• Journal of Physiology & Pathology in Korean Medicine
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• v.22 no.4
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• pp.903-906
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• 2008

Woodfordia fruticosa Kurz (Lythraceae) is used in the treatment of various ailments in traditional medicines. DPPH activity guided fractionation and purification process was used to identify the free radical-scavenging components from the flowers of this plant. The methanolic extract of the plant was first fractionated into four extracts; namely, n-hexane, chloroform, ethyl acetate and water fractions. Among them, the ethyl acetate fraction was found to be the most effective and was further subjected to activity guided-fractionation and isolation procedures. After successive column chromatography on silica gel and Sephadex LH-20, gallic acid, which is responsible for the radical scavenging activity, was isolated and its structure was elucidated by spectral methods ($^1H$ NMR, $^{13}C$ NMR) and by comparison with literature.

• Archives of Pharmacal Research
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• v.29 no.3
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• pp.199-202
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• 2006

From the leaves of Goniothalamus tenuifolius, a new natural product namely 3'-hydroxy-3,5,7,4'-tetramethoxyflavone (1) was isolated, along with seven other known compounds (2-8). Each of these isolates was evaluated for free radical scavenging activity on the DPPH decoloration test. The data obtained in this study suggested that the ortho 3',4'-diphenolic structure was essential for the activity of these flavonol derivatives.

• The Korean Journal of Community Living Science
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• v.26 no.4
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• pp.697-705
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• 2015

This study investigates antimicrobial effects of food-borne pathogens and the antioxidant activity of Torreya nucifera extract. The growth of food-borne pathogens including Staphylococcus aureus, Pseudomonas aeruginosa, and Candida albicans was inhibited by the extract. The antimicrobial activity of the extract was highest for Staphylococcus aureus among seven gram-positive bacteria and for Pseudomonas aeruginosa among six gram-negative bacteria. The extract exhibited slightly lower DPPH radical-scavenging activity, but its ABTS radical-scavenging activity was higher than that of ${\alpha}$-tocopherol. The results demonstrate the extract's antimicrobial effects on food-borne pathogens as well as potent antioxidant capacity and suggest that Torreya nucifera may be used as a natural antibacterial agent and an effective antioxidant in food.

• Journal of Pharmacopuncture
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• v.11 no.1
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• pp.109-118
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• 2008

Objective : The objective of this study was to compare the antioxidant effects of hot pepper extract and capsaicin. Methods : In vitro, antioxidant activities were examined by DPPH radical scavenging activity, total antioxidant capacity(TAC), oxygen radical scavenging capacity(ORAC), inhibition of induced lipid peroxidation using liver mitochonria and total phenolic contents. Results : 1. DPPH free radical scavenging activities at the concentrations of both 1 and $10mg/m{\ell}$ were 1.2 to 1.9 times higher in capsaicin than in hot pepper extract. The concentration of capsaicin required for 50% radical scavenging was lower than that of hot pepper extract(3.9 vs $5.9mg/m{\ell}$), indicating that capsaicin had higher DPPH radical scavenging activity than hot pepper extract. 2. Total antioxidant capacities of capsaicin at the concentrations of 0.1 and 1mg/ml(13.8 and 41.3 nmol Trolox equivalent) were not significantly different from those at the concentrations of 1 and $10mg/m{\ell}$(11.4 and 41.2nmol Trolox equivalent), indicating that capsaicin showed 10 times higher ABTS radical scavenging activity compared to hot pepper extract. 3. ORAC of capsaicin at the concentrations of 1, 5, 10 and 100 mg/ml were 0.04, 0.17, 0.29 and 1.74nmol gallic acid equivalent, respectively. On the other hand, ORAC of hot pepper extract at the concentrations of 1, 5, 10 and $100{\mu}g/m{\ell}$ were 0.15, 0.44, 0.75 and 2.49nmol gallic acid equivalent, respectively, indicating that capsaicin showed higher peroxyl radical scavenging activity than hot pepper extract. 4. Inhibition of lipid peroxidation caused by hot pepper extract at the concentrations of 1 and $10mg/m{\ell}$ were 12.2 and 61.4%, respectively. Inhibition of lipid peroxidation caused by capsaicin at the concentrations of 1 and $10mg/m{\ell}l$ were 64.0 and 96.8%, respectively. Thus capsaicin showed 10 times stronger effect in inhibiton of lipid peroxidation than hot pepper extract. 5. Total phenolic contents of hot pepper extract at the concentrations of 0.1 and $1mg/m{\ell}$ were 1.4 and 20.8nmol gallic acid equivalent, respectively. Total phenolic contents of capsaicin at the concentrations of 0.1 and $1mg/m{\ell}$ were 6.1 and 55.4 nmol gallic acid equivalent, respectively, indicating that capsaicin had 2.7 to 4.3 times higher total phenolic contents than hot pepper extract. Conclusions : In summary, the results of this study demonstrate significant antioxidant activity of hot pepper extract, although the activity was lowered compared to capsaicin, suggesting that hot pepper extract play a role in prevention of oxidative-related diseases.

• Archives of Pharmacal Research
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• v.20 no.5
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• pp.496-500
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• 1997

A strong antioxidant activity, which was measured by the radical scavenging effect on 1, 1-diphenyl-2-picrylhydrazyl(DPPH) radical, was detected in the methanol extract of Salvia miltiorrhiza Bunge (Labiatae). By activity-directed fractionation, compounds 1 and 2 were isolated as antioxidant principles of S. miltiorrhiza. Compounds 1 and 2 were identified as dimethyl lithospermate and 3-(3, 4-dihydroxyphenyl)lactamide, respectively, on the basis of spectral data. The radical scavenging effect of compounds 1 and 2 on DPPH radical exceeded that of L-ascorbic acid which is a well known antioxidant. These two compounds also showed prominent inhibitory activity against free radical generation in dichlorofluorescein (DCF) method and cytoprotective effect against t-BHP in cultured liver cell.

