Multi-Target-Directed Cinnamic Acid Hybrids Targeting Alzheimer's Disease.

Progressive cognitive decline in Alzheimer's disease (AD) is a growing challenge. Present therapies are based on acetylcholinesterase inhibition providing only temporary relief. Promising alternatives include butyrylcholinesterase (BuChE) inhibitors, multi-target ligands (MTDLs) that address the multi-factorial nature of AD, and compounds that target oxidative stress and inflammation. Cinnamate derivatives, known for their neuroprotective properties, show potential when combined with established AD agents, demonstrating improved efficacy. They are being positioned as potential AD therapeutic leads due to their ability to inhibit Aß accumulation and provide neuroprotection. This article highlights the remarkable potential of cinnamic acid as a basic structure that is easily adaptable and combinable to different active groups in the struggle against Alzheimer's disease. Compounds with a methoxy substitution at the para-position of cinnamic acid display increased efficacy, whereas electron-withdrawing groups are generally more effective. The effect of the molecular volume is worthy of further investigation.

Synthesis and Antioxidant Activities of Novel Pyrimidine Acrylamides as Inhibitors of Lipoxygenase: Molecular Modeling and In Silico Physicochemical Studies.

The pyrimidine ring is present in various biomolecules such as DNA and RNA bases, aminoacids, vitamins, etc. Additionally, many clinically used drugs including methotrexate and risperidone contain the pyrimidine heterocyclic scaffold as well. Pyrimidine derivatives present diverse biological activities including antioxidant and anticancer activities and can be considered as privileged scaffolds in drug discovery for the treatment of various diseases. Piperidine pyrimidine amides have gained significant attention due to their enzymatic inhibitory activity. Based on our experience and ongoing investigation on cinnamic acid derivatives, their hybrids and substituted pteridines acting as lipoxygenase inhibitors, antioxidants, anti-cancer, and anti-inflammatory agents a series of novel piperidine pyrimidine cinnamic acids amides have been designed and synthesized. The novel hybrids were studied for their antioxidant and anti-inflammatory potential. They exhibit moderate antioxidant activity in the DPPH assay which may be related to their bulkiness. Moreover, moderate to good lipid peroxidation inhibition potential was measured. With regards to their lipoxygenase inhibitory activity, however, two highly potent inhibitors out of the nine tested derivatives were identified, demonstrating IC50 values of 10.7 µM and 1.1 µM, respectively. Molecular docking studies to the target enzyme lipoxygenase support the experimental results.

A Review on Recent Approaches on Molecular Docking Studies of Novel Compounds Targeting Acetylcholinesterase in Alzheimer Disease.

Alzheimer's disease (AD), a neurodegenerative brain disorder that affects millions of people worldwide, is characterized by memory loss and cognitive decline. Low levels of acetylcholine and abnormal levels of beta-amyloid, T protein aggregation, inflammation, and oxidative stress, have been associated with AD, and therefore, research has been oriented towards the cholinergic system and primarily on acetylcholinesterase (AChE) inhibitors. In this review, we are focusing on the discovery of AChE inhibitors using computer-based modeling and simulation techniques, covering the recent literature from 2018-2022. More specifically, the review discusses the structures of novel, potent acetylcholinesterase inhibitors and their binding mode to AChE, as well as the physicochemical requirements for the design of potential AChE inhibitors.

Development of Novel Pyrrole Derivatives and Their Cinnamic Hybrids as Dual COX-2/LOX Inhibitors.

