Linoleic Acid Emulsion Research Articles

Quantification of Antioxidant Ability Against Lipid Peroxidation with an ‘Area Under Curve’ Approach

AbstractWhen oxygen is passed through a linoleic acid (LA) emulsion containing copper(II), primary (hydroperoxides) and secondary oxidation products (aldehydes and ketones) are formed, monitored by ferric thiocyanate (Fe(III)‐SCN) and thiobarbituric acid reactive substances (TBARS) colorimetry, respectively. As total antioxidant capacity (TAC) against lipid peroxidation was not quantified before, both methods were adapted to an ‘area under curve (AUC)’ approach. LA peroxidation followed pseudo‐first order kinetics in aerated emulsions. Absorbance changes as a function of incubation time exhibited sigmoidal curves, enabling the calculation of ‘area under curve’ (AUC) and net AUC = AUCblank−AUCsample, standard calibration curve as net AUC versus concentration, and trolox‐equivalent antioxidant capacity of the tested compounds. Garlic extract showed an antioxidative effect on hydroperoxide formation, but a prooxidative effect on TBARS. Although inhibition of lipid peroxidation was described qualitatively before, it was not evaluated quantitatively, e.g., the trolox‐equivalent antioxidant capacities (TEAC values) of antioxidants with respect to their inhibitive effect against lipid peroxidation were not calculated and compared. Additionally, real‐time monitoring of lipid oxidation products requires highly sophisticated but costly instrumental techniques, but no single oxidation product is a direct measure of lipid oxidation or its antioxidative prevention. The AUC approach is the first quantitative method measuring antioxidant protection against lipid oxidation, with a slightly different order of antioxidative effectiveness from reductive assays because of interfacial effects.

Effect of extraction and drying methods on antioxidant activity of astaxanthin from Haematococcus pluvialis

The effects of extraction methods (including maceration, microwave, ultrasound and magnetic field assisted extraction) and solvent evaporation methods (including water bath evaporation, vacuum freezing, vacuum and oven drying) on antioxidant activity of astaxanthin from H. pluvialis were studied. The potential antioxidant activities of extracts and dry astaxanthin samples were measured by 2, 2-Diphenyl-1-picrylhydrazyl (DPPH·), Hydroxyl (OH·) radical scavenging activity and linoleic acid emulsion. Being compared with the antioxidant activities of astaxanthin at concentration of 25μg/ml, the magnetic field extracts and sample by treated water bath evaporation showed the highest DPPH radical scavenging activity of 60.76 and 57.6%, respectively. While magnetic field extract and vacuum freeze-drying sample of astaxanthin showed the highest hydroxyl radical scavenging activity of 18.8 and 16.78%, respectively. The results were found to be significantly higher than the other methods processed samples of the respective varieties (p<0.05). All extracts and drying samples exhibited good antioxidant activity against the linoleic acid emulsion system (p<0.05).

Inhibition of lipid oxidation in foods and feeds and hydroxyl radical-treated fish erythrocytes: A comparative study of Ginkgo biloba leaves extracts and synthetic antioxidants.

