Synthesis and evaluation of caffeic acid amides as antioxidants

Semi-synthesis of phenolic-amides and their cytotoxicity against THP-1, HeLa, HepG2 and MCF-7 cell lines

In the present study, we derivatized several hydroxycinnamic and hydroxybenzoic acids to phenolic amides (PAMs) via one step BOP mediated amide coupling reactions. Fifteen PAMs were synthesized in >40% yields and were screened for their cytotoxic activities against four cancer cell lines: THP-1 (leukaemia), HeLa (cervical), HepG2 (liver), and MCF-7 (breast), in comparison to 5-flurouracil (5-FU). Four amides showed IC50 ranging from 5 to 55 µM against all four cell lines. In contrast, tetradecyl-gallic-amide (13) affected only THP-1 leukaemia cells with IC50 of 3.08 µM. The activities of these compounds support the promise of phenolic amides as anticancer agents.

The conjugates of 5'-deoxy-5-fluorocytidine and hydroxycinnamic acids - synthesis, anti-pancreatic cancer activity and molecular docking studies

New amide conjugates 1-6 of hydroxycinnamic acids (HCA) and 5'-deoxy-5-fluorocytidine (5-dFCR), the prodrug of 5-fluorouracil (5-FU), were synthesized and tested in vitro against pancreatic cancer lines (PDAC). The compounds showed slightly higher efficacy against primary BxPC-3 cells (IC50 values of 14-45 μM) than against metastatic AsPC-1 (IC50 values of 37-133 μM), and similar to that of 5-FU for both PDAC lines. Compound 1, which has a para-(acetyloxy)coumaroyl substituent, was found to be the most potent (IC50 = 14 μM) with a selectivity index of approximately 7 to normal dermal fibroblasts (IC50 = 96 μM). The potential pharmacological profiles were discussed on the basis of the ADME data. Docking to the carboxylesterase CES2 showed that the synthesized compounds have the ability to bind via hydrogen bonding between a specific acetate group of the sugar moiety and Ser228, which belongs to the catalytic triad that causes hydrolysis. Docking to albumin, a major transport protein in the circulatory system, revealed a strong interaction of the conjugates at the binding site which is native to warfarin and responsible for its transport in the body.

First In Vitro-In Silico Analysis for the Determination of Antimicrobial and Antioxidant Properties of 2-(4-Methoxyphenylamino)-2-oxoethyl Methacrylate and p-Acetamide

The antibacterial, antifungal, and antioxidant activities of 2-chloro-N-(4-methoxyphenyl)acetamide (p-acetamide) and 2-(4-methoxyphenylamino)-2-oxoethyl methacrylate (MPAEMA) were investigated by in vitro experiments and in silico analyses. MPAEMA has an antibacterial effect only against Gram-positive Staphylococcus aureus. It was determined that this did not affect any other bacteria and Candida glabrata yeast. On the other hand, p-acetamide showed antimicrobial activity against S. aureus ATCC 25923, C. glabrata ATCC 90030, Bacillus subtilis NRRL 744, Enterococcus faecalis ATCC 551289, Escherichia coli ATCC 25922, Klebsiella pneumoniae NRLLB4420, Pseudomonas aeruginosa ATCC 27853, and Listeria monocytogenes ATCC 1911. p-Acetamide showed the greatest antifungal effect by inhibiting the colony growth of Trichoderma longibrachiatum (98%). This was followed by Mucor plumbeus with 83% and Fusarium solani with 21%. MPAEMA inhibited colony growth of T. longibrachiatum by 95% and that of M. plumbeus by 91%. Also, p-acetamide and MPAEMA had a scavenging effect on free radicals. According to results of the in silico analysis, the antimicrobial effect of these compounds is due to their effect on DNA ligase. Based on drug-likeness analysis, they were found to be consistent with the Lipinski, Veber, or Ghose rule. p-Acetamide and MPAEMA may be used as drugs.

Synthesis of Schiff Bases and Secondary Amines with Indane Skeleton; Evaluation of Their Antioxidant, Antibiotic, and Antifungal Activities

In this study, Schiff bases were synthesized by utilizing the reaction of 4- and 5-aminoindane with substituted benzaldehydes. After the reduction of isolated Schiff bases with NaBH4 , the corresponding secondary amine derivatives were obtained. The structures of all synthesized molecules were confirmed by 1 H-NMR, 13 C-NMR, FT-IR, and ESI-MS. Antioxidant activities of all synthesized molecules were investigated by DPPH method, and IC50 values were calculated. In addition, antibacterial activities of targets were investigated by the well diffusion method, and then MIC99 values were calculated. While only four of the sixteen synthesized molecules showed a high level of antioxidant activity, all of the molecules exhibited biological activity against Gram-positive and Gram-negative bacteria to varying degrees. In addition, all the synthesized molecules showed high antifungal activity. In antioxidant capacity studies, the IC50 values of 2-(((2,3-dihydro-1H-inden-5-yl)amino)methyl)-6-methoxyphenol (4 d) and 2-(((2,3-dihydro-1H-inden-4-yl)amino)methyl)-6-methoxyphenol (7 d) were determined to be 18.1 μg and 35.1 μg, respectively, and these values are much stronger than BHT (butylated hydroxytoluene) and BHA (butylated hydroxyanisole) used as positive controls. The fact that targets have the same core structure with different substituents has revealed a good structure-activity relationship.

