Trolox Equivalent Antioxidant Capacity Method Research Articles

Polyphenol recovery from sorghum bran waste by microwave assisted extraction: Structural transformations as affected by grain phenolic profile

Sorghum milling waste stream (bran), contains diverse phenolic compounds with bioactive properties. The study determined the potential of microwave assisted extraction (MAE) to recover the bran phenolic compounds. Red, white, and lemon-yellow pericarp sorghum brans were subjected to MAE and phenolic yield and structural transformation vs conventional extraction (control) assessed by UPLC-MS/MS, Folin-Ciocalteu and Trolox equivalent antioxidant capacity methods. Phenols yield increased from 3.7–20.3 to 12.6–75.5 mg/g, while antioxidants capacity increased average 3.3X in MAE extracts vs controls. Hydroxycinnamic acids increased most dramatically (3.0–32X) in MAE extracts (0.08–2.64 to 2.57–8.01 mg/g), largely driven by release of cell-wall derived feruloyl- and coumaroyl-arabinose. MAE hydrolyzed flavonoid glycosides into aglycones, and depolymerized condensed flavonoid heteropolymers into flavanones, flavanols and (deoxy)anthocyanidins. Thus, MAE dramatically enhances yield of valuable phenolics from sorghum bran waste, but also alters the phenolic profile in ways that may influence their chemical and biological properties.

The Influence of Sulfur Dioxide Concentration on Antioxidant Activity, Total Polyphenols, Flavonoid Content and Individual Polyphenolic Compounds in White Wines during Storage

Wines represent a rich source of bioactive compounds, especially polyphenolic compounds, which mostly contribute to the antioxidant activity. Sulfur dioxide (SO2) has mostly been used as a preservative in winemaking to prevent oxidation during storage. The aim of this paper is to evaluate the changes in SO2 levels and the influence of sulfur dioxide addition at seven different concentrations on the antioxidant activity (detected by DPPH-2,2-diphenyl-1-picrylhydrazyl and the ABTS Trolox equivalent antioxidant capacity methods), total polyphenols, flavonoid content and individual polyphenolic compounds (determined by the HPLC high-performance liquid chromatography method) of white wines during 5 months of storage. The assayed sulfur dioxide concentrations show a decreasing tendency with time, with a final decrease of more than 50% in comparison with the start of the experiment. Between the first and second measurements, the average decrease in sulfur dioxide was 16%. In the following interval, it was found that the maximum decline in SO2 was 26%. The changes in SO2 levels cannot be considered statistically significant. At the same time, we observed a decreasing tendency in the TPC content during storage. The antioxidant activity determined by the DPPH method at the beginning of the experiment ranged from 116.75 up to 270.62 mg·L−1, while the antioxidant activity increased with sulfur dioxide concentration. The AA detected by the ABTS method displayed a decreasing tendency during storage. In the case of the TFC content, we observed a significant influence of sulfur dioxide on the concentration. No addition or addition of high SO2 concentrations negatively influenced the flavonoid content in the samples. During storage, we observed a highly variable content of phenolic compounds in relation to SO2 addition. The most abundant compounds were chlorogenic acid, caffeic acid and epigallocatechin.

Antioxidant potential and antiangiogenic activity of Tetraselmis suecica grown in a semicontinuous culture

AbstractBACKGROUNDA main advantage of microalgae cultivation is its capacity to produce metabolites of biotechnological interest through modification of growth conditions. The aim was to evaluate the effect of strontium addition (Sr) to the culture medium and culture scale‐up of Tetraselmis suecica on antioxidant capacity and antiangiogenic activity.RESULTSAntiradical activity in extracts through the DPPH (α, α‐diphenyl‐β‐picrylhydrazyl free radical) scavenging method was higher for a 5‐L reactor (81.9 ± 2.5%) than for a 80‐L reactor (60 ± 4.6%), and through the TEAC (Trolox equivalent antioxidant capacity) method, the activity measures were 1.38 ± 0.05 and 1.12 ± 0.05 mmol Trolox, respectively. Lipid peroxidation β‐carotene bleaching reached the highest activity coefficients for the 80‐L reactor (ethanol extract 724 ± 35 AAC). Antioxidant activity was similar with and without Sr, although it was affected by the scale‐up. Extractable solids were maximized in the 80‐L reactor (350 ± 6 mg g−1 for methanol–water), whereas phenolic compounds were higher for ethanol extracts (5.5 ± 0.1 mg GAE g−1 for 5‐ and 80‐L reactors, without Sr addition). The antiangiogenic activity was improved in the methanol extract by ≈50% more than the negative control.CONCLUSIONThe antioxidant activity of T. suecica biomass can be improved using different culture scale‐ups and solvents during extraction, increasing the production of natural sources of antioxidant and antiangiogenic compounds for their use in food, health and cosmetics. © 2022 Society of Chemical Industry (SCI).

