Hydroxybenzoic Acid Derivatives Research Articles

Megastigmane and hydroxybenzoic acid derivatives from aqueous leaves extract of Artocarpus heterophyllus lam

The hot water extract of senescent leaves from Artocarpus heterophyllus is used in traditional Sri Lankan medicine for treating diabetes mellitus. This study aimed to isolate phytochemicals in the ethyl acetate soluble fraction of the hot water extract. Bioassay-guided fractionation led to the isolation of three megastigmane derivatives and two hydroxybenzoic acid derivatives from fractions, demonstrating both hypoglycaemic and antidiabetic activities. The elucidated compounds were identified as 3,4-dihydroxy-7-ene-megastigman-9-one, 3,4,6-trihydroxy-7-ene-megastigman-9-one, 9,13-dihydroxy-4,7-dien-megastigman-3-one, 4-hydroxybenzoic acid, and 3,4-dihydroxybenzoic acid. Structural confirmation was carried out by 1H NMR, 2D NMR, 13 C NMR, IR, UV-Vis and mass spectrometry. Notably, while these compounds have been well-documented for their antidiabetic activity, their presence in the A. heterophyllus species is novel, expanding our understanding. Furthermore, their well-established antidiabetic activity profiles highlight their essential role in the observed effects of the hot water extract for diabetes management, reinforcing its traditional remedy status.

Exploring of Chemical Profile and Biological Activities of Three Ocimum Species From Comoros Islands: A Combination of In Vitro and In Silico Insights.

Ocimum species have a great interest in different traditional medicinal systems. This study examined the chemical composition, antioxidant properties, enzyme inhibitory effects, and antibacterial and antifungal activities of the aerial parts of Ocimum gratissimum, Ocimum americanum, and Ocimum basilicum from the Comoros Islands. The extracts were analyzed using high-performance liquid chromatography-mass spectrometry (HPLC-MS) to determine their chemical composition. Antioxidant activity was assessed using 2,2-Diphenyl-1-picrylhydrazyl (DPPH), 2,2'-Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS), cupric reducing antioxidant capacity (CUPRAC), ferric reducing antioxidant power (FRAP), chelating ability, and phosphomolybdenum radical scavenging assays. Enzyme inhibitory activities against acetylcholinesterase (AChE), butrylcholinesterase (BChE), tyrosinase, amylase, and glucosidase were evaluated using spectrophotometric methods. Antibacterial and antifungal activities were tested using the broth microdilution method against selected pathogenic microorganisms. The selected enzymes and proteins were evaluated using in silico methods with biomolecules from these plants. In addition, 111 different metabolites were identified in the tested extracts using advanced HPLC/MS techniques. The most significant number of detected compounds were derivatives of hydroxycinnamic acids, followed by flavonoid glycosides and aglycones and derivatives of hydroxybenzoic acids. All three Ocimum species exhibited significant antioxidant activities, O. gratissimum exhibited the best-reducing abilities in CUPRAC and FRAP assays. In addition, enzyme inhibitory assays revealed that O. americanum had the most potent inhibitory effect on tyrosinase (48.01 ± 3.89 mg kojic acid equivalent [KAE]/g), and amylase (1.08 ± 0.02 mmol acarbose equivalent [ACAE]/g). Antibacterial and antifungal tests demonstrated that the extracts possess broad-spectrum activity. Molecular docking results showed that compounds exhibited remarkable binding energies with target enzymes and proteins. The molecular dynamics simulations identified chicoric acid with MurE of Staphylococcus aureus complex as the most promising drug candidate. These findings support their traditional medical and nutraceutical uses and suggest possibilities for natural functional applications.

Antioxidant and Anti-Inflammatory Capacities of Three Dry Bean Varieties after Cooking and In Vitro Gastrointestinal Digestion.