Synthesis of Thermoresponsive, Catechol-Rich Poly(ethylene glycol) Brush Polymers for Attenuating Cellular Oxidative Stress

Herein, we report a platform to integrate customizable quantities of catechol units into polymers by reacting caffeic acid carbonic anhydride with polymers having pendant amine groups. Brush poly(ethylene glycol)-caffeamide (PEG-CAF) copolymers based on oligo(ethylene glycol)methyl ether methacrylate (OEGMA₅₀₀) were obtained with a catechol content of approximately 30, 40, and 50 mol % (vs OEGMA content). Owing to the hydrophobicity of the introduced CAF groups, the catechol copolymers exhibited cloud points in the range of 23-46 °C and were used to fabricate thermoresponsive Fe^III metal-phenolic network capsules. Polymers with the highest CAF content (50 mol %) proved most effective for attenuating reactive oxygen species levels in vitro, in co-cultured fibroblasts, and breast cancer cells, even in the presence of an exogenous oxidant source. The reported approach to synthesize customizable catechol materials could be generalized to other amine-functional polymers, with potential biomedical applications such as adhesives or stimuli-responsive drug delivery systems.

A Straightforward Access to New Amides of the Melanin Precursor 5,6-Dihydroxyindole-2-carboxylic Acid and Characterization of the Properties of the Pigments Thereof

We report herein an optimized procedure for preparation of carboxamides of 5,6-dihydroxyindole-2-carboxylic acid (DHICA), the main biosynthetic precursor of the skin photoprotective agents melanins, to get access to pigments with more favorable solubility properties with respect to the natural ones. The developed procedure was based on the use of a coupling agent (HATU/DIPEA) and required protection of the catechol function by easily removable acetyl groups. The O-acetylated compounds could be safely stored and taken to the reactive o-diphenol form just before use. Satisfactorily high yields (>85%) were obtained for all amides. The oxidative polymerization of the synthesized amides carried out in air in aqueous buffer at pH 9 afforded melanin-like pigmented materials that showed chromophores resembling those of DHICA-derived pigments, with a good covering of the UVA and the visible region, and additionally exhibited a good solubility in alcoholic solvents, a feature of great interest for the exploitation of these materials as ingredients of dermocosmetic formulations.

Synthesis of Coumarin and Homoisoflavonoid Derivatives and Analogs: The Search for New Antifungal Agents

A set of twenty-four synthetic derivatives, with coumarin and homoisoflavonoid cores and structural analogs, were submitted for evaluation of antifungal activity against various species of Candida. The broth microdilution test was used to determine the Minimum Inhibitory Concentration (MIC) of the compounds and to verify the possible antifungal action mechanisms. The synthetic derivatives were obtained using various reaction methods, and six new compounds were obtained. The structures of the synthesized products were characterized by FTIR spectroscopy: ¹H-NMR, ¹³C-NMR, and HRMS. The coumarin derivative 8 presented the best antifungal profile, suggesting that the pentyloxy substituent at the C-7 position of coumarin ring could potentiate the bioactivity. Compound 8 was then evaluated against the biofilm of C. tropicalis ATCC 13803, which showed a statistically significant reduction in biofilm at concentrations of 0.268 µmol/mL and 0.067 µmol/mL, when compared to the growth control group. For a better understanding of their antifungal activity, compounds 8 and 21 were submitted to a study of the mode of action on the fungal cell wall and plasma membrane. It was observed that neither compound interacted directly with ergosterol present in the fungal plasma membrane or with the fungal cell wall. This suggests that their bioactivity was due to interaction involving other pharmacological targets. Compound 8 was also subjected to a molecular modeling study, which showed that its antifungal action mechanism occurred mainly through interference in the redox balance of the fungal cell, and by compromising the plasma membrane; not by direct interaction, but by interference in ergosterol synthesis. Another important finding was the antifungal capacity of homoisoflavonoids 23 and 24. Derivative 23 presented slightly higher antifungal activity, possibly due to the presence of the methoxyl substituent in the meta position in ring B.

Potential of Caffeic Acid Derivatives as Antimalarial Leads

Background:

Background Malaria remained one of the deadliest infectious diseases in 2021. Indeed, this infection, mostly caused by a protozoan called Plasmodium falciparum, is responsible for more than 200 million cases and around 400 000 related deaths annually, mainly in Africa. Despite the availability of efficient drugs, an increase of patients has occurred since 2015, which could be due to the development of resistances from the parasite, but also from its vectors, Anopheles mosquitoes. Consequently, it is necessary to search for new alternative treatments.

Methods:

Methods Polyphenols, and more precisely small phenolic acids, could represent a good starting point for new antimalarials. Indeed, these molecules, including caffeic acid (1), possess several pharmacological activities and an interesting pharmacokinetic profile. Therefore, we have developed several small derivatives of this scaffold to define the potential pharmacophore responsible for the antiplasmodial properties

Results:

Results A good to low activity on Plasmodium falciparum (IC50 = 16-241 µM) was observed, especially for the small ester derivatives (2-6). These molecules were good antiplasmodials compared to their mother compound (IC50 = 80 µM) and showed selectivity against human cells. These structures have also highlighted the need for catechol and carboxyl moieties in the anti-Plasmodium effect.

