Phenol Research Articles

A facile and selective resonance Rayleigh scattering method for trace nitrite using gold nanocluster surface molecularly imprinted polyisopropylacrylamide probe.

A novel gold nanocluster surface molecularly imprinted polyisopropylacrylamide probe (AuNC@MIP) was synthesized for the specific detection of NO2-, using N-isopropylacrylamide (NIPAM) as the functional monomer, gold nanoclusters (AuNC) as the substrate, ethylene glycol dimethacrylate (EGDMA) as the cross-linking agent, and nitrosophenol (NPN) produced from sodium nitrite (NaNO2) and phenol (PN) as the template molecule, N,N-dimethylformamide (DMF) as the solvent, and azobisisobutyronitrile (AIBN) as the initiator. The nanoprobe was characterized using molecular spectroscopy, XPS, TEM, TGA, and zeta potential analysis. The probes revealed a prominent resonance Rayleigh scattering (RRS) peak at 370 nm. Upon addition of NO2-, the RRS intensity at 370 nm decreased due to the RRS energy transfer enhancing. The linear determination range is 0.125-1.50 nmol/L NO2-, with a limit of detection (LOD) of 0.085 nmol/L. The new RRS method was applied to determine NO2- in meat, dairy products, and water samples, with recovery of 96-107% also relative standard deviations (RSDs) of 1.1-8.0%.

Microalgal Phenolics: Systematic Review with a Focus on Methodological Assessment and Meta-Analysis.

A critical review and analysis of the literature relevant to the phenolic content of eucaryotic microalgae was performed. Several issues were identified and discussed. In summary, the main problems with the reporting on the phenolic content of microalgae are the following: (1) despite its usefulness in the determination of phenolic content in plant samples, the Folin-Ciocalteu assay is non-suitable for microalgal research due to the high presence of interfering compounds in microalgal extracts such as chlorophyll and its derivatives in organic extracts and free aromatic amino acids or nucleotides in aqueous extracts; (2) while there is chromatographic evidence for the presence of simple phenolic acids in most microalgal clades, the lack of critical enzymes of phenolic biosynthesis in most microalgae, as well as the high variability of phenolic profiles even in the same genus, require more extensive research before conclusions are drawn; (3) the accumulation and metabolism of external phenolics by microalgae has been almost universally neglected in studies focusing on the phenolic content of microalgae, even when natural seawater or complex organic media are used in the cultivation process. Despite these issues, the literature focusing on the bioremediation of waste streams rich in phenolics through microalgae demonstrates the ability of those organisms to adsorb, internalize, and in many cases oxidize or transform a wide range of phenolic compounds, even at very high concentrations. Simple phenolics found in waste streams, such as olive mill waste, have been shown to enhance the antioxidant activity and various bioactivities of microalgal extracts, while complex biotransformation products of phenolics have also been characterized. In conclusion, the de novo biosynthesis of phenolic compounds via eucaryotic microalgae requires further investigation with better designed experiments and suitable analytical methods, while the response of microalgae to phenolic compounds in their growth medium is of great practical interest, both in terms of waste treatment and for the production of functional foods, cosmetics, and pharmaceuticals.

Temperature dependence of structural evolution and fragility of glass-forming monohydroxy alcohols

The dynamic, structural, and thermodynamic properties of thirty-four monohydroxy alcohols with varying molecular architectures, including differences in alkyl chain length, OH group position, and presence/type of carbon ring, were investigated. Results of dielectric spectroscopy, temperature-modulated differential scanning calorimetry, and X-ray diffraction, were analyzed to verify correlations between the glass transition temperature (Tg), molar mass (M), boiling temperature (Tb), dynamic and thermodynamic fragility (mα and m), and the structurally related parameter (S). The collected data revealed that primary and secondary alcohols generally adhere to the correlations Tg ∝ M0.51 and Tb = 132 + 2.2Tg, while alcohols with phenyl ring deviate from these trends. Moreover, it was found that the changes in the width of the main diffraction peak normalized by the peak position ΔQM/QM over temperature scaled by Tg correspond to the variable m. However, the extent and course of this relationship varies across alcohols belonging to different structural groups. The weakest correlation and largest scatter between S and m occur for phenyl alcohols exhibiting the greatest structural heterogeneity. This study underscores the challenges of establishing universal correlations between physical variables within the diverse group of monohydroxy alcohols and emphasizes the importance of considering specific molecular features in predicting glass-forming behaviour.