Molecular hybridization has emerged as a promising approach in the treatment of diseases exhibiting multifactorial etiology. With regard to this, dual cyclooxygenase-2/lipoxygenase (COX-2/LOX) inhibitors could be considered a safe alternative to traditional non-steroidal anti-inflammatory drugs (tNSAIDs) and selective COX-2 inhibitors (coxibs) for the treatment of inflammatory conditions. Taking this into account, six novel pyrrole derivatives and pyrrole-cinnamate hybrids were developed as potential COX-2 and soybean LOX (sLOX) inhibitors with antioxidant activity. In silico calculations were performed to predict their ADMET (absorption, distribution, metabolism, excretion, toxicity) properties and drug-likeness, while lipophilicity was experimentally determined as RM values. All synthesized compounds (1-4, 5-8) could be described as drug-like. The results from the docking studies on COX-2 were in accordance with the in vitro studies. According to molecular docking studies on soybean LOX, the compounds displayed allosteric interactions with the enzyme. Pyrrole 2 appeared to be the most potent s-LOX inhibitor (IC50 = 7.5 µM). Hybrids 5 and 6 presented a promising combination of in vitro LOX (IC50 for 5 = 30 µM, IC50 for 6 = 27.5 µM) and COX-2 (IC50 for 5 = 0.55 µM, IC50 for 6 = 7.0 µM) inhibitory activities, and therefore could be used as the lead compounds for the synthesis of more effective multi-target agents.

Novel Pyrimidine Derivatives as Antioxidant and Anticancer Agents: Design, Synthesis and Molecular Modeling Studies.

The heterocyclic ring system of pyrido [2,3-d]pyrimidines is a privileged scaffold in medicinal chemistry, possessing several biological activities. The synthesis of the pyrimidine derivatives was performed via the condensation of a suitable α,ß-unsaturated ketone with 4-amino-6-hydroxy-2-mercaptopyrimidine monohydrate in glacial acetic acid. Chalcones were synthesized, as starting materials, via the Claisen-Schmidt condensation of an appropriately substituted ketone and an appropriately substituted aldehyde in the presence of aqueous KOH 40% w/v in ethanol. All the synthesized compounds were characterized using IR, 1H-NMR, 13C-NMR, LC-MS and elemental analysis. The synthesized compounds were evaluated for their antioxidant (DPPH assay), anti-lipid peroxidation (AAPH), anti-LOX activities and ability to interact with glutathione. The compounds do not interact significantly with DPPH but strongly inhibit lipid peroxidation. Pyrimidine derivatives 2a (IC50 = 42 µΜ), 2f (IC50 = 47.5 µΜ) and chalcone 1g (IC50 = 17 µM) were the most potent lipoxygenase inhibitors. All the tested compounds were found to interact with glutathione, apart from 1h. Cell viability and cytotoxicity assays were performed with the HaCaT and A549 cell lines, respectively. In the MTT assay towards the HaCaT cell line, none of the compounds presented viability at 100 µM. On the contrary, in the MTT assay towards the A549 cell line, the tested compounds showed strong cytotoxicity at 100 µM, with derivative 2d presenting the strongest cytotoxic effects at the concentration of 50 µΜ.

Novel Multi-Target Agents Based on the Privileged Structure of 4-Hydroxy-2-quinolinone.

In this work, the privileged scaffold of 4-hydroxy-2quinolinone is investigated through the synthesis of carboxamides and hybrid derivatives, as well as through their bioactivity evaluation, focusing on the ability of the molecules to inhibit the soybean LOX, as an indication of their anti-inflammatory activity. Twenty-one quinolinone carboxamides, seven novel hybrid compounds consisting of the quinolinone moiety and selected cinnamic or benzoic acid derivatives, as well as three reverse amides are synthesized and classified as multi-target agents according to their LOX inhibitory and antioxidant activity. Among all the synthesized analogues, quinolinone-carboxamide compounds 3h and 3s, which are introduced for the first time in the literature, exhibited the best LOX inhibitory activity (IC50 = 10 µM). Furthermore, carboxamide 3g and quinolinone hybrid with acetylated ferulic acid 11e emerged as multi-target agents, revealing combined antioxidant and LOX inhibitory activity (3g: IC50 = 27.5 µM for LOX inhibition, 100% inhibition of lipid peroxidation, 67.7% ability to scavenge hydroxyl radicals and 72.4% in the ABTS radical cation decolorization assay; 11e: IC50 = 52 µM for LOX inhibition and 97% inhibition of lipid peroxidation). The in silico docking results revealed that the synthetic carboxamide analogues 3h and 3s and NDGA (the reference compound) bind at the same alternative binding site in a similar binding mode.

