Chemical composition and antioxidant activities of Myrtus communis L. berries extracts

Myrtle (Myrtus communis L.) berries extracts were prepared with solvents at different polarity (water, ethanol, and ethyl acetate) and analysed using different in vitro tests in order to evaluate their antioxidant properties. Antiradical and total antioxidant activities were measured with DPPH and FRAP tests, respectively. Their ability to protect biological molecules was assessed using the cholesterol and LDL oxidation assays. In addition, phenolic compounds and unsaturated fatty acids composition was analysed by HPLC–DAD and HPLC–MS/MS. Ethanol and water extracts showed the highest amount of extracted compounds, but the highest antiradical and antioxidant activities were found in ethanol and ethyl acetate extracts. These extracts were also the ones with the highest content of phenolic compounds. In addition, our results showed a highly significant correlation between the amount of total phenols and antiradical (R² = 0.9993) or antioxidant activities (R² = 0.9985) in these extracts. HPLC–DAD and HPLC–MS analyses showed significant quantitative and qualitative differences among these three extracts. The ethyl acetate extract had the highest protective effect in assays of thermal (140 °C) cholesterol degradation and Cu²⁺-mediated LDL oxidation, inhibiting the reduction of polyunsaturated fatty acids and cholesterol, and the increase of their oxidative products. These results suggest that because of these properties, myrtle berries could be used in dietary supplements preparations or as food additives.     

Comprehensive analysis of Phyteuma orbiculare L., a wild Alpine food plant

Plants which have been traditionally eaten by the alpine population may provide new opportunities for agricultural development in mountain regions. In this context we have investigated the chemical composition of Phyteuma orbiculare (Campanulaceae), a perennial herb whose leaves have been eaten as salad by rural populations in Valais (Switzerland). Extracts of different polarities were subjected to comprehensive metabolite profiling using a dereplication platform combining HPLC–PDA-MS, and offline NMR analysis. Twenty-three compounds, including various phenolic glycosides, a new dimeric phenylpropanoid glucoside, saponins, and fatty acids were identified online, or after targeted isolation. Selected phenolic constituents were quantitatively assessed by HPLC–PDA analysis. In addition, substances relevant for nutrition, such as β-carotene, fatty acids, ascorbic acid and minerals were quantified in leaves and flowers. The antioxidant capacity was determined with an ORAC assay, and total phenolic compounds were quantified. Finally, the phytochemical profile was compared to that of the related species P. spicatum, P. hemisphaericum and P. ovatum.     

Chemical and antioxidative assessment of dietary turnip (Brassica rapa var. rapa L.)

The phenolic compounds and organic acids of turnip (Brassica rapa var. rapa L.) edible parts (leaves and stems, flower buds and roots) were determined by HPLC–DAD and HPLC–UV, respectively. The results revealed a profile composed of 14 phenolics (3-p-coumaroylquinic, caffeic, ferulic and sinapic acids, kaempferol 3-O-sophoroside-7-O-glucoside, kaempferol 3-O-sophoroside-7-O-sophoroside, kaempferol 3-O-(feruloyl/caffeoyl)-sophoroside-7-O-glucoside, kaempferol 3,7-O-diglucoside, isorhamnetin 3,7-O-diglucoside, kaempferol 3-O-sophoroside, 1,2-disinapoylgentiobiose, 1,2′-disinapoyl-2-feruloylgentiobiose, kaempferol 3-O-glucoside and isorhamnetin 3-O-glucoside) and six organic acids (aconitic, citric, ketoglutaric, malic, shikimic and fumaric acids). The quantification of the identified compounds showed kaempferol 3-O-sophoroside-7-O-glucoside, kaempferol 3-O-(feruloyl/caffeoyl)-sophoroside-7-O-glucoside, isorhamnetin 3,7-O-diglucoside and isorhamnetin 3-O-glucoside as the main phenolics, and malic acid as the organic acid present in highest amounts. A screening of the antioxidative potential was also performed by means of the DPPH radical scavenging assay. Turnip flower buds exhibited the strongest antioxidant capacity.     