Caffeic acid enhances the postharvest quality by maintaining the nutritional features and improving the aroma volatiles for nectarine fruit

Maintaining the quality of postharvest nectarine fruit is considerably challenging owing to their vigorous metabolism processes. This study explored the effectiveness of the natural preservative caffeic acid in extending the shelf-life and improving the flavor quality of nectarine. The decay rate of caffeic acid-treated fruit was only 40.00 % but 73.33 % in control group at the end of storage. Other results showed that caffeic acid inhibited fruit quality deterioration, reflected in weight loss, peel color, pulp softening, respiration rate, malondialdehyde accumulation and ethylene biosynthesis. Findings might be attributed to increased levels of antioxidant compounds, such as ascorbic acid, simple phenols and flavonoids, which maintained high antioxidant capacity and metal reducing power of fruit cells. Notably, the content of phenolics was maintained at 241.11 mg kg−1 in caffeic acid-treated fruit by 8 d, which was only 138.21 mg kg−1 in control. Importantly, nectarine treated with caffeic acid possessed a suitable sugar-to-acid ratio, imparting the fruit with an excellent taste. Additionally, caffeic acid facilitated the effective release of esters and lactones, especially γ- and δ-decalactone with fruity aroma, and prevented green aroma and alcoholic off-flavor. The level of lactones in caffeic acid-treated fruit reached 126.76 μg kg−1 during mid-storage, giving the fruit an attractive flavor quality, while was only 50.61 μg kg−1 in control. Overall, caffeic acid exhibited the potential to preserve the quality of nectarine, ensuring both nutritional and edible value for fruit.

Phytochemical Characterization of Two New Olive Oil Genotypes Growing in Southern Tunisia.

This research can be considered as the first complete survey for the valorization of new olive genotypes cultivated in the South-East of Tunisia as well as their oils. The study aimed to characterize the phytochemical composition of virgin olive oil produced from two olive cultivars, namely Nourgou and Gousalani. The pomological characterization of fruits, the quality criteria and the phytochemical profile were quantified. Additionally, antioxidant activity was evaluated using Ferric reducing antioxidant power (FRAP) and Oxygen radical absorbance capacity (ORAC) tests to also obtain a bioactive characterization of these monovarietal olive oils. The obtained results revealed that the analyzed olive oils samples can be classified into Extra Virgin category (EVOO) according to the regulated physicochemical characteristics. Our findings showed a significant variability in the chemical parameters of the analyzed EVOO likely associated with the genetic potential, mainly for chlorophylls contents (1.37-1.64 mg/kg), in carotenoids pigments (3.97-10.86 mg/kg), in α-tocopherol (175.59-186.87 mg/kg), in sterols (1036.4-1931.4 mg/kg) in oleic acid (65.33-68.73%), in palmitic acid (C16:0) (13.32-17.48%), in linoleic acid (C18:2) (11.06-13.47%). Additionally, the HPLC-MS/MS analysis showed that the two EVOOs analyzed contained appreciable amounts of total polyphenols, ranging from 348.03 up to 516.16 mg/kg, in Nourgou and Gousalani oils, respectively. Regarding the individual phenolic compounds, the EVOO samples were mainly characterized by phenolic alcohols, phenolic acids, secoiridoids, verbascoside, flavonoids and phenolic aldehydes. The prevalent simple phenolics detected were secoiridoids with the dominance of the oleuropein aglycone in Gousalani oil. In addition, findings from in vitro antioxidant assays (FRAP and ORAC) revealed that the two studied oils possessed a powerful antiradical activity and a good reducing power capacity. In conclusion, these new EVOOs exhibited a superior quality compared to other Tunisian varieties, considering their antiradical activity and reducing power capacity.