Novel quinolinone-pyrazoline hybrids: synthesis and evaluation of antioxidant and lipoxygenase inhibitory activity.

The present project deals with the investigation of structure-activity relationship of several quinolinone-chalcone and quinolinone-pyrazoline hybrids, in an effort to discover promising antioxidant and anti-inflammatory agents. In order to accomplish this goal, four bioactive hybrid quinolinone-chalcone compounds (8a-8d) were synthesized via an aldol condensation reaction, which were then chemically modified, forming fifteen new pyrazoline analogues (9a-9o). All the synthesized analogues were in vitro evaluated in terms of their antioxidant and soybean lipoxygenase (LOX) inhibitory activity. Among all the pyrazoline derivatives, compounds 9b and 9m were found to possess the best combined activity, whereas 9b analogue exhibited the most potent LOX inhibitory activity, with IC50 value 10 µM. The in silico docking results revealed that the synthetic pyrazoline analogue 9b showed high AutoDock Vina score (- 10.3 kcal/mol), while all the tested derivatives presented allosteric interactions with the enzyme.

Pyrazoles and Pyrazolines as Anti-Inflammatory Agents.

The five-membered heterocyclic group of pyrazoles/pyrazolines plays important role in drug discovery. Pyrazoles and pyrazolines present a wide range of biological activities. The synthesis of the pyrazolines and pyrazole derivatives was accomplished via the condensation of the appropriate substituted aldehydes and acetophenones, suitable chalcones and hydrazine hydrate in absolute ethanol in the presence of drops of glacial acetic acid. The compounds are obtained in good yields 68-99% and their structure was confirmed using IR, 1H-NMR, 13C-NMR and elemental analysis. The novel derivatives were studied in vitro for their antioxidant, anti-lipid peroxidation (AAPH) activities and inhibitory activity of lipoxygenase. Both classes strongly inhibit lipid peroxidation. Compound 2g was the most potent lipoxygenase inhibitor (IC50 = 80 µM). The inhibition of the carrageenin-induced paw edema (CPE) and nociception was also determined, with compounds 2d and 2e being the most potent. Compound 2e inhibited nociception higher than 2d. Pyrazoline 2d was found to be active in a preliminary test, for the investigation of anti-adjuvant-induced disease (AID) activity. Pyrazoline derivatives were found to be more potent than pyrazoles. Docking studies of the most potent LOX inhibitor 2g highlight hydrophobic interactions with VAL126, PHE143, VAL520 and LYS526 and a halogen bond between the chlorine atom and ARG182.

Synthesis, Bioactivity, Pharmacokinetic and Biomimetic Properties of Multi-Substituted Coumarin Derivatives.

