Characterization Of Phenolic Compounds Research Articles

LC-ESI-QTOF-MS/MS Identification and Characterization of Phenolic Compounds from Leaves of Australian Myrtles and Their Antioxidant Activities

Phenolic compounds, present in plants, provide substantial health advantages, such as antioxidant and anti-inflammatory properties, which enhance cardiovascular and cognitive well-being. Australia is enriched with a wide range of plants with phytopharmacological potential, which needs to be fully elucidated. In this context, we analyzed leaves of aniseed myrtle (Syzygium anisatum), lemon myrtle (Backhousia citriodora), and cinnamon myrtle (Backhousia myrtifolia) for their complex phytochemical profile and antioxidant potential. LC-ESI-QTOF-MS/MS was applied for screening and characterizing these Australian myrtles’ phenolic compounds and the structure–function relation of phenolic compounds. This study identified 145 and quantified/semi-quantified 27 phenolic compounds in these Australian myrtles. Furthermore, phenolic contents (total phenolic content (TPC), total condensed tannins (TCT), and total flavonoids (TFC)) and antioxidant potential of phenolic extracts from the leaves of Australian myrtles were quantified. Aniseed myrtle was quantified with the highest TPC (52.49 ± 3.55 mg GAE/g) and total antioxidant potential than other selected myrtles. Catechin, epicatechin, isovitexin, cinnamic acid, and quercetin were quantified as Australian myrtles’ most abundant phenolic compounds. Moreover, chemometric analysis further validated the results. This study provides a new insight into the novel potent bioactive phenolic compounds from Australian myrtles that could be potentially useful for functional, nutraceutical, and therapeutic applications.

Characterization of Phenolic Compounds in Extra Virgin Olive Oil from Granada (Spain) and Evaluation of Its Neuroprotective Action.

The olive oil sector is a fundamental food in the Mediterranean diet. It has been demonstrated that the consumption of extra virgin olive oil (EVOO) with a high content of phenolic compounds is beneficial in the prevention and/or treatment of many diseases. The main objective of this work was to study the relationship between the content of phenolic compounds and the in vitro neuroprotective and anti-inflammatory activity of EVOOs from two PDOs in the province of Granada. To this purpose, the amounts of phenolic compounds were determined by liquid chromatography coupled to mass spectrometry (HPLC-MS) and the inhibitory activity of acetylcholinesterase (AChE) and cyclooxygenase-2 (COX-2) enzymes by spectrophotometric and fluorimetric assays. The main families identified were phenolic alcohols, secoiridoids, lignans, flavonoids, and phenolic acids. The EVOO samples with the highest total concentration of compounds and the highest inhibitory activity belonged to the Picual and Manzanillo varieties. Statistical analysis showed a positive correlation between identified compounds and AChE and COX-2 inhibitory activity, except for lignans. These results confirm EVOO's compounds possess neuroprotective potential.

Anti-inflammatory Effect of the Hydroethanolic Extract from Dacryodes kukachkana Leaves in Mice: Role of Macrophage Nitric Oxide

Aims: This study aimed to characterize and evaluate the effect of the hydroethanolic extract from D. kukachkana leaves (HEDkL) in mice models of acute inflammation and in isolated macrophages stimulated with carrageenan, along with possible adverse effects in the central nervous system. Study Design: After characterization of phenolic constituents, HEDkL was injected in the animals 60 min before the administration of inflammatory stimulis. The anti-inflammatory effect of HEDkL was evaluated in the models of paw edema, peritonitis and air pouch and in peritoneal macrophages stimulated with carrageenan in vitro. The per se effect of HEDkL was evaluated for behavioral alterations. Place and Duration of Study: Higher Institute of Biomedical Sciences and Animal Health Research Center, State University of Ceara; Physiopharmacology Laboratory, Federal University of Acre; between March 2021 and March 2023. Methodology: The characterization of phenolic compounds was performed by HPLC-DAD. Swiss mice (25 - 35 g) received HEDkL (25 - 200 mg/kg; per oral) 60 min before carrageenan. Macrophages were incubated with HEDkL (100 - 200 µg/mL) before being stimulated.  The anti-inflammatory effect was assessed for edema, hypernociception, vascular permeability, leukocyte infiltrate, oxidative stress and inflammatory. Behavioral alterations (exploratory, anxiolytic, depressant activities) were evaluated in the animals treated with HEDkL (50 mg/kg). Results: The HPLC-DAD revealed the presence of ellagic acid, epicatechin and gallic acid. In the paw edema model, HEDkL (50 mg/kg) inhibited the edema late phase (2 - 5h) by 45% and the activity of the enzyme myeloperoxidase by 48%. In the peritonitis model, HEDkL (50 mg/kg) reduced leukocyte migration (45%), hypernociception (73%), total proteins (20%) and NO2-/NO3- (23%). In the air pouch model, HEDkL (50 mg/kg) reduced the migration of total leukocytes (76%) and neutrophils (88%). In vitro HEDkL (200 µg/mL) reduced by 31% the NO2-/NO3- in the supernatant of macrophages. HEDkL did not alter the animals exploratory, anxiolytic, or depressant behaviors. Conclusion: HEDkL containing flavonoids and phenols presents anti-inflammatory effect in vivo and in vitro involving nitric oxide inhibition, being devoid of behavioral alterations.

