Multitarget molecular hybrids of cinnamic acids

Enhanced production of trans-cinnamic acid in Photorhabdus luminescens with homolog expression and deletion strategies

AIM

This study aimed to overproduce industrially relevant and safe bio-compound trans-cinnamic acid (tCA) from Photorhabdus luminescens with deletion strategies and homologous expression strategies that had not been applied before for tCA production.

METHODS AND RESULTS

The overproduction of the industrially relevant compound tCA was successfully performed in P. luminescens by deleting stlB (TTO1ΔstlB) encoding a cinnamic acid CoA ligase in the isopropylstilbene pathway and the hcaE insertion (knockout) mutation (hcaE::cat) in the phenylpropionate catabolic pathway, responsible for tCA degradation. A double mutant of both stlB deletion and hcaE insertion mutation (TTO1DM ΔstlB-hcaE::cat) was also generated. These deletion strategies and the phenylalanine ammonium lyase-producing (PI-PAL from Photorhabdus luminescens) plasmid, pBAD30C, carrying stlA (homologous expression mutants) are utilized together in the same strain using different media, a variety of cultivation conditions, and efficient anion exchange resin (Amberlite IRA402) for enhanced tCA synthesis. At the end of the 120-h shake flask cultivation, the maximum tCA production was recorded as 1281 mg l-1 in the TTO1pBAD30C mutant cultivated in TB medium, with the IRA402 resin keeping 793 mg l-1 and the remaining 488 mg l-1 found in the supernatant.

CONCLUSION

TCA production was successfully achieved with homologous expression, coupled with deletion and insertion strategies. 1281 mg l-1is the highest tCA concentration that achieved by bacterial tCA production in flask cultivation, according to our knowledge.

Exploring acetaminophen prodrugs and hybrids: a review

This critical review highlights the advances in developing new molecules for treating pain syndrome, an important issue for human health. Acetaminophen (APAP, known as paracetamol) and nonsteroidal anti-inflammatory drugs (NSAIDs) are commonly used in clinical practice despite their adverse effects. Research is being conducted to develop innovative drugs with improved pharmaceutical properties to mitigate these effects. A more practical way to achieve that is to study well-known and time-tested drugs in their molecular combinations. Accordingly, the present work explores APAP and their combined chemical entities, i.e., prodrugs (soft drugs), codrugs (mutual prodrugs), and hybrids. Due to their molecular structure, APAP prodrugs or codrugs could be considered merged or conjugated hybrids; all these names are very fluid terms. This article proposed a structural classification of these entities to better analyze their advances. So, the following: carrier-linked O-modified APAP, -linked N-modified APAP derivatives (prodrugs), and direct- and spacer-N,O-linked APAP hybrids (codrugs) are the central parts of this review and are examined, especially ester and amide NSAID-APAP molecules. The C-linked APAP and nitric oxide (NO)-releasing APAP hybrids were also briefly discussed. Prime examples of APAP-based drugs such as propacetamol, benorylate, acetaminosalol, nitroparacetamol, and agent JNJ-10450232 weave well into this classification. The proposed classification is the first and original, giving a better understanding of the SAR studies for new pain relievers research and the design development for the analgesic APAP-(or NSAID)-based compounds.

Exploring the Medicinal Potential of Achillea grandifolia in Greek Wild-Growing Populations: Characterization of Volatile Compounds, Anti-Inflammatory and Antioxidant Activities of Leaves and Inflorescences

