Isobornyl and Isocamphyl Photostabilizers in Poly(lactic acid)-Based Electrospun Fibers.

In this work, electrospun polylactide fibers with new photostabilizing additives, 4-methyl-2,6-diisobornylphenol (DIBP) and N-isocamphylaniline (NICA), have been tested under the influence of UV-C radiation (254 nm). The changes in the polymers' chemical structure under UV-C radiation were revealed through the increase in absorption in the 3600-3100 cm region in regard to the FTIR spectra. In the samples that were irradiated for 1 h, the stabilizing effect of the photoprotectors became most noticeable as the difference in the content of the hydroxyl groups in stabilized and the pure PLA reached a maximum.

Tailoring Photoprotection of Polylactide with New Isobornyl Derivatives of Phenol and Aniline.

This article is devoted to the development of new photostabilizers for polylactide (PLA), a polymer that is an environmentally friendly alternative to polymers and is based on fossil raw materials. We have elucidated the role of the reaction center of two potential PLA photoprotectors: -isobornylaniline and 2-isobornylphenol, in reactions occurring in a polymer matrix under the action of UV-C radiation. PLA samples with the photostabilizers were irradiated under a wavelength of 253.

Experimental Evaluation of the Effectiveness of Isobornylphenols in the Model of Pathospermia and Their Effect on the Antioxidant-Prooxidant Balance of Male Germ Cells.

We studied the effect of antioxidants dibornol (2,6-diisobornyl-4-methylphenol) and its derivative (4-hydroxymethyl-2,6-diisobornylphenol), members of the alkylated phenols group, on the redox potential of male germ cells and their morphological and functional state in the rat model of pathospermia. Pharmacological effect was observed in animals treated with dibornol. The studied compounds led to the normalization of the antioxidant-prooxidant balance.

Synthesis of new coumarin[1,3]oxazine derivatives of 7-hydroxy-6-isobornyl-4-methylcoumarin and their antioxidant activity.

In this work, we synthesized a series of new 9,10-dihydro-2H,8H-chromeno[8,7e][1,3]oxazine-2-on derivatives which incorporate isobornylcoumarin and 1,3-oxazine moieties. A structure-antioxidant activity relationship was analyzed. A comparative evaluation of their radical scavenging activity, antioxidant and membrane-protective properties was carried out in test with DPPH, as well as on the models of Fe /ascorbate-initiated lipid peroxidation and oxidative hemolysis of mammalian red blood cells.

Isobornylchalcones as Scaffold for the Synthesis of Diarylpyrazolines with Antioxidant Activity.

The pyrazoline ring is defined as a "privileged structure" in medicinal chemistry. A variety of pharmacological properties of pyrazolines is associated with the nature and position of various substituents, which is especially evident in diarylpyrazolines. Compounds with a chalcone fragment show a wide range of biological properties as well as high reactivity which is primarily due to the presence of an α, β-unsaturated carbonyl system.

2,6-Diisobornyl-4-Methylphenol Reduces Postishemic Myocardium Remodeling in Delayed Period after Ischemia/Reperfusion in Rats.

2,6-Diisobornyl-4-methylphenol (Dibornol, 10 mg/kg intragastrically daily for 5 days after myocardial ischemia/reperfusion) 1.5-fold increased rat survival during the acute post-infarction period in comparison with the control group. In survivors, Dibornol reliably prevented post-ischemic progression of heart failure in the delayed post-infarction period (30 days after ischemia/reperfusion), which was seen from an increase in the left-ventricular developed pressure by 22%, left-ventricular contractility index by 19%, and +dP/dt by 34%.

Effectiveness of Phenolic Antioxidants in Experimental Model of Benign Prostatic Hyperplasia.

Experimental model of sulpiride-provoked benign prostatic hyperplasia was employed to comparatively assess the effect of phenolic antioxidants (dihydroquercetin, p-thyrozol, dibornol, and prostagenin) on prostate morphology. All examined agents decreased the degree of hyperplasia in acinar epithelium; the greatest efficacy was demonstrated by prostagenin. Moreover, dihydroquercetin and p-thyrozol increased the cross-section area of acinar lumina and prostate volume, which is inadmissible in this pathology.

Synthesis and Biological Evaluation of Novel Coumarins with tert-Butyl and Terpene Substituents.

Coumarins with terpene and tert-butyl substituents were synthesized via Pechmann condensation reaction. New derivatives were investigated in different model system for the exhibition of antioxidant, radical scavenging and membrane-protective activities. It has been found that 4-methylcoumarin derivatives with monoterpene moieties exhibit high antioxidant activities.

