Essential oil in Phlomis tuberosa

Phlomis tuberosa L. (Lamiaceae) is a flowering perennial plant, native to Eurasia, and sparsely distributed in Bulgaria. The species has been proved to accumulate flavonoids, iridoids, phenolic glycosides, as well as essential oil. To now, there is no information on the chemical content of Bulgarian essential oil from the plant. The aim was to study the chemical composition of essential oils, obtained from the species. Four different samples were studied – essential oils produced from leaves and herbs, collected in the fields, and from leaves and flowering parts, harvested from the mountainous location. It was found that β-copaene was the major in the essential oil from both the leaves and of the flowering parts collected from Popitza. In addition, the other major constituent in leaf essential oil from Kladnitza was tau-muurolol. The essential oil, produced from the species, harvested from the higher altitude had phytol as the main component. The sesquiterpenoid content in leaf essential oil suggests that this plant substance is appropriate for medicinal use, due to the pharmacological properties of these compounds

Optimization and validation of RP-HPLC method for evaluation of pyrrole -containing hydrazones in isolated rat synaptosomes

In the current study, RP-HPLC method for evaluation of 2 pyrrol-based hydrazones in isolated rat synaptosomes was optimized and validated according to ICH guidelines. The synaptosomes were obtained by multiple centrifugations with Percoll reagent and the selected 2 N-pyrollyl hydrazide-hydrazones were incubated for 2 hours at 37 °C. Subsequently, the purified fraction through protein precipitation was analyzed by an UltiMateDionex 3000 DAD system with Purospher STAR C18 (4.6 x 12.5 cm, 5 µm) column. The mobile phase, consisting of acetonitrile: phosphate buffer pH 3.5: methanol in ratio 42/36/22 (v/v/v), was eluted isocratically with 0.8 mL/min flow rate. Afterwards, the novel and rapid method was applied effectively for identification of biotransformation in isolated rat brain synaptosomes. The analysis results indicated an absence of new peaks and persistent sample concentration which determined the stability of the analyzed ethyl 5-(4-bromophenyl)-1-(2-(2-(2-hydroxybenzylidene) hydrazinyl)-2- oxoethyl)-2-methyl- 1H-pyrrole-3-carboxylate (11b) and ethyl 5-(4-bromophenyl)-1-(3-(2-(2-hydroxybenzylidene)hydrazinyl)-3-oxopropyl)-2-methyl-1H-pyrrole-3-carboxylate (12b) and pointed these structures as promising

A Comprehensive Evaluation of Sdox, a Promising H2S-Releasing Doxorubicin for the Treatment of Chemoresistant Tumors

Sdox is a hydrogen sulfide (H2S)-releasing doxorubicin effective in P-glycoprotein-overexpressing/doxorubicin-resistant tumor models and not cytotoxic, as the parental drug, in H9c2 cardiomyocytes. The aim of this study was the assessment of Sdox drug-like features and its absorption, distribution, metabolism, and excretion (ADME)/toxicity properties, by a multi- and transdisciplinary in silico, in vitro, and in vivo approach. Doxorubicin was used as the reference compound. The in silico profiling suggested that Sdox possesses higher lipophilicity and lower solubility compared to doxorubicin, and the off-targets prediction revealed relevant differences between Dox and Sdox towards several cancer targets, suggesting different toxicological profiles. In vitro data showed that Sdox is a substrate with lower affinity for P-glycoprotein, less hepatotoxic, and causes less oxidative damage than doxorubicin. Both anthracyclines inhibited CYP3A4, but not hERG currents. Unlike doxorubicin, the percentage of zebrafish live embryos at 72 hpf was not affected by Sdox treatment. In conclusion, these findings demonstrate that Sdox displays a more favorable drug-like ADME/toxicity profile than doxorubicin, different selectivity towards cancer targets, along with a greater preclinical efficacy in resistant tumors. Therefore, Sdox represents a prototype of innovative anthracyclines, worthy of further investigations in clinical settings