The present study delved into the chemical composition, antioxidant, and anti-inflammatory properties of three dry edible beans: Black (BL), Great Northern (GN), and Pinto (PN). The beans were soaked, cooked, and subjected to in vitro gastrointestinal (GI) digestion. BL bean exhibited significantly higher gastric (42%) and intestinal (8%) digestion rates. Comparative assessment of soluble GI-digested fractions (<3 kDa) revealed that the GN bean exhibited the highest abundance of dipeptides (P < 0.05). The BL bean fraction displayed a 4-fold increase in tripeptides (P < 0.05). Both BL and PN bean fractions are high in essential free amino acids, flavonols, and derivatives of hydroxybenzoic acid when compared to the GN bean. All the beans exhibited the ability to mitigate TNF-α-induced pro-inflammatory signaling; however, the BL bean fraction was the most effective at lowering AAPH-induced oxidative stress in HT-29 cells, followed by the GN bean (P < 0.05). In contrast, a low antioxidant effect was observed with PN beans.

Unlocking the potential of Allium dictyoprasum C.A. Meyer ex Kunth: quantum chemical insights into radical scavenging, chemical composition, phenolic content, and antimicrobial activity

ABSTRACT Allium dictyoprasum C.A. Meyer ex Kunth (A. dictyoprasum) underwent comprehensive analysis, encompassing quantum chemical computations to assess its radical scavenging potential, chemical and elemental composition, total phenolic content, and antimicrobial activity. Experimental and theoretical investigations focused on elucidating the radical scavenging properties of polyhydroxy phenolic compounds present in the plant. Quantum chemical calculations were employed to evaluate the antioxidants employed to evaluate selected polyhydroxy phenolic molecules including flavonoids, hydrocinnamic acid derivatives, and hydroxybenzoic acid derivatives from natural sources. Thermochemical parameters of these compounds were calculated by the B3LYP/6–311 G++(d,p) level in both gas and solvent phases to elucidate the radical scavenging mechanism including hydrogen atom transfer (HAT), single electron transfer followed by proton transfer (SET-PT) and sequential proton loss electron transfer (SPLET). Analysis of A. dictyoprasum extracts obtained via various extraction methods revealed the presence of several major compounds, including dimethyl trisulfide, 3,5-Dihydroxy-6-methyl-2,3-dihydro-4 H-pyran-4-one, 2-Methoxy-4-vinylphenol, Dimethyl phthalate, Methyl palmitate, Methyl oleate, Methyl stearate, (9Z)-9-Octadecenamide. Notably, Malic acid and Quinic acid were identified as major compounds, with concentrations of 43.31 and 17.47 mg kg−1 extract, respectively, based on LC-MS/MS analysis. The total phenolic content of the extract was measured as 17.83 mg gallic acid/mL, while its free radical scavenging activity was 80.89% per mg/mL. Elemental analysis revealed significant levels of Mg, K, Na, Fe, and P, with minor concentrations of elements such as Ti, Tl, B, and Be. Furthermore, A. dictyoprasum exhibited notable antibacterial activity against various bacteria strains, surpassing the efficacy of some commercial antibiotics.

Chemical Profile and Healthy Properties of Sicilian Diplotaxis harra subsp. crassifolia (Raf.) Maire.

This study was aimed at investigating the phytochemical profile and bioactivity of Diplotaxis harra subsp. crassifolia (Brassicaceae), a species from central-southern Sicily (Italy), where it is consumed as a salad. For this purpose, LC-ESI/HRMSn analysis of the ethanolic extract was performed, highlighting the occurrence, along with flavonoids, hydroxycinnamic acid derivatives, and oxylipins, of sulfated secondary metabolites, including glucosinolates and various sulfooxy derivatives (e.g., C13 nor-isoprenoids, hydroxyphenyl, and hydroxybenzoic acid derivatives), most of which were never reported before in the Brassicaeae family or in the Diplotaxis genus. Following ethnomedicinal information regarding this species used for the treatment of various pathologies such as diabetes and hypercholesterolemia, D. harra ethanolic extract was evaluated for its antioxidant potential using different in vitro tests such as 2,2-diphenyl-1-picrylhydrazyl, 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid), Ferric Reducing Ability Power, and β-carotene bleaching tests. The inhibitory activity of carbohydrate-hydrolyzing enzymes (α-amylase and α-glucosidase) and pancreatic lipase was also assessed. In the 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid assay, an IC50 value comparable to the positive control ascorbic acid (2.87 vs. 1.70 μg/mL, respectively) was obtained. The wild-wall rocket salad extract showed a significant α-amylase inhibitory effect. Obtained results indicate that Sicilian wild-wall rocket contains phytochemicals that can prevent hyperglycemia, hyperlipidemia, and obesity.