This study explored the effects of butylated hydroxytoluene (BHT) and ethoxyquin (EQ) and ethyl ether extracts, ethyl acetate extracts (EAE), acetone extracts, ethanol extracts and aqueous extracts of Ginkgo biloba leaves (EGbs) on lipid oxidation in a linoleic acid emulsion, fish flesh and fish feed and in hydroxyl radical (·OH)-treated carp erythrocytes. The linoleic acid, fish flesh and fish feed were incubated with BHT, EQ and EGbs at 45°C for 8 d, respectively, except for the control group. The lipid oxidation in the linoleic acid emulsion, fish flesh and fish feed was then measured by the ferric thiocyanate method or thiobarbituric acid method. The carp erythrocytes were treated with BHT, EQ or EGbs in the presence of 40 μmol/L FeSO4 and 20 μmol/L H2O2 at 37°C for 6 h, except for the control group. Oxidative stress and apoptosis parameters in carp erythrocytes were then evaluated by the commercial kit. The results showed that BHT, EQ and EGbs inhibited lipid oxidation in the linoleic acid emulsion, fish flesh and fish feed and ·OH-induced phosphatidylserine exposure and DNA fragmentation (the biomarkers of apoptosis) in carp erythrocytes. Furthermore, BHT, EQ and EGbs decreased the generation of reactive oxygen species (ROS), inhibited the oxidation of cellular components and restored the activities of enzymatic antioxidants in ·OH-treated carp erythrocytes. Of all examined EGbs, EAE showed the strongest effects. The effects of EAE on lipid oxidation in the linoleic acid emulsion and on superoxide anion and malonaldehyde levels, catalase activity and apoptosis in ·OH-treated carp erythrocytes were equivalent to or stronger than those of BHT. Moreover, these results indicated that the inhibition order of EGbs on the generation of ROS and oxidation of cellular components in fish erythrocytes approximately agreed with that for the food and feed materials tested above. And, the antioxidative and anti-apoptotic effects of EGbs were positively correlated with their flavonoid content. Taken together, these results revealed that the fish erythrocyte system can be used as an experimental model to evaluate lipid oxidation in food and feed ingredients. The EAE can be used as a potential natural antioxidant or apoptosis inhibitor. The inhibition effects of EGbs on lipid oxidation and apoptosis may be due to the presence of flavonoid compounds.

Effects of Drying Temperature on Antioxidant Activities of Tomato Powder and Storage Stability of Pork Patties.

This study was performed to evaluate the antioxidant activity of oven-dried tomato powder (OTP) as affected by drying temperature and the effect of OTP on the product quality of pork patties. Three OTP products were obtained by drying of fresh tomato at 60, 80 and 100℃ oven until constant weight was obtained. Total phenolic content of three kinds of OTPs ranged from 1.95 to 5.94 g/100 g. The highest amount of total phenolic compound was observed in OTP dried at 100℃. Antioxidant activity of three kinds of OTPs was measured by 1,1-diphenyl-2-pycrylhydrazyl (DPPH)-radical scavenging activity, iron chelating ability, reducing power and measurement of lipid peroxide in linoleic acid emulsion system. In all parameters, OTP at 100℃ showed the higher antioxidant activity than other temperatures (p<0.05). Based on the model study, the physicochemical properties, and antioxidant and antimicrobial activities of pork patties containing 1% OTP were measured. Redness of pork patties were increased with the addition of OTPs (p<0.05). Thiobarbituric acid reactive substances (TBARS) values of raw pork patties containing OTPs were lower than those of control (CTL) until 7 d of storage, regardless of drying temperatures (p<0.05). Peroxide values of pork patties made with OTP (1%) were lower than those of CTL until the end of storage time (p<0.05). However, no antimicrobial activities were observed among the treatments (p>0.05). Therefore, OTPs could be used as a natural antioxidant in meat products.

Effects on Weight, Blood Lipids, Serum Fatty Acid Profile and Coagulation by an Energy-Dense Formula to Older Care Residents: A Randomized Controlled Crossover Trial

ObjectivesDietary intake in frail old adults is often lower than estimated needs. The aim of this study was to evaluate the effects of an energy-dense oral supplement on nutritional status, food intake, and physical function in residents living in care residential homes. DesignRandomized controlled intervention trial with a crossover design. SettingFive care residential homes in the southern Stockholm area. ParticipantsOlder people living at care residential homes: age 65 or older, malnourished or at risk of malnutrition according to Mini Nutritional Assessment-Short Form (MNA-SF). InterventionEnergy-dense formula (oleic and linoleic acid emulsion enriched with protein and micronutrients) (Calogen Extra, Nutricia) 30 mL distributed 3 times daily for 6 weeks. MeasurementsBody weight, 3-day food and fluid record, appetite rating, and physical function (ie, Short Physical Performance Battery, grip strength, and peak expiratory flow). Biochemical indicators of nutritional status, blood lipids, and serum phospholipid fatty acid (FA) profile. ResultsTwenty-eight participants completed the 2 phases of the crossover study; group A (n = 14, 87 ± 6 years, 50% women) and group B (n = 14, 82 ± 8 years, 71% women). The intervention periods combined resulted in significantly (P < .05) increased energy intake (238 ± 544 kcal), weight gain (1.4 ± 3.7 kg), improved appetite, relative reduction of saturated FA and increase in polyunsaturated FA, increased apoliporotein A, and reduced serum fibrinogen (–0.9 ± 1.5 g/L). ConclusionDistribution of an oleic and linoleic acid based fat emulsion enriched with protein and micronutrients (Calogen Extra) 3 times daily to old people in care residential homes improved nutritional status, had positive effects on fatty acid profile and blood lipids, and a potential antithrombotic effect. ClinicalTrials.gov IdentifierNCT01259999

