Phenolic production and antioxidant properties of some Macedonian medicinal plants

Characterization and antioxidant activity of peel extracts from three varieties of citrus sinensis

High volume of postharvest materials including peels from citrus fruits is periodically generated, which contributes to environmental pollution. Investigating the chemical composition cum antioxidant property of these 'wastes' would be instructive in achieving value addition in the food and pharmaceutical value chain. On this premise, this study carried out phytochemical screening and antioxidant activity of three (3) commonly cultivated citrus varieties namely Citrus sinensis 'valencia', Citrus sinensis 'washinton' and Citrus sinensis 'thompson navel'. The peels were extracted using ethanol and hexane in a Soxhlet extractor and thereafter subjected to phytochemical and Gas Chromatography/Mass Spectrometry (GC/MS) analyses, ferric ion reducing antioxidant power (FRAP), hydrogen peroxide scavenging and cupric ion reducing antioxidant capacity (CUPRAC) assays to evaluate their antioxidant potentials. Results show that Citrus sinensis peel extracts contain alkaloids, flavonoids, phenols, phytosterols, diterpenes, tannins and glycosides. GC/MS analysis identified about 48 compounds in each extract; with the predominant bioactive compounds being limonene (16.5%), ascorbic acid (17.7%), stearic acid (26.3%), linalool (4.7%), linoleic acid (16.18%), palmitic acid (15.23%), pentadecyclic acid (1.1%). Ethanol and hexane extracts of Valencia exhibited higher FRAP (9.09 ± 0.13) and CUPRAC (2.04 ± 0.06) values while the ethanol extract of Ibadan sweet demonstrated greater hydrogen peroxide scavenging activity (1.39 ± 0.00). Citrus peels are rich in bioactive compounds with excellent antioxidant activity and may serve as potential sources of natural antioxidants for food products or pharmaceutical formulations.

Phenolic Profile, EPR Determination, and Antiproliferative Activity against Human Cancer Cell Lines of Anthyllis vulneraria Extracts

In the current work, the leaf and flower extracts of Anthyllis vulneraria were evaluated for their chemical characterization using HPLC-MS and for their radical scavenging capacity toward methoxy radicals produced by a Fenton-type reaction using an electron paramagnetic resonance (EPR) spectroscopy assay. The in vitro antiproliferative activity of these extracts against several human-derived cancer cells (breast: MCF-7; cervical: HeLa; hepatocellular: HepG2) was also evaluated. The results showed that the Anthyllis vulneraria leaf extract was characterized by 17 different phenolic compounds, among which phenolic acids were the most abundant, while its flower extract exhibited higher contents of flavonoids. Furthermore, Anthyllis vulneraria extracts demonstrated a potent radical scavenging activity against methoxy radicals. Both extracts also significantly reduced the viability of the different cancer cell lines. The results of the current study suggested that Anthyllis vulneraria extracts are a promising source of antioxidant compounds with health benefits and pointed to their potential use for treating cancer and developing novel therapeutic agents.

Bioassay-Guided Skin-Beneficial Effects of Fractionated Sideritis raeseri subsp. raeseri Extract

This study aimed to evaluate the potentials for skin-beneficial effects of the hydroethanolic extract of the aerial parts of ironwort (Sideritis raeseri Boiss. & Heldr. subsp. raeseri) and its fractions (petroleum ether, ethyl acetate, n-butanol and water). For these purposes, chemical analysis and in vitro antioxidant, anti-tyrosinase and antimicrobial assays, as well as determination of sun protection factor (SPF), were performed. The highest total phenolic content and quantity of individual flavonoids, chlorogenic acid and verbascoside were determined in the n-butanol fraction, which is in line with results obtained for antioxidant activity. The greatest antimicrobial activity against Staphylococcus aureus, Staphylococcus epidermidis and Pseudomonas aeruginosa, the most common causative agents of the skin infections in humans, was exhibited by the ethyl acetate fraction. The strongest anti-tyrosinase activity was shown by the hydroethanolic extract (52.64% of inhibition at 100 μg/mL). Almost all tested samples showed photoprotective activity with SPF higher than 6 obtained at a low concentration of 0.1 mg/mL, which was more than 15 for the butanol fraction. These findings revealed that the hydroethanolic extract of S. raeseri aerial parts could be a valuable ingredient in the formulation of cosmetic and medicinal products intended to overcome various skin disorders.