Metabolomics Characterization of Phenolic Compounds in Colored Quinoa and Their Relationship with In Vitro Antioxidant and Hypoglycemic Activities.

Chenopodium quinoa Willd. is rich in phenolic compounds and exhibits diverse biological activities. Few studies have focused on the effect of colored quinoa's phenolic profile on potential biological activity. This study used a UPLC-MS/MS-based metabolomic approach to examine the quinoa phenolics and their association with in vitro antioxidant and hypoglycemic properties. In total, 430 polyphenols, mainly phenolic acids, flavonoids, and flavonols, were identified. Additionally, 121, 116, and 148 differential polyphenols were found between the white and black, white and red, and black and red comparison groups, respectively; 67 polyphenols were screened as shared key differential metabolites. Phenylalanine, tyrosine, and the biosynthesis of plant secondary metabolites were the main differently regulated pathways. Black quinoa had better total phenolic contents (643.68 mg/100 g DW) and antioxidant capacity, while white quinoa had better total flavonoid contents (90.95 mg/100 g DW) and in vitro α-amylase (IC50 value of 3.97 mg/mL) and α-glucosidase (IC50 value of 1.08 mg/mL) inhibition activities. Thirty-six polyphenols, including epicatechin and linarin, etc., were highly correlated with in vitro antioxidant activity, while six polyphenols, including tiliroside and chrysoeriol, etc., were highly correlated with in vitro hypoglycemic activity. This study may provide important information for colored quinoa resources to develop their healthy food applications.

Characterization of Phenolic Compounds from Pavetta graciliflora Wall. ex Ridl. (Rubiaceae) and their Lipoxygenase Inhibitory Activity

Characterization of Phenolic Compounds from Pavetta graciliflora Wall. ex Ridl. (Rubiaceae) and their Lipoxygenase Inhibitory Activity

Antioxidant and Antifungal Activities and Characterization of Phenolic Compounds Using High-Performance Liquid Chromatography and Mass Spectrometry (HPLC-MS) in Empetrum rubrum Vahl ex Willd.

In searching for compounds with antioxidant and antifungal activity, our study focused on the subshrub species Empetrum rubrum Vahl ex Willd. (Ericaceae). We measured the antioxidant activity of its methanolic extract (MEE) obtained from the aerial parts (leaves and stems) and of its methanolic extract (MEF) obtained from the lyophilized fruits. The antioxidant activity of the MEE and MEF was evaluated in vitro via a 2,2-Diphenyl-1-picrylhydrazyl (DPPH) free radical and 2,2'-Azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) cationic radical. The results were expressed in gallic acid and Trolox equivalents for the DPPH and ABTS assays, respectively. The antioxidant activities, for the DPPH and ABTS assays, were also evaluated by considering the IC50 values. Concerning the antioxidant activity, the total phenolic content (TPC) in the MEE and MEF was determined using the Folin-Ciocalteu method. Polyphenols contained in the leaves, stems, and fruits of E. rubrum were determined qualitatively by employing high-performance liquid chromatography coupled with mass spectrometry (HPLC-MS) analysis. The antifungal activity of the MEE obtained from the aerial parts of E. rubrum was tested against Rhizoctonia solani. The results of IC50 values measured by the DPPH and ABTS methods with MEE were 0.4145 ± 0.0068 mg mL-1 and 0.1088 ± 0.0023 mg mL-1, respectively, and the IC50 values for MEF were 6.4768 ± 0.0218 mg mL-1 and 0.7666 ± 0.0089 mg mL-1 measured by the DPPH and ABTS methods, respectively. The HPLC-MS analysis revealed the presence of anthocyanins, phenolic acids derivatives, and flavonols. In vitro, mycelial growth of this fungus was reduced from 90% to nearly 100% in the presence of MEE. The observed antifungal effect is related to the presence of the abovementioned phenols, detected in the MEE.