Various species of the genus Achillea L. (Asteraceae) are traditionally used worldwide for wound healing against diarrhea, flatulence, and abdominal pains, as diuretic and emmenagogue agents. In the present study, the essential oils (EOs) obtained separately from the leaves and inflorescences of wild-growing Achillea grandifolia Friv. from Mt. Menoikio and Mt. Pelion (Greece) were analyzed by Gas Chromatography-Mass Spectrometry. The major compounds found in EOs of A. grandifolia inflorescences from Mt. Menoikio were as follows: cis-thujone (36.9%), 1,8-cineole (11.9%), camphor (10.0%), ascaridole (7.3%), α-terpinene (6.4%), sabinene (4.1%), trans-thujone (3.6%), and cis-jasmone (3.4%). In leaves from Mt. Menoikio, they were as follows: cis-thujone (50.8%), 1,8-cineole (20.0%), trans-thujone (5.5%), camphor (5.5%), borneol (3.6%), and α-terpineol (3.1%). In inflorescences from Mt. Pelion, they were as follows: camphor (70.5%), camphene (5.9%), cis-jasmone (3.2%), bornyl acetate (3.2%). In leaves from Mt. Pelion, they were as follows: camphor (83.2%), camphene (3.9%), and borneol (3.7%). Subsequently, the samples were first time tested for their antioxidant activities with the interaction of EOs with DPPH (2,2-diphenyl-1-picrylhydrazyl) and their inhibition of lipid peroxidation, as well as for their anti-inflammatory activity through the soybean LOX (lipoxygenase) inhibition. All of the examined samples were found effective. A. grandifolia leaves presented the highest antioxidant potential according to the DPPH method, and the highest percentage of LOX inhibition. The study herein investigated for the first time the leaves and the inflorescences of A. grandifolia separately, and the results generally align with similar studies from neighboring countries (Turkey and Serbia) in terms of the yields and categorization of main EO compounds (oxygenated monoterpenes). However, the findings were not in agreement with previously studied Greek material, as a higher amount of cis-thujone and lower antioxidant activity are reported herein. Both the EOs of inflorescences and the leaves of the wild-growing population collected from Mt. Menoikio were characterized by a high quantity of cis-thujone (36.9% and 50.8%, respectively).

Design and Synthesis of Coumarin Derivatives as Cytotoxic Agents through PI3K/AKT Signaling Pathway Inhibition in HL60 and HepG2 Cancer Cells

In this study, a series of coumarin derivatives, either alone or as hybrids with cinnamic acid, were synthesized and evaluated for their cytotoxicity against a panel of cancer cells using the MTT assay. Then, the most active compounds were inspected for their mechanism of cytotoxicity by cell-cycle analysis, RT-PCR, DNA fragmentation, and Western blotting techniques. Cytotoxic results showed that compound (4) had a significant cytotoxic effect against HL60 cells (IC₅₀ = 8.09 µM), while compound (8b) had a noticeable activity against HepG2 cells (IC₅₀ = 13.14 µM). Compounds (4) and (8b) mediated their cytotoxicity via PI3K/AKT pathway inhibition. These results were assured by molecular docking studies. These results support further exploratory research focusing on the therapeutic activity of coumarin derivatives as cytotoxic agents.

(E)-1-(3-Benzoyl-4-phenyl-1H-pyrrol-1-yl)-3-phenylprop-2-en-1-one

Over the last decade, there has been an increasing effort to fight inflammatory conditions establishing new multitarget approaches. Chronic inflammation is implicated in many multifactorial diseases, constituting a great economic burden and a chronic health problem. In an attempt to develop new potent multifunctional anti-inflammatory agents, a cinnamic-pyrrole hybrid (6) was synthesized and screened for its antioxidant and anti-Lipoxygenase potential. The new compound, in comparison with its pyrrole precursor (4), showed improved biological activities. In silico calculations were performed to predict its drug-likeness. The examined derivative is considered orally bioavailable according to Lipinski’s rule of five. Compound 6 could be used as a lead for the synthesis of more effective hybrids.

2-((4-((E)-1-(Hydroxyimino)ethyl)phenyl)amino)-2-oxoethyl Cinnamate

Cinnamic acid-nitric oxide (NO) donor hybrids have attracted attention, in recent years, as new pharmacological agents to treat multifactorial diseases. In the present study, hybrid oxime 5 was synthesized and its anti-lipid peroxidation and anti-lipoxygenase activities were evaluated. The new compound showed remarkable anti-LOX activity, while its antioxidant activity was quite good in comparison to the appropriate reference compounds. The examined derivative seems to be orally active in accordance to Lipinski’s rule of five. Compound 5 can be considered as a leading structure for the design and synthesis of new hybrids.

