Monohydroxy Derivatives Research Articles

Effect of Flavone Derivatives on Vincristine and Oxaliplatin Induced Peripheral Neuropathy in Mice

Introduction: Therapy with anticancer drugs like paclitaxel, platinum complexes and vincristine result in severe peripheral neuropathy. Very few treatment options are available to overcome this debilitating side effect. Flavone and its monohydroxy derivatives have been proved to possess anti-nociceptive and anti-inflammatory effects in animal models. Aim: To investigate flavone, 5-hydroxy flavone, 6-hydroxy flavone and 7-hydroxy flavone for their effect on neuropathy induced by vincristine and oxaliplatin in mice. Materials and Methods: In this experimental animal study, neuropathy was induced in mice by multiple doses of vincristine or a single dose of oxaliplatin. The manifestations of mechanical allodynia, cold allodynia and thermal hyperalgesia were measured by von Frey’s hair aesthesiometer, acetone spray test and hot water tail immersion test. The data was subjected to ANOVA followed by Dunnett’s test for multiple comparison and paired t-test at appropriate places. Results: Flavone and monohydroxy flavones significantly reduced the paw withdrawal response scores due to mechanical allodynia and cold allodynia resulting from vincristine or oxaliplatin administration (p<0.05). The tail withdrawal latency due to thermal hyperalgesia was also significantly increased by different flavone derivatives (p<0.05). However, 7-hydroxy flavone was ineffective in oxaliplatin-induced mechanical allodynia and vincristine induced thermal hyperalgesia. Analysis of the results indicated that the manifestations of neuropathy induced by vincristine or oxaliplatin were amenable to treatment with flavone derivatives in the following order; cold allodynia>thermal hyperalgesia>mechanical allodynia. Opioid mediated antinociceptive effect, interaction with cation channels and anti-inflammatory effect of the investigated flavones may be suggested as possible mechanisms for their beneficial effects in neuropathy due to chemotherapeutic agents. Conclusion: Various neuropathic manifestations induced by vincristine and oxaliplatin were effectively attenuated by flavone and monohydroxy flavones.

Adsorption of phenanthrene and its monohydroxy derivatives on polyvinyl chloride microplastics in aqueous solution: Model fitting and mechanism analysis

The pervasiveness of microplastics, which can absorb pollutants, has a certain impact on pollutant migration in natural waters. Differences in functional groups, such as the hydroxyl group, of pollutants will affect their adsorption on microplastics. In this study, the adsorption of phenanthrene (PHE) or its monohydroxy derivatives, including 1-hydroxyphenanthrene (1-OHP), 2-hydroxyphenanthrene (2-OHP), 4-hydroxyphenanthrene (4-OHP), and 9-hydroxyphenanthrene (9-OHP), on polyvinyl chloride (PVC, measured mean particle size = 134 μm) microplastics was studied. The adsorption efficiency of PHE was shown to be higher than that of either of OHPs. A better fit for pseudo-second-order and Freundlich isotherm models was obtained, indicating different binding sites on the surface of PVC microplastics. The adsorption processes of PHE and OHPs on PVC microplastics were demonstrated to be exothermic and spontaneous. Combined with FT-IR analysis, theoretical calculation, and comparative adsorption experiments, hydrophobic interaction was the dominant mechanism during the adsorption process. In contrast, electrostatic repulsion, CH/π interaction, and halogen bonding played a minor role, to an extent, in the adsorption of PHE/OHPs on PVC microplastics. These findings indicate the influence of the hydroxyl group on adsorption and improve the understanding of interactions between PVC microplastics and PHE/OHPs.

Electrospun core-shell nanofibers as an adsorbent for on-line micro-solid phase extraction of monohydroxy derivatives of polycyclic aromatic hydrocarbons from human urine, and their quantitation by LC-MS.