Whey protein isolate/gum arabic intramolecular soluble complexes improving the physical and oxidative stabilities of conjugated linoleic acid emulsions

Protein–polysaccharide intramolecular soluble complexes are proved to have superior emulsifying properties in stabilizing PUFAs-based emulsions.

TOTAL PHENOLIC CONTENTS AND ANTIOXIDANT ACTIVITY OF SOME FRESH THAI CURRY

The objectives of this work were to study the total phenolic contents (TPC) and antioxidant activity of methanolic extracts of six fresh Thai curry. The TPC of the fresh Thai curry were found in the range of 0.989-1.1132 mg GAE/mg of extract. Among the curry, red curry present the highest amount of TPC. Antioxidant activity of the extracts was measured by DPPH-radical-scavenging assay, lipid peroxidation inhibition and metal ion chelating assay. The Thai red curry extract exhibited the highest inhibition of lipid peroxidation of linoleic acid emulsion (81.41±0.55%), radical-scavenging activity (IC50 = 0.0476 mg/mL). In addition, the fresh of Thai red curry had the highest of metal chelating activity (76.58±0.72%). However, all of fresh Thai curry showed metal chelating similar potential activity and not significant statistical differences. These results suggest that the fresh Thai curry had interesting antioxidant activities and should be propose as potential sources of safe natural antioxidants and preservatives for curry industry.

Efectiveness of topical therapies in patients with breast cancer that experience radiodermatitis. A systematic review

After radiation therapy most patients experience acute skin toxicity to some degree. The purpose of this systematic review is to assess the available evidence concerning the effectivity of topical therapies on patients with breast cancer that experience radiodermatitis after radiotherapy. The review included clinical trials aimed to evaluate topical therapies for prevention or treatment of acute radiodermatitis in women with breast cancer, which were published between 2009 and 2014. The bibliographic search was carried out in the following databases: PubMed, Cinahl, Cochrane Plus, IBECS and LILACS. The studies were selected independently by peer reviewers using the Critical Appraisal Skills Programme in its Spanish version. 86 bibliographical references were identified. Twenty full-text articles of clinical trials were assessed and two were excluded because they were not completed; 12 of clinical trials evaluated topical treatment with creams and ointments, three with corticosteroid creams and other three with dressings. The effectivity of human epidermal growth factor cream, linoleic acid emulsion, topical silver sulfadiazine, corticosteroids creams and polyurethane dressings has been shown in these clinical trials. Given that radiodermatitis is a dynamic process, these topical agents were effective in different stages of skin toxicity. Some of them delayed the onset, others decreased the development and severity of acute skin toxicity degree and others improved the subjective symptoms (itching, pain, burning). Only polyurethane dressings suggest effectiveness in all stages of skin toxicity, in prevention, management of the different skin toxicity degrees and improvement of wellbeing.

Synthesis, antioxidant and cathepsin D inhibition activity of quaternary ammonium chitosan derivatives

Two (2-hydroxypropyl) trimethyl ammonium and/or imidazole-based quaternary ammonium chitosan derivatives (NHT-chitosan and Im-OHT-chitosan) were synthesized by using nucleophilic substitution reaction. These two synthesized chitosan derivatives were characterized by Fourier transform infrared spectroscopy, NMR spectra, and UV–visible spectra. The applications as antioxidant agents and cathepsin D inhibitors were further investigated. Both of quaternary ammonium chitosan derivatives exhibited good antioxidant activity upon scavenging against hydroxyl radical and hydrogen peroxide as well as the lipid peroxidation inhibition in the linoleic acid emulsion system. They also exhibited good inhibition activity of cathepsin D protease. NHT-chitosan and Im-OHT-chitosan are potential the natural, healthy and safe preservatives in food industry.