LC-ESI-QTOF-MS/MS characterization of phenolic compounds in Australian native passion fruits and their potential antioxidant activities.

Passion fruits, renowned globally for their polyphenolic content and associated health benefits, have enjoyed growing attention from consumers and producers alike. While global cultivar development progresses, Australia has pioneered several native cultivars tailored for its distinct planting conditions. Despite their cultivation, comprehensive studies on the phenolic profiles and antioxidant capacities of these Australian-native passion fruits are notably lacking. This study aims to investigate and compare the polyphenolic content present in the by-products, which are peel (L), and consumable portions, which are the pulp and seeds (P), of four indigenous cultivars: 'Misty Gem' (MG), 'Flamengo' (FG), 'Sweetheart' (SW), and 'Panama' (SH). Employing LC-ESI-QTOF-MS/MS for profiling, a comprehensive list of polyphenols was curated. Additionally, various antioxidant assays-DPPH, FRAP, ABTS, RPA, FICA, and •OH-RSA-were performed to evaluate their antioxidant potential. A total of 61 polyphenols were identified, categorized into phenolic acid (19), flavonoids (33), and other phenolic substances (9). In the antioxidant assays, the SHP sample exhibited the highest •OH--RSA activity at 98.64 ± 1.45 mg AAE/g, while the FGL sample demonstrated prominent DPPH, FRAP, and ABTS activities with values of 32.47 ± 1.92 mg TE/g, 62.50 ± 3.70 mg TE/g, and 57.84 ± 1.22 mg AAE/g, respectively. Additionally, TPC and several antioxidant assays had a significant positive correlation, including DPPH, FRAP, and ABTS. The Australian-native passion fruits revealed distinct polyphenolic profiles and diverse antioxidant capacities, establishing a foundation for deeper health benefit analyses. This study accentuates the significance of understanding region-specific cultivars and their potential nutraceutical applications.

Screening and Characterization of Phenolic Compounds from Selected Unripe Fruits and Their Antioxidant Potential.

The food sector's interest in sustainability and the demand for novel bioactive compounds are increasing. Many fruits are wasted every year before ripening due to various climatic conditions and harsh weather. Unripe mangoes, grapes, and black lemons could be rich sources of phenolic compounds that need to be fully elucidated. Using fruit waste as a source of bioactive chemicals has grown increasingly appealing as it may have significant economic benefits. Polyphenols are beneficial for human health to inhibit or minimize oxidative stress and can be used to develop functional and nutraceutical food products. In this context, this study aimed to characterize and screen unripe mangoes, grapes, and black lemons for phenolic compounds using LC-ESI-QTOF-MS/MS and their antioxidant activities. Unripe mangoes were quantified with higher total phenolic content (TPC, 58.01 ± 6.37 mg GAE/g) compared to black lemon (23.08 ± 2.28 mg GAE/g) and unripe grapes (19.42 ± 1.16 mg GAE/g). Furthermore, unripe mangoes were also measured with higher antioxidant potential than unripe grapes and black lemons. A total of 85 phenolic compounds (70 in black lemons, 49 in unripe grapes, and 68 in unripe mango) were identified, and 23 phenolic compounds were quantified using LC-MS/MS. Procyanidin B2, gallic acid, epicatechin, caffeic acid, quercetin, and chlorogenic acid were measured with higher concentration in these selected unripe fruits. A positive correlation was found between phenolic contents and the antioxidant activities of unripe fruits. Furthermore, chemometric analysis was conducted to validate the results. This study will explore the utilization of these unripe fruits to develop functional and therapeutic foods.