A method is described for automatted on-line micro-solid phase extraction using polydopamine-modified polystyrene/silica electrospun nanofibers as an adsorbent for monohydroxy metabolites of polycyclic aromatic hydrocarbons (OH-PAHs). They were then quantified by liquid chromatography-mass spectrometry. The sorbent has a network structure, high porosity, stability, hydrophilicity and good extraction capacity. Under optimal experimental conditions, the method has (a) wide linear ranges (0.03-25ng·mL-1 for 3-hydroxyphenanthrene and 1-hydroxypyrene; and 0.05-25ng·mL-1 for 2-naphthol), (b) good precision (with relative standard deviations from 2.0 to 12.4%), (c) highenrichment factors (24-112), (d) low limits of detection (2-21pg·mL-1), and (e) acceptable recoveries from spiked samples (79.1 to 108%). The method was successfully applied for the analysis of trace OH-PAHs in urine. Graphical abstractSchematic illustration of online micro-solid phase extraction using polydopamine-modified polystyrene/silica electrospun nanofibers as adsorbent for the enrichment and determination of monohydroxy metabolites of polycyclic aromatic hydrocarbons (OH-PAHs) prior to LC-MS analysis.

QTAIM Analysis of Mono-Hydroxy Derivatives of closo-Borate Anions [BnHn– 1OH]2– (n = 6, 10, 12)

This theoretical study focused on the structure of mono-hydroxy derivatives of closo-borate anions and nature of bonding interactions in these species. DFT calculations at the ωB97X-D3/6-31++G(d,p) level of theory have been performed and B–B, B–H, B–O, and O–H bonding interactions in the mono-hydroxy derivatives of closo-borate anions [BnHn – 1OH]2– (n = 6, 10, 12) have been studied under the perspective of the Quantum Theory of Atoms in Molecules (QTAIM) and several local and integral topological properties of the electron density involved in these interactions.

Position Impact of Hydroxy Groups on Spectral, Acid-Base Profiles and DNA Interactions of Several Monohydroxy Flavanones.

Structure-related biological activities of flavanones are still considered largely unexplored. Since they exhibit various medicinal activities, it is intriguing to enter deeper into their chemical structures, electronic transitions or interactions with some biomolecules in order to find properties that allow us to better understand their effects. Little information is available on biological activity of flavanone and its monohydroxy derivatives in relation to their physicochemical properties as spectral profiles, existence of protonated/deprotonated species under pH changes or interaction with Calf Thymus DNA. We devoted this work to research demonstrating differences in the physicochemical properties of the four flavanones: flavanone, 2′-hydroxyflavanone, 6-hydroxyflavanone and 7-hydroxyflavanone and linking them to their biological activity. Potentiometric titration, UV–Vis spectroscopy were used to investigate influence of pH on acid–base and spectral profiles and to propose the mode of interaction with DNA. Cyclic voltammetry was applied to evaluate antioxidant potentiality and additionally, theoretical DFT(B3LYP) method to disclose electronic structure and properties of the compounds. Molecular geometries, proton affinities and pKa values have been determined. According to computational and cyclic voltammetry results we could predict higher antioxidant activity of 6-hydroxyflavanone with respect to other compounds. The values of Kb intrinsic binding constants of the flavanones indicated weak interactions with DNA. Structure–activity relationships observed for antioxidant activity and DNA interactions suggest that 6-hydroxyflavanone can protect DNA against oxidative damage most effectively than flavanone, 2′-hydroxyflavanone or 7-hydroxyflavanone.

Development of a liquid chromatography Q Exactive high resolution mass spectrometry method by the Box-Behnken design for the investigation of sibutramine urinary metabolites

Sibutramine is cited by the World Anti-Doping Agency as a stimulant. According to the literature, sibutramine is extensively metabolized into N-desmethyl-sibutramine (M1), N-bisdesmethyl-sibutramine (M2) and monohydroxy derivatives of M1 and M2. Therefore, it is important to verify new sibutramine metabolites through current analytical methodologies, such as liquid chromatography coupled to high resolution mass spectrometry (LC-HRMS). Furthermore, the development of a comprehensive approach to investigate sibutramine metabolism can increase the detection window for stimulant misuse and enable advancements in pharmacological studies. This work aimed to develop and evaluate the performance of an LC-HRMS method applying Design of Experiments (DoE) for sibutramine metabolite analysis in human urine. After optimizing the method by DoE, the final chromatographic conditions were based on reversed-phase chromatography using a C18 column with a ramp time of 25 min, a flow rate of 0.17 mL min−1 and a temperature of 50 °C. Mobile phase A consisted of water with 0.1% formic acid and 5 mM ammonium formate, and mobile phase B consisted of methanol with 0.1% formic acid; the initial gradient percent was 15% B, and the injection volume was 5 μL. In addition to the hydroxylated metabolites previously described in human urine, dihydroxy derivatives of M1 and M2 were observed for the first time. These dihydroxy derivative metabolites can be applied as new targets for doping control.

