Antioxidant activity screening of extracts from Sideritis species (Labiatae) grown in Bulgaria

Plant samples from several species and populations of the genus Sideritis (Labiatae) grown in Bulgaria (S scardica, S syriaca and S montana) were extracted with different solvents. Their antioxidant activities were determined by the β‐carotene bleaching test (BCBT), 2,2′‐diphenyl‐1‐picrylhydrazyl (DPPH^?) radical scavenging method and static headspace gas chromatography (HS‐GC) and compared with the antioxidant activity of two reference compounds of different polarity, viz butylated hydroxytoluene (BHT) and rosmarinic acid. The pure reference compounds were applied in a ten‐times lower concentration than the plant extracts. The highest antioxidant activity in the BCBT, close to that of BHT, was observed for the more apolar extracts. The inhibitory effect on β‐carotene bleaching of the polar extracts and rosmarinic acid was much lower than that of BHT. The inhibition of hexanal formation in bulk safflower oil by most of S syriaca and S scardica extracts was as effective as BHT but less so than rosmarinic acid. S montana extracts showed weak antioxidant or even pro‐oxidant properties. Extracts from butanol and from ethyl acetate and the total methanol extracts from all Sideritis plants studied showed a strong radical scavenging activity against DPPH^?, close to that of rosmarinic acid. S montana extracts were, as a whole, slightly weaker radical inhibitors than the extracts from the other two species. The antioxidant activity of Sideritis extracts was attributed to the presence of flavonoid and phenylpropanoid glycosides. Copyright © 2003 Society of Chemical Industry     

Laboratory assessment of toxic activity of purified peptides extracted from chickpea seeds to two strains of the rice weevil Sitophilus oryzae (L.) (Coleoptera: Curculionidae)

Several peptides with entomotoxic properties were extracted from seeds of different chickpea varieties, by either aqueous or alcoholic phase extraction. The extracts were purified by anion-exchange chromatography followed by membrane dialysis. The toxicity of the purified extracts was tested on two different strains of the rice weevil, Sitophilus oryzae: a French strain feeding only on cereal grain and sensitive to pea phytotoxins (SS strain) and a Chinese strain naturally breeding on split pea (RS strain). The toxic activity of the different fractions isolated from the purified extracts was evaluated by the ‘artificial kernel method’, incorporating the fraction into a reconstituted (‘artificial’) kernel made from whole wheat flour. The toxicity of the fractions was assessed by determining the mortality of young adults of each S. oryzae strain after 7 and 14 d feeding. With the more toxic acidic fraction incorporated into the artificial kernel, the mortality rate of SS strain weevils was 83% and 100% after 7 and 14 d feeding, respectively. With all the alcoholic fractions, mortality of the SS strain remained very low. With RS strain weevils, mortality was negligible after 7 d or 14 d feeding on any peptide fraction of the extracts.     

Effect of condensed tannins prepared from several forages on the in vitro precipitation of ribulose-1,5-bisphosphate carboxylase (Rubisco) protein and its digestion by trypsin (EC 2.4.21.4) and chymotrypsin (EC 2.4.21.1)

A series of in vitro experiments was undertaken to determine the extent to which Sephadex LH-20 treated extracts from a range of temperate forages precipitated ribulose-1,5-bisphosphate carboxylase (Rubisco) and affected the enzymatic hydrolysis of Rubisco protein by trypsin and chymotrypsin at a range of pH values. Rubisco was chosen because it represents the principal dietary protein for ruminants fed fresh forages. Condensed tannins (CT) or proanthocyanidins (PA) are routinely purified by chromatography using Sephadex LH-20 as a matrix. However, these extracts contained non-CT phenolics together with PA so the term ‘CT extract’ was preferred to ‘PA’ to describe the extracts. The in vitro precipitation of Rubisco provided a means to compare the reactivity of the CT extracts. The amount of CT extract required to precipitate all the Rubisco in 10 μg of total soluble leaf protein from white clover (Trifolium repens) when this protein was incubated with CT extracts of Lotus corniculatus, L pedunculatus and sainfoin (Onobrychis viciifolia) was similar, with between 25 and 50 μg of extract required. The CT extract of sulla (Hedysarum coronarium) also precipitated all the Rubisco, however this only occurred with 50 μg of the extract. The CT extract of dock (Rumex obtusifolius) precipitated all the Rubisco when 5 μg of extract or greater was incubated with total soluble leaf protein. However, the differences between the reactivity of all these CT extracts at a range of pH values appeared to be small. Condensed tannin extracts of L corniculatus and L pedunculatus partially inhibited the hydrolysis of Rubisco by trypsin and chymotrypsin to a similar extent, but the extent of the inhibition was affected by pH. The inhibition was greater at pH 6·0 than 7·0, whilst at pH 8·0, CT extracts had little or no affect on trypsin and chymotrypsin. It was concluded that, although the precipitation of Rubisco provided an ideal method for comparing CT extracts, reactivity alone was unlikely to account for the differences in nutritive value that occur with forages containing CT. © 1998 SCI.     

