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 quinoxaline derivatives as antioxidant and anti-inflammatory agents

We report the synthesis, anti-inflammatory and antioxidant activities of novel quinoxaline and quinoxaline 1,4-di-N-oxide derivatives. Microwave assisted methods have been used in order to optimize reaction times and to improve the yields. The tested compounds presented important scavenging activities and promising in vitro inhibition of soybean lipoxygenase. Two of the best lipoxygenase inhibitors (compounds 7b and 8f) were evaluated as in vivo anti-inflammatory agents using the carrageenin-induced edema model. One of them (compound 7b) showed important in vivo anti-inflammatory effect (41%) similar to that of indomethacin (47%) used as the reference drug

Synthesis and pharmacochemical activty of new aryl-acetic acids and derivatives with possible antiinflammatory activity. Quantitative structure activity relations

Inflammation is the biological response of living organisms to tissue damage. It involves interrelationships between humoral and cellular reactions through a number of inflammatory mediators. In inflammatory conditions arachidonic acid esterified in phospholipids billayer of the membrane is liberated and further metabolized by two enzymatic pathways: the prostaglandin synthase (PGSH) and the lipoxyganase (LOX) to the formation of different metabolites. Lipoxygenases (LOXs) constitute a family of dioxygenases containing one non-heme iron atom per molecule, which oscillates between Fe2+ (inactive enzyme) and Fe3+ (active form) during the catalytic cycle. They catalyze the oxygenation of polyunsaturated fatty acids containing a (1Z, 4Z)-penta-1,4-diene system to the corresponding hydroxyperoxy derivatives. Arachidonic acid, which contains four double bonds in its configuration, is metabolised via lipoxygenases to a number of products with the hydroperoxy group in different positions (5-LOXs, 8-LOXs, 9-LOXs, 11-LOXs, 12-LOXs and 15-LOXs). It has been found from the literature that many compounds acting as inhibitors of 5-LOX can form strong complexes with the iron of the enzyme. This property has been exploited to the synthesis of some new aryl-acetic and aryl-hydroxamic acids in order to study their mechanism of action. Furthermore it is well known that some non-steroidal anti-inflammatory drugs posses side effects from the gastrointenstal system and thus they are not freely used. From the literature it has been found that cinnamomic acid derivatives and amides posses anti-inflammatory and analgesic properties. The structures of the new compounds have been verified by their elemental analysis and by their spectroscopic data IR, 1H-NMR, 13C-NMR and MS. The synthesized compounds have been investigated for: Pharmacochemical Studies in vitro: I. Determination of the reducing activity of the stable radical 1,1-diphenyl-2-picrylhydrazyl (DPPH) II. Competition of the tested compounds with DMSO for hydroxyl radicals III. Soybean lipoxygenase inhibition study IV. In vitro PGHS-1 inhibition study V. Heme protein-dependent lipid peroxidation VI. Non enzymatic assay of superoxide radicals-Measurement of superoxide radical scavenging activity VII. Effects of the test compounds on the Fe+3-stimulated peroxidation of linoleic