Effects of Cornus and Its Mixture with Oregano and Thyme Essential Oils on Dairy Sheep Performance and Milk, Yoghurt and Cheese Quality under Heat Stress

The effect of a diet supplemented with a novel cornus extract, enriched with essential oils of oregano and thyme, on the performance of Chios cross-bred dairy sheep was investigated during the summer period. The plant extracts were prepared using a "green" method based on aqueous extraction. A total of 45 lactating ewes were allocated into three equal groups in a randomized block design. The three groups were fed the same feed allowance, roughage based on Lucerne hay and wheat straw and a concentrate based on cereals and oil cakes (the control diet). The diet of two groups was fortified with cornus extract, with or without oregano and thyme essential oils, at a level 0.515 g of plant extract/essential oils per kg of concentrate. Individual milk yield was recorded weekly and feed refusals were recorded on a pen basis daily, during a six-week period of lactation. Milk samples were analyzed for the chemical composition of protein, fat, lactose and solids-not-fat constituents, somatic cell counts and total viable bacteria counts. Moreover, the milk of each group was used for yoghurt and Feta cheese production. The lipid oxidative stability, protein carbonyl content and fatty acid composition of milk, yoghurt and cheese samples were also evaluated. The results showed that the incorporation of novel plant extracts and essential oils increased the milk production per ewe. Dietary supplementation with cornus extracts and essential oils lowered lipid and protein oxidation in milk, yoghurt and cheese samples, compared to the control. However, diet supplementation with herbal extracts did not affect the fatty acid profile in milk, cheese and yoghurt or the serum biochemical parameters. In conclusion, dietary supplementation with cornus in combination with oregano and thyme has the potential to improve feed utilization and the performance of high-yield dairy Chios cross-bred ewes reared under heat stress.

Biological Activities and ADMET-Related Properties of Novel Set of Cinnamanilides

A series of nineteen novel ring-substituted N-arylcinnamanilides was synthesized and characterized. All investigated compounds were tested against Staphylococcus aureus as the reference strain, two clinical isolates of methicillin-resistant S. aureus (MRSA), and Mycobacterium tuberculosis. (2E)-N-[3-Fluoro-4-(trifluoromethyl)phenyl]-3-phenylprop-2-enamide showed even better activity (minimum inhibitory concentration (MIC) 25.9 and 12.9 µM) against MRSA isolates than the commonly used ampicillin (MIC 45.8 µM). The screening of the cell viability was performed using THP1-Blue™ NF-κB cells and, except for (2E)-N-(4-bromo-3-chlorophenyl)-3-phenylprop-2-enamide (IC₅₀ 6.5 µM), none of the discussed compounds showed any significant cytotoxic effect up to 20 μM. Moreover, all compounds were tested for their anti-inflammatory potential; several compounds attenuated the lipopolysaccharide-induced NF-κB activation and were more potent than the parental cinnamic acid. The lipophilicity values were specified experimentally as well. In addition, in silico approximation of the lipophilicity values was performed employing a set of free/commercial clogP estimators, corrected afterwards by the corresponding pK_a calculated at physiological pH and subsequently cross-compared with the experimental parameters. The similarity-driven property space evaluation of structural analogs was carried out using the principal component analysis, Tanimoto metrics, and Kohonen mapping.

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.

Targeting Inflammation with Conjugated Cinnamic Amides, Ethers and Esters

Background:

Cinnamic acid is a key intermediate in shikimate and phenylpropanoid pathways. It is found both in free form, and especially in the form of esters in various essential oils, resins and balsams which are very important intermediates in the biosynthetic pathway of several natural products. The cinnamic derivatives play a vital role in the formation of commercially important intermediate molecules which are necessary for the production of different bioactive compounds and drugs. Different substitutions on basic moiety lead to various biological activities. Furthermore, combination of appropriate pharmacophore groups with cinnamic acid derivatives were developed to give hybrids in order to find out promising drug candidates as inhibitors of multiple biological targets associated with inflammation. We found interesting to continue our efforts to design and synthesise three series of novel cinnamic acid-based hybrids: a) nitrooxy esters of cinnamic acid, b) ethers and c) amides of cinnamic acids with arginine, as pleiotropic candidates against multiple targets of inflammation.

