Total phenolics, flavonoids and antioxidant activity of Saptarangi (Salacia chinensis L.) fruit pulp

Salacia chinensis L. has various beneficial properties including antidiabetic and antioxidant activity. The S. chinensis fruit pulp (SCFP) was extracted with four different solvents (Methanol, ethanol, acetone and water) and was screened for total phenolic content (TPC), total flavonoid content (TFC) and antioxidant activity (AOA). The AOA was assessed by evaluating the 1, 1-diphenyl-2-picrylhydrazyl (DPPH), ferric reducing antioxidant power (FRAP) and metal chelating assay. Methanolic SCFP extract exhibited the highest phenolic content (3.20?±?0.12 mg GAE/g FW) whereas, ethanolic extract showed highest flavonoid content (0.31?±?0.68 mg RE/g FW). The methanolic extract possesses highest antioxidant activity towards DPPH (92.44 %), FRAP (1.939 O.D) and metal chelating activity (74.16 %). AOA (DPPH and FRAP) was significantly correlated with TPC. The results indicated that SCFP is a good natural source of antioxidant compounds for use in food and pharmaceutical industry.     

Determination of phenolic compounds and diterpenes in roots of Salvia miltiorrhiza and Salvia przewalskii by two LC–MS tools: Multi-stage and high resolution tandem mass spectrometry with assessment of antioxidant capacity

Comparative phytochemical analyses of hydroalcoholic (50% EtOH) extracts from roots of S. miltiorrhiza (SM) and S. przewalskii (SP) were performed using two complementary LC–MS systems: the first system HPLC-DAD-MSⁿ an ion trap mass spectrometer and the second system consisted high resolution MS/MS Orbitrap mass spectrometer. The individual compounds were identified using a previously published approach via comparison of the exact molecular masses, mass spectra and retention times to those of standard compounds, online available databases and literature data. Moreover, the determination of antioxidative activities of extracts by DPPH and FRAP methods was carried out. Analysis allowed to identify 39 chemical compounds in extracts from both species. Extract from root of SP differs from SM in the presence of several metabolites such as: przewalskinic acid and their derivatives, przewaquinone C, przewaquinonate A, glycosides of rosmarinic acid, methyltanshinonate, whereas tanshinones, salvianolic acids and lithospermic acids occurred in both species. Moreover, it was shown that hydroalcoholic extract from roots of SM exerted stronger antioxidant properties in a FRAP test (max. 323.92 μM Fe²⁺/L) and in DPPH test (max. 78.64 nM TE) in comparison with SP extract.     

Phytochemical composition,antioxidant, in vitro and in silico studies of active compounds of Curculigo latifolia extracts as promising elastase inhibitor

Curculigo latifolia is a plant in the Hypoxidaceae family commonly used in herbal medicine. The study objective was to evaluate the antioxidant and anti-elastase properties of C. latifolia extracts in vitro and silico as a candidate for antiaging active ingredients. This study identified secondary metabolites of the hexane (HE), ethyl acetate (EAE), and ethanol extracts (EE) from the root (R), stem (S), and leaf (L) organs by LC-ESI-MS and evaluated in vitro antioxidant and inhibitor elastase activity. An antioxidant evaluation was performed using ABTS, Beta Carotene Bleaching (BCB), and Ferric Reduction Antioxidant Power (FRAP). Evaluation of anti-elastase was carried out using elastase and followed by an in silico study of molecular docking using the target protein elastase (1B0F). Fifteen C. latifolia metabolites were identified in C. latifolia extracts, most of which were phenolic compounds. In antioxidant testing, REE, REAE, SEE, and SEAE extracts showed potent antioxidant activity based on the ABTS, BCB, and FRAP methods. In anti-elastase testing, it was found that SEE, REE, REAE, and RHE extracts gave powerful inhibition of elastase activity (in the ranges of 16.89 to 27.91 µg/mL). The in-silico study demonstrated the potential of the identified metabolites to bind to the target protein 1B0F involved in remodeling the skin aging process. This research concludes that the extracts from C. latifolia have the potential to serve as an active antiaging source.     

