• Food Science and Biotechnology
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• v.18 no.6
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• pp.1464-1469
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• 2009

Jiwhang (Rehmannia glutinosa), one of the most widely used medicinal herbs, was dried with various methods such as sun drying, hot air drying, vacuum drying, and freeze drying methods, and their effects on the antioxidant capacity in relation with the content of total phenolic compounds were studied with a steamed-and-dried rehmannia (sookjiwhang) for comparison. Generally, total phenolic contents decreased significantly by all of the drying treatments except the steamed-and-dried rehmannia, in which total phenolic contents increased 2.4 fold compared with fresh rehmannia. Content of verbascoside, a functional phenolic compound, was the highest in the freeze-dried rehmannia ($177.97{\pm}0.02\;{\mu}g/g$ d.m.) followed by vacuum-dried ($105.55{\pm}0.07\;{\mu}g/g$ d.m.), hot air-dried ($23.01{\pm}0.02\;{\mu}g/g$ d.m.), and sun-dried ($4.89{\pm}0.13\;{\mu}g/g$ d.m.) ones comparable to the fresh rehmannia ($80.15{\pm}1.26\;{\mu}g/g$ d.m.). Antioxidant capacity determined by both 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azinobis (3-ethyl-benzthiazoline-6-sulphonic acid) (ABTS) methods agreed with the result of total phenolic contents, that is, the antioxidant capacity was the highest in the steamed-and-dried rehmannia followed by fresh rehmannia, vacuum-dried, hot air-dried, sun-dried, and freeze-dried ones. Conclusively, the total phenolic contents and antioxidant capacity of rehmannia were greatly affected by the drying methods used.

• Korean Journal of Food Science and Technology
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• v.47 no.2
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• pp.261-266
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• 2015

To quantitatively evaluate the total phenolics, total flavonoids, and antioxidant capacity in the leaves, bulbs, and roots of fresh Allium hookeri, they were extracted using various solvents including water, aqueous methanol (20, 40, 60, and 80%; v/v), and absolute methanol. The leaves had the highest levels of total phenolics (240.4-276.6 mg gallic acid equivalents/100 g) and total flavonoids (9.7-34.1 mg catechin equivalents/100 g). The highest antioxidant capacities of 78.7- 103.4 mg vitamin C equivalents (VCE)/100 g, 24.4-59.0 mg VCE/100 g, and 1,798.8-2,169.7 mg VCE/100 g in the leaves were also observed using 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), 2,2-diphenyl-1-picrylhydrazyl (DPPH), and oxygen radical absorbance capacity (ORAC) assays, respectively. The total phenolics had a higher linear correlation with antioxidant capacity than the total flavonoids. In general, 60% (v/v) aqueous methanol extract had higher levels of total phenolics and flavonoids, and higher antioxidant capacity than any other solvents used. This study suggested that A. hookeri might be a good source of phenolics and antioxidants.

• Food Science and Biotechnology
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• v.17 no.2
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• pp.251-256
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• 2008

Changes in antioxidant activity of Rubus coreanus fruit of 3 clones (S13, S114, and S16), which were selected from different sites, were studied at different ripening stages. Antioxidant activities (tree radical scavenging activity and reducing power) were determined and their relationships to total phenolic contents and ascorbic acid were analyzed. The highest tree radical scavenging activities of 3 clones (S13, S14, and S16) were 79.39, 75.80, and 81.16% at $125\;{\mu}g/mL$, respectively. In general, the antioxidant activity and the related parameters, including total phenolic content and vitamin C content decreased during fruit ripening. Total phenolic contents of the R. coreanus fruits (S13, S14, and S16) were correlated with tree radical scavenging activity ($R^2=0.8114$, 0.9186, and 0.9714). These results improve knowledge of the effect of ripening on the antioxidant activity and related compounds contents that could help to establish the optimum R. coreanus fruit harvest data for various usages.