Phenolic composition and biological activities of Salvia halophila and Salvia virgata from Turkey

The aerial parts of Salvia halophila and Salvia virgata were subjected to Soxhlet extraction with different solvents such as n-hexane, ethyl acetate, methanol, and aqueous methanol (50%). Plants were also extracted with water under reflux. The effects of the extracts were studied in p-benzoquinone-induced abdominal constriction test for the assessment of antinociceptive activity and carrageenan-induced hind paw edema and 12-O-tetradecanoyl-13-acetate (TPA)-induced ear edema models in mice for the anti-inflammatory activity. The extracts were analysed using a HPLC–PDA method. Results showed that methanol extract of S. virgata significantly inhibited carrageenan-induced paw edema and p-benzoquinone-induced abdominal constriction at 100 mg/kg dose, while it showed no effect in the TPA-induced ear edema. On the other hand, the other extracts did not show any inhibitory antinociceptive and anti-inflammatory activities in these in vivo models. Rosmarinic acid was found as main constituent in the extracts, while caffeic acid and luteolin derivatives were also detected.     

Comparative analyses of seeds of wild fruits of Rubus and Sambucus species from Southern Italy: Fatty acid composition of the oil,total phenolic content,antioxidant and anti-inflammatory properties of the methanolic extracts

Fruit seeds are byproducts from fruit processing. Characterisation of the bioactive compounds present in seeds and evaluation of their potential biological properties is therefore of particular importance in view of a possible valorisation of seeds as a source of health beneficial components. In this work, we have analysed the seeds of Sambucus and Rubus species in order to identify their bioactive components and to determine the antioxidant and anti-inflammatory activities of the extracts. We first analysed their oil content, in order to assess the fatty acid profile and tocopherol content. Moreover, the methanolic extracts of the seeds were analysed for their total phenolic contents and antioxidant capacities. Polyphenols were identified by HPLC–ESI–MS/MS analysis. Furthermore, extracts were evaluated for their inhibitory effects on the production of LPS-induced inflammatory mediators (NO, CCL-20) in RAW 264.7 cells.     

Antioxidant activity and phenolic composition of sumac (Rhus coriaria L.) extracts

Antioxidant activity and phenolic compounds of sumac extracts were investigated. Sumac was extracted in methanol and subjected to solvent–solvent partitioning to yield two fractions as ethyl acetate and aqueous. Methanol extract was further fractioned over Sephadex LH-20 column. Antioxidant activity of extracts and fractions were screened using ferric thiocyanate and DPPH radical scavenging methods. Phenolic composition of active fraction(s) was determined by HPLC–MS systems. Those fractions which exhibited strong antioxidant activity were rich in anthocyanins and hydrolysable tannins. While gallic acid was the main phenolic acid in the extracts, anthocyanin fraction contained cyanidin, peonidin, pelargonidin, petunidin, and delphinidin glucosides and coumarates. Pentagalloyl glucose was abundant in the hydrolysable tannin fraction. Effective scavenging concentration (EC₅₀) on DPPH radical was 0.70 μg/mL both in ethyl acetate and tannin fractions, and 5.33 μg/mL in anthocyanin rich fraction. Same extracts and fractions showed moderate lipid peroxidation inhibition effect compared with the synthetic antioxidants. The findings demonstrate that sumac can be used as a natural antioxidant.     

Studies on the antioxidant potential of flavones of Allium vineale isolated from its water-soluble fraction

The aim of this work was to examine the chemical constituents and antioxidant potential of water-soluble fractions from the commonly consumed vegetable, Allium vineale. The water-soluble fraction, containing phenolic compounds, was extracted with ethyl acetate to obtain flavonoids which were separated and purified by repeated column chromatography over Sephadex LH-20, RP C18 and silica gel. The isolated compounds were identified according to their physicochemical properties and spectral data (UV, HPLC–TOF/MS, ¹H NMR, ¹³C NMR and 2D NMR). Three flavonoids were isolated and identified as chrysoeriol-7-O-[2″-O-E-feruloyl]-β-d-glucoside (1), chrysoeriol (2), and isorhamnetin-3-β-d-glucoside (3). Antioxidant studies of the aqueous extract and three isolated compounds, 1, 2, 3, were undertaken and they were found to have significant antioxidant activity. Antioxidant activities were evaluated for total antioxidant activity by the ferric thiocyanate method, ferric ion (Fe³⁺) reducing antioxidant power assay (FRAP), ferrous ion (Fe²⁺) metal chelating activity, and DPPH free radical-scavenging activity. The water-soluble ethyl acetate and methanol extraction methods were also compared using HPLC–TOF/MS.     

