Screening for in vitro antioxidant properties and fatty acid profiles of five Centaurea L. species from Turkey flora

Centaurea species are used for the treatment of various ailments in the popular medicine in some countries. This study was designed to examine antioxidant potentials and fatty acid profiles of five Centaurea species from Turkey flora. Antioxidant properties of methanolic extracts from these species were evaluated by six different methods: phosphomolybdenum assay, free radical scavenging assay, β-carotene/linoleic acid test system, metal chelating activity, ferric and cupric reducing power. Total phenolic and flavonoid concentrations of each extract were also determined using the Folin–Ciocalteu reagent and aluminum chloride. The results of these assay showed a significant antioxidant capacity in all researched extracts. Centaurea cheirolopha extract, with the highest amount of total phenolic and flavonoids, showed the highest antioxidant activities in all assay, except for metal chelating. Fatty acid profiles of these species were examined by GC–FID and 30 fatty acids were identified. Palmitic, linoleic, oleic, and linolenic acid were detected as the main components. The results of the study indicated that the Centaurea species can be considered as a source of new natural antioxidants and unsaturated fatty acids for food, cosmetic and pharmaceutical industries.     

The antioxidative effect of Iranian Mentha pulegium extracts and essential oil in sunflower oil

The aim of the present study was to evaluate antioxidative activities of the essential oil, methanol and water extracts of Iranian pennyroyal in vegetable oil during storage. Different concentrations (0, 200, 400, 600, 800 and 1000 ppm) of essential oil, water and methanol extracts and beta-hydroxy toluene (BHT; 200 ppm) were added to sunflower oil emulsion in the presence of cupric ions and incubated for 7 days at 60 °C. Peroxide values (PVs) and thiobarbituric acid reacting substances (TBARS) levels were measured in each day up to day of seven. Furthermore, antioxidant capacity of the essential oil and extracts were determined using DPPH and β-carotene–linoleic acid methods. Values were compared among groups in each incubation time points using ANOVA. Results showed that DPPH and β-carotene–linoleic acid assay findings on the Mentha pulegium extracts were comparable to those found on BHT. Furthermore, in all incubation time points, M. pulegium extracts lowered PVs and TBARS levels when compared to the control (p < 0.001). In this respect, water extract was more potent than the methanol extract. Essential oil did not show considerable antioxidative effect. It seems that water extract of M. pulegium is a potent antioxidant which makes it as a potential antioxidant for oil and oily products during storage.     

Chemical composition,in vitro anti-microbial,antifungal and antioxidant activities of the essential oil and methanolic extract of Hymenocrater longiflorus Benth., of Iran

In this study we identified the chemical composition, anti-microbial and antioxidant effects of essential oil and methanolic extract of Hymenocrater longiflorus Benth. Totally 87 volatile compounds from the essential oil in H. longiflorus, were identified by gas chromatography–mass spectrometry (GC–MS). These compounds are mainly monoterpene hydrocarbons, sesquiterpene hydrocarbons, oxygenated monoterpenes and oxygenated sesquiterpenoids compounds. The anti-microbial and antifungal activity of plants extracts against several pathogenic microorganisms was studied by disc diffusion and minimum inhibitory concentration procedures. The results revealed that the essential oil and polar sub-fraction are effective mostly against Staphylococcus aureus, Aspergillus niger and Candida albicans. The antioxidant activity was also determined by 1,1′-diphenyl-2-picryl-hydrazyl (DPPH) free radical scavenging, β-carotene linoleic acid assay and reducing power. In addition the total phenol of essential oil (54.6 ± 1.2), polar sub-fraction (50.0 ± 1.4) and non-polar sub-fraction (64.7 ± 2.0) were determined.     