Some aspects of the use of high-performance liquid chromatography for the determination of vitamin A in animal feeding stuffs

The application of high-performance liquid chromatography to the determination of vitamin A in animal feeding stuffs has been investigated. Particular emphasis has been given to some of those aspects that would be of importance to official control methods. Vitamin A exists as six geometric isomers, some or all of which may be present in feed extracts. The effect of this on both ultraviolet and fluorescence quantitation is described, using all-trans retinol and 13-cis retinol as examples of the different isomers. The isomers were eluted coincidentally from a reversed-phase column; information on the isomeric composition of the feed extracts was obtained by means of the maleic anhydride reaction. These results were confirmed by a normal phase chromatographic procedure which resolved all-trans and 13-cis retinol.     

Antibacterial Activities of the Extracts of Some Herbs Used in Turkish Herby Cheese Against Listeria Monocytogenes Serovars

In this study, antimicrobial activities of the four different extracts (in methanol, ethanol, n‐hexane and water) of some herbs including Allium vineale, Chaerophyllum macropodum , and Prangos ferulacea were investigated against Listeria monocytogenes serovars 1/2b, 4b, and 4ab. For many centuries, these herbs were used in food production in Turkey. While water extracts of all the plants did not show any antibacterial activity, the other extracts of these plants showed variable degrees of antibacterial activity against L. monocytogenes serovars tested. The extracts of Allium vineale showed higher antibacterial activity than the other plants. The methanol extracts of all the plants exhibited higher activity than the ethanol and n-hexane extracts. L. monocytogenes 4ab was the most sensitive serovar to extracts of these plants. The results indicated that the methanol and ethanol extracts of these plants displayed remarkable activity against L. monocytogenes serovars and therefore, they could be used as natural anti-Listeria monocytogenes additives in herby cheese.     

Antimicrobial and Antioxidant Activities of Cichorium Intybus Root Extract Using Orthogonal Matrix Design

Solvent, impregnation time, sonication repetitions, and ultrasonic power were important factors in the process of ultrasound‐assisted extraction from chicory (Cichorium intybus) root, while there were no studies about optimizing these 4 factors for extract yield, total phenolic content (TPC), antioxidant, antibacterial, and antifungal activity of the extracts using orthogonal matrix design. The present research demonstrated that the solvent composition played a significant role in the improving extract yield, TPC, antioxidant, and antibacterial activities. The other 3 factors had inequable effect on different purposes, ultrasonic power could improve TPC and antioxidant activity, but long time of extraction lowered antioxidant activity. The TPC increased from 22.34 to 27.87 mg GAE (gallic acid equivalents)/100 g (dry extracts) with increasing solvent polarity. The half inhibition concentration (IC_50, μg/mL) of the radical scavenging activity of the chicory extracts ranged from 281.00 to 983.33 μg/mL. The content of caffeoylquinic acids of root extract, which was extracted by the optimal combination was 0.104%. Several extracts displayed antibacterial activities against Escherichia coli, Staphylococcus aureus, Bacillus thuringiensis, Bacillus subtilis, and Salmonella typhi, while Penicillium sp. and Aspergillus sp. resisted against all the extracts. Combination of 70% ethanol v/v, 24‐h impregnation time, 3 sonication rounds, and 300‐W ultrasonic input power was found to be the optimal combination for the chicory extract yield, TPC, antioxidant activity, and antibacterial activity.     

