• Korean Journal of Plant Resources
• /
• v.21 no.4
• /
• pp.254-259
• /
• 2008

The radical scavenging activities of 9 medicinal plants on peroxynitrite ($ONOO^-$) and hydroxyl (${\cdot}OH$) radical were investigated using in vitro system. The water extracts of 9 medicinal plants showed the protective effect against $ONOO^-$ and ${\cdot}OH$ radical. In particular, Akebia quinata, Aster scaber, Cudrania tricuspidata, Diospyros kaki, Eriobotrya japonica, Lycium chinense, Parthenocissus tricuspidata and Polygonum aviculare exhibited $ONOO^-$-scavenging activity by about 50% at the concentration of $10{\mu}g/ml$. Although those $ONOO^-$-scavenging activities were lower than that of penicillamine (94.08${\pm}$3.04%) as a positive control, Eriobotrya japonica (89.87${\pm}$4.57%) was the most potent scavenger of $ONOO^-$ at the concentration of $10{\mu}g/ml$. Also, Diospyros kaki and Urtica angustifolia showed the strong${\cdot}$OH-scavenging activity than thiourea, positive control, at the concentration of lmg/ml. Our results indicate that 9medicinal plants may act as free radical scavengers and reduce damages caused by oxidative stress associated with $ONOO^-$ and${\cdot}$OH radical.

• Korean Journal of Plant Resources
• /
• v.24 no.2
• /
• pp.174-180
• /
• 2011

This study was conducted to investigate the optimum condition of extraction from fronds of Osmunda japonica to increase antioxidant compounds and antioxidant activity. Powder (1 g) of lyophilized fronds were mixed with three different solvents (MeOH, 80% EtOH and water). Extraction was carried out using not only by immersion (room temp.), heating ($60^{\circ}C$) and stirring (200 rpm) for 6 h, but also by sonication in 42 kHz ultrasonic bath for 15, 30 and 45 min. Extracts were filtered, and adjusted up to 50 mL to determine contents of soluble solids, total polyphenols and total flavonoids. Antioxidant capacity was measured by radical scavenging activity of 0.15 mM DPPH (2,2-diphenyl-1-picrylhydrazyl) and 7.4 mM ABTS [2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)] radical. Among the solvents, MeOH and 80% EtOH appeared to be effective for extraction. Extract obtained from sonication in MeOH for 15 min resulted high polyphenol contents (45.15 $mg{\cdot}g^{-1}$ db) and DPPH radical scavenging activity ($RC_{50}$= 0.35 $mg{\cdot}mL^{-1}$). The highest flavonoid contents was obtained from immersion or heating extraction with MeOH (38.10~38.10 $mg{\cdot}g^{-1}$ db). ABTS radical scavenging was high in same extraction with 80% EtOH ($RC_{50}$= 0.21~0.22 $mg{\cdot}mL^{-1}$). Altogether, our results indicate that the extraction using ultrasonic bath with MeOH as a solvent (for 15~30 minutes) was the most effective way not only for increasing various antioxidant activities but also for saving labor and time in case of fronds of Osmunda japonica.

• Korean Journal of Agricultural Science
• /
• v.39 no.4
• /
• pp.511-514
• /
• 2012

In this study, the comparison of antioxidative effect of the methanol (MeOH) extracts from grains were investigated in vitro radical scavenging system. Ten grains (black rice, rice, barley, wheat, millet, sorghum, glutinous millet, buckwheat, phellines linteus rice and brown rice) were extracted with MeOH. Among the MeOH extracts of grains, sorghum and black rice showed effective scavenging activities of 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical. The $IC_{50}$ values of sorghum and black rice were $47.4{\mu}g/mL$ and $50.6{\mu}g/mL$, respectively. In addition, black rice also exerted the strongest activities on hydroxyl radical (${\cdot}OH$) scavenging activity. Furthermore, the MeOH extracts of black rice showed effective and dose dependant scavenging activities of DPPH radical and ${\cdot}OH$. These results indicated that black rice showed strong free radical scavenging activity. It suggested that black rice could be a promising natural antioxidant against free radical-induced oxidative damage.