• Natural Product Sciences
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• v.13 no.3
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• pp.199-206
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• 2007

Antioxidant activity of 70% aqueous ethanolic extract of leaves of Justicia gendarussa (EJ) was evaluated. EJ was prepared by cold maceration method. The antioxidant potency of EJ was investigated employing various established in vitro systems, such as DPPH radical scavenging, nitric oxide (NO) scavenging, ${\beta}-carotene$ linoleic acid module system (${\beta}$ CLAMS), hydroxyl (OH) radical scavenging, anti lipid peroxidation. $IC_{50}$ values were determined in each experiment. Also, ferric ion reduction capacity of extracts in presence and absence of chelating agent (EDTA) and total antioxidant capacity were determined. Preliminary phytochemical investigation was carried out to know the nature of constituents present in the leaves and correlate it with antioxidant activity. Further total phenolic content was determined in EJ. $IC_{50}$ values of EJ were 123.09 ${\pm}$ 3.01, 643.0 ${\pm}$ 61.10, 132.3 ${\pm}$ 6.03, 68.5 ${\pm}$ 11.5 and 68.13 ${\pm}$ 1.38 ${\mu}g/mL$ in DPPH radical scavenging, NO scavenging, ${\beta}$ CLAMS, OH radical scavenging and anti lipid peroxidation activity respectively. In total antioxidant capacity assay, ascorbic acid equivalent value was found to be 205.56 ${\pm}$ 4.69 ${\mu}g/mg$ of extract. Total phenolic content was found to be 43.76 ${\pm}$ 4.27 ${\mu}g$ equivalent of gallic acid per mg of extract. Phytochemical investigation reveals the presence of flavonoids. The results indicate that EJ possess antioxidant activity and flavonoids are responsible for this activity.

• Food Science and Biotechnology
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• v.18 no.3
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• pp.818-821
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• 2009

Total phenol, total flavonoid, reducing powder, electron donating activity, ascorbic acid equivalent antioxidant capacity, antimicrobial and antiproliferative activities of olive leaf extracts were investigated. The contents of total phenol and flavonoid were 257.48 and 92.33 mg in 100 g of olive leaf extract, respectively. The reducing power of the olive leaf extract increased with concentration increasing. Electron donating activity was high in 100 ${\mu}g/mL$ treated olive leaf extract as 95.20%. The ascorbic acid equivalent antioxidant capacity of the olive leaf extract was 68.93 mg/g olive leaf extract. The olive leaf extracts showed relatively high antimicrobial activity against Escherichia coli, Salmonella typhimurium, Bacillus cereus, Staphylococcus aureus, Listeria monocytogenes, and Pseudomonas aeruginosa. All of the cancer cell lines including MKN45, HCT116, NCI-H460, and MCF7 have 70-81% as effective growth inhibition.

• Journal of Pharmacopuncture
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• v.10 no.3
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• pp.53-62
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• 2007

Objective The objective of this study was to investigate the antioxidative effects of Puerariae Radix extract. Method Total antioxidant capacity (TAC), Total antioxidant response (TAR), Total phenolic content, Reactive oxygen species (ROS), 1,1-Diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging activities, lipid peroxidation were examined. Result Total antioxidant status was examined by total antioxidant capacity(TAC) and total antioxidant response(TAR) against potent free radical reactions. TAC and TAR of Puerariae Radix extract at the concentration of 5 mg/ml were 2.02 and 1.50 mM Trolox equivalents, respectively. Total phenolic content of Puerariae Radix extract at the concentration of 5 mg/ml was 2.29 mM gallic acid equivalent. Concentration of Puerariae Radix extract at which DPPH radical scavenging activity was inhibited by 50% was 5.91 mg/ml as compared to 100% by pyrogallol solution as a reference. The inhibitory effect of the extract on lipid peroxidation was examined using rat liver mitochondria induced by FeSO4/ascorbic acid. Puerariae Radix extract at the concentration of 1 mg/ml slightly but significantly decreased TBARS concentration. The extract further prevented lipid peroxidation in a dose-dependent manner. The effect of Puerariae Radix extract on reactive oxygen species (ROS) generation was examined using cell-free system induced by hydrogen peroxide/FeSO4. Addition of 1 mg/ml of Puerariae Radix extract significantly reduced dichloroflurescein (DCF) fluorescence. The extract caused concentration-dependent attenuation of the increase in DCF fluorescence, indicating that the extract significantly prevented ROS generation in vitro. Thus antioxidant effects of Puerariae Radix extract seem to be due to, at least in part, the prevention from free radicals-induced oxidation, followed by inhibition of lipid peroxidation. Conclusion As a result, Puerariae Radix seems to have antioxitative effect and antioxidant compount.