Methods:

The synthesis of cinnamic was established by a Knoevenagel-Doebner condensation of the suitable aldehyde either with malonic acid in the presence of pyridine and piperidine, or with phenylacetic acid in the precence of triethylamine in acetic anhydride. The synthesis of the corresponding esters was conducted in two steps. The ethers were synthesized in low yields, with 1,2 – dibromoethane in dry acetone, in the presence of K2CO3, to give oily products. The corresponding cinnamic amides were synthesised in a single step. The synthesised hybrids were tested as lipoxygenase (LOX) and cyclooxygenase (COX) inhibitors in vitro. In silico docking was applied to all the novel derivatives. Several molecular properties of the hybrids were calculated in order to evaluate their drug likeness.

Results:

A number of esters, ethers and amides of selected cinnamic acids, either phenyl substituted or not, has been synthesised and subjected to modelling studies. The compounds were studied in vitro/in vivo for their inhibitory activities on cox and lox, and as antioxidants. Log P values of all the title compounds except of 3a (5.38) were found to be less than 5 and are in agreement to Lipinski’s rule of five, suggesting satisfactory permeability across cell membrane. The molecular modelling study seems to be in accordance with the experimental results for LOX and COX-2. The result of antioxidant activity for amide 3b supports the anti-lox activity. Compound 5d presents the higher in vivo anti-inflammatory.

Conclusion:

According to the experimental findings compounds 3b and 5d can be used as lead compounds for the design of new molecules to target inflammation.

Rational Design of Multitarget-Directed Ligands: Strategies and Emerging Paradigms

Due to the complexity of multifactorial diseases, single-target drugs do not always exhibit satisfactory efficacy. Recently, increasing evidence indicates that simultaneous modulation of multiple targets may improve both therapeutic safety and efficacy, compared with single-target drugs. However, few multitarget drugs are on market or in clinical trials, despite the best efforts of medicinal chemists. This article discusses the systematic establishment of target combination, lead generation, and optimization of multitarget-directed ligands (MTDLs). Moreover, we analyze some MTDLs research cases for several complex diseases in recent years and the physicochemical properties of 117 clinical multitarget drugs, with the aim to reveal the trends and insights of the potential use of MTDLs.

Synthesis and Spectrum of Biological Activities of Novel N-arylcinnamamides

A series of sixteen ring-substituted N-arylcinnamamides was prepared and characterized. Primary in vitro screening of all the synthesized compounds was performed against Staphylococcus aureus, three methicillin-resistant S. aureus strains, Mycobacterium tuberculosis H37Ra, Fusarium avenaceum, and Bipolaris sorokiniana. Several of the tested compounds showed antistaphylococcal, antitubercular, and antifungal activities comparable with or higher than those of ampicillin, isoniazid, and benomyl. (2E)-N-[3,5-bis(trifluoromethyl)phenyl]-3-phenylprop-2-enamide and (2E)-3-phenyl-N-[3-(trifluoromethyl)phenyl]prop-2-enamide showed the highest activities (MICs = 22.27 and 27.47 µM, respectively) against all four staphylococcal strains and against M. tuberculosis. These compounds showed an activity against biofilm formation of S. aureus ATCC 29213 in concentrations close to MICs and an ability to increase the activity of clinically used antibiotics with different mechanisms of action (vancomycin, ciprofloxacin, and tetracycline). In time-kill studies, a decrease of CFU/mL of >99% after 8 h from the beginning of incubation was observed. (2E)-N-(3,5-Dichlorophenyl)- and (2E)-N-(3,4-dichlorophenyl)-3-phenylprop-2-enamide had a MIC = 27.38 µM against M. tuberculosis, while a significant decrease (22.65%) of mycobacterial cell metabolism determined by the MTT assay was observed for the 3,5-dichlorophenyl derivative. (2E)-N-(3-Fluorophenyl)- and (2E)-N-(3-methylphenyl)-3-phenylprop-2-enamide exhibited MICs = 16.58 and 33.71 µM, respectively, against B. sorokiniana. The screening of the cytotoxicity of the most effective antimicrobial compounds was performed using THP-1 cells, and these chosen compounds did not shown any significant lethal effect. The compounds were also evaluated for their activity related to the inhibition of photosynthetic electron transport (PET) in spinach (Spinacia oleracea L.) chloroplasts. (2E)-N-(3,5-dichlorophenyl)-3-phenylprop-2-enamide (IC₅₀ = 5.1 µM) was the most active PET inhibitor. Compounds with fungicide potency did not show any in vivo toxicity against Nicotiana tabacum var. Samsun. The structure–activity relationships are discussed.