Functional characterization of pressurized liquid extracts of Spirulina platensis

Three different parameters (temperature, solvent, and extraction time) were studied regarding to pressure liquid extraction (PLE) of antioxidant and antimicrobial compounds from Spirulina platensis. Two different antioxidant methods, β-carotene bleaching method and DPPH^• (2,2-Diphenyl-1-picrylhydrazyl hydrate) free radical scavenging assay, were used to determine the optimal PLE conditions for antioxidants extraction. The selected conditions were as follows: extraction temperature equal to 115 °C, extraction time equal to 15 min and ethanol as extracting solvent. The main antioxidant compounds found in this extract were identified as zeaxanthin, a myxoxanthophyll-like compound and very polar phenolic compounds. Moreover, antimicrobial activity of different PLE fractions was tested against Staphylococcus aureus ATCC 25923, Escherichia coli ATCC 11775, Candida albicans ATCC 60193, and Aspergillus niger ATCC 16404. Data obtained showed the hexane and petroleum ether extracts were slightly more active than ethanolic extracts. As for water extracts, none of them were active against the microorganisms tested. Data indicated that both 115 and 170 °C were the best extraction temperatures conditions in order to optimize the extraction of antimicrobial compounds, whereas 9 min was the optimal extraction time. Besides, C. albicans was the most sensitive microorganism to all Spirulina PLE extracts.     

Use of proteases to improve oxidative stability of fermented sausages by increasing low molecular weight compounds with antioxidant activity

Forty fermented sausages from Iberian pigs were manufactured using 3 different proteases with a potential antioxidant activity (batch 1: without proteases, batch 2: neutral bacterial protease, batch 3: fungal protease and batch 4: fungal protease concentrate). The antioxidant properties of extracts (< 3 kDa) from Iberian dry-cured sausages were assessed using four different methods: (i) 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity (RSA), (ii) metal chelating assay (MQA), (iii) reducing power (RP) and (iv) inhibition of linoleic acid autoxidation (ILAA). Dry-cured sausage extracts from of all the manufactured batches showed antioxidant activity as indicated by RSA, MQA and ILAA. Manufacturing sausages with the used proteases increased the antioxidant activity of the sausage extracts, except for the MQA. Moreover, extracts from dry-cured sausages which were manufactured without proteases showed the highest levels of both thiobarbituric acid-reactive substances (TBARs) and hexanal content.     

Antioxidant capacity and total phenolic content of selected plants from Turkey

A total of 28 different plants from different regions of Çanakkale, Turkey, were investigated for their antioxidant capacity and total phenol contents to find new potential sources of natural antioxidants. The antioxidant capacity of methanolic extracts prepared from various parts of plants was evaluated by both trolox equivalent antioxidant capacity (TEAC) and 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) assays, while the total phenolics were determined using the Folin‐Ciocalteu method. The TEAC values of plant extracts ranged in a large scale from 1472.36 to 17.61 μmol of trolox equivalents per g dry weight (dw), and EC₅₀ values (concentration at which 50% radical scavenging occurred) varied from 0.174 to 42.475 mg dw of plant, while the total phenol content of plant extracts ranged between 117.20 and 1.27 mg of gallic acid equivalents per g dw. There was a positive linear correlation between the TEAC and total phenols of plant materials (r = 0.916). The extracts of Hypericum perforatum, Arbutus andrachne and Paliurus spina‐christii showed higher antioxidant activities (both TEAC and DPPH assays). However, there was no clear relationship between TEAC and EC₅₀ values (r = 0.477) of plant extracts.     

Polarity-Based Solvents Extraction of Opuntia dillenii and Zingiber officinale for In Vitro Antimicrobial Activities

Extracts from dried stem of Opuntia dillenii and rhizome of Zingiber officinale were evaluated for antimicrobial activities by extraction in non-polar (petroleum ether and chloroform) and polar solvents (methanol and water). Bacillus subtilis and Staphylococcus aureus showed considerable susceptibility to all extracts of Opuntia dillenii and Zingiber officinale. Ether and chloroform extracts of Opuntia dillenii showed improved antimicrobial activity against Escherichia coli (gram negative) as compared to that of its methanolic and water extracts. On the other hand, methanolic and water extracts of Zingiber officinale showed better susceptibility for Escherichia coli. Salmonella typhi (gram negative) was found to be resistant to all extracts of both Opuntia dillenii and Zingiber officinale. Our results indicated that both Opuntia dillenii and Zingiber officinale have potent antimicrobial activity that is also based on solvent polarity during extraction.     

