Ferric Thiocyanate Assay Research Articles

Antioxidant Properties of Soft Coral Dendronephthya sp.

Present study was conducted to determine the antioxidant property of soft corals belong to the genus: Dendronephthya (Family: Nephtheidae) using α, α-Diphenyl-β-PicrylHydrazyl (DPPH) radical-scavenging and Ferric Thiocyanate (FTC) methods using vitamin E as a positive control. Crude extracts were prepared from 4 Dendronephthya sp. using aqueous, dichoromethane: methanol and methanol extraction. All crude extracts of Dendronephthya sp. exhibited antioxidant properties and the white spots appeared during the rapid screening using Dot-Blot and 1, 1-Diphenyl-2-picryl-hydrazyl (DPPH) staining where the concentration of crude extract was 1.00 g mL-1 against the DPPH concentration of 0.4 mM. In DPPH assay, not all crude extracts showed a significant value in antioxidant activities thus it could be considered as weak free radical species scavenger. The crude extract were diluted to 1000, 500, 250, 125, 63, 31, 15, 7, 4 and 2 μg mL-1, respectively and tested against highly diluted DPPH (0.06 mM). The IC50 for all crude extracts were greater than 1000 μg mL-1. The percentage of free radical scavenging exhibited by the crude extract was at 2 μg mL-1 concentration (the lowest concentration in serial dilution) with 0.81 to 2.89%. Ferric Thiocyanate (FTC) assay, showed absorbance ranges for control, vitamin E and sample were recorded as 0.012-0.858, 0.001-0.315 and 0.001-0.886, respectively. Inhibition percentage of all the crude extract was closer to the control indicated that they are weak lipid peroxidation inhibitor. However, the aqueous extract of species A and C showed higher inhibition percentage from other extract with the percentage value of 10.8 and 10.5% , respectively.

Antioxidant and Free Radical Scavenging Activities of Some Fruits

Phenols, a major group of antioxidant phytochemicals, have profound importance due to their biological and free radical scavenging activities. To identify their potential sources extracts of some fruits and their different parts were studied for total phenolic contents (TPC), antioxidant (AOA) and free radical scavenging activities (FRSA). The amount of TPC varied from 10.5 (Carissa carandus, fruit peel) to 343.2 mg/g (Caesalpinia Mexicana, fruits) and AOA from 20.3% (Musa paradisiacal, fruits) to 96.7% (Caesalpinia Mexicana, fruits). Fruits of Caesalpinia Mexicana, Acacia auriculiformis, fruit pericarp green fibres of Cocus nucifera, and fruits of Emblica officinalis were found to have high TPC (73.1-343.2 mg/g) and high AOA (68.5-96.7%). Promising fruits were studied for their FRSA and reducing power (RP) measured by DPPH assay where the fruits of Caesalpinia mexicana, fruit pericarp fibres of Cocus nucifera, fruits of Emblica officinalis showed very low IC50 ranging from 0.009 to 0.016 mg/ml, EC50 from 0.39 to 0.70 mg/mg DPPH and reasonably high values (142.1-256.3) of anti radical power (ARP), indicating their strong FRSA and reducing power (RP) as evident by their low ASE/ml values (0.42-1.08). They also showed better inhibition of lipid peroxidation measured by using ferric thiocyanate assay and by using egg yolk compared to the reference standard quercetin. The ferrous and ferric ion chelating capacity of the promising fruits and their underutilized parts in terms of IC50 varied from 0.12 (Emblica officinalis, fruits) to 2.44 mg/ml (Mangifera indica, Seed kernel) and 0.22 (Caesalpinia Mexicana, fruits) to 2.59 mg/ml (Litchi chinensis, fruit peel) respectively. Fruit pulp, peel and seeds of Litchi chinensis with reasonable amount of phenols (48.3, 43.9, 50.1 mg/ml) showed low ARP (23.5, 38.3, 33.8) and ASE/ml (3.13, 2.18, 2.62) respectively in contrast to Aegle marmelos with comparatively lower phenols (35.1 mg/g) exhibited good ARP (57.4) and RP (1.67 ASE/ml). Extracts (20 μg/ml) of fruits of Acacia auriculiformis, Caesalpinia Mexicana, Emblica officinalis, fruit pericarp fibres of Cocus nucifera, were found effective in protecting plasmid DNA nicking induced by Fenton’s reagent generated hydroxyl radicals. They were further assayed for their specific phenolic composition through HPLC and MS/MS where the amount of caffeic acid varied from 48.5 to 2231 μg/g, chlorogenic acid 63.8 to 912.1 μg/g, ellagic acid 46.4 to 1429.1 μg/g, ferulic acid 36.7 to 762.9 μg/g, gallic acid 181.6 to 2831.6 μg/g, protocatechuic acid 41.7 to 322.8 μg/g, and quercetin 44.6 to 367.6 μg/g.