Neuroprotective Effects of Dibornol in Focal Cerebral Ischemia/Reperfusion in Rats.

Neuroprotective activity of 2,6-diisobornyl-4-methylphenol (Dibornol) was studied under conditions of experimental focal cerebral ischemia/reperfusion modeled by intraluminal occlusion of the left middle cerebral artery for 1 h followed by recirculation. Dibornol administered in a dose of 10 mg/kg intragastrically 24 h and 30 min before and 24 h after focal ischemia/reperfusion modeling reduced the size of the brain infarction zone by 52% (48 h after recirculation) and neurological deficit by 1.7-2.

Neuroprotective Activity of D-HES in Transient Global Cerebral Ischemia in Rats.

We studied the effect of O-((((4-hydroxy-3,5-di(1,7,7-trimethylbicyclo[2.2.1]hept-exo-2-yl) benzyl)oxy)ethyl)-O-(2-hydroxyethyl)-(1→4)-α-D-glucan (D-HES, 80 mg/kg, intravenously) and reference preparation ethylmethylhydroxypyridine succinate (EMHP-S, 50 mg/kg, intravenously) on rat survival and neurological deficit in 24 h after transient global cerebral ischemia in Wistar rats.

Cardioprotective Activity of 2,6-Diisobornyl-4-Methylphenol in Acute Myocardial Ischemia/Reperfusion in Rats.

We studied the cardioprotective effect of 2,6-diisobornyl-4-methylphenol under conditions of myocardial ischemia/reperfusion in rats. Daily administration of 2,6-diisobornyl-4-methylphenol (100 mg/kg intragastrically) over 3 days before and 5 days after modeling of myocardial ischemia/reperfusion prevented the increase in the infarction area by almost 2 times in comparison with the control by day 5 after recirculation. The type and severity of pathological changes in ECG parameters reflecting necrotic changes in the myocardium under the action of the compound significantly decreased by day 35 of the experiment.

Antiradical Activity of Porphyrins with a Diisobornylphenol Fragment at the Macrocycle Periphery.

This article focuses on the antiradical activity of a number of 2,6-diisobornylphenol-porphyrin conjugates with various spacers between the porphyrin and phenolic fragments in the model reaction of ethylbenzene oxidation initiated by azoisobutyric acid dinitrile. The study has shown that the electronic effects of the groups directly related to the 2,6-diisobornylphenol fragment exert the predominant influence both on the reactivity of the phenolic hydroxyl group in interaction with free radicals and on the antiradical activity of the molecule as a whole. The antiradical activity of the molecule is generally less affected by the nature of the substituents in the porphyrin macrocycle, mainly due to a change in the stoichiometric inhibition coefficient in the presence of relatively easily oxidizable groups.

Bioavailability of the Phenolic Antioxidant 4-Methyl-2,6-Diisobornylphenol After Oral Administration.

We compared bioavailability of 4-methyl-2,6-diisobornylphenol after single intragastric administration to rats in a dose of 200 mg/kg in starch suspension and in almond oil. Absorption of 4-methyl-2,6-diisobornylphenol in the gastrointestinal tract after administration in almond oil was much more efficient than after administration in aqueous starch mucus.

[Distribution of 4-methyl-2,6-diisobornylphenol in rat tissues].

We have studied the distribution of the new compound 4-methyl-2,6-diisobornylphenol in rats after a single oral administration in a dose of 20 mg/kg. The pharmacokinetic parameters have been estimated by the noncompartmental method. It is established that the drug is nonuniformly distributed in the body and has a high affinity for liver and heart.

Hemorheologic effects of dibornol in a model of myocardial ischemia/reperfusion.

We studied the effects of novel sterically hindered phenol, 4-methyl-2,6-diisobornyl phenol (dibornol) on the rheological properties of the blood in the model of myocardial ischemia/reperfusion. Dibornol (100 mg/kg intraperitoneally for 3 days before and 5 days after ischemia/reperfusion) decreased blood viscosity by 9-25% in comparison with that in sham-operatedanimals by modulating cellular (erythrocyte deformability and aggregation) and plasma (plasma viscosity) rheological parameters. Normalization of blood rheology under the influence of dibornol increased the availability of oxygen to tissues at high shear rates by 9-18% after acute ischemia/reperfusion in rats.