Enhanced algin oligosaccharide production through selective breeding and optimization of growth and degradation conditions in Cobetia sp. cqz5-12-M1

Algin oligosaccharides have been applied in diverse industries and could be innovative synthesized by alginate-degrading bacteria. For enhance the alginate degradation efficiency to produce more algin oligosaccharides, a mutant strain (Cobetia sp. cqz5-12-M1) was obtained through the complex mutagenesis using UV and the alkylating agent 1-methyl-3-nitro-1-nitrosoguanidine. The enzyme activity of the fermentation supernatant of mutant exhibited a significant 38.09% (53.98 ± 0.69 U/mL) increase, and its optimal growth conditions were determined as: 5 g/L sodium alginate, 5 g/L yeast powder, 30 g/L NaCl, 2 g/L K2HPO4, 2 g/L KH2PO4, 1 g/L MgSO4•7H2O, 0.01 g/L FeSO4•7H2O, pH 6.5, and 34 ℃. Moreover, its optimal degradation conditions were identified as: 5 g/L sodium alginate, 5 g/L yeast powder, 30 g/L NaCl, 2 g/L K2HPO4, 2 g/L KH2PO4, 1 g/L MgSO4•7H2O, 0.01 g/L FeSO4•7H2O, pH 6.5, 31 ℃ and 72 h, yielding an enzyme activity of 120.98 ± 1.40 U/mL in the fermentation supernatant. Conclusive experiments on reagent tolerance revealed the growth of the mutant strain was significantly inhibited by 3% hydrogen peroxide, 5% carbolic acid, and 10 mg/mL gatifloxacin. Additionally, the alginate degradation capacity of mutant strain was highly significantly inhibited by 75% ethanol and all tested antibiotics.

19F NMR Reveals the Dynamics of Substrate Binding and Lid Closure for Iodotyrosine Deiodinase as a Complement to Steady-State Kinetics and Crystallography.

Active site lids are common features of enzymes and typically undergo conformational changes upon substrate binding to promote catalysis. Iodotyrosine deiodinase is no exception and contains a lid segment in all of its homologues from human to bacteria. The solution-state dynamics of the lid have now been characterized using 19F NMR spectroscopy with a CF3-labeled enzyme and CF3O-labeled ligands. From two-dimensional 19F-19F NMR exchange spectroscopy, interconversion rates between the free and bound states of a CF3O-substituted tyrosine (45 ± 10 s-1) and the protein label (40 ± 3 s-1) are very similar and suggest a correlation between ligand binding and conformational reorganization of the lid. Both occur at rates that are ∼100-fold faster than turnover, and therefore these steps do not limit catalysis. A simple CF3O-labeled phenol also binds to the active site and induces a conformational change in the lid segment that was not previously detectable by crystallography. Exchange rates of the ligand (130 ± 20 s-1) and protein (98 ± 8 s-1) in this example are faster than those above but remain self-consistent to affirm a correlation between ordering of the lid and binding of the ligand. Both ligands also protect the protein from limited proteolysis, as expected from their ability to stabilize a compact lid structure. However, the minimal turnover of simple phenol substrates indicates that such stabilization may be necessary but is not sufficient for efficient catalysis.

Pelatihan Dilan (Distilasi Sederhana) sebagai Upaya Revitalisasi Program Serenisasi di Malang

Codo Village, located in Malang Regency, once held a serenization program. Local PKK women pioneered this program, whose actions were realized through a movement to plant lemongrass throughout the vacant village land to avoid the spread of dengue fever in 2016. A lack of knowledge about the potential of lemongrass plants caused a decline in enthusiasm for the serenization program, marked by many broken lemongrass plants. So, the DILAN (Simple Distillation) training provides a solution to revitalize the serenization program, starting with the formation of cadres, delivery of materials related to lemongrass plants and simple extraction of essential oils using the DILAN method, introduction to e-commerce, supervision and evaluation. The result of this program is that PKK women can produce marketable products from essential lemongrass oil, such as soap, aromatherapy candles, and carbolic acid. The products produced are codo asri and can be obtained from online sales sites. This program can increase the knowledge, productivity and abilities of the population to improve the community's economic status so that the revitalization program can be successfully implemented.

A multilevel LC-HRMS and NMR correlation workflow towards foodomics advancement: Application in table olives