Phytochemical Profiles, Antioxidant Activity and Antiproliferative Mechanism of Rhodiola rosea L. Phenolic Extract

The phenolic profiles, antioxidant activity, antiproliferative property and the underlying molecular mechanisms of cell apoptosis of Rhodiola rosea free phenolic (RFE) were analyzed in this work. Overall, Rhodiola rosea rhizome phenolic extract (RE) contained Rhodiola rosea rhizome free phenolic extract (RFE) and Rhodiola rosea rhizome bound phenolic extract (RBE). Compared with RBE, RFE contained higher phenolic contents and possessed stronger antioxidant activity. High-performance liquid chromatography (HPLC) results demonstrated that the main phenolics of were epigallocatechin (EGC), epigallocatechin gallate (EGCG), gallic acid (GA) and catechin. Gas chromatography–mass spectrometry (GC-MS) analysis found that Rhodiola rosea L. was rich in volatile phytochemicals. In addition, many types of vitamin E and a few kinds of carotenoids were found in Rhodiola rosea. In addition, the main compounds in RFE (GA, EGC, EGCG) and RFE all exhibited excellent antiproliferative activity, indicating the antiproliferative activity of RFE was partly attributed to the synergy effects of the main compounds. Further study confirmed that RFE could block 16.99% of HepG2 cells at S phase and induce 20.32% programmed cell death compared with the control group. Specifically, RFE dose-dependently induced cell apoptosis and cell cycle arrest via modulating the p53 signaling pathway including up-regulation of the expression of p53 and Bax while down-regulation of the Bcl-2, cyclin D1 and CDK4 levels. Therefore, RFE exhibited the potential of being developed as an auxiliary antioxidant and a therapeutic agent for cancer.

CONTENIDO DE POLIFENOLES, CAPACIDAD ANTIOXIDANTE Y TOXICIDAD DE Solanum ferrugineum (SOLANACEAE) CON POTENCIAL MEDICINAL

Solanum ferruginium es una planta que crece en lugares perturbados como maleza, es de uso medicinal poco utilizada que presenta un gran potencial como fuente de antioxidantes debido a su alto contenido en polifenoles. Debido a esto se analizó el contenido de polifenoles, flavonoides, proantocianidinas y capacidad antioxidante in vitro (ensayo de captación de radicales DPPH) en hojas, tallos y planta completa de tres localidades (Las agujas, Parque el Nabo y Bosque la Primavera) de Zapopan, Jalisco, así como su toxicidad subcronica en hojas. En general se observó diferencia significativa (p£ 0,05), en las muestras de las tres localidades, las hojas presentaron el mayor contenido de polifenoles (15,3±0,7 a 22±0,4 mg expresado como equivalente de ácido gálico (EAG/g) en muestras de Parque el Nabo, flavonoides (7,8±0,3 a 13,3±0,3 mg EC/g) y proantocianidinas (3,4±0,1 a 4,2±0,05 mg expresado como equivalente de catequina (EC/g) en el Bosque la Primavera. La capacidad antioxidante fue similar en todas las muestras, con valores de 8,3 a 17 µg/mL de concentración media inhibitora (CI50). En la prueba toxicológica, los ratones no mostraron signos de toxicidad a ninguna dosis por efecto de la administración de la planta en estudio, por lo que la dosis letal media (DL50) es > 15 000 mg/kg de peso corporal. El contenido de polifenoles y actividad antioxidante en S. ferruginium sobre todo en hojas indican un alto potencial con propiedades farmacológicas además de su inocuidad, por lo que es importante realizar estudios de sus compuestos fenólicos individuales, antes de ser utilizada en farmacología.

UHPLC-DAD Characterization of Origanum vulgare L. from Atacama Desert Andean Region and Antioxidant, Antibacterial and Enzyme Inhibition Activities

The Lamiaceae family is an important source of species among medicinal plants highly valued for their biological properties and numerous uses in folk medicine. Origanum is one of the main genera that belong to this family. The purpose of the study was to determine the phenolic composition of the Origanum vulgare extract and evaluate the antimicrobial, antioxidant, and inhibitory activities of this species that grows in the Andean region of the Atacama Desert. High-performance liquid chromatography was performed to determine the main phenols. Rosmarinic acid was identified as the predominant phenolic compound in this species (76.01 mg/100 g DW), followed by protocatechuic acid, which to our knowledge, no previous study reported similar concentrations in O. vulgare. The oregano extract exhibited a content of total phenolic (3948 mg GAE/100 g DW) and total flavonoid (593 mg QE/100 g DW) with a higher DPPH antioxidant activity (IC₅₀ = 40.58 µg/mL), compared to the same species grown under other conditions. Furthermore, it was found to inhibit α-glucosidase activity with an IC₅₀ value (7.11 mg/mL) lower than acarbose (129.32 mg/mL). Pseudomonas syringae and Pantoea agglomerans (both MIC 0.313 mg/mL and MBC 1.25 mg/mL) were the bacteria most susceptible to oregano extract with the lowest concentration necessary to inhibit bacterial growth. These results open the door for the potential use of this plant to manage chronic diseases, and they expand the knowledge of the species cultivated in arid environmental conditions.