[Evaluation of the linearity of pharmacokinetics of the phenolic antioxidant 4-methyl-2,6-diisobornylphenol upon intragastric administration].

The linearity of pharmacokinetics of 4-methyl-2,6-diisobornylphenol after single intragastric administration in doses within 10 - 200 mg/kg has been studied in rats. It has been established that pharmacokinetics of 4-methyl-2,6-diisobornilphenol in the indicated dose range is not linear due to a limited absorption of the drug from the intestine.

[Membrane protective properties of diastereomers of methylpheophorbide a 13(2)-n-n-octyl-N-(2-hydroxy-3-isobornyl-5-methylbenzyl)amide].

Two diastereomers of methylpheophorbide a 13(2)-N-n-octyl-N-(2-hydroxy-3-isobornyl-5-methylbenzyl)amide were obtained from (+)- and (-)-enantiomers of 2-isobornyl-4-methylphenol. Evaluation of membrane protective and antioxidant activity of individual diastereomers on the model of H2O2-induced hemolysis of blood erythrocytes showed that the stereochemistry of isobornyl substituent in the synthesized conjugates has no effect on their biological activity.

[Antioxidant properties of conjugates of polyethylene glycols, having a terpenophenolic fragments].

A series of water-soluble conjugates has been synthesized from polyethylene glycols of various lengths and 4-bromomethyl-2,6-diisobornylphenol. Evaluation of membrane protective and antioxidant activity of synthesized products on the model of H2O2-induced hemolysis of blood erythrocytes showed that conjugates have considerable antioxidant activity. A significant membrane protective effect was showed in conjugates with 0.

[Ionic conjugates of sulfate carboxymethyl cellulose with dialkylaminomethyl derivatives of 2-isobornyl-4-methylphenol: synthesis and study of anti-inflammatory and analgesic activity].

Water-soluble sulfate polysalts of carboxymethyl cellulose and tertiary aminomethyl derivatives of 2-isobornyl-4-methylphenol was obtained. For the synthesized conjugates investigated in vivo anti-inflammatory activity in the test of acute formalin inflammation and analgesic activity in tests the "hot plate" and "vinegar cramps".

[Synthesis of novel terpenophenol-chlorin conjugates and evaluation of their membranotropic and membrane protective properties].

A series of terpenophenol-chlorin conjugates where terpenophenolic fragment has amide bond with macrocycle of methylpheophorbide a, formed by amidation of 13(2)-ester group were obtained by interaction of methylpheophorbide a and ortho-aminomethyl derivatives of 2-isobornyl-4-methylphenol. The substances investigated ability to interact with the cell membrane was shown in blood erythrocytes surface structure with scanning electron microscope. The conjugates studied were established to have antioxidant and membrane protective properties resulted from inhibiting H2O2-induced erythrocytes hemolysis and decrease of lipid peroxidation secondary product accumulation.

[Surface active properties of isobornylphenols in systems with different degrees of complexity].

Interrelations between the structure of the semi-synthetic phenolic antioxidants -- isobornylphenols and their surface active properties were studied in the chemical (the lecithin aggregation in hexane) and biological (the incubation with the blood erythrocytes) model systems. It has been shown that all studied compounds are able to affect the lecithin aggregation in hexane: the share of the main fraction of the L micelles decreases with increasing the share of particles of greater size. The effect substantially depends on hindered OH group and the presence of the intramolecular hydrogen bond in molecule.

[Pharmacokinetics of phenolic antioxidant 4-methyl-2,6-diisobornylphenol upon intravenous injection].

The pharmacokinetics of 4-methyl-2,6-diisobornylphenol (MDIBP) in rat blood plasma has been studied after intravenous injection. The drug concentration in the plasma was determined using a reverse-phase HPLC procedure. It is shown that MDIBP rapidly penetrates into intensively perfused organs, but is slowly eliminated from the organism (MRT value amounting to 9 h).

[Structural changes of eye chorioretinal complex after total cerebral ischemia and their correction].

Structural changes of eye chorioretinal complex were investigated in 40 adult male outbred albino rats after total transient cerebral ischemia using electron microscopy and morphometric analysis. Furthermore, the influence of a new sterically hindered phenolic antioxidant dibornol on these processes was estimated. Our studies demonstrated that total transient cerebral ischemia in rats resulted in the capillary thrombosis of the choriocapillary lamina of the uvea, structural disturbances of the blood-retinal barrier, degeneration of the retinal neurons and radial glia.