Bee Pollen Extracts: Chemical Composition, Antioxidant Properties, and Effect on the Growth of Selected Probiotic and Pathogenic Bacteria.

This paper evaluated the chemical and biological properties of bee pollen samples from Romania. Firstly, the bee pollen alcoholic extracts (BPEs) were obtained from raw bee pollen harvested by Apis mellifera carpatica bees. The chemical composition of BPE was obtained by determination of total phenol content and total flavonoid content, UHPLC-DAD-ESI/MS analysis of phenolic compounds, and GC-MS analysis of fatty acids, esters, and terpenes. Additionally, the antioxidant activity was evaluated by the Trolox Equivalent Antioxidant Capacity method. Furthermore, the biological properties of BPE were evaluated (antimicrobial and cytotoxic activity). The raw BP samples studied in this paper had significant phenolic acid and flavonoid content, and moderate fatty acid, ester, and terpene content. P1, P2, and P4 have the highest TPC and TFC levels, and the best antioxidant activity. All BPEs studied had antimicrobial activity on pathogenic strains isolated from the clinic or standard strains. A synergistic antimicrobial effect of the BPEs was observed along with the soluble compounds of L. rhamnosus MF9 and E. faecalis 2M17 against some pathogenic (clinical) strains and, considering the tumour proliferation inhibitory activity, makes BP a potential prebiotic and antitumour agent for the gut environment.

Evaluation of Galantamine, Phenolics, Flavonoids and Antioxidant Content of Galanthus Species in Turkey

Aims: The aim of the present study was to determine the total phenolic and flavonoid content and antioxidant activities in Galanthus species (Gaalanthus woronowii, Galanthus nivalis, and Galanthus elwesii) indigenous to Turkey.
 Study Design: The plant materials used in the study, Galanthus elwesii samples were collected in Antalya province, Galanthus nivalis samples were collected in Istanbul province, and Galanthus woronowii samples were collected in Çaykara, Trabzon province in September 2018.
 Place and Duration of Study: Plant samples were stored in Herbarium Material Warehouse at Afyon Kocatepe University. The plant leaves and grated bulbs were dried in an incubator at 60°C. The bulb and leaf samples were then pulverized to 80 mesh particle size for analysis.
 Methodology: Total phenolic content was determined spectrophotometrically with Folin-Ciocalteu procedure and calculated as gallic acid equivalent (GAE). Total flavonoid content was determined with aluminum chloride colorimetric method and calculated as catechin equivalent (CAE). Antioxidant activities were determined with TEAC (Trolox equivalent antioxidant capacity) and DPPH (diphenyl-p-picrylhydrazyl radical) methods. The phenolic acid and galantamine content were determined by reversed phase HPLC.
 Results: The highest total flovanoid content was determined as 33 mg CAE/g DW in Galanthus woronowii leaves and as 27 mg CAE / g DW in bulbs. DPPH removal activity was 77% in 500 μg/mL Galanthus woronowii leaf extract concentration and 93% in the ascorbic acid control group. The highest antioxidant content was observed in the leaves of Galanthus woronowii as 23 µmol Trolox/100 g DW and as 21 µmolTrolox/100 g DW in the bulbs. Higher galantamine content was determined in aerial parts (leaves) when compared to the underground parts (bulbs). The galantamine content in the leaves of all three Galanthus species was about 0.082%. The galantamine content in the bulbs of all three species was about 0.045%. Gallic, protocatechic, vanilic, caffeic, syringic, rosmarinic acid and catechin were identified in the leaves and bulbs of the three species with HPLC phenolic acid analysisIt was determined that the major phenolic acid was gallic acid.
 Conclusion: The present study findings demonstrated that Galantthus species has antioxidant capacity. Galanthus spp. leaves had higher antioxidant activity when compared to the bulbs. Galanthus woronowii exhibited the highest antioxidant activity among the scrutinized species.