HPLC/ESI-MS Characterization of Phenolic Compounds from Cnicus benedictus L. Roots: A Study of Antioxidant, Antibacterial, Anti-Inflammatory, and Anti-Alzheimer's Activity.

The phenolic composition of Cnicus benedictus roots from four Algerian regions was investigated. Extractions were performed in both hydro-methanolic (30 : 70, v/v) and hydro-ethanolic (30 : 70, v/v) solvents. Their efficiency was determined in terms of the qualitative and quantitative composition in phenolic compounds by HPLC-LC/MS of the different extracts isolated from C. Benedictus roots. Cnicus benedictus roots extract have been characterized by high content of phenolic compounds, where the trans chalcone, 2,3-dihydro flavone, 3-hydroxy flavone and cinnamic acid constitute the major components, in addition to fourteen minor acidic compounds and flavonoids as rutin. The hydro-methanolic extract was the richest in phenolic compounds yield from C benedictus. On the other hand, hydro methanolic (30 : 70, v/v) and hydro ethanolic (30 : 70, v/v) extracts exhibited a high anti-inflammatory activity by in vitro 5-lipoxygenase inhibitory activity (IC50 : 6.05±94.16 μg/mL) as well as by in silico docking according two methods. Likewise, anti-Alzheimer activity of extracts was confirmed by this last technique taking into account the major compounds identified. Antibacterial tests revealed interesting results compared to amoxicillin for the different regions studied with a high content in trans chalcone and 3-hydroxy Flavone.

Characterization of phenolic compounds in Eugenia uniflora leaves by ESI(-) FT-ICR MS, analysis of cytotoxic activity on gastric adenocarcinoma (AGS cells), and anti-Helicobacter pylori activity

Eugenia uniflora leaves are a source of flavonoids and ellagitannins, and the Brazilian population uses them to treat various diseases, including gastrointestinal disorders. This study aimed to determine if the ethanol extract and other derivatives are effective cytotoxic agents against gastric adenocarcinoma (AGS cells) and anti-H. pylori agent, its chemical composition, and mass spectrometry characterization of the more abundant compounds. The results were compared with the literature. The aqueous fraction, rich in Oenothein B and Gemin D/Hippomanin A, showed anti-H. pylori activity and higher cytotoxicity on AGS cells compared to the other samples analysed. Furthermore, the ESI(-) FT-ICR MS characterized the more abundant phenolic compounds, including Quinic Acid, Myricitrin, Gemin D/Hippomanin A, and Oenothein. Therefore, the activity of the ethanolic extract and aqueous fraction for gastric cancer and against H-pylori seems to originate from the antiproliferative and bacteriostatic effects of tannins and flavonoids.

Ruellia angustiflora (Nees) Lindau ex Rambo: extraction and characterization of phenolic compounds and evaluation of antiradical, photoprotective and antimicrobial activities

Ruellia angustiflora is a shrub popularly known as flower of fire, used in traditional medicine as a healing agent. This study aims to verify the presence of characteristics of pharmaceutical interest in extracts from the root, stem and leaves of this species. The ideal time for ultrasound-assisted extraction is 60 min with a solid-liquid ratio of 1% (w/v). The kinetics of the reaction of the extracts with DPPH is biphasic, and IC50 values are related to the total phenolic compounds. Five phenolic compounds were identified in the extracts, where ferulic acid, rutin and quercetin showed to be the main responsible for the antiradical activity. The extracts displayed considerable photoprotective activity, mainly Ra-LE (SPF = 23). Ra-RE showed an inhibition halo similar to erythromycin against Streptococcus pyogenes. Taken together, these data reveal that Ruellia angustiflora is a source of phenolic compounds and has relevant antiradical, photoprotective and antibacterial activities.

Up-Cycling Grape Pomace through Sourdough Fermentation: Characterization of Phenolic Compounds, Antioxidant Activity, and Anti-Inflammatory Potential.