• Journal of Applied Biological Chemistry
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• v.53 no.1
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• pp.8-12
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• 2010

The antioxidant activity of hawthorn fruit (Crataegus pinnatifida Bunge var. typica Schneider) extracts was investigated by several in vitro antioxidants properties, including DPPH free radical scavenging activity, total phenolic and flavonoid contents, hydroxyl radical scavenging activity, reducing power activity, iron-chelating capacity and nitrite scavenging activity. Among the extracts in this study, the 70% EtOH extract showed higher antioxidant activity than the others. The $IC_{50}$ value of DPPH free radical scavenging activity was $99.26\;{\mu}g/mL$. Furthermore, the 70% EtOH extract also showed significantly high total phenolic and flavonoids contents and reducing power activity. However, the MeOH extract exhibited stronger effects on hydroxyl radical scavenging activity, iron-chelating capacity and nitrite scavenging activity. All the results implicated that, the hawthorn fruit may has the available potential to be utilize as a potential source of natural antioxidant.

• Food Science and Biotechnology
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• v.17 no.6
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• pp.1151-1155
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• 2008

This study aimed to investigate the alterations in plasma antioxidant activity after the consumption of a single oral dose of curcumin, vitamin C, and E administered individually or in combination to (i) assess possible synergies or antagonism between the antioxidants and (ii) determine the optimal composition of the antioxidant mixture such that the duration of action is prolonged to beyond that of individual antioxidants. Each antioxidant was administered to male Sprague-Dawley rats, and blood samples were drawn at different time points up to 180 min to measure the plasma total antioxidant capacity (TAC). Five antioxidant compositions (M1-M5) were evaluated to assess the possible synergies or antagonisms among them and to determine the optimal composition of the antioxidant mixture. Blood samples were collected up to 360 min post-consumption. A single oral dose of individual antioxidants significantly increased the TAC values; however, the time to reach the peak TAC value varied. Among the 5 antioxidant compositions, M2 exhibited the highest and most prolonged antioxidant effect in plasma; this was greater than the proportional sum of the effects of the individual antioxidants in the composition. This result indicates a synergistic interaction among antioxidants in the optimal composition M2.

• Preventive Nutrition and Food Science
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• v.20 no.3
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• pp.169-175
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• 2015

Shinseoncho and kale were made into green vegetable juices by building block [shinsenocho branch (SB), shinsenocho leaf (SL), kale branch (KB), and kale leaf (KL)]. Fluctuations in their phenolic contents and antioxidant capacities were analyzed during refrigerated storage at $4^{\circ}C$ for 28 days. Total polyphenolic contents of leaf parts showed a decreasing tendency after 4 days (SL) or 7 days (KL), whereas branch parts showed fluctuating values during the entire storage period. The 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) radical scavenging capacity was rapidly decreased in SB and in SL at 28 days (P<0.001), whereas KL showed a slightly increasing tendency after 14 days. For the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging capacity, SL showed a sharp fall at 28 days (P<0.001), and KL showed a decreasing tendency after 14 days (P<0.001). SB showed a steady decrease during the entire storage period and KB indicated a nearly zero (0.97%) at 28 days. Pearson's coefficients for the correlation between antioxidant capacities measured by the ABTS and DPPH assays, and the total polyphenolic contents were determined. The results showed that the ABTS assay (r=0.934, P<0.001) was more strongly positively correlated with the total phenolic contents than the DPPH assay (r=0.630, P<0.001). In conclusion, when considering all building blocks, green vegetable juices, including kale and shinseoncho may have kept antioxidant capacities for up to 14 days under refrigeration, and the ABTS assay better reflects a positive correlation with the total phenolic contents when compared to the DPPH assay.

• Journal of Microbiology and Biotechnology
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• v.27 no.2
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• pp.388-394
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• 2017

Although several analytical methods for measuring total antioxidant capacity (TAC) have been applied to biological samples, there were often dissimilar results due to the different principles of methods applied. Thus, this study aimed to validate four conventional analytical methods for measuring plasma TAC, including the ABTS assay, DPPH assay, FRAP assay, and ORAC assay, by comparing with urinary 8-isoprostane concentration. In addition, TAC results were compared with antioxidant enzyme activities including superoxide dismutase (SOD) and glutathione peroxidase in erythrocyte, and catalase in plasma. Plasma TAC measure by ABTS assay was strongly correlated with the result by FRAP assay. Plasma TAC by FRAP and ORAC assays were negatively correlated with erythrocyte SOD activity. The agreement among the four TAC assay methods and 8-isoprostane was determined using 95% prediction limits of linear regression, expressed as the mean of 8-isoprostane ${\pm}95%$ prediction limits. The ABTS method better agreed with 8-isoprostane than the other methods, demonstrating narrow prediction of limits. Furthermore, only plasma TAC determined by the ABTS assay was inversely correlated with urinary 8-isoprostane (r = -0.35, p < 0.05). In summary, the ABTS assay would be an appropriate method to measure overall plasma antioxidant capacity and predict the body's antioxidant status.