• Journal of Life Science
• /
• v.10 no.4
• /
• pp.347-353
• /
• 2000

This study was designed to investigate the effects of silkworm (Bombyx mori L.) powder (SWP) on oxygen radicals and their scavenger enzymes in liver membranes of rats. Sprague-Dawley(SD) male rats(160$\pm$10g) were fed basic diet (control group), and experimental diets(SWP-200 and SWP-400 groups) added 200 and 400 mg/kg BW/day for 6 weeks. Hydroxyl radical (.OH) levels resulted in a consistent decreases (4.0% and 7.2%, 5.0% and 14.1%, respectively) in liver mitochondria and microsomes of SWP-200 SWP-400 groups compared with control group, and O2 radical level was significantly decreased about 12% in liver cytosol of SWP-400 group compared with control group. Lipid peroxide(LPO) levels were significantly decreased (14.4% and 9.1%, respectively) in liver mitochondria and microsomes of SWP-400 group only compared with control group. Oxidized protein (OP) levels were remarkably decreased about 12.7% and 16.3% in liver microsomes only of SWP-200 and SWP-400 groups, but significant difference between liver mitochondria could not obtained. Mn-SOD activities were remarkably increased (15.8% and 25.2%, respectively) in mitochondria of SWP-200 and SWP-400 groups, but significant difference between Cu, Zn-SOD activities in these group could be not obtained. GSHPx activity was significantly increased in liver cytosol of SWP-400 group compared with control group. These results suggest that silkworm powder may play an effective role in a attenuating a oxidative stress and increasing a scavenger enzyme activity in liver membranes.

• BMB Reports
• /
• v.32 no.5
• /
• pp.486-491
• /
• 1999

An engineered cDNA from Phanerochaete chrysosporium encoding both the mature and propeptide-sequence regions of lignin peroxidase H2 (Lip H2) was overexpressed in Escherichia coli BL21 (DE3) to evaluate its catalytic characteristics and potential application as a pollution scavenger. All expressed proteins were aggregated in an inactive inclusion body, which might be due to inherent disulfide bonds. Active enzyme was obtained by refolding with glutathione-mediated oxidation in refolding solution containing $Ca^{2+}$, heme, and urea. Propeptide-sequence region was not processed as evidenced by N-terminal sequence analysis. Recombinant Lip H2 (rLip H2) had the same physical properties of the native protein but differed in the $K_{cat}$. Catalytic efficiency ($k_{cat}/K_m$) of rLip H2 was slightly higher than that of the native enzyme. In order to express an active protein, fusion systems with thioredoxin or Dsb A, which have disulfide isomerase activity, were used. The fused proteins expressed by the Dsb A fusion vector were aggregated, whereas half of the thioredoxin fusion proteins were recovered as a soluble form but still catalytically inactive. These results suggest that Lip H2 may not be expressed as an active enzyme in Escherichia coli although the activity can be recovered by in vitro refolding.

• Clinical and Experimental Pediatrics
• /
• v.56 no.3
• /
• pp.107-111
• /
• 2013

Preterm infants are vulnerable to the oxidative stress due to the production of large amounts of free radicals, antioxidant system insufficiency, and immature oligodendroglial cells. Reactive oxygen species (ROS) play a pivotal role in the development of periventricular leukomalacia. The three most common ROS are superoxide ($O2^{\cdot-}$), hydroxyl radical ($OH^{\cdot}$), and hydrogen peroxide ($H_2O_2$). Under normal physiological conditions, a balance is maintained between the production of ROS and the capacity of the antioxidant enzyme system. However, if this balance breaks down, ROS can exert toxic effects. Superoxide dismutase, glutathione peroxidase, and catalase are considered the classical antioxidant enzymes. A recently discovered antioxidant enzyme family, peroxiredoxin (Prdx), is also an important scavenger of free radicals. Prdx1 expression is induced at birth, whereas Prdx2 is constitutively expressed, and Prdx6 expression is consistent with the classical antioxidant enzymes. Several antioxidant substances have been studied as potential therapeutic agents; however, further preclinical and clinical studies are required before allowing clinical application.

• Microbiology and Biotechnology Letters
• /
• v.18 no.1
• /
• pp.103-108
• /
• 1990

The enzymatic studies on the methylglyoxal metabolism in yeast and bacterial cells indicated that organisms are equipped with the common and manifold systems for the detoxification of methylglyoxal. Among these systems, the glyoxalase I is the most important route for methylglyoxal detoxification. The molecular structure of glyoxalase I is apparently distinct from the enzyme sources, and zinc ion is an essential cofactor in enzyme activity. The gene for Pseudomonas putida glyoxalase I functioned as a scavenger of methylglyoxal and regulated the cell size of the bacterium. Comparison of the nucleotide sequence of the P. putida glyoxalase I gene with the N-terminal amino acid sequence of the purified enzyme revealed that the N-terminal methionine residue was removed after translation. Possible physiological role of glyoxalase I was also discussed.

