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

Bioavailability and dose proportionality of a highly lipophilic phenolic antioxidant

IBP (2,6-diisobornyl-4-methylphenol) is a camphene derivative with unique pharmacological properties and low toxicity. It exhibits pronounced antioxidant and membrane-protective effects, making it a promising cardio- and neuroprotector.The aim of the study was investigating the pharmacokinetics of IBP in rats after intravenous (1 mg/kg) and oral administration at three doses (10, 25, 50 mg/kg). Specifically, we focused on assessing the bioavailability and dose proportionality following oral administration.Blood samples were collected via a jugular vein catheter, and plasma samples were analysed using a validated HPLC-MS/MS method. The calculation of pharmacokinetic parameters was performed by both non-compartmental and compartmental approaches. The proposed dosage form for intravenous administration was a multicomponent mixture containing N-methyl-2-pyrrolidone.Concentration of IBP in the body after intravenous administration decreased over time, exhibiting bi-exponential decay kinetics. IBP reached peak concentrations immediately and was rapidly distributed into the peripheral compartment after intravenous administration. The systemic exposure after oral administration was proportional to the dose. The calculated absolute oral bioavailability of IBP was no more than 20%.The value of the average half-life of IBP after intravenous administration exceeded similar values after oral administration by 1.5-1.6 times.

Studying the Influence of Ischemic Liver Damage on the Pharmacokinetics of a Phenolic Antioxidant

A new approach has been developed to study the pharmacokinetics of 2,6-diisobornyl-4-methylphenol, a phenolic antioxidant, after intragastric administration at a dose of 10 mg/kg to male Wistar rats with ischemia/reperfusion liver injury. The control group consisted of rats without pathology. A catheter previously implanted into the jugular vein of the animals, allowed repeated blood sampling and monitoring of the pharmacokinetic profile of the substance in each animal. Pharmacokinetic studies usually involve healthy animals, but the ischemia/reperfusion injury of the liver disrupted its functions, potentially altering drug metabolism and pharmacokinetics. Analysis of actual blood plasma samples confirmed the effectiveness of the proposed approach: changes in the pharmacokinetics of the phenolic antioxidant were revealed during liver ischemia/reperfusion injury in rats.

LC-MS/MS method for the determination of a semi-synthetic phenolic antioxidant 2,6-diisobornyl-4-methylphenol in rats after different administration routes

IBP (2,6-diisobornyl-4-methylphenol) is a small drug molecule with antioxidant properties considered to be a promising neuro-, cardio-, and retinoprotective agent. In this study, a bioanalytical LC-MS/MS method for its determination in rat plasma was developed using 11H-indeno[1,2-b]quinoxalin-11-one oxime as an internal standard (IS). The analytes were extracted from plasma by liquid-liquid extraction technique using isopropyl alcohol:chloroform mixture (1:5, v/v) followed by evaporation and reconstitution of the residues in acetonitrile. The chromatographic separation was carried out on the EC Nucleodur C8 ec column (150 × 4.6 mm, 5 μm) under an isocratic elution mode using acetonitrile and water containing 0.1% (v/v) formic acid (97:3, v/v) as a mobile phase at a flow rate of 0.55 mL/min (40 °C). The IS and IBP were eluted at 3.79 ± 0.02 and 6.30 ± 0.02 min, respectively. The total analysis time was 7.00 min. Multiple reaction monitoring was used to conduct the MS/MS detection in the negative ion mode with transitions at m/z 245.9 → 214.9 (IS) and 379.2 → 256.0 (IBP). Validation studies of the developed method revealed good linearity over the range of 10-5,000 ng/mL. Within- and between-run accuracy was in the range of 92-110%, while within- and between-run precision was below 8%. Additionally, low matrix effects and high recovery (above 98%) were observed. IBP remained stable in rat plasma at room temperature for 4 h, at -80 °C for 21 days, over three freeze-thaw cycles, under vacuum concentrator (45 °C, dried residues) and auto-sampler (15 °C, processed samples) temperatures for 1 h and 24 h, respectively. Subsequently, the validated LC-MS/MS method has been successfully applied to quantitate IBP in actual plasma samples after a single oral, intramuscular, and subcutaneous dose of IBP (10 mg/kg in the peach oil) to rats. Pharmacokinetic studies show that more rapid and complete IBP absorption with a satisfactory excretion rate were observed after oral administration route compared to the intramuscular and subcutaneous ones.

Effects of Siberian fir terpenes extract Abisil on antioxidant activity, autophagy, transcriptome and proteome of human fibroblasts

Background: Abisil is an extract of Siberian fir terpenes with antimicrobial and wound healing activities. Previous studies revealed that Abisil has geroprotective, anti-tumorigenic, and anti-angiogenic effects. Abisil decreased the expression of cyclin D1, E1, A2, and increased the phosphorylation rate of AMPK.

Objective: In the present study, we analyzed the effect of Abisil on autophagy, the mitochondrial potential of embryonic human lung fibroblasts. We evaluated its antioxidant activity and analyzed the transcriptomic and proteomic effects of Abisil treatment.

Results: Abisil treatment resulted in activation of autophagy, reversal of rotenone-induced elevation of reactive oxygen species (ROS) levels and several-fold decrease of mitochondrial potential. Lower doses of Abisil (25 μg/ml) showed a better oxidative effect than high doses (50 or 125 μg/ml). Estimation of metabolic changes after treatment with 50 μg/ml has not shown any changes in oxygen consumption rate, but extracellular acidification rate decreased significantly. Abisil treatment (5 and 50 μg/ml) of MRC5-SV40 cells induced a strong transcriptomic shift spanning several thousand genes (predominantly, expression decrease). Among down-regulated genes, we noticed an over-representation of genes involved in cell cycle progression, oxidative phosphorylation, and fatty acid biosynthesis. Additionally, we observed predominant downregulation of genes encoding for kinases. Proteome profiling also revealed that the content of hundreds of proteins is altered after Abisil treatment (mainly, decreased). These proteins were involved in cell cycle regulation, intracellular transport, RNA processing, translation, mitochondrial organization.

Conclusions: Abisil demonstrated antioxidant and autophagy stimulating activity. Treatment with Abisil results in the predominant downregulation of genes involved in the cell cycle and oxidative phosphorylation.