Antioxidant activity and total phenolic content of Agaricus brasiliensis (Agaricus blazei Murril) in two stages of maturity

The antioxidant capability and total phenolic contents of methanolic extracts of Agaricusbrasiliensis in two stages of maturity, young (YB) and mature (MB), were evaluated in this work. Four complementary assays, reducing power, radical scavenging capacity, inhibition of lipid peroxidation and chelating ability for ferrous ions were used to screen the antioxidant properties of extracts. Minor differences in the composition of phenolic compounds were detected, but the extracts showed similar antioxidant activities, except for the chelating ability for ferrous ions, higher in MB than in YB. Our results support the use of both young and mature fruiting bodies of Agaricus blazei as sources of antioxidant compounds.     

Antioxidant activity and chemical constituents of essential oil and extracts of Rhizoma Homalomenae

Antioxidant activity and composition of essential oil and extracts of Rhizoma Homalomenae were determined. The extracts, especially the ethyl acetate extract (QJ4 fraction) of the aqueous residue after oil distillation, had considerable antioxidant potency which was significantly associated with their total phenolic and flavonoid contents, but the essential oil showed only weak or moderate activity. GC–MS analysis of the essential oil (yield: 0.82%, v/w) resulted in the identification of 77 compounds, accounting for 96.5% of the content of the oil. The major components, epi-α-cadinol (14.8%), α-cadinol (14.8%), α-terpineol (13.8%), linalool (11.1%), terpinen-4-ol (4.92%), and δ-cadinene (4.91%) constituted 64.3% of it. LC–MS/MS and HPLC analyses showed seven phenolic compounds (protocatechuic acid, vanillic acid, syringic acid, caffeic acid, p-coumaric acid, ferulic acid and apigenin) with a great amount in the ethyl acetate extract (QJ4 fraction). The strong antioxidant properties of the plant extracts may be attributed to the presence of these phenolics.     

Antioxidant capacity and hydrophilic phytochemicals in commercially grown native Australian fruits

Hydrophilic phytochemicals and antioxidant capacities of eight commercially grown native Australian fruits were determined. Kakadu plum (Terminalia ferdinandiana) contained a 6-fold higher level of total phenolic compounds and quandong (Santalum acuminatum) a 1.9-fold higher level of total phenolic compounds (TP, Folin–Ciocalteu assay) than blueberry (Vaccinum sp., cv. Biloxi). Both fruits displayed superior oxygen radical-scavenging capacity (ORAC-H assay) that was, respectively 4.1-fold and 6.5-fold of that of blueberry. The total reducing capacity (TRC; ferric reducing antioxidant power (FRAP) assay) of Kakadu plum and quandong exceeded the TRC of blueberry, respectively, 13.1- and 2.3-times. The primary sources of antioxidant capacities in the evaluated fruits were phenolic acids (benzoic and cinnamic) and flavonoids (flavonols, flavanones and anthocyanins) tentatively detected by liquid chromatography–mass spectrometry (LC–PDA–MS/MS). A high level of vitamin C was recorded for Kakadu plum and Australian citrus fruits. The major organic acids detected were citric and malic acid.     

Phytochemical profiles and inhibitory effect on free radical-induced human erythrocyte damage of Dracaena draco leaf: A potential novel antioxidant agent

The present study reports for the first time the metabolite profile and antioxidant activity of aqueous extract obtained from Dracaena draco L. leaf. Volatiles profile was determined by HS-SPME/GC-IT-MS, with 34 compounds being identified, distributed by distinct chemical classes: 2 alcohols, 5 aldehydes, 16 carotenoid derivatives and 8 terpenic compounds. Carotenoid derivative compounds constituted the most abundant class in leaf (representing 45% of total identified compounds). Phenolics profile was determined by HPLC/DAD and 9 constituents were identified: 2 hydroxycinnamic acid derivatives – 5-O-caffeoylquinic and 3,5-O-dicaffeoylquinic acids; 4 hydroxycinnamic acids – caffeic, p-coumaric, ferulic and sinapic acids and 3 flavonol glycosides – quercetin-3-O-rutinoside, kaempferol-3-O-glucoside and kaempferol-3-O-rutinoside. The most abundant phenolic compound is quercetin-3-O-rutinoside (representing 50.2% of total polyphenols). Organic acids composition was also characterised, by HPLC–UV and oxalic, citric, malic and fumaric acids were determined. Oxalic and citric acids were present in higher amounts (representing 47%, each). The antioxidant potential of this material was assessed by the ability to protect against free radical-induced biomembrane damage, using human erythrocyte as in vitro model. Leaf extract strongly protected the erythrocyte membrane from haemolysis (IC₅₀ of 39 ± 11 μg/ml), in a time- and concentration-dependent manner. This is the first report showing that D. draco leaf is a promising antioxidant agent.     

