• Preventive Nutrition and Food Science
• /
• v.8 no.1
• /
• pp.85-88
• /
• 2003

Effects of irradiation on color removal, tyrosinase inhibition, xanthine oxidase inhibition and nitrite scavenging capacity of Lonicera japonica extracts were evaluated. Lonicera japonica extracts were irradiated at 10, 20, and 30 kGy. Hunter color $L^{*}$- and $a^{*}$-values increased but $b^{*}$-values decreased dose-dependently following irradiation. The extracts were potent inhibitors of tyrosinase and xanthine oxidase. Tyrosinase inhibition was higher in the irradiated sample than non-irradiated, and subsequently increased with increasing irradiation doses. The extracts had a higher inhibitory effect against xanthine oxidase, and the effect was not changed by irradiation. Nitrite scavenging capacity was the highest in the extract at pH 1.2, and was not significantly affected by irradiation. These results indicate that gamma irradiation may not influence the biological activities of Lonicera japonica extracts when irradiated up to 30 kGy. Furthermore, color of the extracts can be improved to have improved applicability for the food and cosmetic industries without any adverse change in biological functions.ons.s.

• Journal of the East Asian Society of Dietary Life
• /
• v.19 no.2
• /
• pp.195-201
• /
• 2009

The antioxidative activities of two varieties of egg plant (Chunyang No 2: Dangaji, Jinju Janggaji: Janggaji) extracts were investigated. The total polyphenol contents of Dangaji peel hot water extract and the Janggaji flesh and fruit hot water extracts were higher than those of the other samples. However, the DPPH radical scavenging activities(electron donating activity) of Dangaji flesh-ethanol, peel-cold water, and fruit- ethanol extracts, as well as the Janggaji peel cold water extract, were higher than those of the other samples. Furthermore, the in vitro inhibitory effects of the Dangaji peel cold water and hot water extracts on rat hepatic xanthine oxidase were highest among the samples, and were exhibited in a dose dependant manners. Although there were marked changes in the xanthine oxidase Km values for xanthine as a substrate, the Vmax value changes by the addition of the Dangaji water extracts were minor compared with the control. This result suggests that Dangaji water extracts may regulate the activity of xanthine oxidase-via the inhibition of binding affinity between the enzyme and substrate. The present study provides experimental evidence that constituents of egg plant extracts may ameliorate reactive oxygen species(ROS)-induced oxidative stress via hepatic hepatic xanthine oxidase activity, but further studies to identify the active antioxidants and compounds and inhibitors of xanthine oxidase are required.

• Analytical Science and Technology
• /
• v.36 no.1
• /
• pp.44-52
• /
• 2023

This protocol clarifies a simple and precise method for measuring the activity of xanthine oxidase (XO) enzyme inhibitor. XO enzyme, which accelerates oxidative stress-related disorders through its capacity to generate hydrogen peroxide and superoxide anion radicals (O₂^•-), has been found to be inhibited by several plant extracts. Enzyme samples were incubated with a suitable buffer containing adequate amounts of xanthine as a substrate to determine XO activity. The method depends on direct measurements of uric acid and hydrogen peroxide production to test XO with and without interference. The CUPRAC reagent (Cu(Nc)₂²⁺) was used to inhibit enzyme reaction after incubation was complete. The generated urate and peroxide reduced the Cu(II)-neocuproine complex (Cu(Nc)₂²⁺) to a brightly colored Cu(I)-neocuproine complex (Cu(Nc)₂⁺), which was assessed with a spectrophotometer at 450 nm. XO activity was found to be directly related to the increased absorbance of the colored Cu(I)-neocuproine complex (Cu(Nc)₂⁺). To eliminate catalase enzyme interference, the proposed method used sodium azide and was validated against XO activity using the UV method in matched samples with t-test analysis. The proposed assay can determine XO activity with high precision, as indicated by the correlation coefficient (R² = 0.9935) from comparison with the reference protocol.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.36 no.4
• /
• pp.389-394
• /
• 2007