• Nutritional Sciences
• /
• v.9 no.1
• /
• pp.14-19
• /
• 2006

Breast cancer may be the consequence of free radical damage, which is partially caused by the excessive intake of dietary fat and imbalances in antioxidant scavenger system;. In this experiment, we examined! the effects of dietary peroxidizability index (PI) values on hepatic thiobmbituric acid reaction substances (TBARS) and antioxidant enzyme activities in rats treated with 7,12-dimethylbenz[$\alpha$]anthracene (DMBA). Female Sprague-Dawley rats were used and 7,12-DMBA (20 mg/kg body weight) was gastrically intubated at seven weeks of age in order to induce mammary tumors (MT). The levels of dietary PI were 36, 81, 126 and 217 (LPI, MLPI, MHPI and HPI), while dietary polyunsaturated/saturated fatty acids ratio was maintained at the same level (1.0). Fat used in the experiment was mixed with soybean oil, com oil, palm oil, perilla oil, sesame oil, fish oil, and beef tallow. Experimental diets were given for the following 20 weeks. We measured tumor numbers and weights, and then assayed the hepatic TBARS levels and antioxidant enzyme activities such as superoxide dismutase (SOD), catalase, glutathione peroxidase, glutathione-S-transferase (GST) and glutathione reductase (GR). The incidence of Mr was the lowest in the MHPI group. The hepatic TBARS level was significantly raised with increasing dietary PI value. The hepatic SOD and GR activities were differed significantly by dietary PI value. The hepatic SOD activity was negatively correlated with dietary PI value and GR activity was the highest in the rats fed the MHPI diet. When the dietary P/S ratio is kept at 1.0, adequate dietary PI value (PI value of 126) may reduce the incidence and growth of Mr, but this benefit may be lost with higher dietary PI value. These results suggest that the awareness of dietary PI values may help to decrease breast cancer incidence and growth.

• Environmental Analysis Health and Toxicology
• /
• v.15 no.1_2
• /
• pp.7-12
• /
• 2000

Scavenging effects on paraquat induced toxicity were investigated by using methanol (MeOH) and ethylacetate (EtoAC) extracts of Lonicera japonica. The results are summerized as follows: 1. To Fe(III)-ADP-NADPH induced microsomal lipid peroixdation, MeOH and EtoAC extracts showed antioxidative activiies and inhibition ratio at 100 $\mu\textrm{g}$/$m\ell$ 44.4% and 73.8% respectively 2. To microsomal NADPH dependent cytochrome p -450 reductase in rat liver, MeOH and EtoAC extracts inhibited the enzyme activiies and inhibition ratio were 26.3% and 44.8% respectively. 3. Administration (30 mg/kg, iv) of paraquat to rats caused the marked elevation of GOT, GPT, LDH, ALP in the serum and lipid peroxides in the microsome as compared to the control group. Serum GTP, LDH, ALP and liver microsomal LPO were reduced significantaly by administration of MeOH extract. (1,000 mg/kg), EtoAC extract (40 mg/kg) and Silymarin (150 mg/kg) as compared to the paraquat group. From the results, MeOH and EtoAc exuacts. of Lonicera japonica showed the useful scavenger and reducer on the paraquat induced hepatotoxicty.

• Korean Journal of Pharmacognosy
• /
• v.33 no.4 s.131
• /
• pp.359-363
• /
• 2002

Antioxidant properties of the extracts of Acanthopanax senticosus were investigated. The dried roots, stems or leaves were extracted with hot water or ethanol each. The ethanol extracts exhibited higher potency than aqueous extracts in scavenging free radicals and in inhibiting microsomal lipid peroxidation: the aqueous extracts of stems showed higher anti-oxidant effects than the root extracts. Copper-mediated LDL oxidation was also protected by the ethanol exlracts: antioxidant effects of the extracts tested were stronger than ascorbic acid, but not butylated hydroxytoluene. The activity of angiotensin converting enzyme was effectively suppressed by the aqueous extracts of the stems. However, in vivo antioxidant properties of the ethanol extracts of the stems did not seem to be significant, judged from the lipid peroxide values of serum and liver in normal mice. Thus, the ethanol extracts of the stems were shown to be more potent for protecting biological systems against various oxidant stresses in vitro, but not in vivo.