In vitro antioxidant activity and phenolic contents in methanol extracts from medicinal plants

Antioxidant activities and phenolic contents of 26 species extracts from 20 botanical families grown in north-western Himalaya were investigated. Antioxidant activities were determined using DPPH (1,1-diphenyl-2-picrylhydrazyl) radical scavenging and ferric reducing antioxidant power (FRAP) assays. Total phenolic content (TPC) was determined using a Folin-Ciocalteu assay. Quantitative and qualitative analysis of phenolic compounds was also carried out by reverse phase high performance liquid chromatography (RP-HPLC) using diode array detector (DAD). Major phenolics determined using RP-HPLC in analyzed species were gallic acid, chlorogenic acid, p-hydroxy benzoic acid, caffeic acid, vanillic acid, syringic acid, p-coumaric acid and ferulic acid. Antiradical efficiency (1/EC₅₀) determined using DPPH radical scavenging assay ranged from 0.13 to 5.46. FRAP values ranged from 8.66 to 380.9 μmol Fe(II)/g dw. Similarly, the total phenolic content in the analyzed species varied from 3.01 to 69.96 mg of gallic acid equivalents (GAE)/g dry weight. Gallic acid was found in the majority of the samples, being most abundant compound in Syzygium cumini bark (92.64 mg/100 g dw). Vanillic acid was the predominant phenolic compound in Picrorhiza kurroa root stolen (161.2 mg/100 g dry weight). The medicinal plants with highest antioxidant activities were Taxus baccata and Syzygium cumini. A significant positive correlation, R ²?=?0.9461 and R ²?=?0.9112 was observed between TPC determined using Folin-Ciocalteu method and antiradical efficiency and FRAP values respectively, indicating that phenolic compounds are the major contributor of antioxidant activity of these medicinal plants.     

Phytochemical Content,Antidiabetic, Anticholinergic,and Antioxidant Activities of Endemic Lecokia cretica Extracts

The aim of this work was to investigate the enzyme inhibition, antioxidant activity, and phenolic compounds of Lecokia cretica (Lam .) DC. Acetylcholinesterase (AChE), butyrylcholinesterase (BChE), and α‐glycosidase enzymes were strongly inhibited by the L. cretica extracts. IC₅₀ values for the three enzymes were found as 3.21 mg/mL, 2.1 mg/mL, and 2.07 mg/mL, respectively. Antioxidant activities were examined in both aqueous and ethanol (EtOH) extracts using CUPRAC, FRAP, and DPPH method. Also, the phenolic compounds of the endemic plant were identified and quantified by using HPLC/MS/MS. According to the results, the extracts have remarkable antioxidant activities. The most abundant phenolic acids of L. cretica in EtOH extract were determined as quinic acid (12.76 mg/kg of crude extract), chlorogenic acid (3.39 mg/kg), and malic acid (2.38 mg/kg).     

Phytochemicals,antioxidant, antimicrobial and phytotoxic activities of Ailanthus altissima (Mill.) Swingle leaves

A comprehensive study on the volatile oil and phenolic constituents of Ailanthus altissima Swingle (Simaroubaceae) leaves was performed. Methanolic extracts of leaves and their hydrodistilled residues were screened for their antioxidant, antimicrobial and phytotoxic properties. The results showed that the leaf volatile oils were a complex mixture of more than a hundred components, mainly composed by non-terpenic compounds (tetradecanol, heneicosane, tricosane and docosane) and sesquiterpene hydrocarbons (α-curcumene and α-gurjunene). Methanolic extracts from leaves contain the highest level of total phenolic content, while those from the hydrodistilled residues showed the highest total flavonoid content. The most frequent phenolic compounds identified by HPLC-DAD–MS were gallic acid, chlorogenic acid, HHDP-galloylglucose, epicatechin, rutin, hyperoside and quercetin-3-galloyl hexoside. Evaluation of the antioxidant activities by using four complementary tests (DPPH, ABTS, 2-deoxyribose and FRAP) showed that both extracts exhibited strong concentration-dependent antioxidant activities. These extracts were efficient against Gram-positive bacteria, but not active against Gram-negative bacterial strains and the yeast Candida albicans. They also exhibited strong inhibitory effects on the germination and the radicle growth of the wild Daucus carota. This work provides scientific supports for the high antioxidant and phytotoxic activities of this species and thus, it may find potential applications in the development of natural herbicides and antioxidants for agro-food and pharmaceutical industries.     