Genotypic Variation in Anthocyanins, Phenolic Compounds, and Antioxidant Activity in Cob and Husk of Purple Field Corn

Information on phytochemicals in the cob and husk of field corn is important for the use of corn waste in the production of value-added corn products. The objectives of this study were to evaluate the variation in monomeric anthocyanin content (MAC), total phenolic content (TPC), and antioxidant activity, as determined by 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging activity and Trolox equivalent antioxidant capacity (TEAC) in 53 purple field corn genotypes, and to study the correlations of these traits with color parameters. Fifty-three corn genotypes were planted in a randomized complete block design with three replications in two locations in the dry season of 2015/2016. The effects of genotype, location, and the interaction between genotype and location were significant for most characters. Genotypic variation contributed to a large portion of the total variance for all traits, accounting for 63.9–86.9%. Corn genotypes were classified into six groups based on MAC, TPC, and antioxidant activity determined by the DPPH and the TEAC methods. The highest MAC, TPC, and antioxidant activity were obtained in TB/KND//PF3 and TB/KND//PF8 for husk, and only TB/KND//PF8 for cob. They should be used as parental lines to develop corn varieties with high phytochemicals. Chroma (C*) and hue (H°) of color parameters could potentially be used as an indirect selection criterion for improving MAC, TPC, and antioxidant activity in cob. The information is useful for the improvement of phytochemicals in cob and husk of field corn.

The Effect of an Edible Coating with Tomato Oily Extract on the Physicochemical and Antioxidant Properties of Garambullo (Myrtillocactus geometrizans) Fruits

The Myrtillocactus geometrizans (Mart. ex. Pfeiff.) fruit, locally called garambullo, is an important source of bioactive compounds, mainly betalains, polyphenols, and ascorbic acid. However, information on the application of post-harvest technologies that prolong the shelf life of the fruits is still insufficient. The objective of the present research was to evaluate the effect of a gelatin coating incorporating 0%, 1%, or 3% tomato oily extract (TOE), compared to a control (without coating), on the physicochemical and antioxidant properties of garambullo fruits stored for 15 days at 5 °C. The gelatin coatings with TOE significantly (p ≤ 0.05) delayed changes in weight loss, brix degrees, titratable acidity and pH, compared to the control during storage. Fruits coated with TOE-gelatin had a higher content of betalains, ascorbic acid, total phenols, and flavonoids. The results showed that a higher concentration of phytochemicals increased antioxidant activity in vitro; the maximum values found for Trolox equivalents per kg of fresh weight were 10.46 and 17.65 mM for the 2,2′-diphenyl-1-picrylhydrazyl (DPPH) and Trolox Equivalent Antioxidant Capacity Method (TEAC) tests, respectively. The gelatin coating with TOE-3% (COTE-3%) reduced water loss by 1.66 times, compared to the control. In addition, the fruits covered with COTE-3% showed the highest concentration of bioactive compounds during storage.

Antioxidant activity of mangaba (Hancornia speciosa) and acerola (Malpighia emarginata) fruit pulp and residues

Antioxidants are compounds which protect the biological system against the damaging effects of processes or reactions that can cause excessive oxidation. Fruits contain various antioxidants whose activities have been well proven in reduction of degenerative diseases. The aim of the study was to determine the total antioxidant activity by free radical capture method DPPH (2,2-diphenyl-1-picryl hydrazyl), TEAC (Trolox Equivalent Antioxidant Capacity) and ORAC (Oxygen Radical Absorbance Capacity) and compare the levels of total phenolic compounds in ethanol, methanolic and aqueous extracts of pulp and residue of mangaba and acerola fruits. The flour was obtained by the residue of the peel and seeds of the fruits after pulping, the extracts were obtained by ethanol, methanol and water using ultrasound. The DPPH and TEAC tests were performed with a spectrophotometer at 517 and 750 nm, respectively, while ORAC was carried out with the aid of fluorimeter, using 520 nm emission and 485 nm excitation filters. The results showed better antioxidant activity with the aqueous extracts in all methods, but the TEAC method had the highest antioxidant activity for acerola pulp and residue (429 µM Trolox g-1 and 90.89 µM Trolox g-1, respectively), followed by mangaba pulp and residue (201 µM Trolox g-1 and 61.87 µM Trolox g-1, respectively). In addition, the highest content of phenolic compounds was found in the residue of acerola (31 mg gallic acid 100 g-1), followed by the mangaba pulp (21 mg gallic acid 100 g-1).