Chemical composition and antioxidant activities of the essential oil and methanol extracts of Psammogeton canescens

This study is outlined to probe the chemical composition of essential oil and in vitro antioxidant activity of the essential oil and methanol extracts of Psammogeton canescens. The chemical composition of the hydrodistilled essential oil of the aerial parts of P. canescens was analyzed by GC and GC/MS. The main constituents of the oil were found to be β-bisabolene (33.35%), apiole (28.34%), α-pinene (11.86%) and dill apiole (8.17%). Antioxidant activities of the samples were determined by three various testing systems namely DPPH, β-carotene/linoleic acid, and reducing power assay. In DPPH system, the highest radical-scavenging activity was seen by the polar subfraction of methanol extract (49.5 ± 1.21 μg/ml). Furthermore, in the second case the inhibition capacity (%) of the polar subfraction (92.40% ± 0.72) found to be the stronger one. However, in the reducing power assay, a reverse activity pattern more than in the first two systems was observed, and the essential oil was stronger radical reducer than was the methanol extract in all of the concentration tested. Our findings demonstrate that the essential oil and methanol extracts of P. canescens possess significant antioxidant activities and may be suggested as a new potential source of natural antioxidant.     

Antioxidant activities of leaf extract of Salvia miltiorrhiza Bunge and related phenolic constituents

Leaf of Salvia miltiorrhiza Bunge, the waste part during the root harvest, is rich in health-promoting phenolics and is a novel resource of natural antioxidants. The acetone and methanol extracts of leaves (AL and ML, respectively) of S. miltiorrhiza were evaluated by various in vitro antioxidant assays. The total phenolic contents of AL and ML were 39.0 ± 1.13 and 54.3 ± 1.1 mg gallic acid equivalents/g extract tested, respectively. EC₅₀ of ML was 7.0 ± 0.28 μg/mL in DPPH radical scavenging assay and 246.5 ± 10.35 μg/mL in superoxide radical quenching assay. It was also found that ML has prominent effects on the inhibition of linoleic acid oxidation (93.2%), which was equivalent to the positive control, butylated hydroxytoluene (BHT, p > 0.05), and was significantly higher than α-tocopherol (VE, p < 0.05). The reducing power of leaf extracts was as strong as roots (p > 0.05). HPLC and correlation analysis show that salvianolic acid B and rosmarinic acid constitute the most abundant phenolic compounds. They are the major contributors to antioxidant activities. The results suggested that S. miltiorrhiza leaves could be considered as a new potential source of natural phenolic antioxidants for food, pharmaceutical, cosmetics or nutraceutical industries.     

Antioxidant,free radical scavenging activities of Salvia brachyantha and its protective effect against oxidative cardiac cell injury

In this study, antioxidant and free radical scavenging activities of an endemic Salvia species (Salvia brachyantha (Bordz) probed. was assessed in vitro using 1,1-diphenyl-2-picryhydrazyl (DPPH) radical, β-carotene linoleic acid, superoxide anion radical, hydroxyl radical, and reducing power assays. Regarding our data, the plant extract exhibited antioxidant and radical scavenging activities at different magnitudes of potency. In addition, this study was undertaken to assess whether methanol extract of S. brachyantha could increase the endogenous antioxidant enzymes in cells, and where such increased cellular defences could provide protection against oxidative cell injury. Pre treatment of rat heart cell lines with 100 μg/ml of plant extract for 24 h significantly prevented cell damage and enhanced activity of antioxidant enzymes induced by a treatment with xanthine/xanthine oxidase. Increased reactive oxygen species and cell apoptosis induced by xanthine/xanthine oxidase was dose-dependently prevented when cells were pre treated for 24 h with plant extract. These results indicated that S. brachyantha could protect against cell injury via induction of the antioxidant enzyme defences. The extract of this plant might be valuable antioxidant natural sources and seemed to be applicable in both healthy medicine and food industry.     

Antioxidant activity and ultra-performance LC-electrospray ionization-quadrupole time-of-flight mass spectrometry for phenolics-based fingerprinting of Rose species: Rosa damascena, Rosa bourboniana and Rosa brunonii