Evaluation of antioxidant and antibacterial activity of methanolic extracts of Gentiana kurroo royle

In this study our objective was to evaluate the antioxidant and antimicrobial activity of methanolic extracts of leaves and roots of Gentiana kurroo. The antioxidant activities of the extracts were examined using different biochemical assays namely diphenylpicrylhydrazyl (DPPH), nitroblue tetrazolium (NBT) and ferric reducing power (FRAP). In all the assays, root extract exhibited stronger antioxidant activity than that of leaves. The antibacterial activity of the extracts was also evaluated and MIC values were calculated by broth dilution method. Although, the extracts prevented the growth of both Gram positive and Gram negative bacteria, the MIC values of methanolic extract of the leaves were higher than those of the root extract. The antibacterial and antioxidant activity of the extracts was found to be positively associated with the total phenolic and flavonoid content of the extracts.     

Salt stress enhanced antioxidant response in callus of three halophytes (Salsola baryosma, Trianthema triquetra, Zygophyllum simplex) of Thar Desert

Effects of salinity on growth, protein content, proline, catalase and antioxidant enzyme activity in callus of three halophytes of the Thar Desert; Salsola baryosma, Trianthema triquetra and Zygophyllum simplex were evaluated. Callus tissues were cultured on Murashige and Skoog’s medium containing different concentrations of NaCl (50, 100 and 200 mM). Increase in dry weight and soluble proteins were observed in the callus exposed to lower salinity (50 and 100 mM NaCl) in all the three species, whereas on the medium containing 200 mM NaCl, significant decrease in these two growth parameters was recorded. Under the salinity stress maximum proline accumulation was found in S. baryosma with parallel increase in soluble sugars. Among the three species, T. triquetra callus showed maximum CAT activity with 50 and 100 mM NaCl treatment, whereas the enzyme activity decreased at 200 mM NaCl treatment in all three species. The antioxidant potential steadily elevated under salt treatment in all the above three species using 1, 1-diphenyl-2-picrylhydrazyl (DPPH) and ferric reducing antioxidant potential (FRAP) assay. Whereas, superoxide dismutase (SOD) quenching were recorded maximum at low (50 and 100 mM) concentrations in all the three species. However, T. triquetra callus showed maximum total phenolic content (TPC) 15 mg GAE g^?1 with the elevated concentration of NaCl up to 200 mM, and S. baryosma callus showed lower TPC as compared to both species. A significant correlation between antioxidant capacity and TPC was observed indicating that phenolic compounds are the major contributors to the antioxidant potential in these halophyte species. FRAP and DPPH activity of Z. simplex showed maximum correlation (R = 0.992), as compared to other two species. We can conclude that all the three species exhibit a protection mechanism by sustaining growth parameters and antioxidant capacity. Due to high antioxidant property of all these species, the plant extracts may be included in nutraceutical formulations.     

Antioxidant activities of different parts of Gnetum gnemon L.