Analysis of phenolic compounds in cork from Quercus suber L. by HPLC–DAD/ESI–MS

The aim of the present work was to identify the extractable phenolic compounds present in cork from Quercus suber L. The structures of thirty three compounds were tentatively identified by liquid chromatography coupled to electrospray ionisation mass spectrometry (HPLC–DAD/ESI–MS). The majority of those compounds were gallic acid derivatives, in the form of either galloyl esters of glucose (gallotannins), combinations of galloyl and hexahydroxydiphenoyl esters of glucose (ellagitannins), dehydrated tergallic-C-glucosides or ellagic acid derivatives. Others were found to correspond to low molecular weight phenolic compounds, like acids and aldehydes. Mongolicain, a flavanoellagitannin in which hydrolysable tannin and flavan-3-ol moieties are connected through a carbon–carbon linkage, was also detected in cork from Q. suber L. The results illustrate the rich array of phenolic compounds present in cork.     

Antioxidant activity of phenolic and phenylethanoid glycosides from Teucrium polium L

In the present study, the chemical composition and antioxidant activities of Teucrium polium L. (Lamiaceae) were assessed. Fractionation of methanol extract obtained from the aerial parts of T. polium yielded one new phenylethanoid glycoside, named poliumoside B, together with four known flavonoids, two iridoid glycosides and a known poliumoside. The structures of all of these compounds were elucidated on the basis of spectroscopic data from 1D and 2D NMR experiments and MS spectral analyses. The antioxidant activities of the crude extracts and of the isolated compounds were evaluated through tests such as DPPH radical-scavenging capability, reducing power, xanthine oxidase inhibitory effect and inhibition of linoleic acid peroxidation. The highest antioxidant activity was found in the n-butanol extract, which also contained active polyphenols, thus suggesting that this plant could be used as a source of natural molecules, to provide safe antioxidant additives and nutraceuticals. The structure–activity relationships of the isolated compounds are also discussed.     

Antioxidant potential and phenolic constituents of Salvia cedronella

The acetone extract of the aerial parts of the plant Salvia cedronella Boiss. was screened for its total phenolic content and flavonoid content. The antioxidant potential was evaluated, in vitro, by using three different assays; β-carotene–linoleic acid test system for total antioxidant activity, DPPH for free radical scavenging activity, Fe²⁺–ferrozine test system for metal chelation. A high content of phenolics, potent radical scavenging ability and significant iron chelating effect were observed. However, the inhibition of lipid peroxidation was not significant in β-carotene–linoleic acid test system. A phytochemical analysis yielded a new coumarin, 3-methoxy-4-hydroxymethyl coumarin, together with p-hydroxyphenylethyl docosanoate, and two triterpenoids oleanolic acid and betulinic acid.     

In vitro antioxidant activities of methanol extracts of five Phyllanthus species from India

In this study, the antioxidant activity of methanol extracts of five plants from the genus Phyllanthus was evaluated by various antioxidant assays, including total antioxidant, free radical scavenging, superoxide anion radical scavenging, hydrogen peroxide scavenging, nitric oxide scavenging, reducing power and metal ion chelating activities. The various antioxidant activities were compared to standard antioxidants such as butylated hydroxytoluene and ascorbic acid. All the extracts showed strong antioxidant activity in all the tested methods. Among the five plants Phyllanthus debilis has been found to possess the highest activity in all tested models, the activity decreased in the order Phyllanthus debilis>Phyllanthus urinaria>Phyllanthus virgatus>Phyllanthus maderaspatensis>Phyllanthus amarus. In addition to the antioxidant activity of these plants, the total phenolic compounds, flavonoids and flavonols were measured in the extracts. A correlation between the antioxidant activity and total phenolic content was observed.     