Foodomics employs advanced analytical techniques to provide answers regarding food composition, authenticity control, marker identification and issues related to food quality and safety. Nuclear magnetic resonance (NMR) spectroscopy and chromatography hyphenated to mass spectrometry (MS) are the main analytical platforms used in this field. Nevertheless, they are rarely employed in an integrated manner, and even then, the contribution of each technique remains vague. Table olives (Olea europaea L.) are a food commodity of high economic and nutritional value with an increasing production tendency over the last two decades, which, however, suffers from extensive fraud incidents and quality determination uncertainties. Thus, the current attempt aims towards two axes with the first being the multilevel integration of LC-HRMS and NMR data of the same samples and table olives being the selected matrix. In more detail, UPLC-HRMS/MS-based analysis was compared at different stages within an untargeted metabolomics workflow with an NMR-based study and the complementarity of the two platforms was evaluated. Furthermore, statistical heterospectroscopy (SHY), rarely employed in foodomics, combining the spectroscopic with spectrometric datasets and aiming to increase the confidence level of annotated biomarkers was applied. Amongst these lines, the second parallel axis of this study was the detailed characterization of table olives' metabolome in search for quality markers considering the impact of geographical (from Northern to Southern Greece) and botanical origin (Kalamon, Konservolia, Chalkidikis cultivars), as well as processing parameters (Spanish, Greek). To that end, using deep dereplication tools including statistical methods, with SHY employed for the first time in table olives, different biomarkers, belonging to the classes of phenyl alcohols, phenylpropanoids, flavonoids, secoiridoids and triterpenoids were identified as responsible for the observed classifications. The current binary pipeline, focusing on biomarkers’ identification confidence, could be suggested as a meaningful workflow not only in olive-based products, but also in food quality control and foodomics in general.

Harnessing in vivo synthesis of bioactive multiarylmethanes in Escherichia coli via oxygen-mediated free radical reaction induced by simple phenols

BackgroundXanthenes and multi-aryl carbon core containing compounds represent different types of complex and condensed architectures that have impressive wide range of pharmacological, industrial and synthetic applications. Moreover, indoles as building blocks were only found in naturally occurring metabolites with di-aryl carbon cores and in chemically synthesized tri-aryl carbon core containing compounds. Up to date, rare xanthenes with indole bearing multicaryl carbon core have been reported in natural or synthetic products. The underlying mechanism of fluorescein-like arthrocolins with tetra-arylmethyl core were synthesized in an engineered Escherichia coli fed with toluquinol remained unclear.ResultsIn this study, the Keio collection of single gene knockout strains of 3901 mutants of E. coli BW25113, together with 14 distinct E. coli strains, was applied to explore the origins of endogenous building blocks and the biogenesis for arthrocolin assemblage. Deficiency in bacterial respiratory and aromatic compound degradation genes ubiX, cydB, sucA and ssuE inhibited the mutant growth fed with toluquinol. Metabolomics of the cultures of 3897 mutants revealed that only disruption of tnaA involving in transforming tryptophan to indole, resulted in absence of arthrocolins. Further media optimization, thermal cell killing and cell free analysis indicated that a non-enzyme reaction was involved in the arthrocolin biosynthesis in E. coli. Evaluation of redox potentials and free radicals suggested that an oxygen-mediated free radical reaction was responsible for arthrocolins formation in E. coli. Regulation of oxygen combined with distinct phenol derivatives as inducer, 31 arylmethyl core containing metabolites including 13 new and 8 biological active, were isolated and characterized. Among them, novel arthrocolins with p-hydroxylbenzene ring from tyrosine were achieved through large scale of aerobic fermentation and elucidated x-ray diffraction analysis. Moreover, most of the known compounds in this study were for the first time synthesized in a microbe instead of chemical synthesis. Through feeding the rat with toluquinol after colonizing the intestines of rat with E. coli, arthrocolins also appeared in the rat blood.ConclusionOur findings provide a mechanistic insight into in vivo synthesis of complex and condensed arthrocolins induced by simple phenols and exploits a quinol based method to generate endogenous aromatic building blocks, as well as a methylidene unit, for the bacteria-facilitated synthesis of multiarylmethanes.

Natural Phenolic Compounds with Antithrombotic and Antiplatelet Effects: A Drug-likeness Approach.