Analyses on biological activities of Gnetum gnemon were done to determine the total phenolic and antioxidants of the plant. Four parts of G. gnemon were used in this study, which were leaf, bark, twig, and seeds of the plant. All parts were extracted in methanol, ethanol, hexane, chloroform and hot water using reflux. The total phenolic content of the plant extracts were determined by using Folin-Ciocalteu method. The results demonstrated that the bark from hot water extract showed the highest total phenolic at 10.71?±?0.01 mg GAE/ FDW, while the lowest was chloroform extract of seed at 2.15?±?0.01 mg GAE/ FDW. The antioxidant activity of the plant extracts were determined by using DPPH and FRAP assays, respectively. The DPPH results showed that all plant extracts demonstrated weak free radical scavenging activity tested at the final concentration of 300 μg/ml. In contrast, the methanolic twig extract showed strong reducing power activity (FRAP) at 83.55?±?1.05%, while the hot water seed extract showed the least activity at 41.86?±?4.22% tested at the final concentration of 300 μg/ml. However, there were no correlation between total phenolics and both antioxidant assays tested.     

Phytochemical Profile and Nutraceutical Value of Old and Modern Common Wheat Cultivars

Among health-promoting phytochemicals in whole grains, phenolic compounds have gained attention as they have strong antioxidant properties and can protect against many degenerative diseases. Aim of this study was to profile grain phenolic extracts of one modern and five old common wheat (Triticum aestivum L.) varieties and to evaluate their potential antiproliferative or cytoprotective effect in different cell culture systems.Wheat extracts were characterized in terms of antioxidant activity and phenolic composition (HPLC/ESI-TOF-MS profile, polyphenol and flavonoid contents). Results showed that antioxidant activity (FRAP and DPPH) is mostly influenced by flavonoid (both bound and free) content and by the ratio flavonoids/polyphenols. Using a leukemic cell line, HL60, and primary cultures of neonatal rat cardiomyocytes, the potential antiproliferative or cytoprotective effects of different wheat genotypes were evaluated in terms of intracellular reactive oxygen species levels and cell viability. All tested wheat phenolic extracts exerted dose-dependent cytoprotective and antiproliferative effects on cardiomyocytes and HL60 cells, respectively. Due to the peculiar phenolic pattern of each wheat variety, a significant genotype effect was highlighted. On the whole, the most relevant scavenging effect was found for the old variety Verna. No significant differences in terms of anti-proliferative activities among wheat genotypes was observed. Results reported in this study evidenced a correspondence between the in vitro antioxidant activity and potential healthy properties of different extracts. This suggests that an increased intake of wheat grain derived products could represent an effective strategy to achieve both chemoprevention and protection against oxidative stress related diseases.     

Evaluation of antioxidant and anticancer activities of chemical constituents of the Saururus chinensis root extracts

Evaluation of antioxidant and anticancer activities were screened by various Saururus chinensis root extracts. Four solvents (ethyl acetate, methanol, ethanol, and water) extracts were investigated for their total flavonoids, phenol contents and their antioxidant activity of DPPH (2,2-diphenyl-1-picrylhydrazyl), NO (nitric oxide), H₂O₂ (hydrogen peroxide), ABTS 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonicacid)diammonium assays, FRAP (ferric reducing ability of plasma) assays and anticancer activity. The total phenolic and flavonoid content of extracts were determined by using FC (Folin–Ciocalteu) and AlCl₃ colorimetric assay method. Total flavonoid content in these plants ranged from 24.7 to 72.1 mg g^?1 and amount of free phenolic compounds was between 11.2 and 67.1 mg g^?1 extract. The all extracts have significant levels of phenolics and flavonoids content. Anticancer activity was screened for MCF-7 breast cancer cell line. Ethanol extract shows significant of antioxidant activity and water extract shows significant of anticancer activity compared with standard (BHT) butylated hydroxy toluene. These ethanol and water extracts could be considered as a natural source for using antioxidant, and anticancer agents compared to commercial available synthetic drugs.     