Changes in the Aroma Profile and Phenolic Compound Contents of Different Strawberry Cultivars during Ripening.

Secondary metabolites, namely, phenolic and volatile organic compounds, contribute to the nutritional and organoleptic quality of the strawberry fruit. This study focuses on the changes in the content of phenolic compounds and volatile organic compounds during the ripening, from green to overripe fruit, of five strawberry cultivars ('Asia', 'CIVN 766', 'Aprica', 'Clery', and 'Malwina'). Additionally, these changes are compared with the colour of the fruit and peroxidase and polyphenol oxidase activity. Our results show that the accumulation of secondary metabolites (phenolic and volatile organic compounds) significantly changed during the ripening process for all of the studied cultivars. As for phenolic compounds, flavanols and hydroxybenzoic acid derivatives comprised between 87 and 95% of the total phenolic compound content in unripe green fruit. In contrast, anthocyanins and hydroxycinnamic acid derivatives comprised between 64 and 77% of the total phenolic compound content in overripe fruit, except in the fruit of the cultivar 'CIVN766'. When it comes to the aroma profile, the content of aldehydes decreased by 24-49% as the fruit ripened, and the accumulation of esters increased. Our study also shows that the ripening process differs among cultivars, and it is therefore necessary to define ripening indicators separately for each cultivar.

Exploring the Efficacy of Hydroxybenzoic Acid Derivatives in Mitigating Jellyfish Toxin-Induced Skin Damage: Insights into Protective and Reparative Mechanisms.

The escalation of jellyfish stings has drawn attention to severe skin reactions, underscoring the necessity for novel treatments. This investigation assesses the potential of hydroxybenzoic acid derivatives, specifically protocatechuic acid (PCA) and gentisic acid (DHB), for alleviating Nemopilema nomurai Nematocyst Venom (NnNV)-induced injuries. By employing an in vivo mouse model, the study delves into the therapeutic efficacy of these compounds. Through a combination of ELISA and Western blot analyses, histological examinations, and molecular assays, the study scrutinizes the inflammatory response, assesses skin damage and repair mechanisms, and investigates the compounds' ability to counteract venom effects. Our findings indicate that PCA and DHB significantly mitigate inflammation by modulating critical cytokines and pathways, altering collagen ratios through topical application, and enhancing VEGF and bFGF levels. Furthermore, both compounds demonstrate potential in neutralizing NnNV toxicity by inhibiting metalloproteinases and phospholipase-A2, showcasing the viability of small-molecule compounds in managing toxin-induced injuries.

Neuroprotective action of hydroxybenzoic acid derivative with glycine (C40) in the middle cerebral artery occlusion in rats with chronic cerebral circulation insufficiency