acid VIII. Stability studies and incubation with glutathione IX. Cytotoxic and antiproliferative activity and in vivo: I. the anti-inflammatory activity by the inhibition of the carrageenan induced rat paw edema II. colitis An attempt has been made to correlate the experimental biological results with some physicochemical parameters and some quantitative structure activity relationships have been derived. The physicochemical parameters have been depicted from the literature or calculated by the C-QSAR program of Biobyte. An attempt was also made to evaluate QSAR for LOX inhibitors by retreiving biological data from the literature and using the C-QSAR program by Biobyte. The relationships have been studied, explained and compared to several QSAR equations derived from the literature concerning LOX inhibitors. The lipophilicity as clog P (theoretically calculated lipophilicity) plays the most important role. Steric effects also seem to be important for the interaction of the molecule with the active site of the enzyme. In most of the examples some indicator variables indicating the presence of some functional groups has been used whereas no role for electronic effects has been found.Η φλεγμονή είναι η φυσιολογική προστατευτική απάντηση του οργανισμού σε βλάβη των ιστών. Σ΄ αυτήν εμπλέκονται πολλοί παράγοντες μεταξύ αυτών και ελεύθερες ρίζες. Κατά τη διάρκεια αυτής της διαδικασίας το αραχιδονικό οξύ που βρίσκεται εστεροποιημένο στα φωσφολιπίδια της κυτταρικής μεμβράνης απελευθερώνεται και με τη δράση των δύο ενζυμικών συστημάτων της προσταγλανδινικής συνθετάσης και της λιποξυγονάσης, μετατρέπεται σε διάφορους μεταβολίτες με διαφορετικό ρόλο στη διεργασία της φλεγμονής (προσταγλανδίνες, προστακυκλίνες, θρομβοξάνια, λευκοτριένια κ.α.). Οι λιποξυγονάσες είναι μονομερείς πρωτεΐνες ευρέως διαδεδομένες στη φύση. Αποτελούν οικογένεια κυτοσολικών ενζύμων, που καταλύουν την οξυγόνωση των ελευθέρων και εστεροποιημένων λιπαρών οξέων που περιέχουν ένα (1Ζ, 4Ζ)-πεντα-1,4-διενικό σύστημα προς σχηματισμό των αντιστοίχων υδροϋπεροξυ-παραγώγων. Τα ένζυμα αυτά αναγνωρίζουν τα λιπαρά οξέα με δύο cis διπλούς δεσμούς μεταξύ των οποίων παρεμβάλεται μια μεθυλενική ομάδα. Ανάλογα με τη θέση εισαγωγής του οξυγόνου στο μόριο του αραχιδονικού οξέος διακρίνονται στις 5-LOXs, 8-LOXs, 9-LOXs, 11-LOXs, 12-LOXs και 15-LOXs. Έχει βρεθεί από τη βιβλιογραφία ότι πολλές ενώσεις αναστολείς της LΟΧ παρουσιάζουν δράση λόγω της ικανότητας σχηματισμού χηλικού συμπλόκου με το σίδηρο του ενζύμου. Για το λόγο αυτό συνετέθηκαν μερικά νέα α,β-ακόρεστα καρβοξυλικά οξέα και υδροξαμικά οξέα με στόχο την μελέτη της δράσης τους ως αναστολέων της LOX και την ποσοτική συσχέτιση της δομής με τη δράση. Ακόμη είναι γνωστό ότι τα όξινα μη στεροειδή αντιφλεγμονώδη φάρμακα παρουσιάζουν ανεπιθύμητες ενέργειες από το γαστρεντερικό σύστημα, με αποτέλεσμα να περιορίζεται η θεραπευτική τους εφαρμογή. Από τη βιβλιογραφία έχουν βρεθεί παράγωγα του κινναμωμικού οξέος και αμίδια με αντιφλεγμονώδεις και αναλγητικές ιδιότητες. Οι δομές των νέων ενώσεων επιβεβαιώθηκαν με τις στοιχειακές αναλύσεις και τα φασματοσκοπικά δεδομένα UV, IR, 1H-NMR, 13C-NMR και MS. Οι ενώσεις, που παρασκευάστηκαν, α,β-ακόρεστα οξέα, υδροξαμικά οξέα και αμίδια μελετήθηκαν στα ακόλουθα πειράματα: Φαρμακοχημικές δοκιμασίες in vitro