In vitro metabolic stability and biotransformation of isosteviol in human and rat liver fractions

Isosteviol is a lead compound whose cardioprotective property has been partly explained by its regulation of ion channels and interference with signalling pathways in the metabolism of some fatty acids. This study determined the metabolic stability of isosteviol in human liver microsomes and H9c2 cell line, and the identity of its metabolites in human and rat liver fractions. Isosteviol was largely unmetabolized in H9c2 cells and in NADPH-only supplemented human liver fractions, suggesting a very limited contribution of phase I biotransformation to its hepatic clearance. The in vitro half-life of isosteviol in UDPGA-only supplemented medium was observed to be 24.9 min with an estimated intrinsic clearance of 0.349 mL/min/kg in man. Analysis by LC-MS/MS and Q-tof showed that isosteviol is mainly metabolised to its acyl-β-D-glucuronide in humans and rats. Mono-hydroxy-isosteviol and dihydroisosteviol were also identified. Rat liver fraction, however, generated dihydroxy-isosteviol in addition to two mono-hydroxy derivatives. Further studies confirmed that dihydroisosteviol is subsequently biotransformed to its acyl-β-D-glucuronide in man and rat. These findings suggest that future studies of the efficacy and toxicity of isosteviol might have to consider xenobiotics that alter the glucuronidation pathways significantly in man.

Use of Lactobacillus rhamnosus (ATCC 53103) as Whole-Cell Biocatalyst for the Regio- and Stereoselective Hydration of Oleic, Linoleic, and Linolenic Acid

Natural hydroxy fatty acids are relevant starting materials for the production of a number of industrial fine chemicals, such as different high-value flavour ingredients. Only a few of the latter hydroxy acid derivatives are available on a large scale. Therefore, their preparation by microbial hydration of unsaturated fatty acids, affordable from vegetable oils, is a new biotechnological challenge. In this study, we describe the use of the probiotic bacterium Lactobacillus rhamnosus (ATCC 53103) as whole-cell biocatalyst for the hydration of the most common unsaturated octadecanoic acids, namely oleic acid, linoleic acid, and linolenic acid. We discovered that the addition of the latter fatty acids to an anaerobic colture of the latter strain, during the early stage of its exponential growth, allows the production of the corresponding mono-hydroxy derivatives. In these experimental conditions, the hydration reaction proceeds with high regio- and stereoselectivity. Only 10-hydroxy derivatives were formed and the resulting (R)-10-hydroxystearic acid, (S)-(12Z)-10-hydroxy-octadecenoic acid, and (S)-(12Z,15Z)-10-hydroxy-octadecadienoic acid were obtained in very high enantiomeric purity (ee > 95%). Although overall conversions usually do not exceed 50% yield, our biotransformation protocol is stereoselective, scalable, and holds preparative significance.

Water-soluble octahedral molybdenum cluster compounds Na2[Mo6I8(N3)6] and Na2[Mo6I8(NCS)6]: Syntheses, luminescence, and in vitro studies

The octahedral molybdenum cluster compounds Na2[Mo6I8(N3)6] and Na2[Mo6I8(NCS)6] were synthesized and their luminescent properties and biological activity were investigated. Most molybdenum cluster compounds reported so far have had low solubility in water and/or underwent hydrolysis connected with aggregation, sedimentation, and diminishing luminescence and singlet oxygen-sensitizing properties. This behavior prevented the investigation of their photophysical properties and in vitro biological activities in aqueous media. Title compounds behave differently. They are well soluble in water and have red luminescence, which is quenched by oxygen to produce singlet oxygen, O2(1Δg), in high quantum yields. Even though [Mo6I8(N3)6]2− and [Mo6I8(NCS)6]2− gradually hydrolyze to mono-hydroxy derivatives, they do not form sedimenting aggregates, luminescence properties are well-defined, and the quantum yields of O2(1Δg) remain unchanged. These attractive features, suitable for luminescent probes or O2(1Δg) sensitizers in living cells, are overshadowed by the toxicity, especially of [Mo6I8(NCS)6]2−, and by the limited uptake by the HeLa and HEK 293T cell lines.