CARYOPTERIS ODORATA: A RICH SOURCE OF ANTIOXIDANTS FOR PROTECTION AGAINST CHRONIC DISEASES AND FOOD PRODUCTS

ABSTRACT This study was designed to examine the in vitro antioxidant potential of the different fractions of Caryopteris odorata (Ham. ex Roxb.). The methanolic extract of this plant was dissolved in distilled water and partitioned with n -hexane, chloroform, ethyl acetate and n -butanol, successively. These organic fractions and the remaining aqueous fraction were screened for their possible antioxidant activities by different methods: 1,1-diphenyl-2-picrylhydrazyl radical (DPPH) scavenging activity, total antioxidant activity, ferric reducing antioxidant power (FRAP) assay and ferric thiocyanate assay. The total phenolics were also determined. The results revealed that among these fractions ethyl acetate soluble fraction showed very good antioxidant potential, having an IC 50 value of 8.01 ± 0.254 µg/mL. It also exhibited the highest total antioxidant activity (2.358 ± 0.035), FRAP value (2505.8 ± 0.58 µg/mL), inhibition of lipid peroxidation (77.53 ± 0.784 %) value and total phenolic contents (87.08 ± 1.5µg/g) as compared to other fractions.

Antioxidant Potential of Some Under-Utilized Fruits

To identify their potential sources extracts of some fruits and their different parts were studied for total phenolic contents (TPC), antioxidant (AOA) and free radical scavenging activities (FRSA). Phenols have profound importance due to their biological and free radical scavenging activities. The amount of TPC varied from 10.5 to 343.2 mg/g and AOA from 20.3 to 96.7%. Fruits of Caesalpinia mexicana, Acacia auriculiformis, fruit pericarp fibres of Cocus nucifera, and fruits of Emblica officinalis were found to have high TPC (73.1-343.2 mg/g) and high AOA (68.5-96.7%). Promising fruits were studied for their FRSA and reducing power (RP) measured by DPPH assay where the fruits of Caesalpinia mexicana, fruit pericarp fibres of Cocus nucifera, fruits of Emblica officinalis showed very low IC50 ranging from 0.009 to 0.016 mg/ml, EC50 from 0.39 to 0.70 mg/mg DPPH and reasonably high values (142.1- 256.3) of anti radical power (ARP), indicating their strong FRSA and reducing power (RP) as evident by their low ASE/ml values (0.42- 1.08). They also showed better inhibition of lipid peroxidation measured by using ferric thiocyanate assay and by using egg yolk compared to reference standard, quercetin. The ferrous and ferric ion chelating capacity of the promising fruits and their underutilized parts in terms of IC50 varied from 0.12 (Emblica officinalis, fruits) to 2.44 mg/ml (Mangifera indica, Seed kernel) and 0.22 (Caesalpinia mexicana, fruits) to 2.59 mg/ml (Litchi chinensis, fruit peel) respectively. Fruit of Acacia auriculiformis, Caesalpinia mexicana, Emblica officinalis, fruit pericarp fibres of Cocus nucifera, were also assayed for their specific phenolic composition through HPLC where the amount of caffeic acid varied from 48.5 to 2231 µg/g, chlorogenic acid 63.8 to 912.1 µg/g, ellagic acid 46.4 to 1429.1 µg/g, ferulic acid 36.7 to 762.9 µg/g, gallic acid 181.6 to 2831.6 µg/g, protocatechuic acid 41.7 to 322.8 µg/g, and quercetin 44.6 to 367.6 µg/g. © 2011 IGJPS. All rights reserved

In vitro assessment of the protection from oxidative stress by various fractions of Artemisia incisa Pamp.

