α-glucosidase (IC₅₀ = 5.11 ± 1.46 µM) and α-amylase (IC₅₀ = 4.27 ± 1.51 µM). Kinetic study indicated that compound 6j was reversible and a mixed type inhibitor against α-glucosidase and α-amylase. In silico studies revealed the binding interaction between 6j and two enzymes, respectively. Finally, cells cytotoxicity assay revealed that compound 6j showed low toxicity against 3 T3-L1 cells and HepG2 cells.

Role of dietary polyphenols on gut microbiota, their metabolites and health benefits

The beneficial health roles of dietary polyphenols in preventing oxidative stress related chronic diseases have been subjected to intense investigation over the last two decades. As our understanding of the role of gut microbiota advances our knowledge of the antioxidant and anti-inflammatory functions of polyphenols accumulates, there emerges a need to examine the prebiotic role of dietary polyphenols. This review focused onthe role of different types and sources of dietary polyphenols on the modulation of the gut microbiota, their metabolites and how they impact on host health benefits. Inter-dependence between the gut microbiota and polyphenol metabolites and the vital balance between the two in maintaining the host gut homeostasis were discussed with reference to different types and sources of dietary polyphenols. Similarly, the mechanisms behind the health benefits by various polyphenolic metabolites bio-transformed by gut microbiota were also explained. However, further research should focus on the importance of human trials and profound links of polyphenols-gut microbiota-nerve-brain as they provide the key to unlock the mechanisms behind the observed benefits of dietary polyphenols found in vitro and in vivo studies.

Inhibition of Human Cathepsins B and L by Caffeic Acid and Its Derivatives

Caffeic acid (CA) and its derivatives caffeic acid phenethyl ester (CAPE) and chlorogenic acid (CGA) are phenolic compounds of plant origin with a wide range of biological activities. Here, we identify and characterize their inhibitory properties against human cathepsins B and L, potent, ubiquitously expressed cysteine peptidases involved in protein turnover and homeostasis, as well as pathological conditions, such as cancer. We show that CAPE and CGA inhibit both peptidases, while CA shows a preference for cathepsin B, resulting in the strongest inhibition among these combinations. All compounds are linear (complete) inhibitors acting via mixed or catalytic mechanisms. Cathepsin B is more strongly inhibited at pH 7.4 than at 5.5, and CA inhibits its endopeptidase activity preferentially over its peptidyl-dipeptidase activity. Altogether, the results identify the CA scaffold as a promising candidate for the development of cathepsin B inhibitors, specifically targeting its endopeptidase activity associated with pathological proteolysis of extracellular substrates.

Cinnamic Acid Derivatives and Their Biological Efficacy

The role played by cinnamic acid derivatives in treating cancer, bacterial infections, diabetes and neurological disorders, among many, has been reported. Cinnamic acid is obtained from cinnamon bark. Its structure is composed of a benzene ring, an alkene double bond and an acrylic acid functional group making it possible to modify the aforementioned functionalities with a variety of compounds resulting in bioactive agents with enhanced efficacy. The nature of the substituents incorporated into cinnamic acid has been found to play a huge role in either enhancing or decreasing the biological efficacy of the synthesized cinnamic acid derivatives. Some of the derivatives have been reported to be more effective when compared to the standard drugs used to treat chronic or infectious diseases in vitro, thus making them very promising therapeutic agents. Compound 20 displayed potent anti-TB activity, compound 27 exhibited significant antibacterial activity on S. aureus strain of bacteria and compounds with potent antimalarial activity are 35a, 35g, 35i, 36i, and 36b. Furthermore, compounds 43d, 44o, 55g–55p, 59e, 59g displayed potent anticancer activity and compounds 86f–h were active against both hAChE and hBuChE. This review will expound on the recent advances on cinnamic acid derivatives and their biological efficacy.