Roses are one of the most important groups of ornamental plants and their fruits and flowers are used in a wide variety of food, nutritional products and different traditional medicines. The antioxidant activity of methanolic extracts from fresh flowers of three rose species (Rosa damascena, Rosa bourboniana and Rosa brunonii) was evaluated by 1,1-diphenyl-2-picryl hydrazyl (DPPH) free-radical method. The ability to scavenge DPPH radical was measured by the discoloration of the solution. The methanolic extract from R. brunonii exhibited maximum free-radical-scavenging activity (64.5 ± 0.38%) followed by R. bourboniana (51.8 ± 0.46%) and R. damascena (43.6 ± 0.25%) at 100 μg/ml. Simultaneously, ultra-performance liquid chromatography coupled with electrospray ionization-quadrupole time-of-flight mass spectrometry (UPLC-ESI-QTOF-MS) was used to study phenolic composition in the methanolic extracts from the fresh flowers of rose species. The phenolic constituents were further investigated by direct infusion-ESI-QTOF-MS/MS in negative ion mode. Characteristic Electrospray ionization tandem mass spectrometry (ESI-MS/MS) spectra with other diagnostic fragment ions generated by retro Diels–Alder (RDA) fragmentation pathways were recorded for the flavonoids. Distinct similarities were observed in the relative distribution of polyphenolic compounds among the three species. The dominance of quercetin, kaempferol and their glycosides was observed in all the three species.     

Prophylactic effect of α-linolenic acid and α-eleostearic acid against MeHg induced oxidative stress,DNA damage and structural changes in RBC membrane

The present study was undertaken to evaluate under in vivo condition the effects of α-linolenic acid and α-eleostearic acid against methyl mercury (MeHg) induced oxidative stress. Male albino rats were divided into six groups. Group 1 was under normal control and Group 2 was treated with methyl mercury chloride (MeHgCl; 5 mg/kg BW/day). Groups 3, 4, 5 and 6 were orally treated with different doses of the two fatty acids (0.5% and 1.0% of total lipid given for each kind of linolenic acid isomer) along with MeHgCl (5 mg/kg BW). Comet assay of blood lymphocytes showed that administration of α-linolenic acid reduced DNA damage significantly (P < 0.05). Results also showed that activity of antioxidant enzymes of plasma and brain tissue and total antioxidant capacity in plasma decreased significantly due to oxidative stress generated by MeHgCl. Administration in higher dose of both kind of linolenic acid restored all the activities of the antioxidant enzymes and also reduced lipid peroxidation and increased total antioxidant capacity in plasma. Both kinds of linolenic acid successfully maintained the RBC membrane integrity which was totally disrupted and became flat due to MeHgCl stress. α-Linolenic acid was more efficient antioxidant than α-eleostearic acid against oxidative DNA damage.     

Wild mushrooms Clitocybe alexandri and Lepista inversa: In vitro antioxidant activity and growth inhibition of human tumour cell lines

The in vitro antioxidant and growth inhibitory activity of extracts obtained from two Portuguese wild mushrooms (Clitocybe alexandri and Lepista inversa) was studied in human tumour cell lines. The extracts were phenolic (methanolic and ethanolic) and polysaccharidic (boiling water). The antioxidant activity assays included evaluation of radical-scavenging capacity, reducing power and inhibition of lipid peroxidation measured in liposome solutions. Extract-induced cell growth inhibition was measured in four different tumour cell lines (lung, breast, colon and gastric cancer) using the SRB assay. The polysaccharidic extract of L. inversa was the most potent as antioxidant (EC₅₀ < 1.8 ± 0.1 mg/ml), while the phenolic ethanolic extract of C. alexandri was the most potent as inhibitor of growth of the studied cancer cell lines (GI₅₀ < 26.0 ± 1.3 μg/ml). Together, these activities indicate that these mushrooms are promising sources of bioactive compounds.     

Antioxidant activity and total phenolic content of ethanolic extract of Caesalpinia bonducella seeds

The aim of this study was to assess the in vitro potential of ethanolic extract of Caesalpinia bonducella seeds as a natural antioxidant. The DPPH activity of the extract (20, 40, 50, 100 and 200 μg/ml) was increased in a dose dependent manner, which was found in the range of 38.93–74.77% as compared to ascorbic acid (64.26–82.58%). The IC₅₀ values of ethanolic extract and ascorbic acid in DPPH radical scavenging assay were obtained to be 74.73 and 26.68 μg/ml, respectively. The ethanolic extract was also found to scavenge the superoxide generated by EDTA/NBT system. Measurement of total phenolic content of the ethanolic extract of C. bonducella was achieved using Folin–Ciocalteau reagent containing 62.50 mg/g of phenolic content, which was found significantly higher when compared to reference standard gallic acid. The ethanolic extract also inhibited the hydroxyl radical, nitric oxide, superoxide anions with IC₅₀ values of 109.85, 102.65 and 89.84 μg/ml, respectively. However, the IC₅₀ values for the standard ascorbic acid were noted to be 70.79, 65.98 and 36.68 μg/ml respectively. The results obtained in this study clearly indicate that C. bonducella has a significant potential to use as a natural antioxidant agent.     