The methanolic extract of Artemisia incisa Pamp. was dissolved in distilled water and successively partitioned with n-hexane, chloroform, ethyl acetate and n-butanol. The antioxidant potential of all these fractions and remaining aqueous fraction was evaluated by four methods, i.e., the scavenging activity of the 1,1-diphenyl-2-picrylhydrazyl radical (DPPH), the total antioxidant activity, the ferric reducing antioxidant power (FRAP) assay and the ferric thiocyanate assay. In addition, the total phenolics was determined. The obtained results revealed that among the studied fractions the ethyl acetate soluble fraction showed the most potent DPPH-radical scavenging activity with an IC50 value of 5.3 ? 0.71 ?g mL-1, which is even more effective than the standard antioxidant butylated hydroxytoluene (BHT) (IC50 value 0f 12.1? 0.92 ?g mL-1). The ethyl acetate fraction also showed the highest FRAP value (3677.13 ? 27.1 ?g TE mL-1), inhibition of lipid peroxidation (60.93 ? 0.84 % at 500 ?g mL-1) and total phenolic content (95.5 ? 0.05 ?g GAE g-1) as compared to other fractions. However, the remaining aqueous fraction was found to posses the highest antioxidant activity of all the fractions.

프로폴리스 에탄올 및 물 추출물의 항산화 활성

To obtain basic information on the potential use of propolis as a raw material in functional food, proximate composition, total phenolics content and antioxidant activities of different propolis extracts in Korea were investigated. Propolis had the highest level of crude fat and the lowest level of crude fiber. The total phenolics content of ethanol and water extract of propolis from Geochang (GEE and GWE), ethanol and water extract of propolis from Jeju (JEE and JWE) were 184.17, 316.19, 204.33 and 47.83 ㎎ gallic acid equivalent/g, respectively. GWE contained relatively higher levels of total phenolics than the other extracts. The antioxidant potential of the extracts was assessed by different in vitro assays such as DPPH, ABTS, reducing power, ferric reducing/antioxidant power (FRAP) and peroxidation inhibiting activities through linoleic acid emulsion system. DPPH and ABTS radical scavenging activities of all the extracts were dose dependent. The GWE exhibited the best performance in reducing power, FRAP, and lipid peroxidation using ferric thiocyanate (FTC) assay. These results demonstrated that GWE has excellent antioxidant activities and thus it has great potential as a raw material for functional food.

Antigenotoxic Effect of Chamomilla recutita (L.) Rauschert Essential Oil in Mouse Spermatogonial Cells, and Determination of Its Antioxidant Capacity in Vitro

Chamomilla recutita (L.) Rauschert (Asteraceae), popularly known as chamomile, is a plant used in traditional medicine for various therapeutic purposes. Chamomile essential oil (CEO) is particularly known to inhibit the genotoxic damage produced by mutagens in mice somatic cells. The aim of this research was to determine the inhibitory potential of CEO on the genotoxic damage produced by daunorubicin (DAU) in mice germ cells. We evaluated the effect of 5, 50, and 500 mg/kg of essential oil on the rate of sister chromatid exchange (SCE) induced in spermatogonia by 10 mg/kg of the mutagen. We found no genotoxicity of CEO, but detected an inhibition of SCE after the damage induced by DAU; from the lowest to the highest dose of CEO we found an inhibition of 47.5%, 61.9%, and 93.5%, respectively. As a possible mechanism of action, the antioxidant capacity of CEO was determined using the 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging method and ferric thiocyanate assays. In the first test we observed a moderate scavenging potential of the oil; nevertheless, the second assay showed an antioxidant capacity similar to that observed with vitamin E. In conclusion, we found that CEO is an efficient chemoprotective agent against the damage induced by DAU in the precursor cells of the germinal line of mice, and that its antioxidant capacity may induce this effect.