Despite its appealing composition, because it is rich in fibers and polyphenols, grape pomace, the major by-product of the wine industry, is still discarded or used for feed. This study aimed at exploiting grape pomace functional potential through fermentation with lactic acid bacteria (LAB). A systematic approach, including the progressively optimization of the grape pomace substrate, was used, evaluating pomace percentage, pH, and supplementation of nitrogen and carbon sources. When grape pomace was used at 10%, especially without pH correction, LAB cell viability decreased up to 2 log cycles. Hence, the percentage was lowered to 5 or 2.5% and supplementations with carbon and nitrogen sources, which are crucial for LAB metabolism, were considered aiming at obtaining a proper fermentation of the substrate. The optimization of the substrate enabled the comparison of strains performances and allowed the selection of the best performing strain (Lactiplantibacillus plantarum T0A10). A sourdough, containing 5% of grape pomace and fermented with the selected strain, showed high antioxidant activity on DPPH and ABTS radicals and anti-inflammatory potential on Caco2 cells. The anthocyanins profile of the grape pomace sourdough was also characterized, showing qualitative and quantitative differences before and after fermentation. Overall, the grape pomace sourdough showed promising applications as a functional ingredient in bread making.

LC-ESI-QTOF-MS/MS Characterization of Phenolic Compounds in Common Commercial Mushrooms and Their Potential Antioxidant Activities

Mushrooms have a long history of use as food and medicine. They are rich in various nutrients and bioactive compounds, particularly phenolic compounds. In this study, ten mushroom species were selected, and solvent extraction using 80% ethanol was used to extract phenolic compounds. Total phenolic content (TPC), total flavonoid content (TFC) and total condensed tannin content (TCT) were measured to evaluate phenolic content in different mushroom varieties. In the mushroom varieties tested, brown portobello mushroom had the highest TPC (396.78 ± 3.12 µg GAE/g), white cup mushroom exhibited the highest TFC (275.17 ± 9.40 μg CE/g), and shiitake mushroom presented the highest TCT (13.80 ± 0.21 µg QE/g). Antioxidant capacity was evaluated using 2,2-diphenyl-1-picrylhydrazyl (DPPH), ferric reducing antioxidant power (FRAP), 2,2′-azino-bis-3ethylbenzothiazoline-6-sulfonic acid (ABTS) and total antioxidant capacity (TAC) assays. The highest DPPH free radical scavenging ability was found in white cup mushroom (730.14 ± 55.06 µg AAE/g), while the greatest iron-reducing ability (FRAP) was recorded for shiitake mushroom (165.32 ± 10.21 μg AAE/g). Additionally, Swiss brown mushroom showed the highest ABTS antioxidant capacity (321.31 ± 5.7 μg AAE/g), and the maximum TAC value was found in shiitake mushroom (24.52 ± 1.2 μg AAE/g). These results highlight that most of the mushroom varieties studied showed high phenolic contents and demonstrated strong antioxidant activity, with shiitake mushrooms standing out due to their high TCT and FRAP values, and the highest TAC value among the varieties studied. In addition, LC-ESI-QTOF-MS/MS was used to characterize the mushroom samples, and tentatively identified a total of 22 phenolic compounds, including 11 flavonoids, 4 lignans, 3 phenolic acids, 2 stilbenes and 2 other phenolic compounds in all mushroom samples. The research results of this study showed that mushrooms are a good source of phenolic compounds with strong antioxidant potential. The results can provide a scientific basis for the development of mushroom extracts in functional food, health products, and other industries.

Rheum turkestanicum and R. ribes: Characterization of phenolic compounds and a LCESI-QqTOF MS based comparison with the officinal Chinese rhubarb, R. palmatum