Identification of components and metabolites in plasma of type 2 diabetic rat after oral administration of Jiao-Tai-Wan using ultra-performance liquid chromatography/quadrupole time-of-flight mass spectrometry

Jiao-Tai-Wan, which is composed of Coptis Rhizoma and Cinnamon Cortex, has been recently used to treat type 2 diabetes. Owing to lack of data on its prototypes and metabolites, elucidation of the pharmacological and clinically safe levels of this formula has been significantly hindered. To screen more potential bioactive components of Jiao-Tai-Wan, we identified its multiple prototypes and metabolites in the plasma of type 2 diabetic rats by ultra high performance liquid chromatography/quadrupole-time-of-flight mass spectrometry. A total of 47 compounds were identified in the plasma of type 2 diabetic rats, including 22 prototypes and 25 metabolites, with alkaloids constituting the majority of the absorbed prototype components. In addition, this is the first study to detect vanillic acid, gallic acid, chlorogenic acid, protocatechuic acid, 2-hydroxycinnamic acid, 3-hydroxycinnamic acid, 4-hydroxycinnamic acid, and 2-methoxy cinnamic acid after oral administration of Jiao-Tai-Wan. The prototypes from Jiao-Tai-Wan were extensively metabolized by demethylation, hydroxylation, and reduction in phase Ⅰ metabolic reactions and by methylation or conjugation of glucuronide or sulfate in phase Ⅱ reactions. This is the first systematic study on the components and metabolic profiles of Jiao-Tai-Wan in vivo. This study provides a useful chemical basis for further pharmacological research and clinical application of Jiao-Tai-Wan.

Does Fermentation Really Increase the Phenolic Content in Cereals? A Study on Millet

Millet is underutilized in Europe, despite its advantages compared to other common cereals. In Asia and Africa, millet is mainly eaten in fermented form; its consumption has beneficial properties on human health. Three millet batches were compared in terms of free and bound phenols by High Performance Liquid Chromatography-Diode Array Detector-Mass Spectrometry (HPLC-DAD-MS). The richest one in terms of bound phenols was selected for testing via a basic (0.1 M NaOH) and an acidic (1.2 M H₂SO₄) hydrolysis, in which 149.3 and 193.6 mg/100 g of phenols were recovered, respectively. The ability of fermentation, with yeast and Lactobacilli, to increase the content of phenolic compounds was verified. Five withdrawalswere performed to verify the influence of fermentation time on the total phenolic content. The greatest phenolic content was observed after 72 h. Fermentation increased the cinnamic acids and flavonoids contents by approximately 30%. Vitexin and vitexin 2″-O-rhamnoside contents were significantly higher in the fermented millet; these compounds partially inhibit the protein tyrosine phosphatase enzyme, which is overexpressed in type-2 diabetes. A molecular dynamic simulation showed the two flavonoids to be allosteric inhibitors. The phenolic extract from fermented millet demonstrated a higher level of antioxidant protection on human erythrocytes by ex vivo cellular antioxidant activity in red blood cells. In this context, functional foods based on fermented millet could represent a new trend in European markets.

Study on a Fermented Whole Wheat: Phenolic Content, Activity on PTP1B Enzyme and In Vitro Prebiotic Properties

Fermented cereals, staple foods in Asia and Africa, are recently receiving a growing interest in Western countries. The object of this work is the characterization of a fermented wheat used as a food ingredient and dietary supplement. To this aim, the phenolic composition, the activity on protein tyrosine phosphatase 1B (PTP1B), an enzyme overexpressed in type-II diabetes, the in vitro prebiotic properties on Lactobacillusreuteri and the microbial composition were investigated. Basic and acidic hydrolysis were tested for an exhaustive recovery of bound phenols: the acidic hydrolysis gave best yields. Methyl ferulate and neocarlinoside were identified for the first time in wheat. The inhibitory power of the extracts of several batches were investigated on PTP1B enzyme. The product was not able to inhibit the enzyme, otherwise, for the first time, a complete inhibition was observed for schaftoside, a major C-flavonoid of wheat. The microbial composition was assessed identifying Lactobacillus, Enterococcus, and Pediococcus as the main bacterial species. The fermented wheat was a suitable substrate for the grown of L. reuteri, recognized for its health properties in the human gut. The proposed method for phenols is easier compared to those based on strong basic hydrolysis; our results assessed the bound phenols as the major fraction, differently from that suggested by the literature for fermented cereals.