Conclusion:

Conclusion None of the synthetic caffeate derivatives reported here seemed sufficiently effective to become a potential antimalarial (IC50 < 1 µM). However, the significant increase of their efficacy on the malarial agent and the selectivity to human cells, highlighted their potential as new leads for future developments

A Comparative DFT Study on the Antioxidant Activity of some Novel 3-hydroxypyridine-4-one Derivatives

The current study on the antioxidant activity of Kojic acid and 3-hydroxypyridine-4-one derivatives was performed by implementation of density functional theory calculations with the B3LYP hybrid functional and the 6-311++ G** basis set in Polarizable Continuum Model. Compounds under evaluation were previously synthesized by our research group. The DPPH scavenging effect and IC 50 values of them in mM concentrations were evaluated. Subsequently, various electronic and energetic descriptors such as HOMO and LUMO energy gaps, bonding dissociation enthalpy of OH bond, ionization potential, electron affinity, hardness, and softness, NBOs and spin density of radical and neutral species were used to study antioxidant properties of investigated compounds. The computations detected two compounds, HP3 and HP4 , with significant antioxidant activity. Energetic descriptors indicated that SPLET mechanism is preferred over than other antioxidant mechanism and computational results were in accordance with the experimental results.

Comprehensive review on ethnobotanical uses, phytochemistry, biological potential and toxicology of Parthenium hysterophorus L.: A journey from noxious weed to a therapeutic medicinal plant

ETHNO-PHARMACOLOGICAL RELEVANCE

Parthenium hysterophorus L. is a noxious weed and a species of flowering plant in the Asteraceae family. It is regarded as the seventh most deadly weed in the world: harmful to both humans and livestock. It is widely known as Congress Grass or Feverfew. Despite its pitfalls, P. hysterophorus bestows medicinal effects. Although prolific in nature and difficult to control, many novel applications of this controversial herb have been discovered as an approach to manage the weed.

AIM

The current review aims to compile all the ethnobotanical, phytochemistry, biological activities and utilities, clinical studies and toxicity data available on P. hysterophorus and its major chemical constituent parthenin.

MATERIALS AND METHODS

Extensive literature surveyed Google search, Google scholar, Wiley online library, Elsevier, Springer, Science direct, American Chemical Society, Royal Society of Chemistry and Research Gate.

RESULT

According to the study, P. hysterophorus is utilized as a traditional medicine throughout Central America and the Caribbean. It can be used to treat skin infections, dermatitis, amoebic dysentery, and as an analgesic in the treatment of muscular rheumatism. The extracts obtained from P. hysterophorus have anti-inflammatory, antioxidant, larvicidal, anti-microbial, insecticidal, hypoglycaemic and anti-cancer activity.

CONCLUSION

The earlier investigations confirmed that P. hysterophorus has numerous traditional and biological applications. However, the scientific data are limited in clinical and toxicological studies. Therefore, further research is required on clinical and toxicological aspects to understand the complete potential and effects of P. hysterophorus.

Tailored Functionalization of Natural Phenols to Improve Biological Activity

Phenols are widespread in nature, being the major components of several plants and essential oils. Natural phenols' anti-microbial, anti-bacterial, anti-oxidant, pharmacological and nutritional properties are, nowadays, well established. Hence, given their peculiar biological role, numerous studies are currently ongoing to overcome their limitations, as well as to enhance their activity. In this review, the functionalization of selected natural phenols is critically examined, mainly highlighting their improved bioactivity after the proper chemical transformations. In particular, functionalization of the most abundant naturally occurring monophenols, diphenols, lipidic phenols, phenolic acids, polyphenols and curcumin derivatives is explored.

Synthesis of Caffeoyl-Prolyl-Histidyl-Xaa Derivatives and Evaluation of Their Activities and Stability upon Long-Term Storage

Antioxidants play a critical role in the treatment of degenerative diseases and delaying the aging of dermal tissue. Caffeic acid (CA) is a representative example of the antioxidants found in plants. However, CA is unsuitable for long-term storage because of its poor stability under ambient conditions. Caffeoyl-Pro-His-NH₂ (CA-Pro-His-NH₂, CA-PH) exhibits the highest antioxidant activity, free radical scavenging and lipid peroxidation inhibition activity among the histidine-containing CA-conjugated dipeptides reported to date. The addition of short peptides to CA, such as Pro-His, is assumed to synergistically enhance its antioxidative activity. In this study, several caffeoyl-prolyl-histidyl-Xaa-NH₂ derivatives were synthesized and their antioxidative activities evaluated. CA-Pro-His-Asn-NH₂ showed enhanced antioxidative activity and higher structural stability than CA-PH, even after long-term storage. CA-Pro-His-Asn-NH₂ was stable for 3 months, its stability being evaluated by observing the changes in its NMR spectra. Moreover, the solid-phase synthetic strategy used to prepare these CA-Pro-His-Xaa-NH₂ derivatives was optimized for large-scale production. We envision that CA-Pro-His-Xaa-NH₂ derivatives can be used as potent dermal therapeutic agents and useful cosmetic ingredients.

New Hybrids Based on Curcumin and Resveratrol: Synthesis, Cytotoxicity and Antiproliferative Activity against Colorectal Cancer Cells

We synthesized twelve hybrids based on curcumin and resveratrol, and their structures were elucidated by spectroscopic analysis. The chemopreventive potential of these compounds was evaluated against SW480 human colon adenocarcinoma cells, its metastatic derivative SW620, along with the non-malignant CHO-K1 cell line. Among the tested compounds, hybrids 3e and 3i (for SW480) and 3a, 3e and 3k (for SW620) displayed the best cytotoxic activity with IC₅₀ values ranging from 11.52 ± 2.78 to 29.33 ± 4.73 µM for both cell lines, with selectivity indices (SI) higher than 1, after 48 h of treatment. Selectivity indices were even higher than those reported for the reference drug, 5-fluorouracil (SI = 0.96), the starting compound resveratrol (SI = 0.45) and the equimolar mixture of curcumin plus resveratrol (SI = 0.77). The previous hybrids showed good antiproliferative activity.