Antioxidant, free radical scavenging, anti-inflammatory and hepatoprotective potential of the extract from Parathelypteris nipponica (Franch. et Sav.) Ching

Aim of the study The present study was conducted to evaluate the antioxidant, free radical scavenging, hepatoprotective and anti-inflammatory potential of Parathelypteris nipponica (Franch. et Sav.) Ching. Methods and results Antioxidant activity of the methanolic extract of Parathelypteris nipponica (Franch. et Sav.) Ching (TMPN) was studied using in vitro and in vivo models, total flavonoids content in TMPN was found to be 262 ± 5.6 mg/g (w/w). The TMPN exhibited strong antioxidant activity with EC 50 values in reductive ability (0.18 ± 0.02 mg/ml) and ferric thiocyanate (FTC) assay (0.10 ± 0.01 mg/ml), strong free radical scavenging activity as evidenced by the low EC 50 values in DPPH (1,1-diphenyl-2-picrylhydrazyl) (2.00 ± 0.02 mg/ml), superoxide anion (0.60 ± 0.05 mg/ml), OH radicals (0.26 ± 0.03 mg/ml), and hydrogen peroxide (0.45 ± 0.03 mg/ml) methods. Acute toxicity study revealed that the LD 50 value of the extract was more than the dose 2000 mg/kg bodyweight of mice. Hepatoprotective activity of TMPN was determined by the carbon tetrachloride (CCl 4)-induced oxidative tissue injury in rat liver, the extract showed significant hepatoprotective activity that was evident by enzymatic examination and histopathological study. In assessing anti-inflammatory activity the carrageenan-induced rat paw oedema test was used, the extract reduced carrageenan-induced rat paw oedema in dose-dependent manner, achieving high degree of anti-inflammatory activity. Conclusion This study provides a scientific basis for the ethnomedical claims that Parathelypteris nipponica (Franch. et Sav.) Ching is effective against inflammation and liver injury.

Antioxidative activities of some peptides isolated from hydrolyzed potato protein extract

Three peptides ( 5A, 5C and 6C), purified from potato protein hydrolysate fractions, possessed antioxidative activities. Isolation and purification were carried out using gel permeation chromatography and successive reverse-phase HPLC. These three peptide fractions were sequenced and identified as Phe-Gly-Glu-Arg, Phe-Asp-Arg-Arg and Phe-Gly-Glu-Arg-Arg, respectively. The fractions 5A, 5C and 6C inhibited linoleic acid oxidation by 55.3%, 58.5% and 61.7% using β-carotene decolorization assay system, while the inhibition ratio was 32.1%, 93.0% and 93.4% in the ferric thiocyanate assay system, respectively. The peptide fractions 5A, 5C and 6C also repressed lipid oxidation by 24.2%, 14.7% and 26.4% in the erythrocyte membrane ghost assay system, respectively. Oral administration of 100 mg/kg of body weight of the chemically synthesized peptides, 5A, 5C and 6C to rats (male Wistar) 30 min prior to ethanol injection reduced ethanol-induced gastric mucosal damage by 67.9%, 57.0% and 60.3%, respectively. Conclusively, these peptides have shown real potent antioxidative activities and could further be investigated for potential use as food additives.

Antioxidant and Antimicrobial Activities of Extracts from a Medicinal Plant, Sea Buckthorn

This study was performed to evaluate the antioxidant and antimicrobial activities from the methanol extracts of the root and stem of Hippophae rhamnoides and their further partitioned fractions including hexane, ethyl acetate, butanol, and water. Antioxidant activities of the plant parts were measured by l,l-dephenyl-2-picryl-hydrazyl (DPPH), superoxide dismutase (SOD)-like activity, and ferric thiocyanate (FTC) assays, and compared to standard antioxidants of butylated hydroxyl anisole, butylated hydroxyl toluene, a-tocopherol, and ascorbic acid. Antimicrobial activity of the plant extracts and fractions were evaluated by determining the minimum inhibitory concentration values. DPPH assay showed that the overall strong antioxidant activities from the methanol extracts and fractions. The values of SOD-like activities in hexane fractions of the root and stem were close to the measurement of a reference, ascorbic acid at 1,000 ppm. The methanol extract of the root in FTC assay showed a remarkable antioxidant and free radical scavenging activity. The extracts and fractions of the root and stem showed better antimicrobial activity than compared antimicrobial agents, (+)-catechin, ketoconazol, and mycostantin. This study indicates that the plant root and stem contain a variety of compounds contributing to antioxidant and antimicrobial activity, which could be used for food additives and the development of useful natural compounds.