• The Korean Journal of Pharmacology
• /
• v.21 no.1
• /
• pp.34-48
• /
• 1985

In vitro effects of nitrofurantoin, an antimicrobial agent for acute and chronic urinary tract infection, on the lung microsomal lipid peroxidation and the generation of reactive oxygen radicals were investigated to elucidate the biochemical mechanisms of its in vivopulmonary toxicity. The interaction of nitrofurantoin with porcine lung microsome resulted in significant lipid peroxidation. In addition, nitrofurantoin stimulated the generation of reactive oxygen radicals, $O^{-}_{2}{\cdot},\;H_2O_2$ as well as a highly reactive secondary oxygen species, $OH{\cdot}$. The stimulation of lipid peroxidation was inhibited not only by superoxide dismutase and catalase, but also by hydroxyl radical scavengers, mannitol and thiourea. Neither singlet oxygen $({^1}O_{2})$ was detected during the incubation of microsome with nitrofurantoin, nor lipid peroxidation was inhibited by singlet oxygen scavengers. When incubated anaerobically under the nitrogen atmosphere, the ability of nitrofurantoin to stimulatle lipid peroxidation was abolished. It appears that NADPH-dependent metaboliam of nitrofurantoin in pulmonary microsome under aerobic condition is accompanied by the stimulation of lipid peroxidation through the mediation of reactive oxygen radicals, particularly hydroxyl radical. It is strongly suggested from these results that the stimulation of pulmonary microsomal lipid peroxidation by the reactive oxygen radical may be a in vivo mechanism of pulmonary toxicity caused by nitrofurantoin.

• Bulletin of the Korean Chemical Society
• /
• v.25 no.12
• /
• pp.1907-1910
• /
• 2004

Generation of hydroxyl radical, one of their major active species in ozonation of water was directly observed with spin-trapping/electron spin resonance (ESR) technique using 5,5-dimethyl-pyrrolidine-1-oxyl (DMPO) as a spin-trapping reagent. Hydroxyl radical was trapped with DMPO as a stable radical, DMPO-OH. 80 mM of ozone produced $1.08{\times}10^{-6}$M of DMPO-OH, indicating that 1.4% of ${\cdot}$OH is trapped with DMPO if ${\cdot}$OH is produced stoichiometrically from ozone. Humic acid suppressed DMPO-OH generation in a dose-dependent manner. Generation rate of DMPO-OH was determined with ESR/stopped-flow measurement. Phenol derivatives increased the amount and generation rate of DMPO-OH, indicating that phenol derivatives enhance·OH generation during ozonation of water.

• Bulletin of the Korean Chemical Society
• /
• v.27 no.11
• /
• pp.1785-1790
• /
• 2006

A novel kinetic method for determination of $HO_2{^{\cdot}}/O_2{^{{\cdot}-}}$ in ozone decomposition in water is described. In this study, potential interferences of $O_3$ and the hydroxyl radicals, $^{\cdot}OH_{(O3)}$, are suppressed by $HSO_3{^-}/SO_3{^{2-}}$. $HO_2{^{\cdot}}/O_2{^{{\cdot}-}}$ formed in ozone decomposition reduces $Fe^{3+}$-EDTA into $Fe^{2+}$-EDTA and subsequently the well-known Fenton-like (FL) reaction of $H_2O_2$ and $Fe^{2+}$-EDTA produces the hydroxyl radicals, $^{\cdot}OH_{(FL)}$. Benzoic acid (BA) scavenges $^{\cdot}OH_{(FL)}$ to produce OHBA, which are analyzed by fluorescence detection (${\lambda}_{ex}=320nm$ and ${\lambda}_{ex}=400nm$). The concentration of $HO_2{^{\cdot}}/O_2{^{{\cdot}-}}$ in ozone decomposition has been determined by the novel kinetic method using the experimentally determined half-life ($t_{1/2}$). The steady-state concentration of $HO_2{^{\cdot}}/O_2{^{{\cdot}-}}$ is proportional to the $O_3$ concentration at a given pH. However, the steady-state concentration of $HO_2{^{\cdot}}/O_2{^{{\cdot}-}}$ in ozone decomposition is inversely proportional to pH values. This pH dependence is due to significant loss of $O_2{^{{\cdot}-}}$ by $O_3$ at higher pH conditions. The steady-state concentrations of $HO_2{^{\cdot}}/O_2{^{{\cdot}-}}$ are in the range of $2.49({\pm}0.10){\times}10^{-9}M(pH=4.17){\sim}3.01({\pm}0.07){\times}10^{-10}M(pH=7.59)$ at $[O_3]_o=60{\mu}M$.