Antioxidant and Anticancer Properties of Functionalized Ferrocene with Hydroxycinnamate Derivatives-An Integrated Experimental and Theoretical Study

Two ferrocenyl derivatives, Fc-CA and Fc-FA, were synthesized by a condensation reaction between the amino ferrocene and hydroxycinnamic acids, that is, caffeic acid (CA) and ferulic acid (FA). The structures and purity of all compounds were characterized by ¹H- and ¹³C NMR spectroscopies, Mass spectrometry (MS), and elemental analysis. The antioxidant properties of Fc-CA and Fc-FA and of its ligand were studied for free radical scavenging activity toward DPPH^•, superoxide anion (O₂^•-), NO^•, and ABTS^•+ by UV-vis and electron spin resonance spectroscopies. The cytotoxicity of Fc-CA and Fc-FA against MCF-7 and MDA-MB-231 breast cancer cells and MRC-5 human lung fibroblasts cell was higher than that of cisplatin. The geometry and electronic structures of all compounds were then simulated using density functional theory at M05-2X/6-311+G(d,p) level of theory. Thermodynamics of the free radical quenching reactions by common mechanisms reveal the higher antioxidant properties of the Fc-CA and Fc-FA in comparison to their ligands. An in-depth study of the free radical scavenging activity against HOO^• and HO^• radicals was performed for two of the most favorable and competitive mechanisms, the hydrogen transfer (either hydrogen atom transfer or proton-coupled electron transfer mechanisms) and the radical adduct formation. The in silico studies indicated that ferrocenyl derivatives exhibited prominent binding affinity to protein models in comparison to CA and FA. Their dock scores were notable at ligand binding sites of ERα, Erβ, and JAK2 proteins. Dock pose analysis also shed light into the possible mechanism of action for the studied compounds.

Stereoselective Formal Hydroamidation of Si-Substituted Arylacetylenes with DIBAL-H and Isocyanates: Synthesis of (E)- and (Z)-α-Silyl-α,β-unsaturated Amides

An efficient and stereoselective method for the synthesis of (E)- and (Z)-α-silyl-α,β-unsaturated amides and its synthetic applications are presented herein. The solvent-controlled hydroaluminations of Si-substituted alkynes with DIBAL-H generate diastereomerically enriched alkenylaluminum reagents that are directly reacted with isocyanates at ambient temperature to afford α-silyl-α,β-unsaturated amides in high yields with retained stereoselectivity. In particular, this process enables the synthesis of a broad range of (E)-α-silyl-α,β-unsaturated amides, which are the less studied isomers. The synthetic utility of this method is highlighted by its short reaction time, ease of purification, easily accessible substrates and reagents, gram-scale synthesis, and the further transformations of C-Si bonds into C-H, C-X, and C-C bonds.

Synthesis of caffeic acid sulfonamide derivatives and their protective effect against H2O2 induced oxidative damage in A549 cells

Exogenous antioxidants are considered as important therapeutic tools for oxidative stress associated disorders as they can regulate the redox state, which is associated with cell and organ function. Inspired by natural polyphenols, six new caffeic acid sulfonamide derivatives were synthesized by coupling sulfonamides to the backbone of caffeic acid with good yields. Their structure and lipophilicity were characterized by 1H nuclear magnetic resonance (NMR), 13C{1H} NMR, infrared spectroscopy (IR) and oil-water partition coefficient assay. Their free radical scavenging activity and antioxidant activity were assessed by DPPH assay and hydrogen peroxide (H2O2) induced oxidative stress in human lung carcinoma A549 cells. The oil-water partition coefficient results indicate that the conjugation of sulfonamides increases the lipophilicity of caffeic acid. The CASMD, CASDZ and CASN results show higher free radical scavenging effects compared with vitamin C. The derivatives do not show any inhibitory effect on the proliferation of A549 cells up to a concentration of 200 μM, except CASDZ which significantly inhibits the growth of A549 cells at a concentration of 200 μM. In addition, the obtained derivatives markedly attenuate H2O2 induced decrease of cell viability, inhibit the production of ROS and MDA, and promote the activities of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px). Besides, treatment of H2O2 stimulated A549 cells with caffeic acid sulfonamide derivatives further increases mRNA expression of NF-E2-related factor 2 (Nrf2) and its target genes, including heme oxygenase-1 (HO-1), NAD(P)H quinone dehydrogenase 1 (NQO1) and thioredoxin reductase 1 (TXNRD1). These results suggest that these new caffeic acid sulfonamide derivatives have higher lipophilicity and better antioxidant activities than the parent caffeic acid, and they might be able to control the antioxidant response in cells via the Nrf2 pathway.

Caffeates and Caffeamides: Synthetic Methodologies and Their Antioxidant Properties

Polyphenols are secondary metabolites of plants and include a variety of chemical structures, from simple molecules such as phenolic acids to condensed tannins and highly polymerized compounds. Caffeic acid (3,4-dihydroxycinnamic acid) is one of the hydroxycinnamate metabolites more widely distributed in plant tissues. It is present in many food sources, including coffee drinks, blueberries, apples, and cider, and also in several medications of popular use, mainly those based on propolis. Its derivatives are also known to possess anti-inflammatory, antioxidant, antitumor, and antibacterial activities, and can contribute to the prevention of atherosclerosis and other cardiovascular diseases. This review is an overview of the available information about the chemical synthesis and antioxidant activity of caffeic acid derivatives. Considering the relevance of these compounds in human health, many of them have been the focus of reviews, taking as a center their obtaining from the plants. There are few revisions that compile the chemical synthesis methods, in this way, we consider that this review does an important contribution.