Antioxidant and antiproliferative activities of the n-butanol extract of Centaurea maroccana Ball aerial parts

The aim of the present study is to evaluate the total phenolic contents, antioxidant and anti-proliferative activities of the n-BuOH extract of Centaurea maroccana (BECM). The total phenolic and flavonoid of the butanolic extract of the plant were assessed by using Folin-Ciocalteau and aluminium chloride colorimetric assays, respectively, and the quantitative estimation of total flavonoids and phenols revealed the richness of the extract in these compounds. Antioxidant activity was evaluated using standard lab colorimetric methods, while the anti-proliferative activity was evaluated using sulforhodamine B (SRB) assay against C6 (Rattus norvegicus brain glioma) and HT29 (Homo sapiens colorectal adenocarcinoma) cell lines. The n-butanolic extract of Centaurea maroccana showed a strong antioxidant activity through DPPH, ABTS•+, DMSO alkalin, Reducing power, β-Carotene-linoleic acid and CUPRAC assays. Furthermore, the anti-proliferative activity against C6 and HT29 of Centaurea maroccana exhibited a high effect by the decrease in viability of both cancer cell lines. Our results suggest a possible use of Centaurea maroccana as a source of natural antioxidant and chemo-preventive agents against cancer.

Extracts Characterization and In Vitro Evaluation of Potential Immunomodulatory Activities of the Moss Hypnum cupressiforme Hedw

Recently, there has been an increasing interest in the chemistry and biological potential of mosses, since a large number of biologically active compounds have been found within these species. This study aimed at examining the chemical composition and immunomodulatory potential (antioxidant, antidiabetic, anti-neuroinflammatory/antineurodegenerative, and antitumor activities) of moss Hypnum cupressiforme Hedw. extracts. Corresponding extracts have been obtained applying Soxhlet extractor. The chemical characterization was performed using spectrophotometric assays and liquid chromatography-mass spectrometry (LC-MS). The extracts were analyzed for antioxidant activity and for inhibitory activities on α-glucosidase, α-amylase, acetylcholinesterase, and tyrosinase. Additionally, extracts were tested against four cell lines-MRC-5, BV2, HCT-116, and MDA-MB-231-for antitumor and anti-inflammatory activities. Chemical analysis of extracts revealed the presence of flavonoids, phenolic acids, and triterpenoids. Major compounds identified by LC-MS in H. cupressiforme were kaempferol and five phenolic acids: p-hydroxybenzoic, protocatechuic, p-coumaric, gallic, and caffeic acid. According to biochemical assays the investigated extracts exhibited significant immunomodulatory potential. Significant antiproliferative potential against MDA-MB-231 cells has been observed together with the promising anti-neuroinflammatory application. The obtained data suggest that moss H. cupressiforme is a valuable natural source of biologically active compounds with potential application in the pharmaceutical industry.

Parameters of antioxidant activity of Galega officinalis L. and Galega orientalis Lam. (Fabaceae Lindl.) plant raw material