Oxcarbazepine and its active metabolite, (S)-licarbazepine, exacerbate seizures in a mouse model of genetic generalized epilepsy.

Oxcarbazepine (OXC), widely used to treat focal epilepsy, is reported to exacerbate seizures in patients with generalized epilepsy. OXC is metabolized to monohydroxy derivatives in two enantiomeric forms: (R)-licarbazepine and (S)-licarbazepine. Eslicarbazepine acetate is a recently approved antiepileptic drug that is rapidly metabolized to (S)-licarbazepine. It is not known whether (S)-licarbazepine exacerbates seizures. Here, we test whether OXC or either of its enantiomers exacerbates the number of spike-and-wave discharges (SWDs) in mice harboring the human γ-aminobutyric acid A receptor (GABAA)γ2(R43Q) mutation. OXC (20 mg/kg), (S)-licarbazepine (20 mg/kg), and (R)-licarbazepine (20 mg/kg) all significantly increased the number of SWDs, while their duration was unaffected. The potential for (S)-licarbazepine to exacerbate SWDs suggests that eslicarbazepine acetate should be used with caution in generalized epilepsy. Furthermore, generalized seizure exacerbation for first-, second-, and third-generation carbamazepine-based compounds is likely to occur through a common mechanism.

SPE-LC-FD Determination of Polycyclic Aromatic Hydrocarbon Monohydroxy Derivatives in Cephalopods

A new analytical methodology, based on liquid chromatography with fluorescence detection (LC-FD), after extraction, enzymatic hydrolysis, and solid-phase extraction (SPE) through Oasis HLB cartridges, was developed and validated for the simultaneous determination of three monohydroxy derivatives of polycyclic aromatic hydrocarbons (PAHs). The optimized analytical method is sensitive, accurate, and precise, with recoveries between 62 and 110% and limits of detection of 227, 9, and 45 ng/g for 1-hydroxynaphthalene, 2-hydroxyfluorene, and 1-hydroxypyrene, respectively. Their levels were estimated in different cephalopod matrices (edible tissues and hemolymph). The methodology was applied to samples of the major cephalopod species consumed worldwide. Of the 18 samples analyzed, 39% were contaminated with 1-hydroxynaphthalene, which was the only PAH metabolite detected. Its concentration ranged from 786 to 1145 ng/g. This highly sensitive and specific method allows the identification and quantitation of PAH metabolites in forthcoming food safety and environmental monitoring programs.

Efficient Preparation of Apically Substituted Diamondoid Derivatives

We present an effective three-step chromatography-free sequence for the preparation of apical monohydroxy derivatives of diamantane, triamantane, and [121]tetramantane from the corresponding bis-apical diols utilizing tert-butyldimethylsilyl chloride as the monosilylating agent. The procedure was successfully applied to the monoprotection of several other aliphatic and aromatic diols. Additionally, 9-aminodiamantan-4-carboxylic acid, which has significant potential in medicinal and material sciences, was prepared through Ritter reaction of 4,9-dihydroxydiamantane in trifluoroacetic acid.

Biocatalyst mediated production of 6β,11α-dihydroxy derivatives of 4-ene-3-one steroids

Biotransformation of steroids with 4-ene-3-one functionality such as progesterone (I), testosterone (II), 17α-methyltestosterone (III), 4-androstene-3,17-dione (IV) and 19-nortestosterone (V) were studied by using a fungal system belonging to the genera of Mucor (M881). The fungal system efficiently and quantitatively converted these steroids in regio- and stereo-selective manner into corresponding 6β,11α-dihydroxy compounds. Time course experiments suggested that the transformation was initiated by hydroxylation at 6β- or 11α-(10β-hydroxy in case of V) to form monohydroxy derivatives which upon prolonged incubation were converted into corresponding 6β,11α-dihydroxy derivatives. The fermentation studies carried out using 5L table-top fermentor with substrates (I and II) clearly indicates that 6β,11α-dihydroxy derivatives of steroids with 4-ene-3-one functionality can be produced in large scale by using M881.