NFBTA: A Potent Cytotoxic Agent against Glioblastoma

Piplartine (PPL), also known as piperlongumine, is a biologically active alkaloid extracted from the Piper genus which has been found to have highly effective anticancer activity against several tumor cell lines. This study investigates in detail the antitumoral potential of a PPL analogue; (E)-N-(4-fluorobenzyl)-3-(3,4,5-trimethoxyphenyl) acrylamide (NFBTA). The anticancer potential of NFBTA on the glioblastoma multiforme (GBM) cell line (U87MG) was determined by 3-(4,5-dimethyl-2-thia-zolyl)-2, 5-diphenyl-2H-tetrazolium bromide (MTT), and lactate dehydrogenase (LDH) release analysis, and the selectivity index (SI) was calculated. To detect cell apoptosis, fluorescent staining via flow cytometry and Hoechst 33258 staining were performed. Oxidative alterations were assessed via colorimetric measurement methods. Alterations in expressions of key genes related to carcinogenesis were determined. Additionally, in terms of NFBTA cytotoxic, oxidative, and genotoxic damage potential, the biosafety of this novel agent was evaluated in cultured human whole blood cells. Cell viability analyses revealed that NFBTA exhibited strong cytotoxic activity in cultured U87MG cells, with high selectivity and inhibitory activity in apoptotic processes, as well as potential for altering the principal molecular genetic responses in U87MG cell growth. Molecular docking studies strongly suggested a plausible anti-proliferative mechanism for NBFTA. The results of the experimental in vitro human glioblastoma model and computational approach revealed promising cytotoxic activity for NFBTA, helping to orient further studies evaluating its antitumor profile for safe and effective therapeutic applications.

Amides Derived from Vanillic Acid: Coupling Reactions, Antimicrobial Evaluation, and Molecular Docking

A series of amides derived from vanillic acid were obtained by coupling reactions using PyBOP ((Benzotriazol-1-yloxy)tripyrrolidinophosphonium hexafluorophosphate) and DCC (Dicyclohexylcarbodiimide) coupling reagents. These were submitted to biological evaluation for species of Candida, Staphylococcus, and Pseudomonas. The microdilution method in broth was used for the antimicrobial testing to determine the Minimum Inhibitory Concentration (MIC) and to verify the likely mechanism of action for antifungal activity. The ten amides were obtained with yields ranging from 28.81 to 86.44%, and three compounds were novel. In the antibacterial evaluation, the amides (in their greatest concentrations) were bioactive against Staphylococcus aureus strain ATCC 25925. Meanwhile, all of the tested amides presented antifungal activity against at least one strain. The amide with best antifungal profile was compound 7, which featured an MIC of 0.46 μmol/mL, and a mechanism of action involving the plasma membrane and fungal cell wall. The presence of a methyl group in the para position of the aromatic ring is suggested which enhances the activity of the compound against fungi. Docking studies of the ten compounds using the protein 14α-demethylase as a biological target were also performed. The biological results presented good correlation with molecular docking studies demonstrating that a possible site of antifungal action for bioactive amides is the enzyme 14α-demethylase.

Effect of cinnamamides on atopic dermatitis through regulation of IL-4 in CD4+ cells

This study aimed to evaluate the effects of cinnamamides on atopic dermatitis (AD) and the mechanisms underlying these effects. To this end, the actions of two cinnamamides, (E)-3-(4-hydroxyphenyl)-N-phenylethyl acrylamide (NCT) and N-trans-coumaroyltyramine (NCPA), were determined on AD by orally administering them to mice. Oral administration of the cinnamamides ameliorated the increase in epidermal and dermal thickness as well as mast cell infiltration. Cinnamamides suppressed serum immunoglobulin (Ig) levels and expression of T-helper (Th)1/Th2 cytokines. Moreover, cinnamamides suppressed interleukin (IL)-4, which plays a crucial role in preparing naïve clusters of differentiation (CD)4⁺ T cells, and decreased the cervical lymph node size and weight. Interestingly, in almost all cases, NCPA exhibited higher anti-AD activity compared to NCT. These results strongly indicate that NCPA may have potential as an anti-AD agent, and further mechanistic comparative studies of NCT and NCPA are required to determine the cause of differences in biological activity.

Caffeic amide derivatives inhibit allergen-induced bone marrow-derived dendritic cell maturation

BACKGROUND

Caffeic amides are derivatives of caffeic acid, which have antioxidant and anti-inflammatory properties, and high in vivo stability. The therapeutic effect of caffeic amides on allergic diseases, and especially on the maturation of bone marrow-derived dendritic cells (BM-DCs), remains unclear. In this study, we investigated the therapeutic potential of caffeic amides on allergic diseases by evaluating the maturation of DCs and evaluated their potential in inducing the differentiation of T_H2 cells.

METHODS

BM-DCs isolated from BALB/c mice were treated with different caffeic amide derivatives for 48 h and the expression of surface markers was analyzed by flow cytometry. The differentiation of CD4⁺ T cells was detected by the 5-bromo-2-deoxyuridine (BrdU) incorporation assay and cytokine production was analyzed by ELISA.

RESULTS

Our results showed that among the six caffeic amides tested herein, only 36 M significantly inhibited the antigen-induced maturation of DCs associated with the expression of CD80, CD86, and major histocompatibility complex II (VC ovalbumin (OVA)+ thymic stromal lymphopoietin (TSLP) vs. 36 M OVA + TSLP). Additionally, the isolation and co-culture of antigen-specific CD4⁺ T cells with 36 M-treated BM-DCs suppressed the antigen-specific differentiation of T_H2 cells.