Variation in phenolic compounds and antioxidant activity in apple seeds of seven cultivars

Polyphenols are the predominant ingredients in apple seeds. However, few data are available on the phenolic profile or antioxidant activity in apple seeds in previous researches. In this study, low-molecular-weight phenolic compounds and antioxidant activity in seeds, peels, and flesh of seven apple cultivars grown in northwest China were measured and analyzed using HPLC and FRAP, DPPH, ABTS assays, respectively. HPLC analysis revealed phloridzin as the dominant phenolic compound in the seeds with its contents being 240.45–864.42 mg/100 gDW. Total phenolic content (TPC) measured by the Folin–Ciocalteu assay in apple seed extracts of seven cultivars ranged from 5.74 (Golden Delicious) to 17.44 (Honeycrisp) mgGAE/gDW. Apple seeds showed higher antioxidant activity than peels or flesh; antioxidant activity in seeds varied from 57.59 to 397.70 μM Trolox equivalents (TE)/g FW for FRAP, from 37.56 to 64.31 μM TE/g FW for DPPH, and from 220.52 to 708.02 μM TE/g FW for ABTS. TPC in apple seeds was significantly correlated with all three assays. Principal component analysis (PCA) indicated that Honeycrisp was characterized with high contents of total polyphenols and phloridzin. Our findings suggest that phenolic extracts from apple seeds have good commercial potential as a promising antioxidant for use in food or cosmetics.     

Total phenolics,flavonoids and antioxidant properties of three Ceropegia species from Western Ghats of India

The aim of present work was to assess the total phenolic content (TPC), total flavonoid content (TFC), phenolic compounds and antioxidant properties of various extracts of three Ceropegia spp.: Ceropegia spiralis, Ceropegia panchganiensis and Ceropegia evansii from Western Ghats of India. TPC of the samples varied from 0.3 ± 0.2 to 28.5 ± 0.3 mg TAE/g FW, whereas, TFC of the samples ranged between 0.1 ± 0.1 and 15.3 ± 0.3 mg RE/g FW. The major phenolic compounds identified were gallic acid, vanillin, cathechol and ferulic acid. All the extracts possess 1,1-diphenyl-2-picryl hydrazyl (DPPH) radical scavenging activity, ferric reducing antioxidant power (FRAP) as well as metal chelating ability and this was also supported by significant correlation with TPC and TFC. To the best of our knowledge, this is the first paper presenting comprehensive data on TPC, TFC, phenolic profile and antioxidant properties of the Ceropegia spp.     

Antioxidant and antibacterial capacity of stingless bee honey from Borneo (Sarawak)

Stingless honey bees form a large group of bees that lack of a sting and are found among Meliponinae species indigenous to various tropical and subtropical regions. They are able to produce “stingless bee honey” that contains divergent categories of phenolic and flavonoid compounds and have been associated with antioxidant and antibacterial activity. This study examines the physicochemical properties, antioxidant-activity and anti-microbial activity of stingless bee honey from Malaysia that was produced by Geniotrigona thoracica, Heterotrigona itama and Heterotrigona erythrogastra. The results show that G. thoracica honey has the highest concentration of the total phenolic context (99.04?±?5.14?mg/ml) and the greatest reducing power (19.05?±?0.79%), while flavonoids (17.67?±?0.75?mg/ml), reducing power (18.10?±?0.35%), DPPH (47.40?±?3.18%) and FRAP (50.66?±?5.77?mM of Fe²⁺/100?g) of H. itama honey is significantly higher than those of the other honeys. In addition, G. thoracica honey has the highest antibacterial activity against Staphylococcus xylosus (2.10?±?0.10?cm), which is Gram-positive bacterium, and against Pseudomonas aeruginosa (1.60?±?0.10?cm) and Vibrio parahaemolyticus (2.03?±?0.06?cm), which are Gram-negative bacteria. These results suggest that stingless bee honeys possess useful amounts of phenolic and flavonoid compounds that are able to act as natural anti-oxidants and also have significant anti-microbial activity.     