The study was carried out to optimize the electron donating ability (EDA), superoxide dismutase (SOD)-like activity, nitrite scavenging ability, and the inhibitory activities of xanthine oxidase and tyrosinase of Ailanthus altissima ethanol extracts from roots, stems and leaves. The EDA of the roots and stem extracts were 64.04% and 63.27% at $1,000{\mu}g/mL$, respectively. The SOD-like activity of the leaves extract was the highest (50.00%) at $1,000{\mu}g/mL$. The nitrite scavenging ability of the leaves extracts was over 98% at pH 1.2 and 3.0. The xanthine oxidase inhibitory rates of the extracts were $93.62%{\sim}95.40%$ and the tyrosinase inhibitory rate of the roots was the highest (62.01%) at the concentration of $1,000{\mu}g/mL$. These results indicated that the roots extract showed the highest EDA and tyrosinase inhibition, while the leaves extract had tile highest SOD-like activity and nitrate scavenging ability.

• Journal of the Korean Society of Food Culture
• /
• v.18 no.5
• /
• pp.443-456
• /
• 2003

The lyophilization of the solution extracted from 60 percent of acetone applied to persimmon leaves, the compounding process in accordance with the solution's concentration, and the gel filteration through Sephadex G-50 of biologically activated substances obstructing enzyme activity, such as tyrosinase, xanthine oxidase, and angiotesin converting enzyme (ACE) led to the assumption that polyphenol was the compound serving as biologically activated substances obstructing enzyme activity. Xanthine oxidase involved in pruine metabolism oxidizes hypoxanthine to xanthine and xanthine to uric acid. In the continuous study for natural compound, nine flavan-3-ols have been isolated from the persimmon leaves. The structures of (+)-catechin, (+)-gallocatechin, procyanidin B-1, pyrocyanidin C-1, prodelphinidin B-3, gallocatechin-$(4{\alpha}{\rightarrow}8)$-catechin, procyanidin B-7-3-O-gallate, procyanidin C-1-3'-3'-3'-O-trigallate and (-)-epigallocatechin-$(4{\alpha}{\rightarrow}8)$-epigallocatechin-$(4{\alpha}{\rightarrow}8)$-catechin were established by NMR and their inhibitory effect on xanthine oxidase activity was investigated. Procyanidin B-7-3-O-gallate, (-)-epigallocatechin-$(4{\alpha}{\rightarrow}8)$-epigallocatechin-$(4{\alpha}{\rightarrow}8)$-catechin and procyanidin C-1-3'-3'-3'-O-trigallate showed 94%, 90.69%, 80.90% inhibition at $100\;({\mu})M$ and inhibited on the angiotensin converting enzyme respectively. Procyanidin B-7-3-O-gallate and procyanidin C-1-3'-3'-3'-O-trigallate showed 66%, 63% inhibition at $100\;({\mu})M$ and inhibited on the xanthine oxidase competitively. Procyanidin C-1-3'-3'-3'-O-trigallate showed 70% inhibition at $100\;({\mu})M$ and inhibited on the tyrosinase competitively.