CONCLUSION

Among the six caffeic amides tested herein, 36 M (N-octyl caffeamide) might possess therapeutic potential for allergic diseases.

The cytotoxic and genotoxic effects of daidzein on MIA PaCa-2 human pancreatic carcinoma cells and HT-29 human colon cancer cells

Daidzein (DZ) has anti-inflammatory and antioxidant effects, as well as the dose-dependent inhibition effect on cancer cells. In this study, the cytotoxic and genotoxic effects of DZ on HT-29 (human colorectal adenocarcinoma cells) and MIA PaCa-2 (human pancreatic cancer cells) cell lines were determined using the XTT method and Comet assay, respectively. IC₅₀ concentrations of DZ were found to be 200 µM in both MIA PaCa-2 and HT-29 cells treated with DZ for 48 hours (h). When the cells were treated with 200 μM of DZ for 48 h, DNA damage was observed in both cell lines. DNA tail length (TL), tail moment (TM), and tail intensity (TI) increased more in MIA PaCa-2 cells treated with 200 μM of DZ than those in the control cell (untreated MIA PaCa-2 cell) group (p < 0.01). However, only DNA-TI and DNA-TM exhibited higher increases in HT-29 cells treated with 200 μM of DZ than those in the control cell (untreated HT-29 cell) group (p < 0.01). This shows that DZ has cytotoxic and genotoxic effects on both cell lines. The observed genotoxic effects of DZ still need to be confirmed in additional future studies.

Piplartine Analogues and Cytotoxic Evaluation against Glioblastoma

Piplartine (1) is an alkamide extracted from plants of the genus Piper which shows several pharmacological properties, including antitumor activity. To improve this activity, a series of analogues based on 1 have been synthesized by esterification and amidation using the 3,4,5-trimethoxycinnamic acid-like starting material. During the study, the moieties 3-(3,4,5-trimethoxyphenyl)acrylate and 3-(3,4,5-trimethoxyphenyl)acrylamide were maintained on esters and amides respectively. Meanwhile, functional changes were exploited, and it was revealed that the presence of two aromatic rings in the side-chain was important to improve the cytotoxic activity against the U87MG cell line, such as the compound (E)-benzhydryl 3-(3,4,5-trimethoxyphenyl)acrylate (10), an ester that exhibited strong cytotoxicity and a similar level of potency to that of paclitaxel, a positive control. Compound 10 had a marked concentration-dependent inhibitory effect on the viability of the U87MG cell line with apoptotic and oxidative processes, showing good potential for altering main molecular pathways to prevent tumor development. Moreover, it has strong bioavailability with non-genotoxic and non-cytotoxic properties on human blood cells. In conclusion, the findings of the present study demonstrated that compound 10 is a promising agent that may find applications combatting diseases associated with oxidative stress and as a prototype for the development of novel drugs used in the treatment of glioblastoma.

Targeting matrix metalloproteinases with novel diazepine substituted cinnamic acid derivatives: design, synthesis, in vitro and in silico studies

Lung cancer is the notable cause of cancer associated deaths worldwide. Recent studies revealed that the expression of matrix metalloproteinases (MMPs) is extremely high in lung tumors compared with non-malignant lung tissue. MMPs (-2 and -9) play an important part in tumor development and angiogenesis, which suggests that creating potent MMP-2 and -9 inhibitors, should be an important goal in lung cancer therapy. In the present study, an effort has been made to develop new anti-metastatic and anti-invasive agents, wherein a series of novel diazepine substituted cinnamic acid derivatives were designed, synthesized and assayed for their inhibitory activities on MMP-2 and MMP-9. These derivatives were prepared via microwave assisted reaction of tert-butyl (3-cinnamamidopropyl)carbamate derivatives mixed with 2,3-dibromopropanoic acid and potassium carbonate was added to obtain 4-(tert-butoxycarbonyl)-1-cinnamoyl-1,4-diazepane-2-carboxylic acid derivatives. The newly synthesized compounds were characterized by IR, NMR and mass spectroscopy. All the tested compounds showed good to excellent cytotoxic potential against A549 human lung cancer cells. The active compounds displaying good activity were further examined for the inhibitory activity against MMPs (-2 and -9). In addition, the structure and anticancer activity relationship were further supported by in silico docking studies of the active compounds against MMP-2 and MMP-9.

Targeting the Nrf2/Amyloid-Beta Liaison in Alzheimer's Disease: A Rational Approach

Amyloid is a prominent feature of Alzheimer's disease (AD). Yet, a linear linkage between amyloid-β peptide (Aβ) and the disease onset and progression has recently been questioned. In this context, the crucial partnership between Aβ and Nrf2 pathways is acquiring paramount importance, offering prospects for deciphering the Aβ-centered disease network. Here, we report on a new class of antiaggregating agents rationally designed to simultaneously activate transcription-based antioxidant responses, whose lead 1 showed interesting properties in a preliminary investigation. Relying on the requirements of Aβ recognition, we identified the catechol derivative 12. In SH-SY5Y neuroblastoma cells, 12 combined remarkable free radical scavenger properties to the ability to trigger the Nrf2 pathway and induce the Nrf2-dependent defensive gene NQO1 by means of electrophilic activation of the transcriptional response. Moreover, 12 prevented the formation of cytotoxic stable oligomeric intermediates, being significantly more effective, and per se less toxic, than prototype 1. More importantly, as different chemical features were exploited to regulate Nrf2 and Aβ activities, the two pathways could be tuned independently. These findings point to compound 12 and its derivatives as promising tools for investigating the therapeutic potential of the Nrf2/Aβ cellular network, laying foundation for generating new drug leads to confront AD.