The neuroprotective effect of a novel conjugate of hydroxybenzoic acid with glycine (C40) was investigated in a model of ischemic stroke in rats with chronic cerebral circulation insufficiency (CCCI). The study was conducted in two stages: first, CCCI was modeled by stenosing the common carotid arteries by 50 %, followed by a 60-minute middle cerebral artery occlusion (stroke) after 40 days. Compound C40 and the reference drug citicoline were administered for 10 days before stroke and for 3 days after. Further, neurological deficit (the Garcia and Combs D’Alecy scales), sensorimotor functions (Open Field test, Adhesive Removal test, and Rotarod test), cognitive impairments (Novel Object Recognition and Morris Water Maze tests), cerebral blood flow level, and endothelial function were evaluated. Animals receiving the test substances demonstrated a statistically significant reduction in neurological deficit, less pronounced motor coordination and sensorimotor function impairments, as well as fewer short-term and long-term memory deficits compared to the negative control group. The observed decrease in neurological deficit in the experimental groups was accompanied by improved endothelial function and increased cerebral blood flow. The neuroprotective effect of the novel hydroxybenzoic acid derivative with glycine (C40) was comparable to that of reference drug citicoline.

A Comprehensive Study on Lathyrus tuberosus L.: Insights into Phytochemical Composition, Antimicrobial Activity, Antioxidant Capacity, Cytotoxic, and Cell Migration Effects.

In this study, in vitro antioxidant, antimicrobial, cytotoxic, and cell migration effects of phenolic compounds of Lathyrus tuberosus leaves, known in the Transylvanian ethnomedicine, were investigated. Ultra-high-performance liquid chromatography-tandem mass spectrometry was employed for the analysis of the ethanolic and aqueous extracts. The antimicrobial properties were determined using a conventional microdilution technique. Total antioxidant capacity techniques were used using cell-free methods and cell-based investigations. Cytotoxic effects were conducted on 3T3 mouse fibroblasts and HaCaT human keratinocytes using a multiparametric method, assessing intracellular ATP, total nucleic acid, and protein levels. Cell migration was visualized by phase-contrast microscopy, employing conventional culture inserts to make cell-free areas. Together, 93 polyphenolic and monoterpenoid compounds were characterized, including flavonoid glycosides, lignans, hydroxycinnamic acid, and hydroxybenzoic acid derivatives, as well as iridoids and secoiridoids. The ethanolic extract showed high antioxidant capacity and strong antimicrobial activity against Bacillus subtilis (MIC80 value: 354.37 ± 4.58 µg/mL) and Streptococcus pyogenes (MIC80 value: 488.89 ± 4.75 µg/mL). The abundance of phenolic compounds and the results of biological tests indicate the potential for L. tuberosus to serve as reservoirs of bioactive compounds and to be used in the development of novel nutraceuticals.

Phenolic Compounds from Ocimum basilicum Revealed as Antibacterial by Experimental and Computational Screening‐Based Studies against Oral Infections

Dental infections are initiated by Streptococcus sanguinis and Streptococcus mutans through the biofilm formation. In streptococcal, the ComA enzyme catalyzes the first step to produce signalling molecules in quorum sensing that influence biofilm formation. Ocimum basilicum is one of the natural sources which is potential for antibacterial agent. This study is aimed to isolate phenolic compounds from O. basilicum leaves with antibacterial activity against oral pathogens by experimental and computational screening studies. Isolation of phenolic compounds 1–4 was carried out by bioactivity guided using column chromatography. Methylparaben (1), methyl protocatechuate (2), caffeic acid (3), and methyl caffeate (4) were characterized by 1D and 2D‐NMR. The antibacterial activity was tested by disk diffusion, microdilution methods. 1 (625 μg·mL−1) provided moderate activity, and 2 (156.3 μg·mL−1) provided strong activity against S. mutans. 3 (125 μg·mL−1) and 4 (312.5 μg·mL−1) provided strong activity against S. sanguinis. In addition, phenolic compounds and their derivatives were predicted against ComA using Autodock 4.0 tools. The activity correlated positively with in silico tests against ComA where 2 (−7.69 kcal·mol−1) had a stronger binding affinity than 1 (−6.64 kcal·mol−1). 3 (−6.86 kcal·mol−1) provided a slightly stronger bond strength than 4 (−6.65 kcal·mol−1). The strongest binding affinity of hydroxybenzoic acid derivatives is 3,5‐dihydroxybenzoic acid (−8.10 kcal·mol−1). In addition, the strongest binding affinity of hydroxycinnamic acid derivatives is chlorogenic acid (−9.16 kcal·mol−1). The pharmacokinetics were predicted by ADMET analysis, and methyl caffeate (4) showed the best potential as a drug compound. The conclusion is that phenolic compounds isolated from O. basilicum have potential as natural antibacterials. In silico tests also showed the relationship between the structure and activity by the presence of the hydroxyl group in hydroxybenzoic acid derivatives and the presence of an alkyl group in the unsaturated side chain in hydroxycinnamic acid derivatives.