Acethylcholinesterase inhibitory potential and antioxidant properties of pyrogallol

Pyrogallol is found naturally in crops and fruits of many plants. It is also an active ingredient of many pharmaceuticals. For this reason, we employed different in vitro antioxidant assays such as cupric ion Cu2+ reducing power, Fe3+ reducing power, total antioxidant activity by ferric thiocyanate method, ABTS radical scavenging, DMPD radical scavenging, DPPH • scavenging, Fe2+ chelating, scavenging and H2O2 scavenging activities of pyrogallol. Pyrogallol inhibited 77.95% lipid peroxidation of linoleic acid emulsion at 30 μg/mL concentration. BHA, BHT, α-tocopherol and trolox exhibited inhibitions of 89.88, 89.97, 83.82 and 91.85% against peroxidation of linoleic acid emulsion at the same concentration, respectively. In addition, pyrogallol was an effective of all the scavenging and reducing power results. In this study, pyrogallol was also evaluated as potential inhibitor for acethycholinesterse enzyme. The results showed that pyrogallol exhibited potent acetylcholinesteras inhibitory activity with IC50 and Ki values 10.2 and 8.6 μM, respectively.

Identification and Characterization of Novel Antioxidant Peptides Involved in Redox Homeostasis of Frog, Limnonectes fragilis.

Previous studies have proved that a novel antioxidant system composed of various antioxidant peptides (AOPs) exists in the skin of ranid frogs, keeping the redox homeostasis. However, only a small number of AOPs have been identified so far. Here, a total of 47 cDNA sequences encoding 21 different AOPs belonging to 11 families were cloned from the skin cDNA library of Limnonectes fragilis. Among them, fragilin-A1 (VKRRGQDCIHGFCSD) and fragilin-B1 (GQFNDKRWIPFG) were also purified from skin secretions. They were selected with odorranain-Q-Lf (APIRMWYMYRKLTDMEPKPVA), the newest sequence among all 21 AOPs, to evaluate the antioxidant activities by direct free radical scavenging and lipid peroxidation inhibition assay. Results demonstrated that all peptides possessed strong DPPH and ABTS(.+) scavenging activities, and effectively inhibited lipid peroxidation in linoleic acid emulsion system during a 7- day test. No cytotoxic and hemolytic activity against human erythrocytes was observed for the three AOPs. The homology modeling analysis revealed that they all adopt tertiary structures ideally suited for the key residues to come into contact with the radicals. Current results reveal the existence of antioxidant system constituted of AOPs in the skin of the L. fragilis, and furthermore provide excellent templates for the development of novel antioxidant agents.

Antioxidant activity of taxifolin: an activity–structure relationship

Taxifolin is a kind of flavanonol, whose biological ability. The objectives of this study were to investigate the antioxidants and antiradical activities of taxifolin by using different in vitro bioanalytical antioxidant methods including DMPD√+, ABTS√+, , and DPPH√-scavenging effects, the total antioxidant influence, reducing capabilities, and Fe2+-chelating activities. Taxifolin demonstrated 81.02% inhibition of linoleic acid emulsion peroxidation at 30 µg/mL concentration. At the same concentration, standard antioxidants including trolox, α-tocopherol, BHT, and BHA exhibited inhibitions of linoleic acid emulsion as 88.57, 73.88, 94.29, and 90.12%, respectively. Also, taxifolin exhibited effective DMPD√+, ABTS√+, , and DPPH√-scavenging effects, reducing capabilities, and Fe2+-chelating effects. The results obtained from this study clearly showed that taxifolin had marked antioxidant, reducing ability, radical scavenging and metal-chelating activities. Also, this study exhibits a scientific shore for the significant antioxidant activity of taxifolin and its structure-activity insight.