• Applied Biological Chemistry
• /
• v.49 no.2
• /
• pp.114-124
• /
• 2006

The objective of this research was to evaluate the ability of water and 80% ethanol extracts from one hundred eight mulberry leaves (Morus alba L.) to influence the inhibitory activity of angiotensin converting enzyme (ACE) and xanthine oxidase (XOase). The total phenol contents were that water extracts of ten species (Kakjayongsan (Morus alba L.), Daejungsun (Morus alba L.) etc.) and 80% ethanol extracts of twenty three species (Waryoung (Morus alba L.), Hasusang (Morus alba L.) etc.) showed more than 15 mg/g. The inhibitory activity on angiotensin converting enzyme (ACE) were that ten species (YamanakkadakKaskke (Morus alba L.), Mijiro (Morus alba L.) etc.) showed 100% inhibition rate both of water extracts and 80% ethanol extracts. The rest, water extracts of thirty four species (Cheongilppong (Morus alba L.) etc.) and 80% ethanol extracts of thirty four species (Wonjukojo (Morus alba L.) etc.) showed inhibitory activity (above 90%) on ACE. Also, to search of xanthine oxidase (XOase) inhibition were that water extracts of five species (Cheongsipjosaeng (Morus alba L.), Suwon 3 (Morus alba L.) etc.) and 80% ethanol extracts of Jeokmok (Morus alba L.) showed inhibitory activity (above 50%) on XOase. This result revealed, strong biological activity in spite of has a little total phenol contents. These water and 80% ethanol extracts from mulberry leaves (Morus alba L.) are expected good candidate for development into anti-hypertentive and anti-gout sources.

• Applied Biological Chemistry
• /
• v.40 no.3
• /
• pp.254-258
• /
• 1997

To examine the characteristics of the antioxidative property of Buckwheat components, acetone extracts from a buckwheat, Suwon 5, was fractionated using five solvents. Hexane, ethylacetate, ether, butanol and water fractions were obtained. Butanol fraction showed the greatest electron donating ability and inhibitory effect on lipid peroxidation. It also showed the most excellent activity in the superoxide radical scavenging activity by xanthine/xanthine oxidase-cytochrome c reduction system. Spectrophotogram of butanol fraction was similar to that of rutin. Superoxide radical scavenging activity was related to the contents of rutin. Inhibitory effect of each fraction on xanthine oxidase was also measured. Butanol fraction had the strongest inhibitory effect on xanthine oxidase and $IC_{50}\;was\;3.1\;{\mu}g$. The inhibition type of butanol fraction on xanthine oxidase turned out to be a mixture of the uncompetitive and non-competitive modes.

• Korean Journal of Food Science and Technology
• /
• v.28 no.6
• /
• pp.1084-1088
• /
• 1996

As a series of study for an anti-gout agent, two flavan-3-ols have been isolated from Oolong tea. They showed positive reaction in $anisaldehyde-H_2SO_4$ solution and $FeCl_3$, which were able to be confirmed in TLC with dimeric flavan-3-ols. The components were identified as procyanidin B-2 and procyanidin B-2-O-3, 3'-di-gallate by spectroscopic analysis. Their inhibitory effect on xanthine oxidase was also investigated and procyanidin B-2-O-3, 3'-digallate showed 60.6% inhibition at $50\;{\mu}mole$. The compound competitively inhibited the xantine oxidase and dimeric flavan-3-ols contanining gallate had higher inhibition activity.

• YAKHAK HOEJI
• /
• v.47 no.5
• /
• pp.307-310
• /
• 2003

Ethanol extract of Actinidia polygama Max. (AP) was examined for hypouricemic activity in potassium oxonateinduced hyperuricemic animal model. Ethanol extract of AP lowered the plasma uric acid level by 20％ when compared to the hyperuricemic control group. AP ether fraction at a dose of 100 mg/kg showed 27％ reduction, whose efficacy was comparable to the probenecid-treated group. AP ether fraction-treated group also showed 23％ reduction of urate in urine and this result suggests that AP ether fraction has anti-gout activity probably due to xanthine oxidase inhibition.

• Proceedings of the Ginseng society Conference
• /
• 1988.08a
• /
• pp.139-140
• /
• 1988

In the screening of those components with comparatively strong xanthine oxidase inhibition activities from Panax ginseng folium. trifolin. panasenoside. kaempferol and so far unconfirmed phenol whose chemical structure still without elucidation have been discovered as such components. Specific inhibitors of xanthine oxidase are thought to be therapeutically useful for the treatment of gout. Such opinion is considered to be useful to support the thought that ginseng folium is effective for the adjustment of gout. Although trifolin. panasenoside. and kaempferol are well known flavonoids. further studies on unidentified new phenols should be continued.