Development of a new measurement method to determine plant antioxidant status


 The antioxidant capacity of 12 cultivar that were harvested in 2014, were determined by FRAP (Ferric Reducing Ability of Plasma), DPPH (1,1-diphenyl-2-picrylhydrazyl radical-scavenging activity) TEAC (Trolox Equivalent Antioxidant Capacity) and photochemiluminescence method. In sour cherry, the most antioxidant effects of natural bioactive compounds are anthocyanins. Our results show that the photochemiluminescence method is the most suitable to determine the antioxidant capacity of red soft fruits and tart cherries

Total antioxidant capacity of the Korean diet.

BACKGROUND/OBJECTIVESThe objective of this study was to measure and/or estimate the total antioxidant capacity of the Korean diet.MATERIALS/METHODSEighty-one plant foods that were expected to exhibit rather high antioxidant activities were selected from the Korean diet using the Fifth Korean National Health and Nutrition Survey (KNHANES V). These foods were categorized into 11 food groups: cereals, potatoes, legumes, nuts, vegetables, kimchies, mushrooms, fruits, fruit juices, sea weeds, and oils. The foods were mixed in the proportions specified in traditional Korean recipes and analyzed. The measured indicators for antioxidant capacities were total phenolics, 2,2-diphenyl-1-picrylhydrazyl (DPPH), oxygen radical absorbance capacity (ORAC), and Trolox equivalent antioxidant capacity (TEAC).RESULTSTotal phenolics were high in the fruit juices, nuts, vegetables, and fruits; and the average DPPH, ORAC, and TEAC values were high in the vegetables, fruits, fruit juices, and nuts. The correlation coefficient between the content of total phenolics of each food and the in vitro antioxidant capacity was relatively high at 0.851. The intake of total phenolics per capita per day in the Republic of Korea was estimated to be 127 mg. The total dietary antioxidant capacity (TDAC) values, which were obtained from the total antioxidant capacity of each food, taking into account the intake of each food, were 20,763, 54,335, and 876.4 µmol of Trolox equivalents using the DPPH, ORAC, and TEAC methods, respectively. The food group that contributed the most to the Korean TDAC was cereals at 39.7%, followed by fruits and vegetables at 27.8% and 13.9%, respectively. The contribution of legumes, nuts, fruit juices, and mushrooms was quite minimal at less than 2% each.CONCLUSIONSThe content of total phenolics and the antioxidant capacity of the Korean diet are significantly correlated and the high contributing food groups are cereals, fruits, and vegetables.

Effect of the French oak wood extract Robuvit on markers of oxidative stress and activity of antioxidant enzymes in healthy volunteers: a pilot study.

We examined in vitro antioxidant capacity of polyphenolic extract obtained from the wood of oak Quercus robur (QR), Robuvit, using TEAC (Trolox equivalent antioxidant capacity) method and the effect of its intake on markers of oxidative stress, activity of antioxidant enzymes, and total antioxidant capacity in plasma of 20 healthy volunteers. Markers of oxidative damage to proteins, DNA, and lipids and activities of Cu/Zn-superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) were determined in the erythrocytes. We have found an in vitro antioxidant capacity of Robuvit of 6.37 micromole Trolox equivalent/mg of Robuvit. One month intake of Robuvit in daily dose of 300 mg has significantly decreased the serum level of advanced oxidation protein products (AOPP) and lipid peroxides (LP). Significantly increased activities of SOD and CAT as well as total antioxidant capacity of plasma after one month intake of Robuvit have been shown. In conclusion, we have demonstrated for the first time that the intake of Robuvit is associated with decrease of markers of oxidative stress and increase of activity of antioxidant enzymes and total antioxidant capacity of plasma in vivo.