Antioxidant and Cytoprotective Effects of Lotus (Nelumbo nucifera) Leaves Phenolic Fraction.

Phenolic rich ethyl acetate fraction (EAF) from lotus leaves was prepared and its bioactive components, antioxidant and cytoprotective effects were investigated. EAF showed high total phenolic content and flavonoid content and contained rutin (11,331.3±4.5 mg/100 g EAF), catechin (10,853.8±5.8 mg/100 g EAF), sinapic acid (1,961.3±5.6 mg/100 g EAF), chlorogenic acid (631.9±2.3 mg/100 g EAF), syringic acid (512.3±2.5 mg/100 g EAF), and quercetin (415.0±2.1 mg/100 g EAF). EAF exerted the IC50 of 4.46 μg/mL and 5.35 μg/mL toward DPPH and ABTS cation radicals, respectively, and showed strong reducing power, which was better than that of ascorbic acid, a positive control. Additionally, EAF protected hydroxyl radical-induced DNA damage indicated by the conversion of supercoiled pBR322 plasmid DNA to the open circular form and inhibited lipid peroxidation of polyunsaturated fatty acid in a linoleic acid emulsion. In cultured hepatocytes, EAF exerted a cytoprotective effect against oxidative stress by inhibiting intracellular reactive oxygen species formation and membrane lipid peroxidation. In addition, depletion of glutathione under oxidative stress was remarkably restored by treatment with EAF. The results suggest that EAF have great potential to be used against oxidative stress-induced health conditions.

Antioxidant, antiradical, and anticholinergic properties of cynarin purified from the Illyrian thistle (Onopordum illyricum L.)

Cynarin is a derivative of hydroxycinnamic acid and it has biologically active functional groups constituent of some plants and food. We elucidated the antioxidant activity of cynarin by using different in vitro condition bioanalytical antioxidant assays like DMPD•+, ABTS•+, , DPPH• and H2O2 scavenging effects, the total antioxidant influence, reducing capabilities, Fe2+ chelating and anticholinergic activities. Cynarin demonstrated 87.72% inhibition of linoleic acid lipid peroxidation at 30 µg/mL concentration. Conversely, some standard antioxidants like trolox, α-tocopherol, butylated hydroxytoluene (BHT), and butylated hydroxyanisole (BHA) exhibited inhibitions of 90.32, 75.26, 97.61, 87.30%, and opponent peroxidation of linoleic acid emulsion at the identical concentration, seriatim. Also, cynarin exhibited effective DMPD•+, ABTS•+, , DPPH•, and H2O2 scavenging effects, reducing capabilities and Fe2+ chelating effects. On the contrary, IC50 and Ki parameters of cynarin for acetylcholinesterase enzyme inhibition were determined as 243.67 nM (r2: 0.9444) and 39.34 ± 13.88 nM, respectively. This study clearly showed that cynarin had marked antioxidant, anticholinergic, reducing ability, radical-scavenging, and metal-binding activities.

Gum Arabic-stabilized conjugated linoleic acid emulsions: Emulsion properties in relation to interfacial adsorption behaviors

Conjugated linoleic acid (CLA) is a dietary supplement due to its multiple health benefits. However, significant loss of biologically active CLA could occur due to oxidation. Oil-in-water emulsion is supposed to be an effective protection system. In a previous study (Yao et al., 2013), physical and chemical stabilities of CLA emulsion stabilized with gum Arabic were investigated, and the optimal gum concentration was identified as 5 wt%. The present study dealt with the interfacial adsorption of three gum Arabic samples (one conventional gum, GA; two matured gums, EM2 and EM10) at the CLA-water interface, in relation to their emulsifying properties. With increasing gum Arabic concentration, particle size (D[3,2]) of CLA emulsion decreased and slowly leveled off, which was accompanied with a gradual saturation of gum Arabic adsorbed at the emulsion interface. Nevertheless, surface load of gum Arabic at the emulsion interface (Γ, mg/m2) reached maximum at a gum concentration of 5 wt%. This could reasonably explain the optimal emulsion stability observed at this gum concentration, as revealed by particle size distribution of fresh emulsions and by acceleration test at 60 °C. Among the three gums, EM10 exhibited the highest emulsifying activity and conferred the best emulsion stability, despite of its lowest surface load. This is presumably due to a larger tendency of the AGP fraction in EM10 toward aggregation at the CLA-water interface.