Radical scavenging and antibacterial activity of caffemides against gram positive, gram negative and clinical drug resistance bacteria

A new series of caffemide were synthesized and their antioxidant and antibacterial activities were explored. Antioxidant and antibacterial activities were measured of different structures of caffemide containing different functional groups. Anti-oxidative caffemides 1b and 1g showed significantly higher activity against different bacteria with MIC values less than 50μg/ml. These anti-oxidative and antibacterial properties of caffemides might be helpful for the treatment of secondary infections and discovery of new antibiotics.

Combined dual effect of modulation of human neutrophils' oxidative burst and inhibition of colon cancer cells proliferation by hydroxycinnamic acid derivatives

Colon cancer is one of the most incident cancers in the Western World. While both genetic and epigenetic factors may contribute to the development of colon cancer, it is known that chronic inflammation associated to excessive production of reactive oxygen and nitrogen species by phagocytes may ultimately initiate the multistep process of colon cancer development. Phenolic compounds, which reveal antioxidant and antiproliferative activities in colon cancer cells, can be a good approach to surpass this problem. In this work, hydroxycinnamic amides and the respective acid precursors were tested in vitro for their capacity to modulate human neutrophils' oxidative burst and simultaneously to inhibit growth of colon cancer cells. A phenolic amide derivative, caffeic acid hexylamide (CAHA) (4) was found to be the most active compound in both assays, inhibiting human neutrophils' oxidative burst, restraining the inflammatory process, inhibiting growth of colon cancer cells and triggering mitochondrial dysfunction that leads cancer cells to apoptosis. Altogether, these achievements can contribute to the understanding of the relationship between antioxidant and anticancer activities and based on the structure-activity relationships (SAR) established can be the starting point to find more effective phenolic compounds as anticancer agents.

Neuroprotective and antioxidant effects of novel benzofuran-2-carboxamide derivatives

In the present study, we synthesized a series of novel 7-methoxy-N-(substituted phenyl)benzofuran-2-carboxamide derivatives in moderate to good yields and evaluated their neuroprotective and antioxidant activities using primary cultured rat cortical neuronal cells and in vitro cell-free bioassays. Based on our primary screening data with eighteen synthesized derivatives, nine compounds (1a, 1c, 1f, 1i, 1j, 1l, 1p, 1q and 1r) exhibiting considerable protection against the NMDA-induced excitotoxic neuronal cell damage at the concentration of 100 μM were selected for further evaluation. Among the selected derivatives, compound 1f (with -CH₃ substitution at R2 position) exhibited the most potent and efficacious neuroprotective action against the NMDA-induced excitotoxicity. Its neuroprotective effect was almost comparable to that of memantine, a well-known NMDA antagonist, at 30 μM concentration. In addition to 1f, compound 1j (with -OH substitution at R3 position) also showed marked anti-excitotoxic effects at both 100 and 300 μM concentrations. These findings suggest that -CH₃ substitution at R2 position and, to a lesser degree, -OH substitution at R3 position may be important for exhibiting neuroprotective action against excitotoxic damage. Compound 1j was also found to scavenge 1,1-diphenyl-2-picrylhydrazyl radicals and inhibit in vitro lipid peroxidation in rat brain homogenate in moderate and appreciable degrees. Taken together, our structure-activity relationship studies suggest that the compound with -CH₃ substitution at R2 and -OH substitution at R3 positions of the benzofuran moiety might serve as the lead exhibiting potent anti-excitotoxic, ROS scavenging, and antioxidant activities. Further synthesis and evaluation will be necessary to confirm this possibility.

DFT study of the effect of solvent on the H-atom transfer involved in the scavenging of the free radicals (·)HO2 and (·)O2(-) by caffeic acid phenethyl ester and some of its derivatives

H-atom transfer from caffeic acid phenethyl ester (CAPE), MBC (3-methyl-2-butenyl caffeate), BC (benzoic caffeate), P3HC (phenethyl-3-hydroxycinnamate), and P4HC (phenethyl-4-hydroxycinnamate) to the selected free radicals (·)HO2 and (·)O2(-) was studied. Such a transfer can proceed in three different ways: concerted proton-coupled electron transfer (CPCET), electron transfer followed by proton transfer (ET-PT), and proton transfer followed by electron transfer (PT-ET). The latter pathway is sometimes competitive with SPLET (sequential proton loss electron transfer) in polar media. Analyzing the thermodynamic descriptors of the reactions of CAPE and its derivatives with co-reactive species-in particular, the free energies of reactions, the activation barrier to the CPCET mechanism, and their rate constants-appears to be the most realistic method of investigating the H-atom transfers of interest. These analyses were performed via DFT calculations, which agree well with the data acquired from experimental studies (IC50) and from CBS calculations. The CPCM solvation model was used throughout the work, while the SMD model-employed as a reference-was used only for CAPE. The main conclusion drawn from the analysis was that SPLET is the mechanism that governs the reaction of phenolic acids with (·)HO2, while PT-ET governs the reaction of phenols with (·)O2(-). In kinetic investigations of the CPCET process, the rate constant decreases as the solvent polarity increases, so the reaction velocity slows down.