Characterization of increased phenolic compounds from fermented Bokbunja (Rubus coreanus Miq.) and related antioxidant activity

This study examined the changes in the phenolic acid-content and antioxidant activity of Rubi Fructus (RF), the fruit of Rubus coreanus Miq., after fermentation with yeast (Saccharomyces cerevisiae). The phenolic acids were fractionated into three forms, free (Fr. A), ester (Fr. B), and insoluble-bound phenolic acids (Fr. C) and quantified by high performance liquid chromatography with a diode array detector (HPLC-DAD). This method was validated and allowed the successful identification of 11 phenolic acids in the RF extracts. HPLC-DAD analysis of the samples showed substantial increases in the levels of protocatechuic, vanillic and p-coumaric acid as the result of yeast fermentation. The total phenolic content (TPH) was also increased by fermentation. The total phenolics in Fr. A and Fr. B increased from 117 to 173 mg GAE/100 g and from 488 to 578 mg GAE/100 g, respectively. The total phenolics in Fr. C decreased from 264 to 175 mg GAE/100 g. The antioxidant activity of the fermented RF was measured as the 1,1-diphenoly-2-picrylhydrazyl (DPPH) radical scavenging capacity, which is expressed as the IC₅₀. The IC₅₀ for Fr. A and Fr. B decreased from 5.9 to 4.0 mg/ml (mg of dried RF equiv./ml) and from 1.2 to 0.8 mg/ml, respectively. In Fr. C, the IC₅₀ value increased from 2.1 to 2.8 mg/ml. In summary, the fermented RF had a higher total phenolic content and better DPPH radical-scavenging activity than the unfermented material.     

Chemical and cellular antioxidant activity of two novel peptides designed based on glutathione structure

Two novel peptides, ECH (Glu-Cys-His) and YECG (Tyr-Glu-Cys-Gly), were designed based on glutathione (Glu-Cys-Gly, GSH) and their antioxidant activities were studied. Various chemical methods based on single-electron-transfer (SET) and hydrogen-atom-transfer (HAT) were applied to evaluate the antioxidant activities of the peptides. For SET-based assay, tripeptide ECH displayed the highest DPPH radical scavenging activity (80.16%) and the strongest reducing power (A₇₀₀ = 0.378). Besides, ECH also exhibited the best inhibition activity toward linoleic acid peroxidation with inhibition rate 98.25% at 7th day, which is a HAT-based assay. However, for another two HAT-based assays, it was tetrapeptide YECG that showed extraordinary oxygen radical absorption capacity (ORAC value = 2.42 μM Trolox/μM) and ABTS free radical scavenging ability (8.88 mM Trolox/mM). In vitro cultured PC12 cell model also suggested that YECG gave the best protection for PC12 cells to resist H₂O₂-treated necrosis. It was found that the discrepancy of antioxidant capacity between ECH and YECG was caused by the presence of antioxidant amino acids (His/Tyr) and their position in peptide chain. With His located at C-terminal position, ECH demonstrated good electrons donating capacity, while with Tyr at N-terminal position, YECG exhibited strong oxygen radical absorbance capacity.     

Comparative analysis of the antioxidant and DNA protection capacities of Anadenanthera colubrina, Libidibia ferrea and Pityrocarpa moniliformis fruits