Determination of Phytochemicals and Antioxidant Activity in Butterhead Lettuce Related to Leaf Age and Position

The effect of leaf position on phytochemical distribution in butterhead lettuce was assessed by rings (from ring 1: outer leaves, to ring 6: inner leaves) or by zones (external, middle, internal). Maximum ascorbic acid was found in middle rings while chlorophyll and carotenoids gradually decreased from external to internal rings. Outermost leaves accumulate more phenolics and present more antioxidant activity as determined by 2,2-diphenyl-1-picrylhydrazyl (DPPH) and trolox-equivalent antioxidant capacity methods. However, the presence of phenolics in this zone also contributes to the enzymatic browning. Quantitative but not qualitative differences were found in the phenolic profiles between inner and outer lettuce zones. The major phenolic compounds identified were the phenolic acids chicoric, chlorogenic and isochlorogenic. For all phenolic compounds, greater content was always found in the external zone except for caffeic acid. A high correlation between DPPH and total phenolics, chlorophyll and carotenes indicated that these compounds were major contributors of antioxidant activity in lettuce. Practical Application During lettuce development, each leaf had a different level of exposure to environmental conditions (light, humidity, nutrients absorption and temperature) and also inner leaves are younger than outer ones. These factors may affect the distribution of phytochemicals and antioxidant capacity in the lettuce head. Knowledge of the bioactive content and antioxidant capacity profile in lettuce plants could be of interest to consumers and the food industry for selecting the more suitable leaves to make salads or other ready-to-eat mixed vegetable dishes with high nutritional value. Additionally this study reveals, from a nutritional point of view, the losses value of regular greengrocers' practices that include the removal of the external lettuce leaves as storage advances and signs of senescence are evident.

Pyridine Based Chalcones: Synthesis and Evaluation of Antioxidant Activity of 1-Phenyl-3-(pyridin-2-yl)prop-2-en-1-one Derivatives

Natural chalcones and also their synthetic derivatives have attracted increasing attention due to various pharmacological applications. Development and discovery of new chalcones with antioxidant activities is one of the attracting areas in medicinal and natural product chemistry. In the present study, a new series of pyridine based chalcones was synthesized and their antioxidant capacity was evaluated by beta carotene bleaching (BCB), DPPH free radical scavenging, ferrous ion chelating (FIC) activity and Trolox equivalent antioxidant capacity (TEAC) methods. All compounds were synthesized via an aldol condensation procedure in methanol or ethanol solvent at room temperature and characterization was carried out by (1)HNMR, IR and MS spectroscopic methods. Related melting points were also measured for each compound. Fortunately, compounds 3e (16.53 ± 1.21 µg/mL), 3g (58.85 ± 1.10 µg/mL) and 3i (58.73 ± 12.94 µg/mL) showed higher antioxidant activity (EC50 ± SD) in comparison with quercetin (87.24 ± 3.93 µg/mL) as reference agent in ferrous ion chelating method. Furthermore, compounds 3g (4.82 ± 0.11 µg/mL) and 3h (6.33 ± 0.30 µg/mL) also exhibited an acceptable antioxidant property compared to Trolox (3.83 ± 0.22 µg/mL) in TEAC method. None of synthesized compounds demonstrated significant antioxidant activity in DPPH free radical scavenging as well as beta carotene bleaching tests. According to the obtained data, synthesized pyridine based chalcones (3a-3j) could be proposed as potential antioxidant lead compounds.

Quality parameters, bioactive compounds and their correlation with antioxidant capacity of commercial fruit-based baby foods

Comprehensive research is required to achieve the optimization of the antioxidant protection through baby foods, in particular, the commercially available fruit-based baby foods. This study investigated the physicochemical properties, ascorbic acid (AA), total carotenoids (TC), total phenolic content (TPC), trolox equivalent antioxidant capacity (TEAC) and oxygen radical absorbance capacity (ORAC) of 23 different commercially available fruit-based baby foods. The main contribution to the total antioxidant capacity (trolox equivalent antioxidant capacity and oxygen radical absorbance capacity) was provided by ascorbic acid, followed by phenolic compounds, in accordance with a mathematical equation obtained from the data: TEAC = 245.906 + 7.727 × (AA) + 1.988 × (TPC) - 0.008 × (TC) and ORAC = 318.662 + 2.775 × (AA) - 0.531 × (TPC) - 0.073 × (TC). Moreover, a positive correlation (r = 0.346, p < 0.05) was found for oxygen radical absorbance capacity and trolox equivalent antioxidant capacity methods. Baby foods with different kind of fruits used as ingredients showed higher antioxidant capacity. Among the commercial baby foods analysed in this work, that treated by gentle steam cooking process had high levels of bioactive compounds and antioxidant capacity.