Thrombosis is one of the major causes of morbidity and mortality in a wide range of vessel diseases. Several studies have been conducted to identify antithrombotic agents from medicinal plants, and phenolic compounds (PCs) have been shown to effectively inhibit plasma coagulation and platelet aggregation. This study aimed to conduct a survey of the natural PCs with proven antithrombotic and antiplatelet activities, as well as to evaluate by computational modeling the physicochemical and toxicological properties of these compounds using drug-likeness approaches. The data were collected from the scientific database: 'Web of Science', 'Scifinder', 'Pubmed', 'ScienceDirect' and 'Google Scholar', the different classes of PCs with antithrombotic or antiplatelet effects were used as keywords. These molecules were also evaluated for their Drug-Likeness properties and toxicity to verify their profile for being candidates for new antithrombotic drugs. In this review, it was possible to register 85 lignans, 73 flavonoids, 28 coumarins, 21 quinones, 23 phenolic acids, 8 xanthones and 8 simple phenols. Activity records for tannins were not found in the researched databases. Of these 246 compounds, 213 did not violate any of Lipinski's rules of five, of which 125 (59%) showed non-toxicity, being promising candidates for new potential antithrombotic drugs. This review arouses interest in the isolation of phenolic compounds that may allow a new approach for the prevention of both arterial and venous thrombosis, with the potential to become alternatives in the prevention and treatment of cardiovascular diseases.

Activating peroxymonosulfate with MOF-derived NiO-NiCo2O4/titanium membrane for water treatment: A non-radical dominated oxidation mechanism

Traditional peroxymonosulfate (PMS) catalytic membranes dominated by radical pathways often face interference from complex components in water bodies. Herein, we employed a controlled electro-deposition technique to coat a Ni-Co metal–organic framework (MOF) precursor onto titanium hollow fiber membrane (THFM), followed by high-temperature calcination to synthesize a MOF-derived NiO-NiCo2O4/THFM (M−NNCO−THFM) PMS catalytic membrane. Then, the M−NNCO−THFM filtration integrated with PMS activation (MFPA process) for water treatment. Experimental results demonstrated that the M−NNCO−THFM MFPA process successfully achieved complete phenol (PE) removal via a non-radical-dominated degradation pathway, involving singlet oxygen (1O2) and electron transfer, while exhibiting wide pH adaptability and exceptional stability in complex water matrices. Mechanism analysis revealed that the electron transfer process was significantly enhanced by the MOF-derived heterojunction structure, which increased the flat-band potential from 0.39 eV to 0.56 eV, thereby facilitating efficient electron transfer for PE removal. The non-radical 1O2 pathway was primarily due to the cycling of metal valence states (Ni2+/Co3+), leading to the reduction of Co2+ and its reaction with PMS, resulting in the generation of reactive species. Furthermore, electrochemical measurements indicated that the M−NNCO−THFM exhibited lower charge transfer resistance and enhanced charge transfer efficiency compared to non-MOF-derived NNCO-THFM, corresponding to the superior catalytic performance and electrochemically active surface area of M−NNCO−THFM.

New mixed ligand oxido-vanadium(V) complexes with O,O-donor and diimine ligands: Synthesis, crystal structure and catalytic activity in eco-friendly oxidation of olefins and phenol

The facile synthesis and structural characterization of a set of three new oxidovanadium(V) complexes of general formula [VO2(L)(diimine)], where L is ethyl-maltol(emal) (1), deferiprone(def) (2) or, maltol(mal) (3), and diimine is 5,6-dimethyl-1,10-phenanthroline(5,6-DMP) are described. The neutral complexes 1–3 have been comprehensively characterized by employing various analytical and spectroscopic techniques including single crystal X-ray diffraction analysis. The coordination geometry around the V(V) in each of the complexes was indicated by XRD-analysis to be distorted octahedral with equatorial plane being occupied by the deprotonated O,O-donor ligands. The complexes 1–3 could be successfully implemented in organic oxidations viz., hydroxylation of phenol (PH) and olefin epoxidation under environmentally clean organic-solvent-free conditions with aqueous H2O2 as oxidant. Phenol was selectively converted into dihydroxybenzene (DHB) products, catechol (CT) and hydroquinone (HQ) (HQ/CT=1.3:1) with aqueous H2O2 as oxidant at room temperature, with a TON value of 266. Moreover, the catalysts showed impressive activity in epoxidation of styrene and a range of cyclic olefins such as cyclohexene, cyclooctene, and norbornene in absence of organic solvent, to provide high conversion (up to 100 %) with excellent epoxide selectivity and good TON values. The catalysts are stable and afford recyclability for multiple cycles of epoxidation with virtually unaltered catalytic activity.

The Public Health Leader Who Brought Antisepsis to William Halsted.