Does oral spirulina protect the cornea from formaldehyde exposure? Application to anatomy laboratories

In this study, the protective effect of spirulina on corneal injury after formaldehyde (FA) exposure was assessed. Thirty adult male albino rats were divided into four groups. Group I: 12 rats were divided into two subgroups: I-a (negative control) and I-b (positive control). Group II (spirulina group): six rats received spirulina via an oral gavage feeding needle at a daily dose of 400 mg/kg b.w. Group III (FA exposure group): six rats were subjected to 10% FA inhalation for 2 h per day for 2 weeks (5 days per week). Group IV (FA exposure group treated with spirulina): six rats were exposed to 10% FA as in group III, with co-administration of spirulina as in group II. After 2 weeks, all the rats were sacrificed; the corneas were dissected and processed for paraffin sections. The sections were stained with hematoxylin and eosin (H&E), Masson's trichrome (MTC), or avidin-biotin peroxidase, and examined by light microscopy. The sections of rat cornea exposed to FA (Group III) showed disorganized and compressed epithelium with erosions. Subepithelial mononuclear cell infiltration and invasion of blood vessels were also evident. Stromal collagen fibers were disorganized and widely separated. All these changes were ameliorated by administration of spirulina (Group IV). Corneal thickness was nearly normal in Group IV, statistically significantly less than in Group III. It was concluded that spirulina protects against FA-induced corneal injury in rats. Clin. Anat. 31:830-837, 2018. © 2018 Wiley Periodicals, Inc.

Cinnamic Acid and Its Derivatives: Mechanisms for Prevention and Management of Diabetes and Its Complications

With recent insight into the development of dietary supplements and functional foods, search of effective phytochemical compounds and their mechanisms involved in prevention and management of diabetes and its complications are now being assessed. Cinnamic acid and its derivatives occur naturally in high levels of plant-based foods. Among various biological activities, cinnamic acid and its derivatives are associated with a beneficial influence on diabetes and its complications. The aim of the review is to summarize the potential mechanisms of these compounds for prevention and management of diabetes and its complications. Based on several in vitro studies and animal models, cinnamic acid and its derivatives act on different mechanism of actions, including stimulation of insulin secretion, improvement of pancreatic β-cell functionality, inhibition of hepatic gluconeogenesis, enhanced glucose uptake, increased insulin signaling pathway, delay of carbohydrate digestion and glucose absorption, and inhibition of protein glycation and insulin fibrillation. However, due to the limited intestinal absorption being a result of low bioavailability of cinnamic acid and its derivatives, current improvement efforts with entrapping into solid and liquid particles are highlighted. Further human clinical studies are needed to clarify the effects of cinnamic acid and its derivatives in diabetic patients.

Synthesis, characterization, and computational study of the supramolecular arrangement of a novel cinnamic acid derivative

In this work, we present the synthesis, characterization, and computational study of the supramolecular arrangement of a new cinnamic acid derivative: ethyl-(2E)-3-(4-hydroxy-3,5-dimethoxyphenyl)-prop-2-enoate (EHD). Single crystals of EHD were obtained using ethyl ether as solvent and a slow evaporation technique. Its crystallographic structure, derived from X-ray diffraction experiments, includes a disordered water molecule on the EHD supramolecular structure. This water molecule participates in four O-H···O hydrogen bonds, which are arranged as a centrosymmetric H-bond array with the water at the center. Electronic and structural properties of the isolated EHD molecule and of the EHD molecule in the presence of one water molecule were calculated at the B3LYP/6-311++G(2d,2p) level of theory. These calculations show that the HOMO-LUMO energy gap of EHD decreases upon the introduction of the water molecule, suggesting that EHD becomes a stronger electron acceptor. These results indicate that the water molecule helps to stabilize the crystal structure in this system containing unequal numbers of acceptor and donor atoms. The supramolecular synthon involving the disordered water molecule and the supramolecular features presented here provide new possibilities in the design of functional materials and should also help us to gain a deeper understanding of the processes by which molecules recognize biological targets.