The limited supply of Chinese officinal rhubarbs (Rheum palmatum L., R. tanguticum Maxim. ex Balf., and R. officinale Baill.) has resulted in the use of other Rheum species in many places. Therefore, investigating the metabolite profile of unofficinal rhubarbs, and an analytical comparison of their metabolite profile with the officinal ones is crucial. Rheum turkestanicum Janisch. and R. ribes L. are two Rheum species distributed in Iran and are widely being traded in traditional markets as substitutes for R. palmatum. Herein, we isolated different phenolic compounds in the roots and rhizomes of R. turkestanicum and R. ribes by chromatographic techniques and identified them by nuclear magnetic resonance spectroscopy (NMR), electronic circular dichroism (ECD), electrospray ionization-mass spectrometry (ESI-MS), and high-resolution mass spectrometry (HRMS). In addition, the metabolite profile of the two above-mentioned species were compared with that of R. palmatum by liquid chromatography-electrospray ionization-quadrupole time-of-flight mass spectrometry (LC-ESI-QqTOF MS). The obtained MS data were statistically compared by non-metric multidimensional scaling (NMDS) and analysis of similarities (ANOSIM) and a heatmap was plotted for comparing the tested samples. The isolated compounds were catechins, anthraquinones, naphthoquinones, chromones and rhododendrol glycosides, among which (-) 3′,4′′-di-O-methyl-catechin-3-O-gallate was a new compound. The results of LC-MS/MS analysis indicated that while catechins were the most abundant compounds in R. ribes, anthraquinones and naphthalenes were the main constituents of R. palmatum and R. turkestanicum. Interestingly, the substitution in the hexosyl residue of anthraquinone and naphthalene hexosides was a malonyl or an acetyl group in R. palmatum, while this substitution was a 3-hydroxy-3-methylglutaryl group in R. turkestanicum. This may be considered as a potential marker for the differentiation of R. palmatum and R. turkestanicum. The statistical analysis showed that R. palmatum, R. turkestanicum, and R. ribes are distinct species, however, R. turkestanicum had some similarities to R. palmatum. In conclusion, R. turkestanicum can be a subject for future phytochemical, pharmacological, and clinical research regarding its ability to be used as a potential substitute for R. palmatum in pharmaceutical industries.

Extraction and Analytical Characterization of Phenolic Compounds from Brazil Nut (Bertholletia excelsa) Skin Industrial by-Product

Pressurized liquid extraction (PLE) and ultrasound assisted extraction (UAE) were applied to extract phenolic antioxidants from defatted Brazil nut skin (DBNS) industrial by-product. Water/alcohol solvents (ethanol and methanol) (0 - 50 % v/v water) were used at temperatures of 50 - 200 °C in PLE and 50 °C was set in UAE. The effect on extraction yield, total phenolic compounds content (TPC), antioxidant capacity and phenolic characterization was determined. The temperature and water/alcohol mixture affected the dielectric constant, and this in turn influenced the yield, TPC, antioxidant activity and phenolic composition. In PLE, at 200 °C and 50 % (v/v) water/alcohol (ethanol and methanol) the highest yields (33.8 and 38.4 %, respectively), TPC (4673 and 5435 mg GAE/100 g DBNS) and antioxidant capacity (397 and 502 µmol TE/g DBNS) were obtained. Furthermore, at 50 °C, PLE had better extraction efficiency than UAE. Characterization of the extracts indicated that at 50 - 100 °C the extraction of protocatechuic acid and ellagic acid derivative were predominant, while at 150 - 200 °C catechin and vanillin derivatives stand out. In general, hydroxybenzoic acids and flavonoids were the most abundant phenolics, and the addition of 25 % v/v water to ethanol resulted in extracts with their highest concentration. Then, Brazil nut skin is an interesting phenolic-rich source with potential use to produce bioactive ingredients. HIGHLIGHTS High temperature and water/alcohol mixtures improves TPC and antioxidant capacity At given temperature, TPC values are linearly correlated with water/alcohol dielectric constant Extraction temperature modifies the abundance and profile of phenolic compounds Hydroxybenzoic acids and flavanols are predominant phenolics in Brazil nut skins At 50 °C, PLE have a better extraction efficiency of phenolic compounds than UAE GRAPHICAL ABSTRACT

Characterization of Phenolic Compounds of Olea europaea L. and Ceratonia siliqua L. Leaf Extracts by HPLC-ESI-MS