A series of novel multi-substituted coumarin derivatives were synthesized, spectroscopically characterized, and evaluated for their antioxidant activity, soybean lipoxygenase (LOX) inhibitory ability, their influence on cell viability in immortalized human keratinocytes (HaCaT), and cytotoxicity in adenocarcinomic human alveolar basal epithelial cells (A549) and human melanoma (A375) cells, in vitro. Coumarin analogues 4a-4f, bearing a hydroxyl group at position 5 of the coumarin scaffold and halogen substituents at the 3-phenyl ring, were the most promising ABTS•+ scavengers. 6,8-Dibromo-3-(4-hydroxyphenyl)-4-methyl-chromen-2-one (4k) and 6-bromo-3-(4,5-diacetyloxyphenyl)-4-methyl-chromen-2-one (3m) exhibited significant lipid peroxidation inhibitory activity (IC50 36.9 and 37.1 µM). In the DCF-DA assay, the 4'-fluoro-substituted compound 3f (100%), and the 6-bromo substituted compounds 3i (80.9%) and 4i (100%) presented the highest activity. The 3'-fluoro-substituted coumarins 3e and 4e, along with 3-(4-acetyloxyphenyl)-6,8-dibromo-4-methyl-chromen-2-one (3k), were the most potent lipoxygenase (LOX) inhibitors (IC50 11.4, 4.1, and 8.7 µM, respectively) while displaying remarkable hydroxyl radical scavenging ability, 85.2%, 100%, and 92.9%, respectively. In silico docking studies of compounds 4e and 3k, revealed that they present allosteric interactions with the enzyme. The majority of the analogues (100 µΜ) did not affect the cell viability of HaCaT cells, though several compounds presented over 60% cytotoxicity in A549 or A375 cells. Finally, the human oral absorption (%HOA) and plasma protein binding (%PPB) properties of the synthesized coumarins were also estimated using biomimetic chromatography, and all compounds presented high %HOA (>99%) and %PPB (60-97%) values.

Exploring the 2'-Hydroxy-Chalcone Framework for the Development of Dual Antioxidant and Soybean Lipoxygenase Inhibitory Agents.

2'-hydroxy-chalcones are naturally occurring compounds with a wide array of bioactivity. In an effort to delineate the structural features that favor antioxidant and lipoxygenase (LOX) inhibitory activity, the design, synthesis, and bioactivity profile of a series of 2'-hydroxy-chalcones bearing diverse substituents on rings A and B, are presented. Among all the synthesized derivatives, chalcone 4b, bearing two hydroxyl substituents on ring B, was found to possess the best combined activity (82.4% DPPH radical scavenging ability, 82.3% inhibition of lipid peroxidation, and satisfactory LOX inhibition value (IC50 = 70 µM). Chalcone 3c, possessing a methoxymethylene substituent on ring A, and three methoxy groups on ring B, exhibited the most promising LOX inhibitory activity (IC50 = 45 µM). A combination of in silico techniques were utilized in an effort to explore the crucial binding characteristics of the most active compound 3c and its analogue 3b, to LOX. A common H-bond interaction pattern, orienting the hydroxyl and carbonyl groups of the aromatic ring A towards Asp768 and Asn128, respectively, was observed. Regarding the analogue 3c, the bulky (-OMOM) group does not seem to participate in a direct binding, but it induces an orientation capable to form H-bonds between the methoxy groups of the aromatic ring B with Trp130 and Gly247.

Novel 3-aryl-5-substituted-coumarin analogues: Synthesis and bioactivity profile.

Eighteen 3-aryl-5-substituted-coumarins-six 5-acetyloxy-derivatives, six 5-hydroxy-derivatives, and six 5-geranyloxy-derivatives-were synthesized, structurally characterized and their antioxidant activity, lipoxygenase inhibitory ability, as well as their cytotoxic activity against human neuroblastoma SK-N-SH and HeLa adenocarcinoma cell lines were evaluated. The 5-acetyloxy-compounds 3a-3f were found to be the best cytotoxic agents among all the compounds studied. The bromo-substituted coumarins 3a and 3b were remarkably active against HeLa cell line showing IC50 1.8 and 6.1 µM, respectively. Coumarin 5e possessing a geranyloxy-chain on position 5 of the coumarin scaffold presented dual bioactivity, while 5-geranyloxy-coumarin 5f was the most competent soybean lipoxygenase inhibitor of this series (IC50 10 µM). As shown by in silico docking studies, the studied molecules present allosteric interactions with soybean lipoxygenases.

Hybridization of Curcumin Analogues with Cinnamic Acid Derivatives as Multi-Target Agents Against Alzheimer's Disease Targets.