Mechanism of inhibitory action of fruit cake extracts as a new environmentally inhibitors of carbon steel corrosion

In this study the firstly study reported on the use of plum, cherry, nectarine and apple pomace extract as corrosion inhibitors of steel in water solution. Potentiodynamic polarization study showed that extracts act as a mixed type inhibitors with dominant cathodic effect. Linear polarization resistance method (LRP) assesses the time-related effect of inhibitors during open circuit potential corrosion. The results show that the inhibitory efficiency of our extract increases with increasing time formation protective film to reach 99 % in a concentration of 500 ppm. LC - MS and FTIR spectroscopy techniques can be concluded that several water-soluble interaction products of chemical reaction in NaCl are identified namely flavanol–anthocyanin and flavanol-aldehyde adducts. Subsequently, the iron-mediated complexation and oxidation of the extract components (flvonoids) in the aqueous solution were explored using UV-spectrophotometric and HPLC methods. With the passage of time, iron-mediated oxidative degradation and coupling reactions occurred, resulting in the production of hydroxybenzoic acid derivatives. Consequently, the inhibition decreased after 24 h. The chemisorption type of interaction of the product formed in the inhibited solution forming the adsorption-polymerization layer with the steel surface is established. Based on the quantum-chemically calculated parameters of the electronic structure of flavanol–anthocyanin and flavanol-aldehyde adducts, it was established for the first time that the combination of reactive fragments in them, which are spatially located in different planes with a higher quantity of hydroxyl groups, increases their adsorption activity and, as a result, their inhibitory capacity.

Decarboxylation and Tandem Reduction/Decarboxylation Pathways to Substituted Phenols from Aromatic Carboxylic Acids Using Bimetallic Nanoparticles on Supported Ionic Liquid Phases as Multifunctional Catalysts.

Valuable substituted phenols are accessible via the selective decarboxylation of hydroxybenzoic acid derivatives using multifunctional catalysts composed of bimetallic iron-ruthenium nanoparticles immobilized on an amine-functionalized supported ionic liquid phase (Fe25Ru75@SILP+IL-NEt2). The individual components of the catalytic system are assembled using a molecular approach to bring metal and amine sites into close contact on the support material, providing high stability and high decarboxylation activity. Operating under a hydrogen atmosphere was found to be essential to achieve high selectivity and yields. As the catalyst materials enable also the selective hydrogenation and hydrodeoxygenation of various additional functional groups (i.e., formyl, acyl, and nitro substituents), direct access to the corresponding phenols can be achieved via integrated tandem reactions. The approach opens versatile synthetic pathways for the production of valuable phenols from a wide range of readily available substrates, including compounds derived from lignocellulosic biomass.

The chemical profile and seasonal variation of the composition of the phenolic acids in different plant parts of Centaurea sp.