Background: Olive (Olea europaea L.) and carob (Ceratonia siliqua L.), which contain considerable amounts of phenolic compounds, are the most important nutritional and therapeutic plants in the Mediterranean basin. Objectives: The goal of this work is to revalue carob and olive leaves as key sources of polyphenols, hence increasing the value of waste goods. Methods: In this study, aqueous acetone or ethanol (80% v/v) extracts of olive (O. europaea L. cultivar aimel) and carob (C. siliqua L.) leaves from Algeria were evaluated for phenolic content, and the extracts were characterized by reverse-phase high-performance liquid chromatography-electrospray ionization mass spectrometry (HPLC-ESI-MS). Discussion and Results: The total phenolic content of olive and carob leaf extracts ranged from 5.6 to 23 mg GAE/g. The use of HPLC-ESI-MS to investigate phenolics revealed that the extracts included a variety of phenolic compounds, including 23 compounds in olive leaf extracts and 17 compounds in carob leaf extracts. In olive and carob, the major phenolic components are oleuropein and myricetin rhamnoside, respectively. Conclusion: According to our findings, olea europaea and Ceratonia siliqua appear to be rich suppliers of natural chemicals. These plants have a lot of potential in terms of medications and functional foods.

LC-ESI-QTOF-MS2 Characterization of Phenolic Compounds in Different Lentil (Lens culinaris M.) Samples and Their Antioxidant Capacity.

Lentil (Lens culinaris M.) is a legume widely consumed worldwide. It is rich in bioactive compounds, including polyphenolic compounds that contribute to positive health benefits. This study aimed to determine the phenolic content and antioxidant activity of black, red, green, and brown whole lentils. Towards this end, the lentils' phenolic compounds were evaluated regarding their total phenolic content (TPC), total flavonoid content (TFC), total tannin content (TTC), total condensed tannin (TCT), total proanthocyanin content (TPAC), total anthocyanin content (TAC). For the antioxidant activity 2,2-diphenyl-1-picrylhydrazyl (DPPH), ferric reducing antioxidant power (FRAP), 2,2'-azinobis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS), hydroxyl radical scavenging activity (•OH-RSA), ferrous ion chelating activity (FICA), reducing power assay (RPA) and phosphomolybdate (PMA) assay were accessed. To identify individual phenolic compounds, liquid chromatography-electrospray ionization quadrupole time-of-flight mass spectrometry (LC-ESI-QTOF-MS2) was used. The results showed that green lentils exhibited the highest TPC (0.96 mg gallic acid equivalents (GAE)/g) whereas red lentils presented the highest TFC (0.06 mg quercetin equivalents (QE)/g). Black lentils were noted with the highest TCT (0.03 mg catechin equivalents (CE)/g), TPAC (0.009 mg cyanidin chloride equivalents (CCE)/g), and TAC (3.32 mg/100 g) contents. While the greatest TTC (2.05 mg tannic acid equivalents (TAE)/g) was observed in the brown lentil. Regarding the total antioxidant capacity, red lentils (4.01 mg ascorbic acid equivalents (AAE)/g) presented the greatest activity, whereas the lowest was found in the brown samples (2.31 mg AAE/g). The LC-ESI-QTOF-MS2 tentatively identified a total of 22 phenolic compounds, containing 6 phenolic acids, 13 flavonoids, 2 lignans, and 1 other polyphenol. The relationships among phenolic compounds by Venn Diagram showed a high number of overlapping compounds in brown and red lentils (6.7%), and a low number of overlapping compounds between the green, brown, and black lentils (2.6%). Flavonoids were the most abundant phenolic compound within the studied whole lentils, with the brown lentils being the richest in phenolic compounds, especially flavonoids. This study emphasized a comprehensive understanding of the antioxidant potential of lentils and disclosed the phenolic distribution across various lentil samples. This may increase interest in the development of functional food products, nutraceutical ingredients, and pharmaceutical applications with lentils.

Screening and characterization of phenolic compounds by LC-ESI-QTOF-MS/MS and their antioxidant potentials in papaya fruit and their by-products activities