This study aimed to explore the antioxidant and DNA protection abilities of hydroalcoholic extracts from fruits of Anadenanthera colubrina (ACHE), Libidibia ferrea (LFHE) and Pityrocarpa moniliformis (PMHE). These extracts were tested by five antioxidant methods (phosphomolibdenium and reducing power assays; superoxide, hydrogen peroxide and nitric oxide scavenging) and DNA protection capacity. Total phenolic content was measured by Folin-Ciocalteu method. ACHE exhibited the highest phenolic content (578 mg/g GAE), followed by LFHE (460 mg/g GAE) and PMHE (448 mg/g GAE). In phosphomolibdenium assay, ACHE showed 24.81% of activity in relation to ascorbic acid, whereas LFHE and PMHE had 21.08% and 18.05%, respectively. These plants showed high ability to inhibit reactive species tested with IC50 values ranged from 10.66 to 14.37 μg/mL for superoxide radical; 26.05 to 45.43 μg/mL for hydrogen peroxide; 178.42 to 182.98 μg/mL for reducing power; and 199.2 to 283 μg/mL for nitric oxide. Furthermore, these extracts had capacity to break the DNA damage induced by hydroxyl radicals. The antioxidant activity of these plants is related with their higher phenolic content and show that they may be used as source of bioactive compounds, relevant to the maintenance of oxidative stability of the food matrix, cosmetics and/or pharmaceutical preparations.     

Antioxidant activity and protective effect of Turnera ulmifolia Linn. var. elegans against carbon tetrachloride-induced oxidative damage in rats

The present study aimed to determine whether the leaves of Turnera ulmifolia Linn. var. elegans extract exert significant antioxidant activity. The antioxidant activity of its hydroethanolic extract (HEETU) was evaluated by assessing (a) its radical scavenging ability in vitro, and (b) its in vivo effect on lipid peroxidation and antioxidant enzyme activities. The in vitro antioxidant assay (DPPH) clearly supported HEETU free radical scavenging potential. Moreover, glutathione content and antioxidant enzyme activities (glutathione peroxidase, superoxide dismutase and catalase) were significantly enhanced in CCl₄-treated rats due to oral HEETU-treatment (500 mg/kg b.w.) over 7 and 21 days. In addition, an improvement was observed in lipid peroxidation and serum biochemical parameters (aspartate aminotransferase and alanine aminotransferase), indicating a protective effect against CCl₄-induced liver injuries, confirmed by histopathological studies. The HEETU effect was comparable to the standard drug Legalon® (50 mg/kg b.w.) under the same experimental condition. Quantitative analysis of the HPLC extract revealed the presence of flavonoids, wich mediate the effects of antioxidant and oxidative stress. In conclusion, extract components exhibit antioxidant and hepatoprotective activities in vitro and in vivo.     

Chemical composition and antioxidant activity of essential oils and solvent extracts of Ptychotis verticillata from Morocco

The objective of this study was to characterize the chemical composition of the essential oil and extracts of Ptychotis verticillata. The antioxidative activities of this species were also evaluated to suggest it as a new potential source of natural antioxidants. Analysis of the chemical composition of P. verticillata essential oil from Morocco was carried out using GC and GC-MS. The oil was dominated by phenolic compounds (48.0%) with carvacrol (44.6%) and thymol (3.4%) as the main compounds. Plant phenolics constitute one of the major groups of components that act as primary antioxidant free radical terminators. The amounts of total phenolics and flavonoids in the solvent extracts (diethyl ether and ethyl acetate) were determined spectrometrically. Furthermore, the antioxidant activities of the essential oil and extracts were determined using a DPPH test system. The DPPH scavenging activity of extracts increased in the order ethyl acetate > ascorbic acid > diethyl ether > essential oil. Finally, a relationship was observed between the antioxidant activity potential and total phenolic and flavonoid levels of the extract.     

Characterization of myrtle seed (Myrtus communis var. baetica) as a source of lipids,phenolics, and antioxidant activities

This study aimed to characterize the chemical composition and antioxidant activity of the oil and the methanolic extract of Myrtus communis var. baetica seed. The oil yield of myrtle seed was 8.90%, with the amount of neutral lipid, especially triacylglycerol, being the highest, followed by phospholipids and glycolipids. Total lipids and all lipid classes were rich in linoleic acid. The content of total phenols, flavonoids, tannins, and proanthocyanidins of the methanolic extract and the oil from myrtle seed was determined using spectrophotometric methods. Antioxidant activities of the oil and the methanolic extract from myrtle seed were evaluated using 1,1-diphenyl-2-picrylhydrazyl radical scavenging, β-carotene–linoleic acid bleaching, and reducing power and metal chelating activity assays. In all tests, the methanolic extract of myrtle seed showed better antioxidant activity than oil. This investigation could suggest the use of myrtle seed in food, industrial, and biomedical applications for its potential metabolites and antioxidant abilities.     

