Corresponding author: Hanna Yeromina (
New 1-phenoxymethyl-4-aryl-5,6,7,8-tetrahydro-2а,4a,8a-triazacyclopenta[
Damage to cells by free radicals with the subsequent development of the oxidative stress plays a central role in the aging process and the progression of many diseases, for example, oral (
However, a number of studies indicate, with some conformity, that the oxidative stress along with the chronic inflammatory condition pave the way for the development of metabolic and cardiovascular diseases (
Antioxidants are our first line of defense against free radical damage, and they are critical to maintaining optimal health and well-being. In the process of the protective action, antioxidants are gradually removed from the body; and therefore, it is necessary to constantly restore their amount with food or pharmaceuticals.
We have already found promising objects for pharmacological screening for the presence of the antihypertensive activity among a number of 1,2,4-triazole derivatives containing piperidine or morpholine fragments in their structure (
Predicting the pharmacokinetic profile of candidate compounds (
The possibility of using this approach does not remove the relevance of
The aim of our work was to synthesize 1-phenoxymethyl-4-aryl-5,6,7,8-tetrahydro-2а,4a,8a-triazacyclopenta[
All solvents were purified before use. Reactions were monitored by thin-layer chromatography (
3-Phenoxymethyl-6,7,8,9-tetrahydro-
To study the antioxidant activity (
At the same time, it is advisable to conduct pharmacological studies of
To study the structure-activity relationship, the initial substance ‒ 1-phenoxymethyl-4-phenyl-5,6,7,8-tetrahydro-2,2a,8-triazacyclopenta[
The 1-phenoxymethyl-4-aryl-5,6,7,8-tetrahydro-2а,4a,8a-triazacyclopenta[
The presence of the antiradical and antioxidant activity of the substances synthesized was studied in the experiments
The experiment was performed under simulated conditions; the variants of the experiment included the control (dimethyl sulfoxide (
To prepare the model system, the yolk was isolated from a chicken egg, then it was mixed with an equal volume of the potassium phosphate buffer solution (40 mM KH2PO4 + 105 mM KCl, pH 7.5). The resulting emulsion of yolk lipoproteins (
The oxidative stress was modeled as follows. To 1 ml of
After incubation the solution was cooled and used to determine the products of lipid peroxidation, their intensity was estimated by the accumulation of TBA-reactive products, in particular malonyldialdehyde (
The interaction between malonyldialdehyde and thiobarbituric acid.
The antioxidant properties of the compounds studied was calculated taking into account the formation of TBA-active adducts formed during the interaction of TBA with
where АDМSО – is the average value of the optical density of solutions containing
Аsubstance – is the average value of the optical density of solutions containing
Аreference_drug – is the average value of the optical density of solutions containing
The content of malonyldialdehyde was calculated by the formula 2 (
where [
А532 – is the optical density of the solution at 532 nm;
106 – is the conversion factor to nmol/ml or µm/L;
1.56·105 – is the molar optical density coefficient of the trimethine complex at 532 nm, mole-1 · cm-1;
5.25 – is the sample dilution factor.
The mathematical processing of the data obtained was performed by calculating the unpaired t-test (
Prediction of the pharmacokinetic properties (
3-(Phenoxymethyl)-6,7,8,9-tetrahydro-5
The synthesis of the 1-phenoxymethyl-4-aryl-5,6,7,8-tetrahydro-2а,4a,8a-triazacyclopenta[cd]azulene-3-carboxylic (or carbothionic) acid derivatives
It should be noted that the reaction of the formation of target compounds occurred more easily by the interaction between the 1-phenoxymethyl-4-aryl-5,6,7,8-tetrahydro-2,2a,8-triazacyclopenta[
The values of C, H and N calculated in the compounds newly synthesized were in excellent agreement with the experimental values found from elemental analysis results. The structure of these compounds proposed was further confirmed by 1Н NMR- and 13С NMR spectral data.