In Silico Evaluation and In Vitro Determination of Neuroprotective and MAO-B Inhibitory Effects of Pyrrole-Based Hydrazones: A Therapeutic Approach to Parkinson’s Disease

Parkinson’s disease is a huge burden in modern medicinal practice. A serious drawback of current antiparkinsonian therapy is its symptomatic nature. This directed our investigations in the search for new more potent derivatives, affecting not only the loss of dopaminergic neurons but also the oxidative damage of neuronal cells. Thus in vitro neurotoxicity and neuroprotective analysis on a group of N-pyrrolyl hydrazide–hydrazones were performed. The neurotoxicity of the target derivatives was determined on a subcellular level in isolated rat synaptosomes, mitochondria and microsomes determining their effect on cellular vitality, GSH depletion and MDA production. The neuroprotective effects of the evaluated hydrazones were measured in three models of induced oxidative stress: 6-OHDA, t-BuOOH and Fe2+/AA-induced lipid peroxidation. Molecular docking simulations along with in vitro evaluation of MAO-B inhibitory potential of the target molecules were also performed. The results identified the ethyl 5-(4-bromophenyl)-1-(3-hydrazinyl-3-oxopropyl)-2-methyl-1H-pyrrole-3-carboxylate (12) as the most promising compound with the lowest neurotoxicity and highest neuroprotection on all evaluated parameters and inhibiting the hMAOB enzyme by 50%, comparable with the activity of the reference, Selegiline. The compatibility of the in silico and in vitro evaluations is a good prerequisite for these methods to be applied in future assessment of pyrrole-based compounds as anti-Parkinson agents

In vitro analysis of the activity of human monoamine oxidase type B (hMAOB), treated with the cyanotoxin anatoxin-a: supposed factor of neurodegenerative diseases

In this study, we investigated the hypothesis that an additional source of free radicals may be hydrogen peroxide formed by monoamino oxidase (MAO) -catalyzed deamination of catecholamines. Also, increased MAO-B activity in the brain has been linked to the development of some neurodegenerative diseases. The toxicant we used to treat recombinant human MAO-B enzyme is the cyanotoxin аnatoxin-a. For anatoxin-a is known that it’s an agonist of neuronal acetylcholine receptors with 20 times greater affinity to them compared to the natural neurotransmitter. In this study, we analyzed the effect of anatoxin at various selected concentrations on the activity of recombinant human MAO-B enzyme. The method we use is to analyze the activity of human MAO-B with the fluorimetric reagent Amplex UltraRed and the substrate tyramine hydrochloride. The aim of this study is to analyze the effect of anatoxin-a on the hMAO-B enzyme activity and its influence as a factor for the development and progression of neurodegenerative diseases

Synthesis and preliminary hepatotoxicity evaluation of new caffeine-8-(2-thio)-propanoic hydrazid-hydrazone derivatives

New series of caffeine-8-(2-thio)-propanoic hydrazid-hydrazone derivatives were designed and synthesized. The targed compounds were obtained in yields of 51 to 96% and their structures were elucidated by FTIR, 1H NMR, 13C NMR, MS and microanalyses. All of the compounds were found to be “drug-like” as they fulfill the criteria of drug-likeness, which includes the MDDR-like rule. The tested compounds were subjected to in silico prediction of substrate/metabolite specificity and Drug Induced Liver Injury (DILI). The prediction for indicated that the evaluated compounds would most probably act as CYP1A2 substrates. The performed in vitro studies didn’t reveal statistically significant hepatotoxicity of the tested compounds, probably due to the pro-oxidant effects expressed on sub-cellular (isolated rat liver microsomes) level. The obtained experimental results confirmed the predicted low hepatotoxicity for the tested structures. Based on these results the compounds may be considered as promising structures for design of future molecules with low hepatotoxicity

Neuroprotective and antioxidant activities of saponins’ mixture from Astragalus glycyphylloides in a model of 6-hydroxydopamine-induced oxidative stress on isolated rat brain synaptosomes