Targeted metabolite analysis of Catharanthus roseus and its biological potential

Catharanthus roseus is nowadays one of the most studied medicinal plants. In this work, further knowledge on different parts of this species (leaves, stems, seeds and petals) was achieved, namely phenolics by HPLC-DAD and organic acids and amino acids by HPLC-UV. Also, the biological potential, expressed as acetylcholinesterase inhibitory activity was accessed and, in some parts, an acetylcholinesterase inhibitory capacity higher than 85% was found (IC₅₀ at 422, 442 and 2683 μg/mL in leaves, stems and petals, respectively). C. roseus aqueous extract revealed to be a rich source of phenolics, namely caffeoylquinic acids and flavonoids derivatives (up to 4127 mg/kg in stems, 4484 mg/kg in seeds, 8688 mg/kg in leaves and 41125 mg/kg in petals), organic acids (962, 6678, 25972 and 12463 mg/kg in seeds, petals, stems and leaves, respectively), such as citric acid (over 85% in some plant parts), and amino acids (31557, 39327, 50540 and 159697 mg/kg in stems, petals, seeds and leaves, respectively), of which arginine was a major compound.     

Chemical composition of five wild edible mushrooms collected from Southwest China and their antihyperglycemic and antioxidant activity

Evaluation of the chemical composition and antihyperglycemic and antioxidant activity of five wild edible mushrooms (Clitocybe maxima, Catathelasma ventricosum, Stropharia rugoso-annulata, Craterellus cornucopioides and Laccaria amethystea) from Southwest China. The chemical composition assay includes proximate analysis (moisture, ash, crude protein, crude fat, total carbohydrates and total energy), bioactive compounds analysis (total phenolic, flavonoid, ascorbic acid, ergosterol, tocopherol), fatty acid analysis, amino acid analysis, phenolic compounds analysis and mineral analysis of these mushrooms. Furthermore, assays of α-glucosidase inhibitory and α-amylase inhibitory activity were used for evaluating antihyperglycemic activity of the mushrooms, and assays of reducing power, chelating effect on ferrous ions, scavenging effect on hydroxyl free radicals and 1,1-Diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity were used for evaluating antioxidant activity of the mushrooms. Based on the results, ethanolic and aqueous extract of these mushroom all showed antihyperglycemic and antioxidant potential. In particular, the aqueous extract of C. ventricosum revealed the highest α-glucosidase inhibitory activity (EC50 value 2.74 μg/mL), DPPH radical scavenging activity (EC50 value 2.86 mg/mL) and reducing power (EC50 value 0.96 mg/mL), while the aqueous extract of L. amethystea showed the highest α-amylase inhibitory activity (EC50 value 4.37 μg/mL) and metal chelating activity (EC50 value 2.13 mg/mL).     

Antioxidant and antimicrobial properties of Teucrium arduini L. (Lamiaceae) flower and leaf infusions (Teucrium arduini L. antioxidant capacity)

Antioxidant and antimicrobial activities, as well as total phenol (TP, Folin–Ciocalteu method) and phenolic acid (UPLC–MS/MS) contents of leaf and flower infusions of Teucrium arduini L. from six different mountainous localities in Croatia (U?ka, Vošac, Sveti Jure, Snje?nica, Vaganac, Šušanj) were analysed in this study. Antioxidant capacity was evaluated using the ferric reducing/antioxidant power (FRAP) assay, as well as 2,2-diphenyl-1-picrylhydrazyl (DPPH), and 2,2′-azinobis (3-ethylbenzthiazoline-6-sulphonic acid) (ABTS) radical scavenging assays. The antioxidant potency composite index (ACI), giving equal weight to all three methods used to quantify antioxidant capacity, was the highest for the sample from Vošac (96.7) among flower infusions, while maximum ACI (100) was determined for the infusion from U?ka among leaf infusions. Strong positive correlation was found between the total phenols and ACI for leaf (r = 0.953) and flower (r = 0.977) infusions. Our results point to significantly (p < 0.05) different TP content between leaf and flower infusions, as well as across localities. Leaf infusions of T. arduini from Šušanj exhibited marked antibacterial activity against Staphylococcus aureus, while none of the tested infusions exhibited antimicrobial activity against gram-negative bacterial species, or the tested fungal species.