Determination of antibacterial effects and total phenolic contents of grape (Vitis vinifera L.) seed extracts

In the study, antibacterial activities of the seed extracts of three different grapes were examined against fifteen bacteria, and total phenolic contents of the extracts were additionally determined. The contents of total phenolic compounds of the grape seed extracts were 589.09 (Hasandede), 506.60 (Emir) and 549.54 (Kalecik Karasi) mg gallic acid equivalent (GAE) per gram with acetone:water:acetic acid (90:9.5:0.5). These extracts at 1%, 2.5%, 5% and 10% concentrations were tested for their antibacterial effects by using the agar diffusion method against some pathogenic and spoilage bacteria including Aeromonas hydrophila, Bacillus cereus, Enterobacter aerogenes, Enterococcus faecalis, Escherichia coli, E. coli O157:H7, Klebsiella pneumoniae, Mycobacterium smegmatis, Proteus vulgaris, Pseudomonas aeruginosa, Pseudomonas fluorescens, Salmonella enteritidis, Salmonella typhimurium, Staphylococcus aureus and Yersinia enterocolitica. All tested bacteria were inhibited by the grape seed extracts using agar well diffusion method. The most sensitive of the bacteria was A. hydrophila while Hasandede grape seed extract was the most inhibitive extract on test bacteria. Hasandede seed extract at 10% concentration gave the largest inhibition zone diameter (30.67 mm) against A. hydrophila. According to serial dilution method, while all the grape seed extracts at 0.5% and 1% concentrations had generally bacteriostatic activities against E. coli O157:H7, the same extracts appeared to have bactericidal effects at concentrations above 2.5%. In addition, the extracts at all concentrations had bactericidal activities against S. aureus at the end of 48 h. and A. hydrophila at the end of 1 h.     

Kinetic study of the effects of extracts from Vicia faba var. equina on intestinal sugar absorption

Alcoholic and water extracts from seed-coats of Vicia faba var. equina were prepared and their effects on in-vivo intestinal sugar absorption across the rat small intestine were investigated. Both extracts significantly (P<0.001) inhibited sugar absorption. The higher and more stable inhibition was induced by the water extract. Pretreatment of the extracts with polyamide significantly (P<0.001) reduced their inhibitory potency but did not abolish it, suggesting the presence in the extracts of some other intestinal sugar absorption inhibitor, different from polyphenols. Although both extracts inhibited intestinal sugar active transport, only the water extract was able to reduce sugar diffusion across the small intestine. These differences in behaviour seem to be related to the polyphenolic content of each extract.     

Antibacterial action of vegetable extracts on the growth of pathogenic bacteria

Under controlled conditions, extracts of garlic, onion, turnip, green peppers and radishes were used to inhibit Escherichia coli, Salmonella typhosa, Shigella dysentriae and Staphylococcus aureus, which are all pathogenic bacteria. It was found that 1–4% by vol. of garlic extract completely inhibited the growth of all the bacteria used. 4% by vol. of onion extract completely inhibited the growth of both Shigella dysentriae and Staphylococcus aureus at 10^–6 dilution. Salmonella typhosa and E. coli were not completely inhibited; the inhibition was 48·3% for E. coli and 95·3% for Salmonella typhosa. At 10^–4 bacterial dilution, onion extract decreased the colony number substantially in all four bacteria. 4% extracts from turnip, green peppers and radishes did not show a definite antibacterial action against any bacterium at the given dilutions. On the contrary some growth stimulating activity of these extracts on some bacteria was observed.     