Evaluation of Antioxidant Activity in Foods with Special Reference to TEAC Method

The antioxidant capacity of complex heterogeneous foods and biological systems is affected by many factors. Considering the importance of antioxidants, it is of great interest to know the antioxidant capacity of the constituents in foods. The Total Antioxidant Capacity (TAC) is a parameter that provides information on the overall status of antioxidants within a complex biological sample. TAC, as determined by Trolox Equivalent Antioxidant Capacity (TEAC) method, offers several advantages over other methods and is relatively easy. Due to its operational simplicity, the TEAC assay has been used for studying antioxidant capacity and TEAC values of many compounds and food samples. The article deals with various developments in the method, its merits and demerits and its application in determining the TAC of various food commodities.

Anticancer and Antimicrobial Activities of Some Antioxidant-Rich Cameroonian Medicinal Plants

Traditional remedies have a long-standing history in Cameroon and continue to provide useful and applicable tools for treating ailments. Here, the anticancer, antimicrobial and antioxidant activities of ten antioxidant-rich Cameroonian medicinal plants and of some of their isolated compounds are evaluated.The plant extracts were prepared by maceration in organic solvents. Fractionation of plant extract was performed by column chromatography and the structures of isolated compounds (emodin, 3-geranyloxyemodin, 2-geranylemodin) were confirmed spectroscopically. The antioxidant activity (AOA) was determined using the 1,1-diphenyl-2-picrylhydrazyl (DPPH) bleaching method, the trolox equivalent antioxidant capacity (TEAC), and the hemoglobin ascorbate peroxidase activity inhibition (HAPX) assays. The anticancer activity was evaluated against A431 squamous epidermal carcinoma, WM35 melanoma, A2780 ovary carcinoma and cisplatin-resistant A2780cis cells, using a direct colorimetric assay. The total phenolic content in the extracts was determined spectrophotometrically by the Folin–Ciocalteu method. Rumex abyssinicus showed the best AOA among the three assays employed. The AOA of emodin was significantly higher than that of 3-geranyloxyemodin and 2-geranylemodin for both TEAC and HAPX methods. The lowest IC50 values (i.e., highest cytotoxicity) were found for the extracts of Vismia laurentii, Psorospermum febrifugum, Pentadesma butyracea and Ficus asperifolia. The Ficus asperifolia and Psorospermum febrifugum extracts are selective against A2780cis ovary cells, a cell line which is resistant to the standard anticancer drug cisplatin. Emodin is more toxic compared to the whole extract, 3-geranyloxyemodin and 2-geranylemodin. Its selectivity against the platinum-resistant A2780cis cell line is highest. All of the extracts display antimicrobial activity, in some cases comparable to that of gentamycin.

Assessing and Comparing the Total Antioxidant Capacity of Commercial Beverages: Application to Beers, Wines, Waters and Soft Drinks Using TRAP, TEAC and FRAP Methods

This work measures and tries to compare the Antioxidant Capacity (AC) of 50 commercial beverages of different kinds: 6 wines, 12 beers, 18 soft drinks and 14 flavoured waters. Because there is no reference procedure established for this purpose, three different optical methods were used to analyse these samples: Total Radical trapping Antioxidant Parameter (TRAP), Trolox Equivalent Antioxidant Capacity (TEAC) and Ferric ion Reducing Antioxidant Parameter (FRAP). These methods differ on the chemical background and nature of redox system. The TRAP method involves the transfer of hydrogen atoms while TEAC and FRAP involves electron transfer reactions. The AC was also assessed against three antioxidants of reference, Ascorbic acid (AA), Gallic acid (GA) and 6-hydroxy-2,5,7,8-tetramethyl- 2-carboxylic acid (Trolox). The results obtained were analyzed statistically. Anova one-way tests were applied to all results and suggested that methods and standards exhibited significant statistical differences. The possible effect of sample features in the AC, such as gas, flavours, food colouring, sweeteners, acidity regulators, preservatives, stabilizers, vitamins, juice percentage, alcohol percentage, antioxidants and the colour was also investigated. The AC levels seemed to change with brand, kind of antioxidants added, and kind of flavour, depending on the sample. In general, higher ACs were obtained for FRAP as method, and beer for kind of sample, and the standard expressing the smaller AC values was GA.