• Archives of Pharmacal Research
• /
• v.27 no.3
• /
• pp.340-345
• /
• 2004

Our work in this study was made in the microsomal fraction to evaluate the lipid peroxidation by measuring superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), and malondialdehyde (MDA) and to elucidate the preventive role of CS in the $CCl_4$-induced oxidative stress. The excessive lipid peroxidation by free radicals derived from $CCl_4$ leads to the condition of oxidative stress which results in the accumulation of MDA. MDA is one of the end-products in the lipid peroxidation process and oxidative stress. MDA, lipid peroxide, produced in this oxidative stress causes various diseases related to aging and hepatotoxicity, etc. Normal cells have a number of enzymatic and nonenzymatic endogenous defense systems to protect themselves from reactive species. The enzymes in the defense systems, for example, are SOD, CAT, and GPx. They quickly eliminate reactive oxygen species (ROS) such as superoxide anion free radicalㆍO$^{[-10]}$ $_2$, hydrogen peroxide $H_2O$$_2$ and hydroxyl free radicalㆍOH. CS inhibited the accumulation of MDA and the deactivation of SOD, CAT and GPx in the dose-dependent and preventive manner. Our study suggests that CS might be a potential scavenger of free radicals in the oxidative stress originated from the lipid peroxidation of the liver cells of $CCl_4$-treated rats.

• International Journal of Oral Biology
• /
• v.41 no.3
• /
• pp.141-147
• /
• 2016

Reactive oxygen species (ROS) and nitrogen species (RNS) are both important signaling molecules involved in pain transmission in the dorsal horn of the spinal cord. Xanthine oxidase (XO) is a well-known enzyme for the generation of superoxide anions ($O_2^{\bullet-}$), while S-nitroso-N-acetyl-DL-penicillamine (SNAP) is a representative nitric oxide (NO) donor. In this study, we used patch clamp recording in spinal slices of rats to investigate the effects of $O_2^{\bullet-}$ and NO on the excitability of substantia gelatinosa (SG) neurons. We also used confocal scanning laser microscopy to measure XO- and SNAP-induced ROS and RNS production in live slices. We observed that the ROS level increased during the perfusion of xanthine and xanthine oxidase (X/XO) compound and SNAP after the loading of 2',7'-dichlorofluorescin diacetate ($H_2DCF-DA$), which is an indicator of intracellular ROS and RNS. Application of ROS donors such as X/XO, ${\beta}-nicotinamide$ adenine dinucleotide phosphate (NADPH), and 3-morpholinosydnomimine (SIN-1) induced a membrane depolarization and inward currents. SNAP, an RNS donor, also induced membrane depolarization and inward currents. X/XO-induced inward currents were significantly decreased by pretreatment with phenyl N-tert-butylnitrone (PBN; nonspecific ROS and RNS scavenger) and manganese(III) tetrakis(4-benzoic acid) porphyrin (MnTBAP; superoxide dismutase mimetics). Nitro-L-arginine methyl ester (NAME; NO scavenger) also slightly decreased X/XO-induced inward currents, suggesting that X/XO-induced responses can be involved in the generation of peroxynitrite ($ONOO^-$). Our data suggest that elevated ROS, especially $O_2^{\bullet-}$, NO and $ONOO^-$, in the spinal cord can increase the excitability of the SG neurons related to pain transmission.

• Journal of Microbiology and Biotechnology
• /
• v.31 no.1
• /
• pp.79-91
• /
• 2021

γ-Glutamylcysteine synthetase (Gcs1) and glutathione reductase (Glr1) activity maintains minimal levels of cellular methylglyoxal in Candida albicans. In glutathione-depleted Δgcs1, we previously saw that NAD(H)-linked methylglyoxal oxidoreductase (Mgd1) and alcohol dehydrogenase (Adh1) are the most active methylglyoxal scavengers. With methylglyoxal accumulation, disruptants lacking MGD1 or ADH1 exhibit a poor redox state. However, there is little convincing evidence for a reciprocal relationship between methylglyoxal scavenger genes-disrupted mutants and changes in glutathione-(in)dependent redox regulation. Herein, we attempt to demonstrate a functional role for methylglyoxal scavengers, modeled on a triple disruptant (Δmgd1/Δadh1/Δgcs1), to link between antioxidative enzyme activities and their metabolites in glutathione-depleted conditions. Despite seeing elevated methylglyoxal in all of the disruptants, the result saw a decrease in pyruvate content in Δmgd1/Δadh1/Δgcs1 which was not observed in double gene-disrupted strains such as Δmgd1/Δgcs1 and Δadh1/Δgcs1. Interestingly, Δmgd1/Δadh1/Δgcs1 exhibited a significantly decrease in H2O2 and superoxide which was also unobserved in Δmgd1/Δgcs1 and Δadh1/Δgcs1. The activities of the antioxidative enzymes erythroascorbate peroxidase and cytochrome c peroxidase were noticeably higher in Δmgd1/Δadh1/Δgcs1 than in the other disruptants. Meanwhile, Glr1 activity severely diminished in Δmgd1/Δadh1/Δgcs1. Monitoring complementary gene transcripts between double gene-disrupted Δmgd1/Δgcs1 and Δadh1/Δgcs1 supported the concept of an unbalanced redox state independent of the Glr1 activity for Δmgd1/Δadh1/Δgcs1. Our data demonstrate the reciprocal use of Eapx1 and Ccp1 in the absence of both methylglyoxal scavengers; that being pivotal for viability in non-filamentous budding yeast.