Antioxidant,Free Radical Scavenging,and Antimicrobial Activities of Ajuga iva Leaf Extracts

The antioxidant capacity, total phenolics, flavonoids, and condensed tannin contents of Ajuga iva leaf extracts obtained with different solvent polarities were investigated. The antibacterial and antifungal proprieties were also studied using different microorganisms. The methanol extract with the highest amounts of total phenolics and flavonoids showed the highest antioxidant activities in all assays, followed by the aqueous chloroform and hexane extracts, respectively. The methanol extracts of Ajuga iva exhibited promising antibacterial and antifungal activities, indicating that Ajuga iva leaves might be used in further investigations for developing new antioxidants.     

Evaluation of polyphenolic fingerprints and antioxidant profiles of wild fruits

High‐performance thin‐layer chromatography and UV–vis spectrometry, coupled with multivariate exploratory techniques, have been investigated to fingerprint some local wild fruit extracts. The study was conducted using extracts of sea buckthorn (Hippophae rhamnoides), bilberry (Vaccinium myrtillus), cranberry (Vaccinium oxycoccos), rose hip (Cynosbati fructus), blackberry (Rubus fruticosus), raspberry (Rubus idaeus) and less‐known berries such as cornelian cherry (Cornus mas) and blackthorn (Prunus spinosa), all acquired from local markets. The extracts were firstly subjected to chromatographic separation coupled with digital image analysis and secondly to spectrophotometric analysis. Also, the DPPH˙ scavenging profiles were investigated through the UV–vis spectrum (200–700 nm), and RSA%–time profiles were determined for the first time using these samples, at different concentrations.     

ANTIOXIDATIVE AND ANTIBACTERIAL POTENTIALS OF ESSENTIAL OILS AND EXTRACTS ISOLATED FROM VARIOUS SPICE MATERIALS†

The antioxidant and antibacterial potentials of essential oils and acetone extracts of black pepper, cumin, black cumin and mace were carried out by different techniques. The antioxidative capacity of the essential oils and acetone extracts were evaluated against mustard oil by measuring peroxide and thibarbituric acid values at fixed intervals. In addition, their antioxidant potential was evaluated by 2, 2′‐diphenyl‐1‐picrylhydracyl radical and conjugated diene assays. Their reducing power was determined with standards, which proved the strong antioxidant capacity of essential oils and extracts. The antioxidant activity of essential oils and extracts exerted by all the antioxidant assays can be compared with synthetic antioxidants such as butylated hydroxyanisole and butylated hydroxytoluene. The antibacterial activity was studied by disk diffusion and poison food methods. Black cumin essential oil showed complete zone of inhibition (P < 0.05) against tested bacterial strains of Staphylococcus aureus, Bacillus cereus and Bacillus subtilis at 2 and 6 µL level by disk diffusion method. Black cumin and black pepper extracts showed complete reduction of colonies against tested bacterial strains of S. aureus, B. cereus and B. subtilisat 5 and 10 µL level by poison food method. Poison food method exhibited good results for the tested essential oils and extracts. Essential oils of black pepper, cumin, black cumin and mace may be used to stabilize mustard oil after screening.     

Value‐added use of mushroom ergothioneine as a colour stabilizer in processed fish meats

BACKGROUND: Ergothioneine (ESH), a potent antioxidant, has been found in certain edible mushrooms. Our previous research showed that ESH extracted from the edible mushroom Flammulina velutipes has a positive effect on the colour stability of beef and tuna meat. The purpose of the present study was to compare the efficacy and applicability of ESH extracts prepared from different mushroom species as a colour stabilizer in fish meats. RESULTS: Levels of ESH higher than 2.8 mg mL^?1 were found in extracts prepared from the fruiting bodies of F. velutipes, Lentinula edodes, Pleurotus cornucopiae and Pleurotus eryngii and the processing waste of F. velutipes. When 1 mL of each of the extracts was added to 100 g of minced bigeye tuna and yellowtail meats, the bright‐red colour remained after 5 and 2 days, respectively, of ice storage. The anti‐discoloration efficacy of 1 mL of the extracts prepared from 10 g of the fresh waste portion of F. velutipes was similar to that of its fruiting body or 0.5 g kg^?1 of sodium ascorbate when added to 100 g of minced bigeye tuna meat under ice storage. CONCLUSION: The results of this study clearly showed that ESH prepared from different mushroom species stabilized the colour of fish meats, and the extract from the F. velutipes was the most effective. Copyright © 2010 Society of Chemical Industry     