• Journal of the Korean Chemical Society
• /
• v.39 no.4
• /
• pp.237-243
• /
• 1995

The measurments of neutral semiquinone radicals, which were formed from the laser flash photolysis of anthraquinone (AQ) in the mixed solvents were carried out by the time resolved electron spin resonance (trESR) spectroscopy. The chemically induced dynamic electron polarization (CIDEP) spectra of the neutral semiquinone radical (AQH${\cdot}$) and semiquinone radical anion (AQ${\cdot}$-) were successively detected in the laser flash photolysis of AQ in the mixtures of 2-propanol (PrOH) and triethylamine (TEA). The neutral semiquinone radical was short-lived with the half-life of 0.8 ${\mu}sec$, whereas the semiquinone radical anion was relatively stable and then its cwESR could be observed. The rate constant of the spin-depolarization of semiquinone radical anion was $2.6{\times}10^5 sec^{-1}$ and the decay of the radical anion was the first order reaction with the rate constant of $3.0{\times}10^2\; sec^{-1}$. No CIDEP of semiquinone radical anion was observed in the mixture of PrOH and the lower concentration of TEA than 2 percent. The CIDEP spectrum of the neutral semiquinone radical was detected in the mixture of benzene and TEA with the half-life of 3.0 ${\mu}sec$. The neutral semiquinone radical could not be detected by cwESR. Neither CIDEP nor ESR absorption could be observed in PrOH, TEA or benzene only.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.19 no.9
• /
• pp.402-407
• /
• 2018

In this study, we investigated the antioxidative effects of AY by measuring 1.1-Diphenyl-2-picrylhydrazyl (DPPH), hydroxyl radical ($^{\cdot}OH$), and superoxide radical ($O_2{^-}$) scavenging activities in vitro. AY was extracted with ethanol and then partitioned with n-hexane, methylene chloride ($CH_2Cl_2$), ethylacetate (EtOAc) and n-butanol (n-BuOH). In the DPPH radical scavenging assay, AY at concentrations of 10 to $100{\mu}g/mL$ dose-dependently increased inhibition of DPPH oxidation, with the EtOAc fraction of AY showing the highest DPPH radical scavenging activity fractions. The $^{\cdot}OH$ radical scavenging activities of the extract and four fractions of AY increased by over 80% at a concentration of $50{\mu}g/mL$. In particular, the IC50 value of the EtOAc fraction was $0.03{\mu}g/mL$, which was the lowest value among all fractions. We also found that the EtOAc fraction of AY was better at $O_2{^-}$ radical scavenging than other fractions. Taken together, these results suggest that AY, especially the EtOAc fraction, can be used as a natural antioxidant against free radicals.

• Korean Journal of Plant Resources
• /
• v.21 no.1
• /
• pp.91-95
• /
• 2008

Reactive oxygen species(ROS) or free radical-mediated oxidative stress plays an important role in the pathophysiologic process of disease state. This study investigated antioxidative effects of Phellinus linteus extract on the generation of 1,1-diphenyl-2-picrylhydrazyl(DPPH) radical, superoxide anion radical(${O_2}^-$), hydroxyl radical(${\cdot}OH$), nitric oxide(NO), and peroxynitrite($ONOO^-$) radical and free radical-mediated protein oxidation under in vitro assay systems. This results showed that Phellinus linteus extract effectively inhibited the generation of free radicals in the all assay system with dose-dependent manner and also significantly reduced the protein oxidative level. Thus, the present study indicates that Phellinus linteus extract possesses a potent antioxidant activity and plays a beneficial role against free radical-induced oxidative injury.

• Preventive Nutrition and Food Science
• /
• v.14 no.1
• /
• pp.86-89
• /
• 2009

In this study, we investigated the free radical [1,1-diphenyl-2-picrylhydrazyl (DPPH), hydroxyl radical (${\cdot}OH$) and superoxide anion (${O_2}^-$)] scavenging activity of MeOH extract and 3 fractions of Citrus junos. Of the tested fractions, the BuOH fraction showed the strongest DPPH scavenging activity, showing the $IC_{50}$ values of 63.4 mg/mL. Therefore, we continuously carried out DPPH, ${\cdot}OH$ and ${O_2}^-$ scavenging activity tests of BuOH fraction of Citrus junos. The BuOH fraction of Citrus junos inhibited DPPH radical to 97.5% at a concentration of 1000 mg/mL and the scavenging activities were increased concentration-dependently. In addition, BuOH fraction from Citrus junos also scavenged ${\cdot}OH$ in a concentration dependent manner from 5 to 1000 mg/mL. Furthermore, BuOH fraction showed about 56% ${O_2}^-$-scavengimg activity at 25 mg/mL concentration but, the scavenging activities were not enhanced in a dose dependent manner. The present results suggest that BuOH fraction of Citrus junos would have the protective potential from oxidative stress induced by free radicals.