Cycloxaprid Insecticide: Nicotinic Acetylcholine Receptor Binding Site and Metabolism

Cycloxaprid (CYC) is a novel neonicotinoid prepared from the (nitromethylene)imidazole (NMI) analogue of imidacloprid. In this study we consider whether CYC is active per se or only as a proinsecticide for NMI. The IC50 values (nM) for displacing [(3)H]NMI binding are 43-49 for CYC and 2.3-3.2 for NMI in house fly and honeybee head membranes and 302 and 7.2, respectively, in mouse brain membranes, potency relationships interpreted as partial conversion of some CYC to NMI under the assay conditions. The 6-8-fold difference in toxicity of injected CYC and NMI to house flies is consistent with their relative potencies as in vivo nicotinic acetylcholine receptor (nAChR) inhibitors in brain measured with [(3)H]NMI binding assays. CYC metabolism in mice largely involves cytochrome P450 pathways without NMI as a major intermediate. Metabolites of CYC tentatively assigned are five monohydroxy derivatives and one each of dihydroxy, nitroso, and amino modifications. CYC appears be a proinsecticide, serving as a slow-release reservoir for NMI with selective activity for insect versus mammalian nAChRs.

Derivatization chemistry of the double-decker dicobalt sandwich ion targeted to design biologically active substances

A synthesis of the first double-decker sandwich ion [(1',2'-C2B9H11)-3,3'-Co-(1,2-C2B8H10)-6,3"-Co-(1",2"-C2B9H11)]2– (DD 2–) derivatives is described, having been developed in connection with our search for biologically active substances. A series of B-substituted hydroxyl derivatives was prepared by direct hydroxylation of the ion using aqueous sulfuric acid. Two isomers of monohydroxy derivatives were isolated. The main product was substituted at the central “canastide” ion fragment, whereas the substitution site for the minor isomer corresponded to a B(8) atom of one of the terminal 11-vertex dicarbollide parts. Similarly, the disubstitution occurred slightly more preferentially on the “canastide” fragment providing the main isomeric derivative with a symmetric structure. The cesium salt of this ion was characterized by X-ray diffraction. Two other isomeric species have one substituent sitting on the “canastide” ion and the second present on the dicarbollide ligand in apart or syn-geometric arrangement. A new zwitterion anion [(1',2'-C2B9H11)-3',3-Co-(8-(CH2)4O-1,2-C2B8H9)-6,3"-Co-(1",2"-C2B9H11)-]1– was prepared by the reaction of the parent ion with tetrahydrofuran (THF), activated by BF3·OEt2. This new compound serves as a versatile building block for constructing organic derivatives, as exemplified by the ring cleavage by various amines or phenolate ions and the synthesis of a basic series of compounds of general formulation [(1',2'-C2B9H11)-3',3-Co-(8-X-(CH2)4O-1,2-C2B8H9)-6,3"-Co-(1",2"-C2B9H11)] n– where the organic end-groups X adjacent to the “canastide” moiety via a B-oxatetramethylene spacer corresponds to C4H9NH2, NC5H5, N(C2H5)3, (C6H5)3P (n = 1), or (4-t-Bu-C6H4-1-O)– and (2-CH3O-C6H4O)– (n = 2). We show that dicluster compounds with two identical DD 2– anion units or asymmetric molecules containing two different clusters, the cobalt bis(dicarbollide) and the DD 2– anion, are accessible using this building block. All compounds were characterized by high-resolution NMR (1H, 13C, and 11B) and mass spectrometry. Some of the compounds were tested by in vitro assay for their ability to inhibit the HIV-protease (HIV-PR) enzyme. The majority of the tested species proved substantially high activity toward the HIV-PR, exhibiting on the other hand a noncompetitive mechanism of the inhibition.

Selective oxidation of phenol and benzoic acid in water via home-prepared TiO2 photocatalysts: Distribution of hydroxylation products

The hydroxylation of phenol (a substrate containing an electron donor group) and of benzoic acid (a substrate containing an electron withdrawing group) has been carried out by the photocatalytic method in aqueous suspensions containing commercial or home prepared TiO2 samples. The aim of the work was to study the distribution of hydroxylation products when different photocatalysts were used and to correlate the selectivity to some physico-chemical features of the powders. The samples were characterized by X-ray diffraction, thermogravimetry, determination of crystalline phase percentage, specific surface area and zero charge point. The photoreactivity results indicate that the products of the primary oxidation of phenol are the ortho- and para-mono-hydroxy derivatives while those of benzoic acid are all the mono-hydroxy derivatives independently of the catalyst. The selectivity toward mono-hydroxy derivatives shows a strong dependence on catalyst hydroxylation and crystallinity degrees: the highest selectivity values were obtained by using the commercial samples that resulted the least hydroxylated and the most crystalline ones. A kinetic model, taking into account the mineralization and the partial oxidation reaction routes, is proposed by using the Langmuir–Hinshelwood model.