Antioxidant and antimicrobial activities of ethyl acetate extract, fractions and compounds from stem bark of Albizia adianthifolia (Mimosoideae)

BackgroundAlbizia adianthifolia is used traditionally in Cameroon to treat several ailments, including infectious and associated diseases. This work was therefore designed to investigate the antioxidant and antimicrobial activities of ethyl acetate extract, fractions and compounds isolated from the stem bark of this plant.MethodsThe plant extract was prepared by maceration in ethyl acetate. Its fractionation was done by column chromatography and the structures of isolated compounds were elucidated using spectroscopic data in conjunction with literature data. The 1,1-diphenyl-2-picrylhydrazyl (DPPH) and trolox equivalent antioxidant capacity (TEAC) assays were used to detect the antioxidant activity. Broth micro-dilution method was used for antimicrobial test. Total phenol content was determined spectrophotometrically in the extracts by using Folin–Ciocalteu method.ResultsThe fractionation of the extract afforded two known compounds: lupeol (1) and aurantiamide acetate (2) together with two mixtures of fatty acids: oleic acid and n-hexadecanoic acid (B1); n-hexadecanoic acid, octadecanoic acid and docosanoic acid (B2). Aurantiamide acetate was the most active compound. The total phenol concentration expressed as gallic acid equivalents (GAE) was found to vary from 1.50 to 13.49 μg/ml in the extracts. The antioxidant activities were well correlated with the total phenol content (R2 = 0.946 for the TEAC method and R2 = 0.980 for the DPPH free-radical scavenging assay).ConclusionsOur results clearly reveal that the ethyl acetate extract from the stem bark of A. adianthifolia possesses antioxidant and antimicrobial principles. The antioxidant activity of this extract as well as that of compound 2 are being reported herein for the first time. These results provide promising baseline information for the potential use of this plant as well as compound 2 in the treatment of oxidative damage and infections associated with the studied microorganisms.

Hypolipidemic Effect of Avocado (Persea americana Mill) Seed in a Hypercholesterolemic Mouse Model

Avocado seed contains elevated levels of phenolic compounds and exhibits antioxidant properties. We investigated the effect of Avocado Seed Flour (ASF) on the lipid levels in mice on a hyperlipidemic diet. The concentration of phenols was determined by high-performance liquid chromatography, antioxidant activity was evaluated using the Trolox equivalent antioxidant capacity method, and dietary fiber was measured using the Association of Official Analytical Chemists (AOAC) method. The LD50 of ASF was determined using Lorke's method and hypolipidemic activity was evaluated in a hypercholesterolemic model in mice. Protocatechuic acid was the main phenolic compound found in ASF, followed by kaempferide and vanillic acid. The total phenolic content in the methanolic extract of ASF was 292.00 ± 9.81 mg gallic acid equivalents/g seed dry weight and the antioxidant activity resulted in 173.3 μmol Trolox equivalents/g DW. In addition, a high content of dietary fiber was found (34.8%). The oral LD50 for ASF was 1767 mg/kg body weight, and treatment with ASF significantly reduced the levels of total cholesterol, LDL-C, and prediction of the atherogenic index. Therefore, the antioxidant activity of phenolic compounds and dietary fiber in ASF may be responsible for the hypocholesterolemic activity of ASF in a hyperlipidemic model of mice.

Effect of leaf position on the distribution of phytochemicals and antioxidant capacity among green and red lettuce cultivars

In recent years, there has been an increasing interest in consumption of red fruits and vegetables due to its rich dietary sources of antioxidant, phenolics and anthocyanins. In this study, phytochemical and antioxidant properties of green and red lettuce cultivars were studied. Particularly, the effect of leaf position on these properties was compared. Eight conventionally grown cultivars of lettuce (Lactuca sativa L.), with four green (Fonseca, Freckles, Krizet and Filipus) and four red (Versai, Nation, Paradai and Cherokee) cultivars were studied. Their leaves were divided into three groups; outer, middle and inner part. Total antioxidant capacity (TAC) of each group of leaves was assessed by both trolox-equivalent antioxidant capacity (TEAC), and the ferric reducing antioxidant power (FRAP) assay. Leaf color, total soluble solids, total phenolics (TP), total anthocyanin (TACY), chlorophyll a and b were determined. The results demonstrated that outer leaves have the highest phytonutrient content and antioxidant properties. Outer leaves exhibited significantly higher TP and TAC than middle and inner leaves in both red and green color lettuce. The average TP content of red lettuce were 845, 297 and 195 μg gallic acid equivalent per gram fresh weight in the outer, middle and inner leaves, respectively. Also TAC of outer leaves was significantly higher than middle and inner leaves in both red and green color lettuce. The magnitude of difference between red and green cultivars was significant as determined by both TEAC and FRAP methods.