The synthesis of the new hybrids followed a hybridization with the aid of hydroxy-benzotriazole (HOBT) and 1-Ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDCI.HCL) in dry DMF or thionyl chloride between curcumin analogues and cinnamic acid derivatives. IR, 1H-NMR, 13C-NMR, LC/MS ESI+, and elemental analysis were used for the confirmation of the structures of the novel hybrids. The lipophilicity values of compounds were calculated theoretically and experimentally via the reversed chromatography method as RM values. The novel derivatives were studied through in vitro experiments for their activity as antioxidant agents and as inhibitors of lipoxygenase, cyclooxygenase-2, and acetyl-cholinesterase. All the compounds showed satisfying anti-lipid peroxidation activity of linoleic acid induced by 2,2'-azobis(2-amidinopropane) hydrochloride (AAPH). Hybrid 3e was the most significant pleiotropic derivative, followed by 3a. According to the predicted results, all hybrids could be easily transported, diffused, and absorbed through the blood-brain barrier (BBB). They presented good oral bioavailability and very high absorption with the exception of 3h. No inhibition for CYP1A2, CYP2C9, CYP2C19, CYP2D6, and CYP3A4 was noticed. According to the Ames test, all the hybrids induced mutagenicity with the exception of 3d. Efforts were conducted a) to correlate the in vitro results with the most important physicochemical properties of the structural components of the molecules and b) to clarify the correlation of actions among them to propose a possible mechanism of action. Docking studies were performed on soybean lipoxygenase (LOX) and showed hydrophobic interactions with amino acids. Docking studies on acetylcholinesterase (AChE) exhibited: (a) hydrophobic interactions with TRP281, LEU282, TYR332, PHE333, and TYR336 and (b) π-stacking interactions with TYR336.

5-(4H)-Oxazolones and Their Benzamides as Potential Bioactive Small Molecules.

The five membered heterocyclic oxazole group plays an important role in drug discovery. Oxazolones present a wide range of biological activities. In this article the synthesis of 4-substituted-2-phenyloxazol-5(4H)-ones from the appropriate substituted aldehydes via an Erlenmeyer-Plochl reaction is reported. Subsequently, the corresponding benzamides were produced via a nucleophilic attack of a secondary amine on the oxazolone ring applying microwave irradiation. The compounds are obtained in good yields up to 94% and their structures were confirmed using IR, 1H-NMR, 13C-NMR and LC/MS data. The in vitro anti-lipid peroxidation activity and inhibitory activity against lipoxygenase and trypsin induced proteolysis of the novel derivatives were studied. Inhibition of carrageenin-induced paw edema (CPE) and nociception was also determined for compounds 4a and 4c. Oxazolones 2a and 2c strongly inhibit lipid peroxidation, followed by oxazolones 2b and 2d with an average inhibition of 86.5%. The most potent lipoxygenase inhibitor was the bisbenzamide derivative 4c, with IC50 41 µΜ. The benzamides 3c, 4a-4e and 5c were strong inhibitors of proteolysis. The replacement of the thienyl moiety by a phenyl group does not favor the protection. Compound 4c inhibited nociception higher than 4a. The replacement of thienyl groups by phenyl ring led to reduced biological activity. Docking studies of the most potent LOX inhibitor highlight interactions through allosteric mechanism. All the potent derivatives present good oral bioavailability.

2-Arylidene-1-indandiones as Pleiotropic Agents with Antioxidant and Inhibitory Enzymes Activities.