The aim of the study was to investigate the possible neuroprotective and antioxidant activity of purified saponins’mixture (PSM), isolated from Astragalus glycyphylloides (Fabaceae), in a model of 6-hydroxydipamine (6-OHDA)-induced oxidative stress on isolated rat brain synaptosomes. Synaptosomes were incubated with 3 different concentrations of PSM: 60 µg/mL; 6 µg/mL; 0.6 µg/mL. The effects of PSM were compared to those of silymarin (S), at the same concentrations. The main parameters, characterized functional and metabolic status of synaptosomes, were investigated: viability (MTT-test) and level of reduced glutathione (GSH). At isolated rat brain synaptosomes, in conditions of 6-OHDA-induced oxidative stress (150 μМ), PSM revealed statistically significant, concentration-dependent, neuroprotective and antioxidant effects, compared to those of silymarin. Effects were most prominent at concentration 60 µg/mL. These neuroprotective effects of PSM might be due to the possible activity as scavenger of reactive oxygen species (ROS), produced by p-quinone (toxic metabolite of 6-OHDA)

Saponins from the roots of Chenopodium bonus-henricus L. with neuroprotective and anti-α-glucosidase activities

Six saponins of phytolaccagenin, bayogenin, medicagenic acid, 2β-hydroxygypsogenin, and 2β-hydroxyoleanoic acid from the roots of Chenopodium bonus-henricus L. were investigated for neuroprotective and anti-α-glucosidase activities. All tested saponins (10 µM) showed statistically significant neuroprotective activities on isolated rat brain synaptosomes using a 6-hydroxydopamine in vitro model. They preserved synaptosome viability as well as the reduced glutathione level. The bayogenin glycoside (Chbhs-05) possessed the most prominent neuroprotective effect. The anti-α-glucosidase activity of the tested saponins was established by measuring the levels of the released 4-nitrophenol using LC-MS. Bonushenricoside B (Chbhs-07) showed the highest inhibitory effect against α-glucosidase (44.1%) compared to the positive control acarbose (36.3%) at a concentration of 625 µM

Synthesis, in silico prediction of sites of metabolism and in-vitro hepatotoxicity evaluationofnew seriesN’-substituted 3-(1,3,7-trimethyl-xanthin-8-ylthio)propanehydrazides

New series of 3-(1,3,7-trimethyl-xanthin-8-ylthio)propanehydrazide derivatives were designed and synthesized. The targed compounds were obtained in yields of 54 to 100% and their structures were elucidated by FTIR,1H NMR,13C NMR, MS and microanalyses. The tested compounds were subjected to in silico prediction of sites of metabolism (SOMs). The predictions show thatthe main metabolic changes will be primarily related to oxidation of the sulfur atom in the side chain, carried out under the action of CYP2C19, as well as O-demethylation of compounds containing methoxy groups.The N-demethylation of the xanthine fragment was determined to be regulated by CYP1A2, CYP2C9, CYP2D6 and CYP3A4. Theperformed in vitro studies confirmed for two of the tested compounds to be low hepatotoxic, due to the presented prooxidant effects at subcellular level (isolated rat liver microsomes). These results highlight these molecules as promising hydrazide-hydrazone structures for the design of compounds with low hepatotoxicity

Activity of an oleanane-type tritrepenoid saponin from A. glycyphyllos on human recombinant MAO enzymes

For centuries, plants have been a leading point in the identification of potential therapeutic agents. Monoamine oxidase inhibition is a key mechanism in the treatment of various neurological and psychiatric diseases. Some triterpenoid saponins are reported to inhibit this enzyme. An extract from the aerial parts of Astragalus glycyphyllos was purified and separated by chromatographic techniques, which led to the isolation of one triterpene saponin. Its structure was analysed by ultra-high-performance liquid chromatography coupled with high-resolution electrospray ionisation mass spectrometry. The compound was subjected to a pharmacological study where human recombinant monoamine oxidase enzymes type A and B (hMAOA and hMAOB) were used. On the activity of hMAOA, the saponin had no effect, but on hMAOB, it exhibited statistically significant inhibition in comparison to the control, Selegiline. The compound could have potential in other models, so further investigations are required