This study investigated the seasonal variation (over seven months) of phenolic acid (PHA) components in different parts of Centaurea sp. The primary objective was to determine the pattern of variation, while the secondary objective was to identify which month or growth stage provides a greater total PHA content or percentage of bioactive components. Different patterns of seasonal variations were highlighted for the different PHA components and their classes (hydroxybenzoic and -cinnamic acids) in different parts of the plant. The leaves exclusively provided the highest PHA contents, with maximum values reached in April (1368.06 μg/g). The major hydroxybenzoic acid derivatives (HBAs) identified in the leaves were vanillic acid (VaA) “154.18–374.06 μg/g” and protocatechuic acid (PA) “9.37–595.61 μg/g”, while the major hydroxycinnamic acid derivatives (HCAs) were p-coumaric acid (p-CoA) “109.35–261.77 μg/g”, m-coumaric acid (m-CoA) “10.22–70.57 μg/g”, and ferulic acid (FeA) “35.54–109.13 μg/g”. The maximum percentage of PA was obtained in April “595.61 μg/g”, while the maximum p-CoA content was obtained in January “261.77 μg/g”. Therefore, the leaves can be recommended as the optimal source of PHAs. If there is a specific interest in certain PHA components, we recommend collection in either January or April. Multivariate statistical analysis (PCA & AHC) showed the existence of two main clusters. The first cluster comprised the leaves, distinguished by the highest VaA, PA, and p-CoA contents. The second cluster comprised roots and the root bark samples. This study provides information on the development of PHAs in different parts of Centaurea sp. and explores potential applications. It will be of considerable interest for determining the optimal harvesting time of shrub species used for their medicinal properties and bio-active phenolic contents.

Synthesis, Docking Study, and Cytotoxicity Evaluation of New Hydroxy benzoic Acid Derivatives

Hydroxy benzoic acid derivatives are an important scaffold in medicinal chemistry. A review of the literature revealed that they have a wide range of biological activities, including anti-inflammatory, antibacterial, and anti-tumor properties. The current study aimed to synthesize three new hydroxy benzoic acid derivatives (compounds 8, 9, and 10) and test them as epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors in silico and in vitro. Traditional organic synthesis methods were applied to produce these compounds. Docking studies revealed that compound 8 had nearly equal binding energy (DG) to erlotinib, the standard EGFR tyrosine kinase inhibitor. -8.56 and -8.75 kcal/mol, respectively. Using the MTT (3-(4, 5-dimethylthiazolyl-2)-2, 5-diphenyltetrazolium bromide) viability assay, the cytotoxicity of the new hydroxy benzoic acid derivatives was tested against DLD-1 colorectal adenocarcinoma cells, HeLa cervical cancer cells, and MCF-7 breast cancer cells. Compound 8 showed cytotoxicity against the three cancer cell lines tested (25.05, 23.88, and 48.36 µM, respectively), while compound 9 showed cytotoxicity against HeLa cells only (37.67 µM), and compound 10 was cytotoxic to DLD-1 and HeLa cells (27.26 and 19.19 µM, respectively. The half maximal inhibitory concentrations (IC50) of compound 8 were comparable to those of the standard tyrosine kinase inhibitor drug erlotinib (13.86, 36.41, and 87.34 µM, respectively). In conclusion, the findings of the present study indicate that compound 8, through its EGFR inhibitory activity, is a promising cytotoxic agent.

A broad assessment of Eremurus spectabilis M. Bieb: chemical and elemental composition, total phenolic and antimicrobial activity analysis, and quantum chemical calculations of radical scavenging potential

ABSTRACT Eremurus spectabilis M. Bieb was extensively investigated experimentally and theoretically, including the antioxidant properties of compounds such as flavonoids, hydroxycinnamic acid derivatives, hydroxybenzoic acid derivatives, and organic acids. Antioxidant activity was investigated using the Density Functional Theory (DFT) method based on three known mechanisms: hydrogen atom transfer (HAT), single electron transfer followed by proton transfer (SET-PT), and sequential proton loss electron transfer (SPLET). Subcritical water extraction (SWE), soxhlet extraction (SE), and solvent extraction (SOE) techniques were applied in the extraction process. Malic acid was the major compound with an extract concentration of 38,532.84 ± 1849.58 µg analyte/kg, total phenolics, and free radical scavenging activity were 10.67 mg gallic acid/mL extract and 73.89% per mg/mL extract, respectively. P, Fe, Na, Mg, K, and Ca were the main elements. The antibacterial activity of E. spectabilis against seven bacteria was evaluated, and it was found to be higher than the commercial antibiotics P10 and AMC30.