Indandiones are a relatively new group of compounds presenting a wide range of biological activities. The synthesis of these compounds was performed via a Knoevenagel reaction between an aldehyde and 1,3-indandione and were obtained with a yield up to 54%. IR, 1H-Nucleic Magnetic Resonance (NMR), 13C-NMR, LC/MS ESI+ and elemental analysis were used for the confirmation of the structures of the novel derivatives. Lipophilicity values of compounds were calculated theoretically and experimentally by reversed chromatography method as values RM. The novel derivatives were studied through in vitro and in vivo experiments for their activity as anti-inflammatory and antioxidant agents and as inhibitors of lipoxygenase, trypsin, and thrombin. The inhibition of the carrageenin-induced paw edema (CPE) was also determined for representative structures. In the above series of experiments, we find that all the compounds showed moderate to satisfying interaction with the stable DPPH free radical in relation to the concentration and the time 2-arylidene-1-indandione (10) was the strongest. We observed moderate or very low antioxidant activities for selected compounds in the decolorization assay with ABTS+•. Most of the compounds showed high anti-lipid peroxidation of linoleic acid induced by AAPH.2-arylidene-1-indandione (7) showed a strongly inhibited soybean LOX. Only 2-arylidene-1-indandione (3) showed moderate scavenging activity of superoxide anion, whereas 2-arylidene-1-indandione (8) and 2-arylidene-1-indandione (9) showed very strong inhibition on proteolysis. 2-arylidene-1-indandione (8) highly inhibited serine protease thrombin. 2-arylidene-1-indandiones (7, 8 and 9) can be used as lead multifunctional molecules. The compounds were active for the inhibition of the CPE (30-57%) with 2-arylidene-1-indandione (1) being the most potent (57%). According to the predicted results a great number of the derivatives can cross the Blood-Brain Barrier (BBB), act in CNS and easily transported, diffused, and absorbed. Efforts are conducted a) to correlate quantitatively the in vitro/in vivo results with the most important physicochemical properties of the structural components of the molecules and b) to clarify the correlation of actions among them to propose a possible mechanism of action. Hydration energy as EHYDR and highest occupied molecular orbital (HOMO) better describe their antioxidant profile whereas the lipophilicity as RM values governs the in vivo anti-inflammatory activity. Docking studies are performed and showed that soybean LOX oxidation was prevented by blocking into the hydrophobic domain the substrates to the active site.

Insights into biological activity of ureidoamides with primaquine and amino acid moieties.

Primaquine (PQ) ureidoamides 5a-f were screened for antimicrobial, biofilm eradication and antioxidative activities. Susceptibility of the tested microbial species towards tested compounds showed species- and compound-dependent activity. N-(diphenylmethyl)-2-[({4-[(6-methoxyquinolin-8-yl)amino]pentyl}carbamoyl)amino]-4-methylpentanamide (5a) and 2-(4-chlorophenyl)-N-(diphenylmethyl)-2-[({4-[(6-methoxyquinolin-8-yl)amino]pentyl}carbamoyl)amino]acetamide (5d) showed antibacterial activity against S. aureus strains (MIC = 6.5 µg/ml). Further, compounds 5c and 5d had weak antibacterial activity against Escherichia coli and Pseudomonas aeruginosa. None of the tested compounds showed a wide spectrum of antifungal activity. In contrast, most of the compounds exerted strong activity in a biofilm eradication assay against E. coli, P. aeruginosa and Candida albicans, comparable to or even higher than gentamycin, amphotericin B or parent PQ. The most active compounds were 5a and 5b. Tested compounds were inactive against biofilm formation by C. parapsylosis, Enterococcus faecalis, C. tropicalis and C. krusei. Compounds 5b-f significantly inhibited lipid peroxidation (80-99%), whereas compound 5c presented interesting LOX inhibition.

Multi-Target Cinnamic Acids for Oxidative Stress and Inflammation: Design, Synthesis, Biological Evaluation and Modeling Studies.