• Korean Journal of Medicinal Crop Science
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• v.17 no.1
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• pp.15-20
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• 2009

This study was carried out in order to determine the biological activities such as antioxidant activities in nine cultivars of Momordica charantia L. (Korea, China, Japan and Philippine native cultivars). Their antioxidant activities were measured using DPPH free radical scavenging, ABTS cation radical scavenging, and Nitrite scavenging ability. The highest total polyphenol content (16.82 ${\mu}g/m{\ell}$) measured in the native Korea cultivar, and this value was 4.0 ${\mu}g/m{\ell}$ higher than that of the 'Verde Beuhas' cultivar (12.82 ${\mu}g/m{\ell}$). The 'Peacock' cultivar had the highest total flavonoid amount which was 4.38 ${\mu}g/m{\ell}$. The free radical scavenging activity using DPPH method was the highest in the native China cultivar ($RC_{50}$ = 102.6 ${\mu}g/m{\ell}$). ABTS cation radical scavenging activity according to cultivars was significantly higher in 'Peacock'. Nitrite scavenging ability showed the most remarkable effect at the pH 1.2, exhibited to 81.5${\sim}$86.9% by addition of ethanol extract 1${\mu}g/m{\ell}$ from Momordica charantia L. These results suggest that Momordica charantia L. had the potent biological activities, and that their activities exhibited differently depending on cultivars.

• Journal of the Korean Society of Food Culture
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• v.27 no.1
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• pp.75-81
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• 2012

This study was conducted to investigate the physiological activity of acai berry (Euterpe oleracea Mart.) extracts from three different solvents (water, methanol, and ethanol). We measured total polyphenol and total flavonoid content, DPPH radical scavenging activity, nitrite scavenging activity, metal chelating effect, and reducing power. The extraction yield from water, methanol, and ethanol was 17.10, 9.50, and 37.51%, respectively. The highest total polyphenol content (10.54 mg/100 g) and total flavonoid contents (1.88 mg/100 g) was observed in water extract. DPPH radical scavenging activity was the highest in both water extract (72.03%) and methanol extract (74.79%) at levels of 5 mg/mL, which was similar to that of BHT (78.90%). Water extract yielded the highest metal chelating effect (92.54%) and reducing power (1.09) at levels of 5 mg/mL. Taken together, these findings suggest that extracts of acai berry can be used as functional food materials with antioxidative and nitrite scavenging activities.

• Korean Journal of Pharmacognosy
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• v.44 no.3
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• pp.230-234
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• 2013

In the course of screening for antioxidant compounds by measuring the DPPH radical scavenging activity, a total extract of the aerial part of Trigonotis peduncularis (Boraginaceae) was found to show potent DPPH radical scavenging activity. Subsequent activity-guided fractionation of the methanolic extract of T. peduncularis led to the isolation of seven compounds, kaempferol (1), quercetin (2), trigonotin A (3), astragalin (4), trigonotin C (5), kaempferol-3-O-${\alpha}$-L-rhamnopyranosyl(1${\rightarrow}$6)-${\beta}$-D-glucopyranoside (6), and rutin (7) from the active ethyl acetate soluble fraction. Their structures were elucidated by spectroscopic studies. Among seven compounds, compounds 1, 2, 4, 6 and 7 were isolated for the first time from this plant, and compounds 2 and 7 showed the significant DPPH free radical scavenging activities.

• Herbal Formula Science
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• v.12 no.1
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• pp.255-262
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• 2004

The inhibitory effect of the aerial parts of Fagopyrum esculentum on the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical was examined. The n-butanol fraction from the methanol extract of title plant showed stronger inhibitory effect than other fractions on DPPH radical. Two flavonoids were isolated from n-butanol fraction having the potent activity and elucidated as quercetin-3-O-${\alpha}$-L-rhamnoside and quercetin-3-O-rutinoside on the basis of spectral evidence. The $IC_{50}$ values of these compounds on DPPH radical were 6.56 ${\mu}M$ and 8.37 ${\mu}M$, respectively.

• Food Science and Biotechnology
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• v.18 no.2
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• pp.312-316
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• 2009

Antioxidant-rich oils were extracted from different parts of sea buckthorn berry with supercritical $CO_2$ (SC-$CO_2$) and n-hexane. The functional components were analyzed and the extracts were screened for their potential as radical scavengers in 1,1-diphenyl-2-picrylhydrazyl radical (DPPH), 2,2'-azinobis-3-ethylbenzotiazoline-6-sulphonic acid (ABTS), galvinoxyl systems. Minor differences were found in fatty acid composition of oils extracted by the two methods. Seed oil contains the highest content of tocopherols while pulp oil and whole berry oil possessed higher concentration of carotenoids. Whole berry oil, pulp oil, and seed oil extracted by SC-$CO_2$ showed 91.7, 90.9, and 93.5% radical scavenging activity (RSA) at 6 mg/mL towards DPPH and 74.3, 54.3, and 74.8% towards galvanoxyl radical at 10 mg/mL. The hexane-extracted oils showed similar scavenging ability. However, the oils obtained by hexane showed significantly higher RSA (p<0.05) than those obtained by SC-$CO_2$ while whole berry oil has the highest RSA towards ABTS among 3 oil samples.