Papaya (Carica papaya L.) is one of the most commonly planted and consumed fruits in the world, especially in tropical and subtropical areas. In recent years, due to the diverse range of nutritional value and medicinal properties of bioactive substances possessed in papaya, papaya fruit and their by-products have gained more attention. The present study aimed to characterize the different parts (pulp, peel, and seed) of two varieties of papaya (yellow- and red-fleshed) at different stages of ripeness (unripe and ripe) for their phenolic compounds using liquid chromatography-electrospray ionization quadrupole time-of-flight mass spectrometry (LC-ESI-QTOF-MS/MS). The phenolic content and antioxidant activity were detected through several assays. Yellow-fleshed unripe papaya seed showed the highest total phenolic content (TPC) (4.73 mg GAE/g). Red-fleshed ripe papaya peel exhibited the highest level of total tannin content (TTC) with 1.98 mg CE/g, while red-fleshed unripe peel exhibited the highest total flavonoid content (TFC) with 2.78 ± 0.04 mg QE/g. In terms of antioxidant potential, yellow-fleshed unripe papaya peels had the highest radical scavenging activities for the DPPH, ABTS, and TAC tests. LC-ESI-QTOF-MS/MS experiment successfully tentatively identified 118 phenolic compounds in total, including phenolic acids (35), flavonoids (61), stilbenes (3), lignans (7) and other polyphenols (12) in all papaya samples. Analyses indicate that the three different parts of the papaya fruit are potential sources of phenolic compounds, particularly the peel. The results of this study provide practical data for the potential application of papaya fruit as a functional food ingredient in the food, pharmaceutical and medicinal industries.

Antioxidant, Antimicrobial Activities, and Characterization of Phenolic Compounds of Thyme (Thymus vulgaris L.), Sage (Salvia officinalis L.), and Thyme–Sage Mixture Extracts

The antioxidant properties of sage (Salvia officinalis L.) and thyme (Thymus vulgaris L.), and their mixtures were examined using the 2,2-Diphenyl-1-picrylhydrazyl (DPPH•) scavenging activity and ferric-reducing activity of plasma (FRAP) methods. The antimicrobial activity of the plant extracts against four bacterial strains (Escherichia coli, Staphylococcus aureus, Bacillus cereus, and Salmonella typhomorium) was determined using the agar well diffusion method. Results showed the highest overall rate of increase in total phenolic (13.67 mg·GAE/g·DW), and flavonoid (6.75 mg·QUE/g·DW) contents in the thyme–sage mixture extract compared with the thyme and sage extracts. As found by GC-MS analysis of methanolic extracts, thymol, apigenin, rosmarinic acid, and carvacrol were the most abundant phenolic compounds in the thyme–sage extract. The lowest EC50 (DPPH•, 55.51 μg·ml−1) and the highest FRAP value (95.51 mM Fe (II) mg−1 extract) were recorded in the extract of the thyme–sage mixture compared with sage and thyme extracts, and butylated hydroxytoluene solution (BHT). The highest antimicrobial activity against E. coli, S. aureus, B. cereus, and S. typhomorium was observed in the thyme–sage mixture with the inhibition zone diameters of 22.13, 28.67, 31.25, and 23.65 mm, respectively. It is concluded that the extract obtained from the thyme–sage mixture has more potential to be used in the pharmaceutical and food industry as a natural antibacterial and antioxidant agent.

Heliotropium procubens Mill: Taxonomic Significance and Characterization of Phenolic Compounds via UHPLC-HRMS- In Vitro Antioxidant and Enzyme Inhibitory Activities.

The aim of the present study was the phytochemical analysis of the aerial parts of Heliotropium procumbens Mill., a herb from Boraginaceae plant family not previously studied. The methanol (ME) and aqueous extracts (WE) of the aerial parts were assayed for their total phenolic and flavonoid content and antioxidant properties, using free radical scavenging (DPPH, ABTS), reducing power (FRAP, CUPRAC), phosphomolybdenum and metal chelating assays. The extracts displayed considerable free radical scavenging activity against DPPH and ABTS radicals, with potential values of 46.88 and 68.31 mg TE/g extract for ME, and 93.43 and 131.48 mg TE/g extract for WE, respectively. Key clinical enzymes involved in neurodegenerative diseases AChE and BChE, diabetes (α-amylase and α-glucosidase) and skin whitening (tyrosinase) were also assayed. The phytochemical profile of the studied species was determined through UHPLC-HRMS, whereby 26 secondary metabolites were identified, three of which (luteolin-7-glucoside, lithospermic and rosmarinic acids) were isolated and structurally determined by NMR spectral means. H. procubens was found to harbor bioactive metabolites and could, hence, serve as a source of biological activities which could be further explored and exploited for potential applications.