Development and validation of an LCMS method to determine the pharmacokinetic profiles of caffeic acid phenethyl amide and caffeic acid phenethyl ester in male Sprague-Dawley rats

A validated LCMS method was developed for the quantitative determination of caffeic acid phenethyl amide (CAPA) and caffeic acid phenethyl ester (CAPE) from rat plasma. Separation was achieved using a reverse-phase C12 HPLC column (150 × 2.00 mm, 4 µm) with gradient elution running water (A) and acetonitrile (B). Mass spectrometry was performed with electrospray ionization in negative mode. This method was used to determine the pharmacokinetic profiles of CAPA and CAPE in male Sprague-Dawley rats following intravenous bolus administration of 5, 10 and 20 mg/kg of CAPA and 20 mg/kg of CAPE. The pharmacokinetic analysis suggests the lack of dose proportionality in the dose range of 5-20 mg/kg of CAPA. Total clearance values for CAPA ranged from 45 to 156 mL/min and decreased with increasing dose of CAPA. The volume of distribution for CAPA ranged from 17,750 to 52,420 mL, decreasing with increasing dose. The elimination half-life for CAPA ranged from 243.1 to 295.8 min and no statistically significant differences were observed between dose groups in the range of 5-20 mg/kg (p > 0.05). The elimination half-life for CAPE was found to be 92.26 min.

Synthesis and biological properties of caffeic acid-PNA dimers containing guanine

Caffeic acid (CA; 3,4-dihydroxycinnamic acid) is endowed with high antioxidant activity. CA derivatives (such as amides) have gained a lot of attention due to their antioxidative, antitumor and antimicrobial properties as well as stable characteristics. Caffeoyl-peptide derivatives showed different antioxidant activity depending on the type and the sequence of amino acid used. For these reasons, we decided to combine CA with Peptide Nucleic Acid (PNA) to test whether the new PNA-CA amide derivatives would result in an improvement or gain of CA's biological (i.e., antioxidant, cytotoxic, cytoprotective) properties. We performed the synthesis and characterization of seven dimer conjugates with various combinations of nucleic acid bases and focused NMR studies on the model compound ga-CA dimer. We demonstrate that PNA dimers containing guanine conjugated to CA exhibited different biological activities depending on composition and sequence of the nucleobases. The dimer ag-CA protected HepG2, SK-B-NE(2), and C6 cells from a cytotoxic dose of hydrogen peroxide (H₂O₂).

Antioxidant therapy: still in search of the 'magic bullet'

The therapeutic potential of natural phenolic antioxidants in human diseases associated with oxidative damage has received great attention to date. Appraisal of literature evidences that, in general, antioxidant therapy has enjoyed relative successes in preclinical studies but little benefits in human intervention studies or clinical trials. In fact, despite the huge, largely untapped potential therapeutic benefit of natural phenolic antioxidants, such as vitamins, non-flavonoid and flavonoid compounds, they appear not to be suitable drug candidates. The problem may be related, among others, to their non-drug-likeness properties. Though controversial the results obtained so far confirm the importance of exploring phenolic natural systems as safe templates for the design of new antioxidants. To support the assumption an outlook of the lead structural optimization process to improve ADME properties was given by means of natural hydroxycinnamic acids as a case study. The optimization of drug physicochemical properties and the development of appropriate delivery antioxidant systems can provide in the next future a way out to attain effective therapeutic antioxidant agents.

Caffeic acid inhibits acute hyperhomocysteinemia-induced leukocyte rolling and adhesion in mouse cerebral venules

OBJECTIVE

To investigate the effects and possible mechanisms of CA on acute HHcy-induced leukocyte rolling and adhesion in mouse cerebral venules.

METHODS

Male C57 BL/6J mice were injected with DL-Hcy (50 mg/kg) and CA (10 mg/kg). The effect of CA on HHcy-induced leukocyte rolling and adhesion in cerebral vessels was assessed using intravital microscopy. Plasma cytokines and chemokines were evaluated by cytometric bead array. ROS production in HUVECs and adhesion molecule expression on leukocytes were determined by flow cytometry. E-selectin and ICAM-1 expression in cerebrovascular endothelium was detected by immunohistochemistry. CD18 phosphorylation and the Src/PI3K/Akt pathway in leukocytes were determined by confocal microscopy and Western blot.

RESULTS

CA inhibited HHcy-elicited leukocyte rolling and adhesion, decreased ROS production in HUVECs, and reduced plasma KC, MIP-2, and MCP-1 levels. CA reduced the E-selectin and ICAM-1 expression on cerebrovascular endothelium and CD11b/CD18 on leukocytes caused by HHcy. Of notice, CA depressed CD18 phosphorylation and the Src/PI3K/Akt pathway in leukocytes.

CONCLUSIONS

CA inhibited HHcy-provoked leukocyte rolling and adhesion in cerebral venules, ameliorating adhesion molecule expression and activation, which is related to the suppression of the Src/PI3K/Akt pathway in leukocytes.

(E)-Methyl 2-({2-eth-oxy-6-[(E)-(hy-droxy-imino)-meth-yl]phen-oxy}meth-yl)-3-phenyl-acrylate

In the title compound, C₂₀H₂₁NO₅, the dihedral angle between the mean planes through the two rings is 47.1 (8)°. The enoate group assumes an extended conformation. The hy­droxy­ethanimine group is essentially coplanar with the benzene ring, the largest deviation from the mean plane being 0.061 (1) Å for the O atom. In the crystal, mol­ecules are linked into cyclic centrosymmetric dimers with an R₂²(6) motif via pairs of O—H⋯N hydrogen bonds. Inter­molecular C—H⋯O hydrogen bonds form a C(8) chain along the b axis. The crystal packing is further stabilized by C—H⋯π inter­actions.