William Halsted wrote to aging surgeon, Stephen Smith, in 1919, that he remembered the lessons Smith had taught him, "when I walked with you through the wards of Bellevue Hospital." Smith was an early advocate of Joseph Lister's antiseptic method, and because of his public health work, he was also an early advocate of environmental hygiene and microbial control based on the unproved germ theory. While Lister's work at the time emphasized germ-killing around the operative site with carbolic acid (antisepsis), Smith adopted and encouraged surgical practices at Bellevue that would be hallmarks of the germ-preventing (asepsis) surgical approach that fully developed after German bacteriologic discoveries in the mid-1880s, and with which Halsted is historically identified. Some physicians and historians have emphasized temporal and conceptual differences between Lister's antisepsis and German asepsis, but Smith and Halsted's experiences argue that surgical asepsis was the evolutionary outcome of germ theory-based surgical changes that began well before scientific proof arrived.

Degradation of organic pollutants by the Cl-/PMS process.

The viewpoints on whether high concentrations of chloride ion (Cl-) promote or inhibit the oxidation activity of activated persulfates are still inconclusive. Furthermore, the degradation of organic pollutants by the persulfates in the presence of high Cl- concentrations without any activation medium has not yet been studied. In this work, the efficiency and mechanism of degradation of organic pollutants such as carbamazepine (CBZ), sulfadiazine (SDZ), and phenol (PN) by Cl--activated PMS (denoted as Cl-/PMS) were investigated. Results showed that Cl- could effectively activate PMS for the complete removal of CBZ, SDZ, and PN with reaction kinetic constants of 0.4516min-1, 0.01753min-1, and 0.06805min-1, respectively. Parameters such as PMS dose, Cl- concentration, solution pH, and initial concentrations of organic pollutants that affect the degradation efficiencies of the Cl-/PMS process were optimized. Unlike conventional activated persulfates, it was confirmed that the free chlorine was the main active species in the Cl-/PMS process. Finally, the degradation by-products of CBZ and SDZ as well as their toxicity were detected, and a possible degradation pathway for CBZ and SDZ was proposed. Though higher toxic chlorinated by-products were generated, the Cl-/PMS process was still an efficient oxidation method for the removal of organic pollutants in aqueous solutions which contain high concentrations of Cl-.

Does Adding CROSS With Carbolic Acid Add Any Clinical Benefit When Doing Erbium Ablative Resurfacing for Acne Scars?

Does Adding CROSS With Carbolic Acid Add Any Clinical Benefit When Doing Erbium Ablative Resurfacing for Acne Scars?

Study of phenoxy radical couplings using the enzymatic secretome of Botrytis cinerea.

Phenoxy radical coupling reactions are widely used in nature for the synthesis of complex molecules such as lignin. Their use in the laboratory has great potential for the production of high value compounds from the polyphenol family. While the enzymes responsible for the generation of the radicals are well known, the behavior of the latter is still enigmatic and difficult to control in a reaction flask. Previous work in our laboratory using the enzymatic secretome of B. cinerea containing laccases has shown that incubation of stilbenes leads to dimers, while incubation of phenylpropanoids leads to dimers as well as larger coupling products. Building on these previous studies, this paper investigates the role of different structural features in phenoxy radical couplings. We first demonstrate that the presence of an exocyclic conjugated double bond plays a role in the generation of efficient reactions. In addition, we show that the formation of phenylpropanoid trimers and tetramers can proceed via a decarboxylation reaction that regenerates this reactive moiety. Lastly, this study investigates the reactivity of other phenolic compounds: stilbene dimers, a dihydro-stilbene, a 4-O-methyl-stilbene and a simple phenol with the enzymatic secretome of B. cinerea. The observed efficient dimerization reactions consistently correlate with the presence of a para-phenol conjugated to an exocyclic double bond. The absence of this structural feature leads to variable results, with some compounds showing low conversion or no reaction at all. This research has allowed the development of a controlled method for the synthesis of specific dimers and tetramers of phenylpropanoid derivatives and novel stilbene derivatives, as well as an understanding of features that can promote efficient radical coupling reactions.

The development of methods for determination the total flavonoids in buds of Populus alba L.