I. αλληλεπίδραση των ενώσεων με την ελεύθερη σταθερή ρίζα του 1,1-διφαινυλο πικρυλυδραζυλίου (DPPH) II. ανταγωνισμός του DMSO στη δέσμευση των ελεύθερων ριζών OH III. δέσμευση ριζών ανιόντος οξυγόνου (υπερόξυ ανιόν) IV. αναστολή της υπεροξείδωσης του αραχιδονικού οξέος V. αναστολή της υπεροξείδωσης του λινελαϊκού οξέος VI. αναστολή του ενζύμου λιποξυγονάσης φυτικής προέλευσης (από σόγια) VII. αναστολή του ενζύμου συνθετάση της προσταγλανδίνης-1 (PGHS-1) VIII. μελέτη της αλληλεπίδρασης με γλουταθειόνη (GSH) IX. προσδιορισμός κυτταροτοξικής-κυτταροστατικής δράσης Βιολογικά πειράματα in vivo I. αναστολή της εμφάνισης του οιδήματος που επάγεται με την ενδοδερμική χορήγηση καρραγενίνης στον άκρο πέλμα επίμυα. II. μελέτη της αναστολής της εκδήλωσης ελκώδους κολίτιδας Ακόμη, έγινε προσπάθεια συσχέτισης των βιολογικών δράσεων που προσδιορίστηκαν, με επιλεγμένες φυσικοχημικές ιδιότητες και οι ποσοτικές σχέσεις που προέκυψαν, να συσχετισθούν με σχέσεις που αναφέρθηκαν στη βιβλιογραφία με σκοπό τη συγκριτική τους μελέτη. Οι τιμές των φυσικοχημικών ιδιοτήτων ελήφθηκαν από τη βιβλιογραφία ή υπολογίσθηκαν πχ. η λιποφιλικότητα ως clogP, με το πρόγραμμα C-QSAR και EHOMO/ELUMO, ενέργεια εφυδατώσεως, διπολική ροπή με το πρόγραμμα Spartan. Από τα αποτελέσματα που λαμβάνονται επιβεβαιώνεται η ύπαρξη της πειραματικής βιολογικής δράσης για τις νέες ενώσεις και είναι ανάλογα με τις τιμές της. Εξάγονται συμπεράσματα σχετικά με τα δομικά και φυσικοχημικά χαρακτηριστικά των εξεταζόμενων ενώσεων, τα οποία είναι σημαντικά για την εμφάνιση της δράσης. Συγκεκριμένα για τη σάρωση των ριζών υδροξυλίου η λιποφιλικότητα ως clog P φαίνεται ότι είναι η σημαντικότερη φυσικοχημική ιδιότητα που επηρεάζει τη δράση. Ενώ για την αλληλεπίδραση με το DPPH η μοριακή διαθλασιμότητα και οι διαστάσεις του μορίου διαδραματίζουν σπουδαίο ρόλο. Τέλος, με επεξεργασία δεδομένων της βιβλιογραφίας που αφορούν αναστολείς των λιποξυγονασών, έγινε προσπάθεια εξαγωγής ποσοτικών σχέσεων δομής-δράσης με το υπολογιστικό πρόγραμμα C-QSAR της Biobyte. Οι σχέσεις που μελετήθηκαν και έγινε προσπάθεια να εξηγηθούν τα συμπεράσματα που προέκυψαν και να συγκριθούν με προηγούμενες σχέσεις που βρέθηκαν από τη βιβλιογραφία και αφορούν την αναστολή των λιποξυγονασών από διάφορα μόρια. Aπό τα αποτελέσματα προκύπτει ότι η λιποφιλικότητα αποτελεί τη σημαντικότερη παράμετρο για την αναστολή του ενζύμου. Στερεοχημικές ιδιότητες φαίνεται να παίζουν κάποιο ρόλο γεγονός που υποδηλώνει ότι το μόριο πρέπει να λαμβάνει συγκεκριμένη διαμόρφωση για αλληλεπίδραση με το ενεργό κέντρο του ενζύμου λιποξυγονάση ανεξαρτήτου προέλευσης και υποστρώματος. Σε ορισμένες εξισώσεις χρησιμοποιήθηκαν επιπλέον και ορισμένοι δείκτες για την παρουσία συγκεκριμένων σημαντικών χαρακτηριστικών (ποιοτικός ρόλος) ενώ δεν υπάρχει τεκμηρίωση για την συμμετοχή των ηλεκτρονιακών επιδράσεων από τα μέχρι στιγμής δεδομένα

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

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

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

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

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

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

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 μM. 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