Hepatoprotective and Antioxidant Activities of Solanum indicum Linn Berries.

In the present investigation, hepatoprotective and antioxidant activities of the crude ethanolic extract of Solanum indicum Linn berries were studied. The total antioxidant activity of the ethanolic extract was investigated in linoleic acid emulsion system. Total phenolic and flavonoid content of the extract was also determined by a colorimetric method. Acute hepatotoxicity was induced in rats by administering CCl4 dissolved in Tween 80 for 14 days. Animals treated with the vehicle alone served as control (Group I). Another group of animals were given orally CCl4 at a concentration of 2ml/kg body weight once daily (Group II) for 14 days. The experimental animals were pre-treated with the extract of Solanum indicum (at a dosage of 200 mg/kg body weight) for 7 days and the treatment continued for another 7 days along with CCl4 (Group III). The same method was followed for Group IV animals except that they were treated with the standard drug, silymarin (50 mg/kg body weight). The animals were sacrificed on 15th day and the degree of liver protection was determined by estimating the levels of serum marker enzymes such as alanine amino transferase (ALT), aspartate amino transferase (AST), alkaline phosphatase (ALP), acid phosphatase (ACP) and lactate dehydrogenase (LDH). The biochemical parameters like total protein, total bilirubin, total cholesterol, triglycerides and urea were also estimated. The results revealed that S.indicum Linn berries extract possessed significant inhibitory activity on peroxides formation in linoleic acid emulsion system in a dose-dependent manner. A marked elevation of serum marker enzyme levels in CCl4 treated rats was observed, which was returned to near normal values in the drug treated animals. The results of this study strongly indicated that the hepatoprotective effect of the plant extract is possibly related to its marked antioxidant activity.

Antioxidant, mutagenic, and antimutagenic activities of Tragopogon longirostis var. longirostis, an edible wild plant in Turkey.

Objectives:The ethanolic extract of Tragopogon longirostis var. longirostis, a wild edible plant in Anatolia was isolated, and its antioxidant, mutagenic, and antimutagenic properties were investigated.Materials and Methods:The antioxidant activity (AA) was determined by the inhibition of 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical, total AA, and phenolic compounds. The mutagenic and antimutagenic activities were investigated by Ames Salmonella/microsome mutagenicity test.Results:The IC50 value for DPPH radicals was 7.84 ± 0.603 mg/mL. The total AA increased with an increase in the concentration of the extracts (1, 5, 10, 20, and 30 mg/mL), containing linoleic acid emulsion. The total phenolic content was 284.71 ± 5.6 mg gallic acid equivalent/g extract. The results showed that the ethanolic extract can be considered safe, because it does not have any mutagenic effect at the tested concentrations. As a result, the ethanolic extract of the leaves exhibited antimutagenic effects at 2.5, 0.25, and 0.025 mg/plate concentrations.Conclusions:To our knowledge, this is the first study of the antioxidant, mutagenic, and antimutagenic activities of T. longirostis var. longirostis. These activities are an important topic in the food industry, as well as in the medical field.

Hypolipidemic and antioxidative effects of aqueous enzymatic extract from rice bran in rats fed a high-fat and -cholesterol diet.