Aquatic photochemistry of paracetamol in the presence of dissolved organic chromophoric material and nitrate

This study contains some new findings connected to the photolysis of the drug paracetamol (hereinafter APAP) especially in light of estimating natural conditions, and it will offer information to better evaluate environmental problems connected with this widely used analgesic agent. Only a few studies, so far, have focussed on the photodegradation process of APAP in the natural environment, and the question about the role of the colored/chromophoric dissolved organic matter (CDOM) and nitrate (NO3-) as photoinductors is almost open. APAP dissolved in freshwater and pure laboratory water in the presence and absence of CDOM and NO3- ions was irradiated using weak-energy photon energies simulating natural conditions. CDOM and NO3- as photoinductors produced only the slow phototransformation of APAP under weak energy radiation, and APAP seemed to be practically resistant to direct photolysis under weak radiant energies available in natural conditions. The estimated reaction efficiencies, in addition to half-lives, speak for that NO3- and CDOM do not act as quite independent photoinductors but their effect in conjunction (CDOM-NO3- -water) is stronger than the separate ones. The principal phototransformation intermediates of APAP were mono-hydroxy derivatives, depending on available photon energies formed via ortho- or meta-hydroxylation, possessing substantial power of resistance to further specific transformation reactions. The estimated half-life of the phototransformation of APAP in the natural aqueous environment and in the presence of suitable photoinductors will be about 30 days or more.

Selective Synthesis of Hydroxy Analogues of Valinomycin using Dioxiranes

A synthesis of representative monohydroxy derivatives of valinomycin (VLM) was achieved under mild conditions by direct hydroxylation at the side chains of the macrocyclic substrate using dioxiranes. Results demonstrate that the powerful methyl(trifluoromethyl)dioxirane 1b should be the reagent of choice to carry out these key transformations. Thus, a mixture of compounds derived from the direct dioxirane attack at the β-(CH(3))(2)C-H alkyl chain of one Hyi residue (compound 3a) or of one Val moiety (compounds 3b and 3c) could be obtained. Following convenient mixture separation, each of the new oxyfunctionalized macrocycles became completely characterized.

Hydroxylation of DHEA, androstenediol and epiandrosterone by Mortierella isabellina AM212. Evidence indicating that both constitutive and inducible hydroxylases catalyze 7α- as well as 7β-hydroxylations of 5-ene substrates

The course of transformation of DHEA, androstenediol and epiandrosterone in Mortierella isabellina AM212 culture was investigated. The mentioned substrates underwent effective hydroxylation; 5-ene substrates--DHEA and androstenediol--were transformed into a mixture of 7α- and 7β- allyl alcohols, while epiandrosterone was converted into 7α- (mainly), 11α- and 9α- monohydroxy derivatives. Ketoconazole and cycloheximide inhibition studies suggest the presence of constitutive and substrate-induced hydroxylases in M. isabellina. On the basis of time course analysis of the hydroxylation of DHEA and androstenediol, the oxidation of allyl C(7)-H(α) and C(7)-H(β) bonds by the same enzyme is a reasonable assumption.

ChemInform Abstract: The 13C NMR Method for Determining the Absolute Configuration of the 1,2-Glycols Consisting of Secondary and Tertiary Hydroxyl Groups.

Abstract The fucofuranoside method, the 13 C NMR method for determining the absolute configuration of secondary alcohols, is applied to five known steroids having a 1,2-glycol group composed of secondary and tertiary hydroxyl groups. The 1,2-alignment of the polar fucofuranosyl and tertiary hydroxyl group was found to have little influence on the requisite conformation of the glycosidic linkage. It showed the normal pattern of the distribution of the Δ δ C (and Δ δ H ) values, as previously observed for simple monohydroxy derivatives, demonstrating the usefulness of the method for this type of compound.