Antioxidant Assays for Plant and Food Components

Recently, research on natural antioxidants has become increasingly active in various fields. Accordingly, numerous articles on natural antioxidants, including polyphenols, flavonoids, vitamins, and volatile chemicals, have been published. Assays developed to evaluate the antioxidant activity of plants and food constituents vary. Therefore, to investigate the antioxidant activity of chemical(s), choosing an adequate assay based on the chemical(s) of interest is critical. There are two general types of assays widely used for different antioxidant studies. One is an assay associated with lipid peroxidations, including the thiobarbituric acid assay (TBA), malonaldehyde/high-performance liquid chromatography (MA/HPLC) assay, malonaldehyde/gas chromatography (MA/GC) assay, beta-carotene bleaching assay, and conjugated diene assay. Other assays are associated with electron or radical scavenging, including the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay, 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) assay, ferric reducing/antioxidant power (FRAP) assay, ferrous oxidation-xylenol orange (FOX) assay, ferric thiocyanate (FTC) assay, and aldehyde/carboxylic acid (ACA) assay. In this review, assays used recently were selected for extended discussion, including discussion of the mechanisms underlying each assay and its application to various plants and foods.

In vitro antioxidant and anticancer activities of ethanolic extract of selenium-enriched green tea

Selenium-enriched green tea is now being increasingly produced in China and is well known as a bioactive beverage, due to its high content of active components. In this study, the antioxidant and anticancer activities of an ethanolic extract and an aqueous extract of Se-enriched green tea were investigated. The results indicated that the ethanolic extract possessed significantly higher antioxidant activity than the aqueous extract and the positive control α-tocopherol, by both α,α-diphenyl-β-picrylhydrazyl (DPPH) radical-scavenging and ferric thiocyanate (FTC) assays. The ethanolic extract inhibited the proliferation of human cervical adenocarcinoma HeLa cell and possessed a significantly higher antitumour activity than the aqueous extract and the positive control 5-fluorouracil (5-FU), in the dose range of 62.5–250 μg/ml. Moreover, the ethanolic extract could significantly inhibit the growth of lung carcinoma A549 and hepatoma HepG2 in a concentration-dependent manner, with IC 50 values of 278.6 μg/ml and 431.6 μg/ml, respectively. Selenium, tea polyphenols and polyphenols constituents, especially epigallocatechin gallate (EGCG), were significantly higher in the ethanolic extract than in the aqueous extract, which were possibly responsible for the higher antioxidant and antitumour activities of the ethanolic extract.

Chemical Constituents of <i>Myristica fragrans</i> Houttuyn Seed and Their Physiological Activities

The antioxidative activity of phenylpropanoid compound extracts from nutmeg (Myristica fragragrans Houttuyn) seed was determined. The antioxidant activity was evaluated using the 1,1-diphenyl-2-picrylhydrazyl radical-scavenging method, superoxide disumutase assay, ferric thiocyanate assay, and radical-scavenging effect assay with electron-spin resonance. High antioxidant activity was found in monoterpenoid extracts including terpinene-4-ol (3), alpha-terpineol (4), and 4-allyl-2,6-dimethoxyphenol (12). Compound, 12 expressed particularly high antioxidant activity.

Antioxidant properties of monomeric, oligomeric, and polymeric fractions in hot water extract from Pinus radiata bark