In vitro scavenging capacity of annatto seed extracts against reactive oxygen and nitrogen species

Bixa orellana L. (annatto), from Bixaceae family, is a native plant of tropical America, which accumulates several carotenoids (including bixin and norbixin), terpenoids, tocotrienols and flavonoids with potential antioxidant activity. In the present study, the in vitro scavenging capacity of annatto seed extracts against reactive oxygen species (ROS) and reactive nitrogen species (RNS) was evaluated and compared to the bixin standard. Annatto extracts were obtained using solvents with different polarities and their phenolic compounds and bixin levels were determined by high performance liquid chromatography coupled to diode array detector. All annatto extracts were able to scavenge all the reactive species tested at the low μg/mL range, with the exception of superoxide radical. The ethanol:ethyl acetate and ethyl acetate extracts of annatto seeds, which presented the highest levels of hypolaetin and bixin, respectively, were the extracts with the highest antioxidant capacity, although bixin standard presented the lowest IC₅₀ values.     

Phenolic acid analysis and antioxidant activity assessment of oil palm (E. guineensis) fruit extracts

Phenolic compounds in oil palm fruit (E. guineensis) were extracted in soluble free (SFP), insoluble-bound (ISBP) and esterified (EFP) forms. The total phenolic content (TPC) of the oil palm fruit extracts was determined using the Folin–Ciocalteu method and found to range from 5.03 to 9.04 g/L per g of dried weight (DW). The antioxidant activities of oil palm phenolic extracts were analysed using free radical scavenging assays and results showed that oil palm phenolic extracts contained antioxidant activities in the order of ISBP > EFP > SFP. Eight different phenolic acids were identified and quantified using a simple reversed-phase high performance liquid chromatography (HPLC) with a diode array detector (DAD) and liquid chromatography/tandem mass spectrometry (LC/MS/MS). Ferulic, p-hydroxybenzoic and p-coumaric acid were the dominant phenolic acids found in oil palm fruit extracts and ranged from 55 to 376 μg/g of DW.     

Quantitative analysis of triterpenoids in different parts of Ilex hainanensis, Ilex stewardii and Ilex pubescens using HPLC–ELSD and HPLC–MS and antibacterial activity

An HPLC–ELSD method was first developed for the quantitative analysis of principle triterpenoids in Ilex hainanensis, Ilex stewardii and Ilex pubescens. The established method, with excellent precision, repeatability and recovery, was successfully applied to determine four triterpenoids in 24 samples from different species and medicinal parts of Ilex, and the changing trend was discussed. HPLC–ESI–MSⁿ was used for the identification of constituents in samples. The proposed method was simple, effective and suitable for investigations of these plants. Furthermore, the ethanol extracts from leaves of Ilex species, as well as their main components, were assessed for their antibacterial activities. The results indicated that the extracts of I. hainanensis, I. stewardii and I. pubescens could inhibit the growth of the tested oral pathogens, Streptococcus mutans and Actinomyces viscosu. Particularly, ilexgenin A was the most effective with MIC values of 7.8 and ?3.9 μg/ml, respectively.     

The in vitro antioxidative properties of the essential oils and methanol extracts of Satureja spicigera (K. Koch.) Boiss. and Satureja cuneifolia ten

This study was designed to examine the in vitro antioxidant activities of the essential oil and methanol extracts of Satureja spicigera and S. cuneifolia from Turkish flora. GC and GC/MS analysis of the essential oils resulted in the identification of 40 and 29 compounds, representing the 99.4% and 99.5% of the oils, respectively. Major constituents of the oils were carvacrol (42.5% and 67.1%), γ-terpinene (21.5% and 15.2%) and p-cymene (20.9% and 6.7%), respectively. Methanol extracts were also obtained from the aerial parts of the plants. The samples were subjected to a screening for their possible antioxidant activities by using 2,2-diphenyl-1-picrylhydrazyl (DPPH) and β-carotene–linoleic acid assays. In general, samples obtained from S. cuneifolia exerted greater antioxidant activities than did those obtained from S. spicigera. In the DPPH test system, free radical-scavenging activity of S. spicigera oil was determined to be 127 ± 1.63 μg/ml, whereas IC₅₀ value of S. cuneifolia was 89.1 ± 2.29 μg/ml. In the β-carotene–linoleic acid test system, antioxidant activities of the oil were 81.7 ± 1.14% and 93.7 ± 1.83%, respectively. Antioxidant activities of the synthetic antioxidant, BHT, ascorbic acid, curcumin and α-tocopherol were also determined in parallel experiments.