Purpose: The aqueous enzymatic extract from rice bran (AEERB) was rich in protein, γ-oryzanol and tocols. The aim of this study was to investigate the effects of AEERB on the regulation of lipid metabolism and the inhibition of oxidative damage. Methods: The antioxidant activity of AEERB in vitro was measured in terms of radical scavenging capacity, ferric reducing ability power (FRAP) and linoleic acid emulsion system-ferric thiocyanate method (FTC). Male Wistar rats were fed with a normal diet and a high-fat and high-cholesterol diet with or without AEERB. After treatment, biochemical assays of serum, liver and feces lipid levels, the antioxidant enzyme activity, malondialdehyde (MDA) and protein carbonyl were determined. Result: AEERB is completely soluble in water and rich in hydrophilic and lipophilic functional ingredients. AEERB scavenged DPPH• and ABTS•+ and exhibited antioxidant activity slightly lower than that of ascorbic acid in the linoleic acid system. The administration of AEERB reduced serum lipid levels and the atherogenic index compared with those of the hyperlipidemic diet group (HD). The administration of AEERB significantly lowered liver lipid levels, inhibited hepatic 3-hydroxyl-3-methylglutaryl CoA reductase activity, and efficiently promoted the fecal excretion of total lipids and total cholesterol (TC) (p < 0.05). Dietary AEERB enhanced antioxidant status in the serum, liver and brain by increasing the antioxidant enzyme activity of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px) and decreasing the content of MDA and protein carbonyl. Conclusions: The results indicated that AEERB might act as a potent hypolipidemic and antioxidant functional food.

Perubahan Aktivitas Antioksidan, Kadar Antosianin dan Polifenol pada Beberapa Tingkat Kemasakan Buah Duwet (syzygium Cumini)

Research on antioxidant activity, anthocyanin, and polyphenol contents of Java plum (Syzygium cumini) from several stages of maturity was carried out with three aims: to prove that the fruit contain anthocyanins; to compare antioxidant activity from three stages of fruit maturity; and to examine the possible correlation between maturation and antioxidant activity, anthocyanin and polyphenol contents. The fruit pulp was separated from the seed, frozen dried, and kept in freezer. The freezer dried fruit was extracted (macerated) with methanol-HCl 1% for overnight at 4ºC, and filtered with Whatman no 1 to obtain fruit extract. Anthocyanin-betacyanin testing was used to indicate that the fruit contain anthocyanin. Antioxidant activity test was conducted with ferri-thiocyanate method in linoleic acid emulsion system. Anthocyanin contents was determined with pH differential method, while its polyphenol with spectrophotometric method with Folin-CIocalteu reagent. The result showed that the fruit contained anthocyanin, ranging from 1,68 mg/g at young stage (green) to 29,39 mg/g at overripe stage (black), and showed that antioxidant activity was influenced by fruit maturity. With regard to fruit maturoty, the antioxidant activity of purple, red, adn green fruit were 64,75%, 62,42%, and 29,86% respectively; whereas that of BHT was 79,45%. It was noted that there were significant correlation between the level of anthocyanins, poluphenols, and the degrees of maturity. As the fruit maturity increased, the anthocyanin increased, but the polyphenol decreased. The fruit contained considerable amount of anthocyanins and had antioxidant activity that was influenced by stages of maturity. It was indicated that the more mature the fruit the higher anthocyanins and the lower polyphenols concentrations.

Carotenoid content and antioxidant activity of hexane extracts from selected Croatian corn hybrids

Carotenoids, which occur naturally in corn grains, have been associated with reduced risk of degenerative diseases. The aim of this research was to measure the carotenoid content of hexane extracts of six commercial high-yield corn hybrids and determine the relationship between carotenoid content and antioxidant activity. Levels of lutein, zeaxanthin, β-cryptoxanthin and β-carotene in hexane extracts were determined using HPLC, and antioxidant activity was assayed using the TEAC system based on the 2,2′-azinobis(3-ethylbenzothiazoline-6-sulphonic acid) radical cation (ABTS+), and the TBARS system based on a linoleic acid emulsion. Corn hybrids varied in carotenoid content and antioxidant activity in both assays. Lutein and zeaxanthin were the predominant carotenoids; their levels were 15-fold higher than those of β-cryptoxanthin and β-carotene. Antioxidant activity in both assays increased linearly with total carotenoid content. Lutein and β-carotene were the primary contributors to TEAC activity, while lutein, β-cryptoxanthin and β-carotene were primary contributors to TBARS activity.