Phenolic Compounds and Allelopathic Potential of Fermented and Unfermented Wheat and Corn Straw Extracts

Total phenolic (TPC) and flavonoid (TFC) content, individual phenolic compounds and antioxidant activities of methanol extracts of wheat and corn straw were determined. Germination bioassay was conducted with Abutilon theophrasti Medik. , Asclepias syriaca L., and Chenopodium album L. seed. Samples were fermented by Lactobacillus plantarum and changes in TPC, TFC, antioxidant, and biological activity were investigated. TPC and TFC were significant in both samples and after fermentation their recovery was improved. All samples contain mainly quercetin, cinnamic acid, p‐coumaric acid, and ferulic acid. Fermentation changed the content of phenolic and flavonoid compounds, differently in each case. All tested extracts showed high DPPH activity with IC₅₀ being significantly lower for fermented samples. FRAP activity was also high. Crude straw extracts were overall more effective than fermented ones concerning inhibition of germination and seedlings growth, mainly without statistically significant differences between wheat and corn. Compared with mesotrione, extracts were more effective in germination and seedling growth inhibition of C. album and in seedling growth inhibition of A. theophrasti.     

Phytochemical analysis,antioxidant and antimicrobial activity of wild and in vitro derived plants of Ceropegia thwaitesii Hook – An endemic species from Western Ghats,India

Ceropegia thwaitesii Hook (Asclepiadaceae), an endemic plant species, due to habitat destruction and over exploitation has a very restricted distribution in the Western Ghats of Tamil Nadu, India. The present wrok aimed to determine the chemical composition, the total phenolic (TPC), flavonoid (TFC) and tannin content (TEC), and to assess the antioxidant properties of various extracts of in vivo plants (IVP) and in vitro regenerated plants (IRP) of C. thwaitesii. Some phenolic compounds like gallic acid, cathechol, vanillin and salicylic acid were identified and quantified by HPLC. All the extracts possessed relevant radical scavenging activity on DPPH, Superoxide radical scavenging activity, and Nitric oxide radicals as well as total antioxidant ability. DPPH assay of in vitro methanol stems extracts and ethanol leaves extracts revealed the best antioxidant properties with important IC₅₀ values of 0.248?±?0.45?µg/mL and 0.397?±?0.67?µg/mL, respectively, whereas in vivo chloroform stems extracts showed a lower antioxidant activity (IC₅₀ of 10.99?±?0.24?µg/mL). The IRP methanol extracts of stem and leaves had good inhibitory activity against all tested microorganisms in a dose-dependent manner. These results suggested that in vitro raised plants of C. thwaitesii are an excellent source of antioxidant compounds to be exploited on an industrial level as food additive.     

Evaluation of Garlic Cultivars for Polyphenolic Content and Antioxidant Properties

Two phenolic compound parameters (total phenolic and flavonoid contents) and 5 antioxidant parameters (DPPH [2, 2-diphenyl-1-picrylhydrazyl] radical scavenging activity, HRSC (hydroxyl radical scavenging capacity), FRAP (ferric ion reducing antioxidant power), CUPRAC (cupric ion reducing antioxidant capacity), and MCA (metal chelating activity) were measured in bulbs and bolts of 43 garlic cultivars. The bulbs of cultivar ‘74-x’ had the highest phenolic content (total phenolic, flavonoids) and the strongest antioxidant capacity (DPPH, FRAP, and CUPRAC), followed by bulbs of cultivar ‘Hanzhong purple’; the bulbs of cultivar ‘Gailiang’ had the lowest phenolic content and antioxidant capacity (FRAP, CUPRAC, MCA). The bolts of ‘Hanzhong purple’ also had higher phenolic content. Principal components analysis (PCA) separated the cultivars into 3 groups according to phenolic and flavonoid contents and strength of antioxidant activity. The first group had higher HRSC, FRAP, and flavonoid content; the second group had higher total phenolic content and MCA; some cultivars in the third group had higher HRSC and FRAP. All 8 test garlic bulb extracts successfully prevented Human Vascular Endothelial Cell death and significantly prevented reactive-oxygen species (ROS) formation in oxidative stress model, in which cultivar ‘74-x’ had highest protection capability, following by cultivar ‘Hanzhong purple’, and the bulbs of cultivar ‘No. 105 from Korea’ had the lower protection capability against cell death and ROS formation. The protection capability in vivo of these garlic cultivars was consistent with their phenolic content and antioxidant capacity.     