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.

Antioxidant Activity and Chemical Composition of Essential Oils of some Aromatic and Medicinal Plants from Albania

The chemical compositions have been investigated of the volatile oils of nine populations of six species from Albania, namely Artemisia absinthium, Calamintha nepeta, Hypericum perforatum, Sideritis raeseri subsp. raeseri, Origanum vulgare subsp. hirtum from two wild populations, and Salvia officinalis (sage) from two wild and one cultivated population,. The essential oils were obtained by hydrodistillation and their analyses were performed by GC–MS. The major constituents were: A. absinthium: neryl isovalerate (19.5%), geranyl isobutanoate (16.4%) and carvacrol (8.8%); C. nepeta: pulegone (31.7%), spathulenol (20.0%) and isomenthone (12.7%); H. perforatum: caryophyllene oxide (31.0%), δ-selinene (10.5%) and carvacrol (10.4%); O. vulgare: carvacrol (81.0, 78.6%), γ-terpinene (5.5, 7.1%) and p-cymene (4.9, 4.1%) for O. vulgare originating from Tepelena and Vlora, respectively; S. raeseri: carvacrol (36.7%), caryophyllene oxide (17.8%), β-caryphyllene (8.7%), spathulenol (7.7%) and myrtenol (6.4%); S. officinalis: camphor (40.2, 47.8, 45.9%), α-thujone (19.2, 22.2, 13.7%), eucalyptol (5.4, 2.6, 6.0%), camphene (5.8, 6.1, 3.9, %), borneol (2.1, 2.9, 5.7%) and bornyl acetate (3.3, 1.4, 5.6%) for samples originating from Tepelena, Tirana and Vlora, respectively. The essential oils were also tested for their free radical scavenging activity using the following in vitro assays: i) interaction with the free stable radical of DPPH (1,1-diphenyl-2-picrylhydrazyl), and ii) inhibition of linoleic acid peroxidation with 2,2'-azobis-2-methyl-propanimidamide, dihydrochloride (AAPH). Finally, their inhibitory activity toward soybean lipoxygenase was evaluated, using linoleic acid as substrate. The essential oil of O. vulgare (OV-VL) presented the highest interaction with the stable radical DPPH (76.5%), followed by that of A. absinthium (54.7%). O. vulgare (OV-TP) and A. absinthium showed high anti-lipid peroxidation activity, 97.5% and 96.5%, respectively, higher than that of the reference compound trolox (73.0%). Only the tested sample of O. vulgare (OV-VL) significantly inhibited soybean lipoxygenase (54.2%).

Synthesis and Pharmacochemistry of New Pleiotropic Pyrrolyl Derivatives

Within the framework of our attempts to synthesize pleiotropic anti-inflammatory agents, we have synthesized some chalcones and their corresponding 3,4-pyrrolyl derivatives. Chalcones constitute a class of compounds with high biological impact. They are known for a number of biological activities, including anti-inflammatory and free radical scavenging activities. They inhibit several enzymes implicated in the inflammatory process, such as lipoxygenase, cyclooxygenase (COX) and lysozymes. The synthesized pyrroles have been studied for: (1) their in vitro inhibition of lipoxygenase; (2) their in vitro inhibition of COX; (3) their in vitro inhibition of lipid peroxidation; (4) their interaction with the stable, N-centered, free radical, 2,2-diphenyl-1-picrylhydrazyl (DPPH); (5) their inhibition on interleukin-6 (IL-6); (6) their anti-proteolytic activity; and (7) their in vivo anti-inflammatory activity using carrageenan-induced rat paw edema. Their physicochemical properties were determined to explain the biological results. Lipophilicity was experimentally determined. 2i and 2v were found to be promising multifunctional molecules with high antiproteolytic and anti-inflammatory activities in combination with anti-interleukin-6 activity.