Inflammation is a complex phenomenon that results as a healing response of organisms to different factors, exerting immune signaling, excessive free radical activity and tissue destruction. Lipoxygenases and their metabolites e.g., LTB4, are associated with allergy, cell differentiation and carcinogenesis. Lipoxygenase 12/15 has been characterized as a mucosal-specific inhibitor of IgA and a contributor to the development of allergic sensitization and airway inflammation. Development of drugs that interfere with the formation or effects of these metabolites would be important for the treatment of various diseases like asthma, psoriasis, ulcerative colitis, rheumatoid arthritis, atherosclerosis, cancer and blood vessel disorders. In this study we extended our previous research synthesizing a series of multi-target cinnamic acids from the corresponding aldehydes with suitable 4-OH/Br substituted phenyl acetic acid by Knoevenagel condensation. The final products 1i, 3i, 3ii, 4i, 6i, 6ii, and 7i were obtained in high yields (52⁻98%) Their structures were verified spectrometrically, while their experimentally lipophilicity was determined as RM values. The novel derivatives were evaluated for their antioxidant activity using DPPH, hydroxyl radical, superoxide anion and ABTS+•, anti-lipid peroxidation and soybean lipoxygenase inhibition assays. The compounds presented medium interaction with DPPH (30⁻48% at 100 µM). In contrast all the synthesized derivatives strongly scavenge OH radicals (72⁻100% at 100 µM), ABTS+• (24⁻83% at 100 µM) and presented remarkable inhibition (87⁻100% at 100 µM) in linoleic acid peroxidation (AAPH). The topological polar surface of the compounds seems to govern the superoxide anion scavenging activity. Molecular docking studies were carried out on cinnamic acid derivative 3i and found to be in accordance with experimental biological results. All acids presented interesting lipoxygenase inhibition (IC50 = 7.4⁻100 µM) with compound 3i being the most potent LOX inhibitor with IC50 = 7.4 µM combining antioxidant activities. The antioxidant results support the LOX inhibitory activities. The recorded in vitro results highlight compound 3i as a lead compound for the design of new potent lipoxygenase inhibitors for the treatment of asthma, psoriasis, ulcerative colitis, rheumatoid arthritis, atherosclerosis, cancer and blood vessel disorders.

Multifunctional Cinnamic Acid Derivatives.

Our research to discover potential new multitarget agents led to the synthesis of 10 novel derivatives of cinnamic acids and propranolol, atenolol, 1-adamantanol, naphth-1-ol, and (benzylamino) ethan-1-ol. The synthesized molecules were evaluated as trypsin, lipoxygenase and lipid peroxidation inhibitors and for their cytotoxicity. Compound 2b derived from phenoxyphenyl cinnamic acid and propranolol showed the highest lipoxygenase (LOX) inhibition (IC50 = 6 µΜ) and antiproteolytic activity (IC50 = 0.425 µΜ). The conjugate 1a of simple cinnamic acid with propranolol showed the higher antiproteolytic activity (IC50 = 0.315 µΜ) and good LOX inhibitory activity (IC50 = 66 µΜ). Compounds 3a and 3b, derived from methoxylated caffeic acid present a promising combination of in vitro inhibitory and antioxidative activities. The S isomer of 2b also presented an interesting multitarget biological profile in vitro. Molecular docking studies point to the fact that the theoretical results for LOX-inhibitor binding are identical to those from preliminary in vitro study.

Design, Synthesis and Biological Evaluation of Novel Primaquine-Cinnamic Acid Conjugates of the Amide and Acylsemicarbazide Type.