The plant raw material of Galega officinalis L. (goat’s rue) and Galega orientalis Lam. (fodder galega) investigated in this study. These species are known as fodder crops with high productivity of green mass and as medicine plants. The current study was aimed to evaluate an accumulation in dry raw of selected plants the total content of phenolic acids (TPA) and flavonoids (TFC) as compounds with antioxidant activity (AA) by spectrophotometric method. AA by DPPH-method and phosphomolybdenum method (reducing power (RP)) was measured. Study of ethanolic extracts of G. officinalis showed accumulation of TPA in different organs in range from 3.65 to 15.17 mg.g-1 caffeic acid equivalent (CAE) and TFC from 10.08 to 65.75 mg.g-1 quercetin equivalent (QE), AA by DPPH-method from 6.02 to 8.45 mg.g-1 Trolox equivalent (TE) and RP of extracts by phosphomolybdenum method from 86.56 to 288.15 mg TE.g-1. In extracts of G. orientalis was identified TPA from 3.52 to 18.52 mg CAE.g-1 and TFC from 6.09 to 46.72 mg QE.g-1, antioxidant activity by DPPH-method from 6.80 to 8.48 mg TE.g-1 and antioxidant capacity by phosphomolybdenum method from 52.52 to 188.51 mg TE.g-1. It was established that less concentration of studied compounds found in the stems for both species. It should be noted that the content of phenolic acids in the leaves was decreased and flavonoids in stems increased during vegetation for both species. Content of phenolic acids in the generative organs and flavonoids in the leaves decreased in raw of G. orientalis during vegetation. Pearson’s correlation analysis demonstrated very strong relations between TFC and AA by DPPH, TPA and RP, TFC and RP for G. officinalis extracts. Very strong correlation in the extracts of G. orientalis found between TFC and RP, TPA and RP. Obtained results can be used in the further biochemical and pharmacological study.

Origanum vulgare ssp. vulgare: Chemical Composition and Biological Studies

The biological properties and main phenolic compounds of the O. vulgare L. ssp. vulgare extract are described in the present paper. The polyphenolic compounds were analyzed by chromatographic and spectrophotometric techniques. The antioxidant potential was evaluated using several methods: CUPRAC (cupric ion reducing antioxidant capacity), FRAP (ferric reducing ability of plasma), inhibition of lipid peroxidation catalyzed by cytochrome c, and superoxide (SO) scavenging assays. The antimicrobial activity of the oregano extract was evaluated by means of agar-well diffusion assay. The hepatoprotective effect of the O. vulgare extract on CCl₄-induced hepatotoxicity was evaluated in rats. Liver injury was estimated by determination of alanine aminotransaminase (ALT), aspartate aminotransaminase (AST), gamma-glutamyl transferase GGT, total protein and albumin concentrations, glutathione peroxidase (GPx), catalase (CAT), superoxide dismutase (SOD) and malondialdehyde (MDA). These values were improved by the administration of oregano extract. A specific phenolic profile was evidenced by these data, with large amounts of rosmarinic and chlorogenic acids. The oregano extract showed very strong antioxidant activity in good agreement with the phenolic content. Antimicrobial activity was good, especially against Salmonella enteritidis and Aspergillus niger strains. The high hepatoprotective, antioxidant and antimicrobial activity, along with polyphenol-rich content, can support the use of O. vulgare in therapy. We also expect our results to open new research directions for designing important new drug products, using indigenous plant material.

Radical Scavenging and Antioxidant Activity of Anthyllis Vulneraria Leaves and Flowers

The main targets of this work were to determine the phenolic content of Anthyllis vulneraria (A. vulneraria) leaves and flowers and to evaluate their antioxidant activity. Total polyphenols and flavonoid content (TPC and TFC, respectively) were determined. Antioxidant capacity was evaluated by the Ferric Reducing Antioxidant Power (FRAP), the Oxygen Radical Absorbance Capacity (ORAC), the Trolox Equivalent Antioxidant Capacity (TEAC) and the diphenyl picrylhydrazyl (DPPH) assays, and by the analysis of primary and secondary oxidation products in oil-in-water emulsions and in raw beef patties during storage. The results revealed that the flowers of the A. vulneraria contained the highest content of total polyphenols and flavonoids and extracts from these tissues exhibited the strongest antioxidant activity, as they were more effective at retarding lipid oxidation in oil-in-water emulsions and raw beef patties than extracts from the leaves which had a potent antioxidant effect only at the beginning of the oxidation process. The results of this study allowed us to obtain a deep knowledge about the properties of A. vulneraria and confirmed the possibility of using its biologically active extracts in the food, cosmetic and pharmaceutical industries.

Comparative Phytonutrient Analysis of Broccoli By-Products: The Potentials for Broccoli By-Product Utilization