Fingerprint and relationship composition-antioxidant activity of the essential oil of Saccocalyx satureioides Coss. & Dur

Saccocalyx satureioides Coss. & Dur. is an endemic Algerian plant species growing in pre-desert area. The aerial parts are commonly used in the folk medicine. The fingerprint of the aerial part of S. satureioides essential oil (EO) collected periodically at different growing stages was established by GC and GC/MS analyses. Besides, the seasonal variations of the EO components were also investigated. In order to highlight the effect of seasonal variation/variability of the EO composition on the fingerprint pattern, chemometrics methods including principal component analysis (PCA) and heatmap associated with hierarchical clustering analysis (HCA) were applied. The antioxidant activity of the EO was measured using 2,2-diphenyl-1-picrylhydrazyl (DPPH) and ferric reducing antioxidant power (FRAP) assays. The relationship between GC fingerprint and antioxidant activity named spectrum-effect relationship was investigated by partial least squares (PLS) regression. The EO fingerprint was essentially marked by the three major oxygenated monoterpenes which were α-terpineol (34.48–42.43%), borneol (15.24–23.37%) and thymol (19.27–26.96%). Successfully, multivariate models were developed to relate the antioxidant activities responses to the EO chemical composition.     

Caesalpinia palmeri: First Report on the Phenolic Compounds Profile,Antioxidant and Cytotoxicity Effect

This study aimed to determine the phenolic compounds profile, antioxidant potential and cytotoxicity of extracts and fractions of Caesalpinia palmeri. Methanolic extracts were generated from C. palmeri berries, stems and flowers. The latter was subjected to liquid-liquid partition, obtaining hexane, ethyl acetate and residues fractions. Results showed that the flower extract and ethyl acetate fraction had a larger concentration of phenolic compounds (148.9 and 307.9 mg GAE/g, respectively), being ellagic acid (6233.57 and 19550.08 μg/g, respectively), quercetin-3-β-glycoside (3023.85 and 8952.55 μg/g, respectively) and gallic acid (2212.98 and 8422.34 μg/g, respectively) the most abundant compounds. Flower extract and ethyl acetate fraction also presented the highest antioxidant capacity on all tested methods (DPPH, ABTS, ORAC and FRAP) and low cytotoxicity against ARPE-19 cells (IC₅₀ >170 μg/mL). C. palmeri possessed high antioxidant potential, associated with the presence of phenolic compounds and low cytotoxicity, suggesting that they could represent an option to counter oxidative stress.     

Seasonal variations of phenolic compounds and biological properties in sage (Salvia officinalis L.)

The aim was to investigate the phenolic content, antioxidant capacity, and antibacterial activity of Dalmatian sage (Salvia officinalis L.) leaves collected during different vegetation periods. Separation and quantification of the individual phenols were performed by reversed-phase (RP)-HPLC coupled with a PDA (photodiode array) detector and using an internal standard, while the contents of total phenols, flavonoids, flavones, and flavonols were determined spectrophotometrically. The antioxidant properties of the sage leaf extracts were evaluated using five different antioxidant assays (FRAP, DPPH, ABTS, Briggs-Rauscher reaction, and β-carotene bleaching). The antimicrobial activity of the extracts was tested against two Gram-positive (Bacillus cereus and Staphylococcus aureus) and two Gram-negative (Salmonella Infantis and Escherichia coli) bacterial reference strains. All extracts were extremely rich in phenolic compounds, and provided good antioxidant and antibacterial properties, but the phenophase in which the leaves were collected affected the phenolic composition of the sage extracts and consequently their biological activity. The May Extract, the richest in total flavonoids, showed the best antioxidant properties and the highest antimicrobial activity. Thus, collection of the plants during May seems the best choice for further use of them in the pharmaceutical and food industry.