The antioxidant activity of derivatives containing the 5,6,7,8-tetrahydro-2,2a,8-triazacyclopenta[
The variant of the experiment | Substituent, or Ar | The |
|||
---|---|---|---|---|---|
|
3.857 ± 0,04 | – | – | – | |
Ionol | 0.787 ± 0,01 | – | – | – | |
Ascorbate | 2.38 ± 0,03 | – | – | – | |
α–Tocopherol | 1.49 ± 0,02 | – | – | – | |
|
– | 0.82 ± 0,019 | 98.70 | 205.41 | 128.27 |
|
CH2CH=CH2 | 2.79 ± 0,014 | 34.74 | 72.30 | 45.15 |
|
CH2Ph | 1.6 5 ± 0,017 | 71.75 | 149.32 | 93.25 |
|
Ph | 1.14 ± 0,031 | 88.60 | 183.78 | 114.77 |
|
2MeC6H4 | 1.25 ± 0,014 | 85.02 | 176.35 | 110.13 |
|
3MeC6H4 | 1.36 ± 0,015 | 81.43 | 168.92 | 105.49 |
|
4MeC6H4 | 1.45 ± 0,032 | 78.50 | 162.83 | 101.69 |
|
2,5Me2C6H3 | 1.85 ± 0,014 | 65.47 | 135.81 | 84.81 |
|
2,4Me2C6H3 | 1.69 ± 0,004 | 70.68 | 146.62 | 91.56 |
|
3,4Me2C6H3 | 1.36 ± 0,008 | 81.43 | 168.92 | 105.49 |
|
2MeOC6H4 | 1.86 ± 0,037 | 65.15 | 135.14 | 84.39 |
|
4MeOC6H4 | 1.02 ± 0,007 | 92.50 | 191.89 | 119.83 |
|
Ph | 2.87 ± 0,008 | 32.24 | 66.89 | 41.77 |
|
3ClC6H4 | 1.88 ± 0,003 | 64.50 | 133.78 | 83.54 |
|
2MeOC6H4 | 1.15 ± 0,050 | 88.27 | 183.11 | 114.35 |
|
3,4Cl2C6H3 | 2.55 ± 0,010 | 42.67 | 88.51 | 55.27 |
|
4ClC6H4 | 1.88 ± 0,003 | 90.55 | 187.84 | 117.30 |
Among the reference drugs, ionol (0.79 nmol
According to the results of the primary pharmacological screening
The initial compound
The interaction between pharmacokinetics, toxicity, and potency is crucial for effective drugs. PkCSM can predict how molecules are distributed within the body based on their structure. The volume of distribution (VD) is the calculated volume that the whole quantity of a drug will be circulated at an equal level of blood plasma. The higher the VD is, the larger the amount of the drug is distributed to the tissue rather than plasma. This model is set from the estimation of the steady-state volume of distribution (
Evaluating the ability of potential antioxidants to pass through the blood-brain barrier (
Based on the pkCSM result it could be assumed as well that all test compounds would be well distributed to the brain (besides the initial compound, 1-phenoxymethyl-4-phenyl-5,6,7,8-tetrahydro-2,2a,8-triazacyclopenta[
Especially 1-phenoxymethyl-4-aryl-5,6,7,8-tetrahydro-2а,4a,8a-triazacyclopenta[
Based on the
The degree of binding to blood proteins for all test compounds is high and amounts to more than 82%.
Cytochrome P450 is an important detoxification enzyme in the body, mainly found in the liver. It oxidizes xenobiotics to facilitate their excretion. Many drugs are deactivated by cytochrome P450, but some can be activated by it. Cytochrome P450 is responsible for the metabolism of many drugs. However, inhibitors of it can dramatically alter the pharmacokinetics of these drugs; therefore, it is important to evaluate whether a given compound is likely to be a cytochrome P450 substrate. Two main isoforms, which are responsible for the drug metabolism, are P2D6 cytochrome (CYP2D6) and P3A4 cytochrome (CYP3A4). Аll test compounds can be substrates or inhibitors of these isoforms.
The results also showed that all test compounds could not be the substrates of Organic Cation transporter 2 (
The potential toxicity of prospective compounds should be assessed. The acute toxicity and relative toxicity of all compounds can be determined by the lethal dose value.
The maximum tolerated dose for all test substances, with the exception of compounds
The value of LD50, the average lethal dose of a substance causing the death of 50% of the experimental animals when administered in one dose, was also predicted. The value of LD50 characterizing the acute toxicity in rats in oral administration of the compounds studied was in the range of 2.29–3.4 mol/kg; moreover, it should be noted that this dose was the lowest for the initial compound
The dose of substances causing the chronic toxicity in rats when administered orally for most compounds is 0.16–0.66, while for compounds
Regarding the toxicological properties of the derivatives containing the 5,6,7,8-tetrahydro-2,2a,8-triazacyclopenta[
Summing up the results obtained, it can be concluded that it is promising to conduct further experimental biological tests for the presence of the antioxidant activity of 1-phenoxymethyl-4-aryl-5,6,7,8-tetrahydro-2а,4a,8a-triazacyclopenta[
We expect that the present analysis and the database would allow identification of potential antioхidant molecules, which follow ADMET properties and act as a valuable lead for the drug development.
Fourteen new 1-phenoxymethyl-4-aryl-5,6,7,8-tetrahydro-2а,4a,8a-triazacyclopenta [cd]azulene-3-carboxylic (or carbothionic) acid derivatives have been synthesized, their structure and purity have been confirmed by 1Н NMR- and 13С NMR-spectroscopy.
All compounds synthesized were tested for the antioxidant activity under conditions of the artificial oxidative stress in vitro.
When individually applying the parameters in each of ADMET group compounds 9b, 9c, 9d, 9e, 9f, 9i and 10 that are absorbable, distributable, metabolized, excreted and nontoxic have been identified.
The molecules showing the promising in vitro and in silico results have been selected for further research in vivo.
Аuthors would like to thank Olexandr Smolskiy for the conducted pharmacological screening for this research.