The phytonutrient concentrations of broccoli (Brassica oleracea var. italica) florets, stems, and leaves were compared to evaluate the value of stem and leaf by-products as a source of valuable nutrients. Primary metabolites, including amino acids, organic acids, and sugars, as well as glucosinolates, carotenoids, chlorophylls, vitamins E and K, essential mineral elements, total phenolic content, antioxidant activity, and expression of glucosinolate biosynthesis and hydrolysis genes were quantified from the different broccoli tissues. Broccoli florets had higher concentrations of amino acids, glucoraphanin, and neoglucobrassicin compared to other tissues, whereas leaves were higher in carotenoids, chlorophylls, vitamins E and K, total phenolic content, and antioxidant activity. Leaves were also good sources of calcium and manganese compared to other tissues. Stems had the lowest nitrile formation from glucosinolate. Each tissue exhibited specific core gene expression profiles supporting glucosinolate metabolism, with different gene homologs expressed in florets, stems, and leaves, which suggests that tissue-specific pathways function to support primary and secondary metabolic pathways in broccoli. This comprehensive nutrient and bioactive compound profile represents a useful resource for the evaluation of broccoli by-product utilization in the human diet, and as feedstocks for bioactive compounds for industry.

Mineral and Phytochemical Profiles and Antioxidant Activity of Herbal Material from Two Temperate Astragalus Species

Only a few species of the large Astragalus genus, widely used for medicinal purposes, have been thoroughly studied for phytochemical composition. The aim of our research was to investigate the rarely studied species A. glycyphyllos L. and A. cicer L. for the distribution of mineral elements and phytochemicals in whole plants at two growth stages and in morphological fractions. We also investigated the capacity of the plant extracts to scavenge 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicals and to chelate ferrous ions. Chemical composition and antioxidant properties depended on species, maturity, and plant part. Herbal material of A. glycyphyllos was richer in Fe, total phenolics, and flavonoids, whereas extracts of A. cicer showed a higher antioxidant activity. Young plants had more isoflavones, showed greater quenching of DPPH radicals, and exhibited better mineral profiles than flowering plants. Among plant parts, leaves were the most valuable plant material according to most characteristics investigated. Isoflavone concentration in flowers was lower than in leaves and stems. None of the Astragalus samples contained detectable amounts of the alkaloid swainsonine. The study demonstrates the potential of plant material from two Astragalus species as a valuable source of iron, phenolic substances including isoflavones, free-radical scavengers, and Fe²⁺ chelators for pharmaceutical use.

Electrospun Phospholipid Fibers as Micro-Encapsulation and Antioxidant Matrices

Electrospun phospholipid (asolectin) microfibers were investigated as antioxidants and encapsulation matrices for curcumin and vanillin. These phospholipid microfibers exhibited antioxidant properties which increased after the encapsulation of both curcumin and vanillin. The total antioxidant capacity (TAC) and the total phenolic content (TPC) of curcumin/phospholipid and vanillin/phospholipid microfibers remained stable over time at different temperatures (refrigerated, ambient) and pressures (vacuum, ambient). ¹H-NMR confirmed the chemical stability of both encapsulated curcumin and vanillin within phospholipid fibers. Release studies in aqueous media revealed that the phenolic bioactives were released mainly due to swelling of the phospholipid fiber matrix over time. The above studies confirm the efficacy of electrospun phospholipid microfibers as encapsulation and antioxidant systems.

RP-HPLC/MS/MS Analysis of the Phenolic Compounds, Antioxidant and Antimicrobial Activities of Salvia L. Species

The identification and quantification of the phenolic contents of methanolic extracts of three Salvia L. species namely S. brachyantha (Bordz.) Pobed, S. aethiopis L., and S. microstegia Boiss. and Bal. were evaluated using reverse phase high performance liquid chromatography, UV adsorption, and mass spectrometry (RP-HPLC/MS). In order to determine the antioxidant capacity of these species, cupric ions (Cu²⁺) reducing assay (CUPRAC) and ferric ions (Fe³⁺) reducing assay (FRAP) were performed to screen the reducing capacity and 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay was employed for evaluation of the radical scavenging activity for both solvents. In further investigation, the antimicrobial activities of Salvia species were tested using the disc diffusion method against three Gram-positive and four Gram-negative microbial species, as well as three fungi species. The results showed that there is a total of 18 detectable phenols, the most abundant of which was kaempferol in S. microstegia and rosmarinic acids in S. brachyantha and S aethiopis. The other major phenols were found to be apigenin, luteolin, p-coumaric acid, and chlorogenic acid. All species tested showed moderate and lower antioxidant activity than standard antioxidants such as butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), and ascorbic acid. The ethanolic extracts of Salvia species revealed a wide range of antimicrobial activity. S. brachyantha and S. microstegia showed the highest antimicrobial activities against B. subtilis, whereas S. aethiopis was more effective on Y. lipolytica. None of the extracts showed anti-fungal activity against S. cerevisiae. Thus these species could be valuable due to their bioactive compounds.