In vitro antioxidant/free radical scavenging and antibacterial properties of endemic oregano and thyme extracts from Greece

The present investigation was to evaluate the antioxidant and antibacterial activities of hexane and methanol extracts from Origanum vulgare ssp. hirtum and Thymus vulgaris (Komotini, Greece). The methanol extracts of oregano and thyme against DPPH radical were more active than the hexane extracts (mean values 0.94 and 0.47, respectively) and oregano exhibited stronger activity than thyme (mean values 0.82 and 0.55, respectively). The results from the β-carotene/linoleic acid assay showed that all plant extracts inhibited linoleic acid oxidation up to 70.78±1.17%. The oregano extracts exhibited the strongest inhibition against Escherichia coli, Listeria monocytogenes, and Staphylococcus aureus using the disc diffusion assay. The chemical composition of the hexane and methanol extracts, by using GC-MS, showed that carvacrol, thymol, and p-cymene were the most prominent compounds. The methanol extract of oregano was found the most potent antioxidant with the highest content of total phenolics (138.92 mg GA/g extract) and carvacrol (76.7%).     

Free‐radical scavenging activity of wormwood (Artemisia absinthium L) extracts

In an effort to discover new antioxidant natural compounds, wormwood (Artemisia absinthium L) an aromatic‐bitter herb, was screened. The sequential extraction was realized with five solvents of different polarities (70% methanol, petroleum ether, chloroform, ethyl acetate, n‐butanol). The antioxidative activity was tested by measuring their ability to scavenge stable 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) free radical and reactive hydroxyl radical during the Fenton reaction trapped by 5,5‐dimethyl‐1‐pyrroline‐N‐oxide (DMPO), using electron spin resonance (ESR) spectroscopy. Results demonstrated that the antiradical and antioxidative activity depend on the type and concentration of applied extracts and increased in the order ethyl acetate > methanol > n‐butanol > chloroform > petroleum ether > remaining water extracts. The investigation showed that the antiradical activity increased with increasing concentration of all extracts. The high contents of total phenolic compounds (25.6 mg g^?1) and total flavonoids (13.06 mg g^?1) indicated that these compounds contribute to the antiradical and antioxidative activity. In a model system, the formation of o‐semiquinone radicals from quercetin and chlorogenic acid was obtained to prove the mechanism (hydrogen donating and/or one‐electron reduction) of free‐radical scavenging activity. Copyright © 2004 Society of Chemical Industry     

ANTILIPOPEROXIDATIVE EFFECT OF THREE EDIBLE PLANTS EXTRACTS: VISCUM ALBUM, ARUM DIOSCORIDIS AND EMINIUM SPICULATUM

ABSTRACT

In this study, evaluation of the antilipoperoxidative activity of the aqueous, boiled and nonboiled, and methanolic extracts of Viscum album (leaves, stems and fruits), Arum dioscoridis and Eminium spiculatum leaves against lipid peroxidation (LPO) induced by a rat liver homogenate model was undertaken. LPO was induced by ascorbate/FeCl₂ mixture and evaluated using thiobarbituric acid reactive species assay. Nonboiled aqueous extracts exhibited the highest LPO inhibition percent, followed by methanolic and boiled aqueous extracts. Moreover, LPO inhibition percent was dose dependent, where 1.65 × 10^?2 mg/mL caused the highest inhibition percent in all aqueous extracts. Aqueous extracts of A. dioscoridis and E. spiculatum exhibited significantly lower LPO inhibition percents than V. album parts, which were comparable to those obtained from the aerial parts of the positive control (Rosmarinus officinalis). Antioxidant capacity was the highest in V. album stems and leaves in all methods of extraction, and was comparable to the R. officinalis results, while V. album fruits, A. dioscoridis and E. spiculatum leaves possessed approximately 50% of antioxidant capacity using all methods of extractions. These results suggest that these plants can be used as a condiment during food processing, to improve the quality, enhance flavor, increase the nutritional value and increase the shelf life of processed food.

PRACTICAL APPLICATIONS

Viscum album, Arum Dioscoridis and Eminium Spiculatum can be used to improve the quality, boost the nutritional value and prolong the shelf life of processed food.