Bioprospecting of Targeted Phenolic Compounds of Dictyota dichotoma, Gongolaria barbata, Ericaria amentacea, Sargassum hornschuchii and Ellisolandia elongata from the Adriatic Sea Extracted by Two Green Methods.

The content of bioactive compounds in four brown and one red algae from the Adriatic Sea (Dictyota dichotoma, Gongolaria barbata, Ericaria amentacea, Sargassum hornschuchii and Ellisolandia elongata) is explored. The efficiency of two different extraction methods viz. ultrasound-assisted extraction (UAE) and matrix solid-phase dispersion (MSPD) to obtain the extracts rich in phenolic compounds was compared. The effect of the extraction solvent to modulate the phenolic profile was assessed. In general, the mixture ethanol/water in an isovolumetric proportion showed the best results. The total phenolic content (TPC) and antioxidant activity (AA), as well as the individual polyphenolic profile, were evaluated for five target algae. TPC values ranged between 0.2 mg GAE/g (for E. elongata) and 38 mg GAE/g (for S. hornschuchii). Regarding the quantification of individual polyphenols by liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis, the presence of a high number of hydroxybenzoic acid derivatives (mainly of 3- and 4-hydroxybenzoic acids) in all species was noted. In G. barbata their concentrations reached up to 500 mg/kg. IC50 values (ABTS assay) ranged between 44 mg/L (for S. hornschuchii) and 11,040 mg/L (for E. elongata). This work contributes to the in-depth characterization of these little-explored algae, showing their potential as a natural source of phenolic compounds.

Blackcurrant (Ribes nigrum L.) Seeds-A Valuable Byproduct for Further Processing.

The rational exploitation of byproducts is important from the point of view of their potential applicability in various fields. In this study, the possibility of further processing of blackcurrant seeds (BCs), which are a byproduct of fruit processing, was investigated. BCs were used as a material for the extraction of oil on a semi-industrial scale, and the residues were assessed in terms of their potential application in skin care products. Supercritical fluid extraction (SFE) using CO2 at pressures of 230 and 330 bar and extraction temperature of 40 °C was exploited for isolation of oil, and the products were characterised taking into account lipophilic constituents. After 120 min, the oil yields were 19.67% and 20.94% using CO2 at 230 and 330 bar, respectively, which showed that SFE was an effective method on a semi-industrial scale, taking into account the extraction yield. The oils had similar fatty acid compositions with a high percentage of linoleic acid (ca. 43%); however, tocopherols and carotenoids were most abundant in the oil obtained at 230 bar. It was also found that the composition of the SFE oils was comparable with that of cold-pressed oil, which shows that supercritical fluid extraction provides a high-quality product; therefore, it can be an alternative to cold pressing. Furthermore, the chemical compositions of the extracts from the oil isolation residues were established using UPLC-MS, and the impact of the extracts on human skin fibroblasts was assessed using the MTT and NR assays. The quantitative analysis revealed that the residues contained high amounts of polyphenolic acids, including gallic, protocatechuic, and hydroxybenzoic acid derivatives, as well as flavonoids, especially quercetin and kaempferol glucoside. Moreover, it was found that the extracts were nontoxic and exerted a stimulatory effect on cell metabolism. Therefore, they can be a valuable additive to natural plant-based cosmetics. Our results showed that blackcurrant seeds, regarded as a byproduct, can be a valuable material for further use.