Chemical Constituents of Euonymus alatus (Thunb.) Sieb. and Their PTP1B and α-Glucosidase Inhibitory Activities

Phytochemical study on the corks of Euonymus alatus resulted in the isolation of a novel 3-hydroxycoumarinflavanol (23), along with ten triterpenoids (1-10), ten phenolic derivatives (11-20), and two flavonoid glycosides (21 and 22). Their structures were determined by extensive 1D and 2D-nuclear magnetic resonance spectroscopic and mass spectrometry data analysis. Furthermore, their inhibitory effects against the protein tyrosine phosphatases 1B (PTP1B) and α-glucosidase enzyme activity were evaluated. Compounds 6, 7, 9, 15, 19, and 23 were non-competitive inhibitors, exhibiting most potency with IC50 values ranging from 5.6 ± 0.9 to 18.4 ± 0.3 µm, against PTP1B. Compound 3 (competitive), compounds 5 and 15 (mixed-competitive) displayed potent inhibition with IC50 values of 15.1 ± 0.7, 23.6 ± 0.6 and 14.8 ± 0.9 µm, respectively. Moreover, compounds 15, 20, and 23 exhibited potent inhibition on α-glucosidase with IC50 values of 10.5 ± 0.8, 9.5 ± 0.6, and 9.1 ± 0.5 µm, respectively. Thus, these active ingredients may have value as new lead compounds for the development of new antidiabetic agents.

Ferulic acid exerts its antidiabetic effect by modulating insulin-signalling molecules in the liver of high-fat diet and fructose-induced type-2 diabetic adult male rat

Ferulic acid (FA) is a phenolic phytochemical known for its antidiabetic property The present study is designed to evaluate the mechanism behind its antidiabetic property in high-fat and fructose-induced type 2 diabetic adult male rats. Animals were divided into 5 groups: (i) control, (ii) diabetic control, (iii) diabetic animals treated with FA (50 mg/(kg body weight · day)(-1), orally) for 30 days, (iv) diabetic animals treated with metformin (50 mg/(kg body weight · day)(-1), orally) for 30 days, and (v) control rats treated with FA. FA treatment to diabetic animals restored blood glucose, serum insulin, glucose tolerance, and insulin tolerance to normal range. Hepatic glycogen concentration, activity of glycogen synthase, and glucokinase were significantly decreased, whereas activity of glycogen phosphorylase and enzymes of gluconeogenesis (phosphoenolpyruvate carboxykinase (PEPCK) and glucose-6-phosphatase (G6Pase)) were increased in diabetic animals and FA restored these to normal levels similar to that of metformin. FA improved the insulin signalling molecules and reduced the negative regulators of insulin signalling. The messenger RNA of gluconeogenic enzyme genes (PEPCK and G6Pase) and the interaction between forkhead transcription factor-O1 and promoters of gluconeogenic enzyme genes (PEPCK and G6Pase) was reduced significantly by ferulic acid. It is concluded from the present study that FA treatment to type 2 diabetic rats improves insulin sensitivity and hepatic glycogenesis but inhibits gluconeogenesis and negative regulators of insulin signalling to maintain normal glucose homeostasis.

Wound healing potential of Spirulina platensis extracts on human dermal fibroblast cells

Blue-green alga (Spirulina platensis) is a well renowned nutri-supplement due to its high nutritional and medicinal properties. The aim of this study was to examine the wound healing efficiency of Spirulina platensis at various solvent extracts using in vitro scratch assay on human dermal fibroblast cells (HDF). Various gradient solvent extracts (50 μg/ml of methanolic, ethanolic and aqueous extracts) from Spirulina platensis were treated on HDF cells to acquire its wound healing properties through scratch assay and in this investigation we have used allantoin, as a positive control to compare efficacy among the phytoextracts. Interestingly, aqueous extract were found to stimulate proliferation and migration of HDF cells at given concentrations and enhanced closure rate of wound area within 24 hours after treatment. Methanolic and ethanolic extracts have shown proliferative effect, however these extracts did not aid in the migration and closure of wound area when compared to aqueous extract. Based on phytochemical profile of the plant extracts analyzed by LC-MS/MS, it was shown that compounds supposedly involved in accelerating wound healing are cinnamic acid, narigenin, kaempferol, temsirolimus, phosphatidylserine isomeric derivatives and sulphoquinovosyl diacylglycerol. Our findings concluded that blue-green algae may pose potential biomedical application to treat various chronic wounds especially in diabetes mellitus patients.