White poplar (Populus alba L., family Saliaceae ) has a similar chemical composition with other species of the genus Populus L. and it can consider as a promising source of raw materials containing phenolic compounds, in particular flavonoids. The pharmacological activity of the buds of pharmacopeial species of genus Populus L., and also of the white poplar is caused by biologically active compounds, mainly of a phenolic nature, including flavonoids (pinostrobin, piriocembrin, quercetin, etc.), phenylpropanoids (caffeic acid, etc.) and simple phenols (salicin).. One of the most well-known biologically active compounds of white poplar is quercetin, for which an antihistamine, anti-inflammatory action has been demonstrated. Differential spectrophotometry carried out in accordance with the OFS was used as a research method.1.2.1.1.0003.15 "Spectrophotometry in the ultraviolet and visible regions". Spectral characteristics of water-alcohol extracts were evaluated on a Specord 40 spectrophotometer (Analytik Jena AG, Germany) in cuvettes with a layer thickness of 10 mm. It was determined that in all electronic spectra of the water-ethanolic extractions from the buds of the white poplar there are two absorption maxima in the area of 290 nm and 370 nm, due to flavanones and flavonols, respectively. It was established that in the electronic spectra of the water-ethanolic extractions from the buds of the white poplar, a significant bathochromic shift of the long-wavelength band in the presence of aluminum chloride is observed, which confirms the presence of flavonoids. Under the conditions of differential spectrophotometry UV spectrum of the water-ethanolic extractions from the buds of the white poplar, an absorption maximum is observed at wavelength of 430 nm, which indicates the expediency of using quercetin in the analysis technique, which has an absorption maximum at a wavelength of 430±2 nm. As a result of the study, the method has been developed for the quantitative determination of the amount of flavonoids in the buds of white poplar using differential spectrophotometry calculated on quercetin at an analytical wavelength of 430 nm. The optimal parameters of extraction of raw materials were determined: extractant – 90% ethyl alcohol, the ratio of "raw material-extractant" – 1:30, extraction time – 60 minutes. The content of the total flavonoids calculated on quercetin in the buds of the white poplar is varied from 0,45±0,02 % to 0.69 ± 0.03%

The β-subunit of tryptophan synthase is a latent tyrosine synthase.

Aromatic amino acids and their derivatives are diverse primary and secondary metabolites with critical roles in protein synthesis, cell structure and integrity, defense and signaling. All de novo aromatic amino acid production relies on a set of ancient and highly conserved chemistries. Here we introduce a new enzymatic transformation for L-tyrosine synthesis by demonstrating that the β-subunit of tryptophan synthase-which natively couples indole and L-serine to form L-tryptophan-can act as a latent 'tyrosine synthase'. A single substitution of a near-universally conserved catalytic residue unlocks activity toward simple phenol analogs and yields exclusive para carbon-carbon bond formation to furnish L-tyrosines. Structural and mechanistic studies show how a new active-site water molecule orients phenols for a nonnative mechanism of alkylation, with additional directed evolution resulting in a net >30,000-fold rate enhancement. This new biocatalyst can be used to efficiently prepare valuable L-tyrosine analogs at gram scales and provides the missing chemistry for a conceptually different pathway to L-tyrosine.

Integrated Membrane Process in Organic Media: Combining Organic Solvent Ultrafiltration, Nanofiltration, and Reverse Osmosis to Purify and Concentrate the Phenolic Compounds from Wet Olive Pomace.

Phenolic compounds from a hydroalcoholic extract of wet olive pomace were purified and concentrated by an integrated membrane process in organic media. First, UF010104 (Solsep BV) and UP005 (Microdyn Nadir) membranes were tested to be implemented in the ultrafiltration stage, with the aim of purifying the extract and obtaining a permeate enriched in phenolic compounds. Despite the high flux observed with the UF010104 membrane (20.4 ± 0.7 L·h-1·m-2, at 2 bar), the UP005 membrane was selected because of a more suitable selectivity. Even though some secoiridoids were rejected, the permeate stream obtained with this membrane contained high concentrations of valuable simple phenols and phenolic acids, whereas sugars and macromolecules were retained. Then, the ultrafiltration permeate was subjected to a nanofiltration step employing an NF270 membrane (DuPont) for a further purification and fractionation of the phenolic compounds. The permeate flux was 50.2 ± 0.2 L·h-1·m-2, working at 15 bar. Hydroxytyrosol and some phenolic acids (such as vanillic acid, caffeic acid, and ferulic acid) were recovered in the permeate, which was later concentrated by reverse osmosis employing an NF90 membrane. The permeate flux obtained with this membrane was 15.3 ± 0.3 L·h-1·m-2. The concentrated phenolic mixture that was obtained may have important applications as a powerful antioxidant and for the prevention of diabetes and neurodegenerative diseases.