Hot water extract (HWE) from Pinus radiata bark was fractionated into monomeric polyphenol (MPP), oligomeric proanthocyanidin (OPA), and polymeric proanthocyanidin (PPA) fractions by monitoring the UV-visible spectrum of the eluted fractions. Nine polyphenols were identified in MPP: three phenolic acids and six flavonoids. The major compounds of MPP were taxifolin (456 μg/mg), catechins (240 μg/mg), and protocatechuic acid (46.2 μg/mg). The OPA components ranged from dimers to hexamers. PPA comprised procyanidin (PC, 94%), a small amount of prodelphinidin (PD, 6%), and also the higher trans configuration, rather than the cis configuration, of C2-C3. The average molecular weight (Mw, Mn), polydispersity (Mw/Mn), and DP of PPA were 3,800 (Mw), 1,200 (Mn), 3.2 and 13, respectively. The potential antioxidant activities of HWE and the three fractions were estimated using proton- or electron-donating assays containing 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical, 2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonate) (ABTS) radical cation, superoxide anion (O2•−), hydrogen peroxide (H2O2), reducing power and lipid peroxidation. All the bark fractions exhibited potent quenching abilities against both commercially available radicals (DPPH•, ABTS•+) and chemically induced radicals (H2O2, O2•−), as well as strong reducing power and inhibitory activity of lipid peroxidation. Particularly, OPA showed a hydrogen peroxide scavenging activity significantly higher (p < 0.05) than that of the other fractions. From 2-thiobarbituric acid reactive substances and ferric thiocyanate assays, PPA was suspected to act by essentially delaying the formation of hydroperoxide by quenching free oxygen radicals that operates in oil-in-water emulsion.

Antioxidant activity, anthocyanins, and phenolics of rabbiteye blueberry ( Vaccinium ashei) fluid products as affected by fermentation

Frozen rabbiteye blueberries ( Vaccinium ashei) were processed into juice (BJ), wines made without (BW1) or with (BW2) skin contact fermentation, and vinegars made from BW1 (JV), BW2 (WV) or blueberries (BV). Total phenolics, total anthocyanins, antioxidant activities (beta-carotene bleaching assay and ferric thiocyanate assay), and antiradical activity (DPPH radical-scavenging method) of these fluid products were determined. The differences in total anthocyanin contents of all blueberry products were significant. The BW2 had the highest content of anthocyanins and polyphenols and the highest beta-carotene bleaching activity and antiradical activity. Acetification decreased total anthocyanin content, total polyphenols and antioxidant activities. Correlations indicate that anthocyanins made significant contributions than did phenolics to antioxidant activities of products. The abilities of BJ, BW1 (wine from blueberry juice), and BW2 to inhibit linoleic acid peroxidation were high (∼95%). The abilities of vinegar products to inhibit linoleic acid peroxidation were low. The results indicate that skin-contact fermentation is a better method for obtaining higher antioxidant activity of blueberry products. Also, acetification significantly decreased anthocyanins and antioxidant activities.

Principal phenolic phytochemicals and antioxidant activities of three Chinese medicinal plants

The principal antioxidant components and content of cinnamon ( Cinnamomum cassia), turmeric ( Curcuma longa) and golden thread ( Coptidis rhizoma) extracts were determined using high performance liquid chromatography (HPLC) with UV detection. In general, C. cassia, C. longa and C. rhizoma extracts from domestic Taiwan were rich in cinnamaldehyde, curcumin, and berberin, respectively. The contents of cinnamaldehyde, curcumin, and berberin in the acetone extracts were 1911, 2029, and 840 mg l −1, respectively. The Folin–Ciocalteu method was used to measure the total phenolic concentrations of extracts, which had the content of 9.6 ( C. cassia), 2.6 ( C. longa), and 4.3 ( C. rhizoma) mM l −1. In addition, DPPH radical-scavenging, ferric-reducing antioxidant power (FRAP), and ferric thiocyanate (FTC) assays were employed to measure antioxidant activities. The C. cassia fresh extracts had higher antioxidant activities which were 84–90% (DPPH), 17–33 μmol l −1 (FRAP), and 53–82% (FTC). The activities of C. longa fresh extracts were 22–44% (DPPH), 7–11 μmol l −1 (FRAP), and 53–81% (FTC) while C. rhizoma were 53–64% (DPPH), 18–26 μmol l −1 (FRAP), and 59–82% (FTC).

Antioxidant activity of ethanol and petroleum ether extracts from Brazilian propolis

Antioxidant activities of ethanol and petroleum ether extracts from Brazilian propolis were determined by α,α-diphenyl-β-picrylhydrazyl (DPPH) radical-scavenging and ferric thiocyanate (FTC) methods, using α-tocopherol and butylated hydroxytoluene (BHT) as references. The DPPH assay showed that ethanol extract possessed significantly higher activity compared with BHT and petroleum ether extract but lower than that of α-tocopherol. Results from the FTC assay indicated that the activity of ethanol extract was higher than that of α-tocopherol and petroleum ether extract but lower than BHT. Basically, this antioxidant activity was dose-dependent and ethanol extract exhibited higher activity than that of petroleum ether extract at the same concentration. Additionally, the chemical constituents of propolis were determined, and results showed that the propolis contained high content of antioxidant compositions, such as flavonoids (73.00 g kg−1), total phenolic compounds (134.40 g kg−1), and Vitamin E (0.16 g kg−1), which contributed greatly to its strong antioxidant activity.