In this paper design and synthesis of a scaffold comprising primaquine (PQ) motif and cinnamic acid derivatives (CADs) bound directly (compounds 3a-k) or via a spacer (compounds 7a-k) are reported. In the first series of compounds, PQ and various CADs were connected by amide bonds and in the second series by acylsemicarbazide functional groups built from the PQ amino group, CONHNH spacer and the carbonyl group originating from the CADs. PQ-CAD amides 3a-k were prepared by a simple one-step condensation reaction of PQ with a series of CAD chlorides (method A) or benzotriazolides 2 (method B). The synthesis of acylsemicarbazides 7a-k included activation of PQ with benzotriazole, preparation of PQ-semicarbazide 6 and its condensation with CAD chlorides 4. All synthesized PQ-CAD conjugates were evaluated for their anticancer, antiviral and antioxidative activities. Almost all compounds from series 3 were selective towards the MCF-7 cell line and active at micromolar concentrations. The o-fluoro derivative 3h showed high activity against HeLa, MCF-7 and in particular against the SW 620 cell line, while acylsemicarbazide 7f with a benzodioxole ring and 7c, 7g and especially 7j with methoxy-, chloro- or trifluoromethyl-substituents in the para position showed high selectivity and high inhibitory activity against MCF-7 cell line at micromolar (7c, 7f, 7g) and nanomolar (7j) levels. Acylsemicarbazide derivatives with trifluoromethyl group(s) 7i, 7j and 7k showed specific activity against human coronavirus (229E) at concentrations which did not alter the normal cell morphology. The same compounds exerted the most potent reducing activity in the DPPH test, together with 7d and 7g, while methoxy (compounds 7c-e), benzodioxole (7f), p-Cl (7g) and m-CF3 (7i) acylsemicarbazides and amide 3f presented the highest LP inhibition (83%-89%). The dimethoxy derivative 7d was the most potent LOX inhibitor (IC50 = 10 µΜ). The performed biological tests gave evidence of acylsemicarbazide functional group as superior binding group in PQ-CAD conjugates.

Synthesis and biological evaluation of new C-10 substituted dithranol pleiotropic hybrids.

Selective alkylation of the antipsoriatic drug dithranol (DTR) at C-10 with tert-butyl bromoacetate, followed by acid-mediated deprotection, produced the corresponding carboxylic acid 4 which was coupled with selectively protected polyamines (PAs), such as putrescine (PUT), spermidine (SPD) and spermine (SPM), dopamine and aliphatic amines and substituted benzylamines producing a series of DTR-PA hybrids, after acid-mediated deprotection, as well as simple amides. The compounds were tested as antioxidants and inhibitors of lipoxygenase (LOX). The amides 4,4'-dimethoxybenzhydrylamide 13 (86% and 95%), 2,4-dimethoxybenzylamide 12 (87% and 81%) and dodecylamide 9 (98% and 74%), and the hybrid DTR-SPM (7) (93% and 87%), showed the highest antioxidant activity in the DPPH and AAPH assays, whereas the most potent inhibitors of LOX were amide 13 (IC50=7 µM), the benzylamide 10 (IC50=7.9 µM) and the butylamide 8 (IC50=10 µM). Molecular binding studies showed that binding of these derivatives into the hydrophobic domain blocks approach of substrate to the active site, inhibiting soybean LOX. Amide 13 presented the highest anti-inflammatory activity (79.7%). The DTR moiety was absolutely necessary for securing high anti-inflammatory potency. Ethyl ester 3 (IC50=0.357 µM) and the amides 9 (IC50=0.022 µM) and 13 (IC50=0.56 µM) exhibited higher antiproliferative activity than DTR (IC50=0.945 µM) on HaCaT keratinocytes whereas amide 13 generally presented better cytocompatibility. Amide 13 is a very promising lead compound for further development as an anti-inflammatory and antiproliferative agent.

Novel cinnamic acid derivatives as antioxidant and anticancer agents: design, synthesis and modeling studies.

Cinnamic acids have been identified as interesting compounds with antioxidant, anti-inflammatory and cytotoxic properties. In the present study, simple cinnamic acids were synthesized by Knoevenagel condensation reactions and evaluated for the above biological activities. Compound 4ii proved to be the most potent LOX inhibitor. Phenyl- substituted acids showed better inhibitory activity against soybean LOX, and it must be noted that compounds 4i and 3i with higher lipophilicity values resulted less active than compounds 2i and 1i. The compounds have shown very good activity in different antioxidant assays. The antitumor properties of these derivatives have been assessed by their 1/IC50 inhibitory values in the proliferation of HT-29, A-549, OAW-42, MDA-MB-231, HeLa and MRC-5 normal cell lines. The compounds presented low antitumor activity considering the IC50 values attained for the cell lines, with the exception of compound 4ii. Molecular docking studies were carried out on cinnamic acid derivative 4ii and were found to be in accordance with our experimental biological results.