UHPLC-DAD-ESI-HRMS/MS profile of phenolic compounds in northern red oak (Quercus rubra L., syn. Q. borealis F. Michx) seeds and its transformation during thermal processing

This paper describes for the first time a complete characterization and quantification of the phenolic compounds in raw and heat-treated northern red oak ( Quercus rubra L.) seeds using UHPLC-DAD-ESI-HRMS/MS. A total 42 phenolic compounds belonging to five different groups of compounds, including ellagitannins, gallotannins, phenolic glycosides, hydroxybenzoic acid derivatives (HBA derivatives) and ellagic acid derivatives (EA derivatives), were identified, and most of them were reported in Q. rubra seeds for the first time. Significant variability of phenolic composition existed among raw and roasted samples under different temperature and time conditions. The total content of the phenolics, ellagitannins, gallotannins and phenolic glycosides was drastically reduced by roasting, regardless of the thermal processing conditions. In turn, an increase the roasting temperature from 135° to 200°C led to an increment in the total content of HBA and EA derivatives. Among the roasted seeds, the highest total phenolics content was found in the samples thermally treated at 185 °C for 25 min, while the lowest amounts were observed in those roasted at 135 °C for 80 min. Ellagitannins were the dominant class of phenolic compounds in the raw samples, while EA derivatives were more abundant in heat-treated seeds. Interestingly, the second most abundant phenolic group in both unroasted and roasted samples were phenolic glycosides. The predominant individual phenolic compounds, in raw seeds, were cretanin, oenothein B and rugosin E isomers. Since, among the phenolics found in the raw seeds, cretanin had the highest thermal stability, while dimeric ellagitannins and high molecular weight gallotannins exhibited the least thermal stability. The roasted samples contained mainly compounds formed by further decomposition of abovementioned compounds. • A total of 42 phenolics were found in Quercus rubra L. seeds for the first time. • In raw oak seeds, the dominant phenolics were cretanin and dimeric ellagitannins. • Ellagitannins and gallotannins showed higher heat sensitivity than other phenolics. • Roasting effectively increased the content of low-molecular-weight phenolics. • The raw and roasted Q. rubra seeds are a valuable source of bioactive phenolics.

Experience in the synthesis of hydroxybenzoic acid derivatives

Experience in the synthesis of hydroxybenzoic acid derivatives

Determination of the polyphenolic content of berry juices using focusing-modulated comprehensive two-dimensional liquid chromatography coupled to mass spectrometry detection.

In this work, a comprehensive two-dimensional liquid chromatography system, comprised of a ZIC-HILIC and C18 columns in the first and second dimensions, respectively, was tuned and employed for attaining high resolution profiles of the polyphenolic pattern in seven commercial berry juices. The developed HILIC × RP-LC method was validated in terms of linearity range, correlation coefficients, limit of detection, limit of quantification, precision (intra- and inter-day), and recovery. A total of 104 polyphenolic compounds belonging to different chemical classes (hydroxybenzoic and cinnamic acid derivatives, flavone glycosides, flavonols, flavonol glycosides, dihydroflavonols, and anthocyanin glycosides) have been characterized and quantified in the juices investigated. Despite the constituents being similar, a notable quantitative variation among the analyzed berry species was observed. Elderberry contained the highest amount of polyphenols (918 ± 1.10mg 100mL-1), followed by chokeberry (516 ± 0.08mg 100mL-1). On the other hand, raspberry contained the lowest amount (104 ± 1.21mg 100mL-1). Further, total phenolic, flavonoid, and anthocyanin contents were determined spectrophotometrically, yielding consistent results. The free-radical scavenging activity (DPPH test) and reducing power of the juices, expressed as IC50 (μL mL-1) and mg ASE mL-1, varied from 2.79 ± 0.03 (honeyberry) to 31.66 ± 0.02 (blueberry) and from 1.71 ± 0.01 (blueberry) to 8.89 ± 0.12 (chokeberry), respectively. Such a ZIC-HILIC × C18 platform based on focusing modulation, never employed so far for berry juices, showed a remarkable separation capability with high values of corrected peak capacity (up to 1372) and orthogonality (Ao up to 0.80), thus providing a great applicability to be advantageously employed for other complex food samples.