Antioxidant activity, anthocyanins, and phenolics of rabbiteye blueberry ( Vaccinium ashei) by-products as affected by fermentation

Basic blueberry processing includes juice processing or winemaking. By-products obtained from the juice and wine industry can be a source of new value-added products such as phenolic antioxidant supplements or ingredients for food processing. The phenolic compositions of products and by-products (pomaces) depend mainly on processing techniques such as duration of skin contact, crushing, pressing, and others. The present study was to evaluate the effects of fermentation type on retention of total anthocyanins, total phenolics, and antioxidant activity of blueberry by-products. Total phenolics (TPH), total anthocyanins (ACY), antioxidant activities (β-carotene bleaching assay and ferric thiocyanate assay), and antiradical activity (DPPH radical-scavenging assay) of rabbiteye blueberry ( Vaccinium ashei) by-products (juice, wine, and vinegar pomaces) were determined. The wine pomace (WP) had higher TPH, antioxidant activities and antiradical activity. Vinegar pomace (VP) had the lowest ACY, TPH, antiradical activity, and antioxidant activities. The results indicate that the antioxidant and antiradical activities of blueberry by-products were not significantly affected by the wine making process. Acetification significantly decreased TPH, ACY, antioxidant activities, and antiradical activity. However, VP still maintained an important phenolics concentration and antioxidant activity.

Antioxidative activities of chromatographic fractions obtained from root, fruit and leaf of Mengkudu ( Morinda citrifolia L.)

Crude extracts of root, leaf and fruit of Morinda citrifolia were fractionated on a Sephadex LH-20 column with ethanol as eluate. Based on UV absorption intensity of phenolic compound (725 mm) the Sephadex LH-20 column was able to separate fruit, leaf and root extracts into six, five and five fractions, respectively. The results showed that all the fractions tested exhibited considerably high antioxidative activity in the ferric thiocyanate assay and thiobarbituric acid test and the activities of some of the fractions were as good as those of either tocopherol or BHT. The fractions from different parts of the plants were found to contain different amounts of total phenolic compounds, which, interestingly, do not correspond to the antioxidative activity measured. This is probably due to the presence of different phenolics in the samples, with different antioxidative activities which involves various mechanisms inhibiting the oxidation process. The study suggested that root, leaf and fruit of M. citrifolia might contribute significantly to exogenous antioxidant which is crucial in combating oxidative stress.

Valorization of cauliflower (Brassica oleracea L. var. botrytis) by-products as a source of antioxidant phenolics.

The present study reports the development of two extraction protocols, with potential industrial applicability, to valorize cauliflower (Brassica oleracea L. var. botrytis) byproducts as a source of antioxidant phenolics. In addition, the nonionic polystyrene resin Amberlite XAD-2 was used to obtain purified extracts. The extract yield, phenolic content, phenolic yield, and correlation between the antioxidant activity and the phenolic content were studied. The water and ethanol protocols yield a phenolic content of 33.8 mg/g freeze-dried extract and 62.1 mg/g freeze-dried extract, respectively. This percentage increased considerably when the extracts were purified using Amberlite XAD-2 yielding a phenolic content of 186 mg/g freeze-dried extract (water extract) and 311.1 mg/g freeze-dried extract (ethanol extract). Cauliflower byproduct extracts showed significant free radical scavenging activity (vs both DPPH(*) and ABTS(*)(+) radicals), ferric reducing ability (FRAP assay), and capacity to inhibit lipid peroxidation (ferric thiocyanate assay). In addition, the antioxidant activity was linearly correlated with the phenolics content. The results obtained indicate that the cauliflower byproducts are a cheap source of antioxidant phenolics very interesting from both the industrial point of view and the possible usefulness as ingredients to functionalize foodstuffs.