• Microbiology and Biotechnology Letters
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• v.49 no.2
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• pp.167-173
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• 2021

Reactive oxygen species (ROS) disrupt the cellular redox balance, exert cytotoxic effects, and consequently promote the development of various diseases in humans. Previous studies have reported that antioxidants counteract the adverse effects of ROS. Several studies examine the whitening effects of various agents based on their ability to inhibit tyrosinase activity. Tyrosinase is a critical enzyme involved in the synthesis of melanin, which protects the skin against radiation. Various agents exhibiting antioxidant and tyrosinase inhibitory activities have been synthesized. However, these synthetic drugs are associated with toxicity, decreased safety, and poor skin penetration in vivo, which has limited the clinical application of synthetic drugs. This study examined the antioxidant and tyrosinase inhibitory activities of some microalgae. The methanol, dichloromethane, and ethyl acetate extracts of four microalgal species (Tetraselmis tetrathele, Dunaliella tertiolecta, Platymonas sp., and Chaetoceros simplex) were prepared. The physiological and whitening effects of microalgal extracts were investigated by measuring the antioxidant and tyrosinase inhibitory activities. The ethyl acetate extract of D. tertiolecta exhibited the highest antioxidant and tyrosinase inhibitory activities. Future studies must focus on examining the whitening effects of microalgae on cell lines to facilitate the development of microalga-based therapeutics for skin diseases, functional health foods, and whitening agents. Thus, microalgae have potential applications in the pharmaceutical, food, and cosmetic industries.

• Applied Biological Chemistry
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• v.32 no.1
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• pp.30-36
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• 1989

Some chelating agents are evaluated as an antioxidant for the autoxidation of soybean oil. Soybean oil is autoxidized under a mild condition (the flow rate of 67ml $O_{2}/min$ and $50^{\circ}C$). The antioxidant effect is measured by active oxygen method, and the spectral change of autoxidized soybean oil examined. The antioxidant effect of chelating agents is increased in order of diphenic acid, naphthoquinone, pyromellitic acid, quinolinic acid and naphthalic acid, and particularly the effect is low in diphenic acid and naphthoquinone. It is found that the effect is more clearly demonstrated by NMR rather than IR and UV and that the effect is dependent on the functional group and geometric molecular structure of chelating agents.

• The Journal of Korean Medicine
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• v.24 no.3
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• pp.96-107
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• 2003

Objective : This study was undertaken to determine if Pyunggangaeuljihyul-tang (Pinggankaiyuzhixue-tang, PG) has a protective effect against cell injury induced by various toxic agents in rabbit liver, Methods : Cell injury in vitro was estimated by measuring lactate dehydrogenase (LDH), and that in vivo was estimated by measuring alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activity in serum. Lipid peroxidation was examined by measuring malondialdehyde, a product of lipid per oxidation. Results : PG prevented the LDH release by $CCl_4$, mercury, menadione, and tert-butyl hydroperoxide treatment in vitro in liver slices. The extent of protection by 2% PG was similar to that of $10{\mu\textrm{M}}$ N,N'-diphenyl-p-phenylenedianline, a potent antioxidant, in tert-butyl hydroperoxide-induced LDH release. PG also prevented lipid peroxidation and depletion of cellular ATP induced by Hg. Hg causes motphological changes including cell necrosis and its effect was significantly prevented by PG. When rats were treated intraperitoneatly with 0.5 ml/kg of $CCl_4$, serum alanine aminotransferase and aspartate aminotransferase activities were increased compared with the control, which was significantly inhibited by pretreatment of PG. PG also prevented reduction in GSH and lipid peroxidation induced by $CCl_4$ Conclusion : These results suggest that PG exerts aprotective effect against various toxic agents by its antioxidant action in liver tissues. Thus, PG may be used in prevention and treatment of drug-induced liver cell injury. However, the precise mechanisms of PG protection remain to be determined.

• Journal of Nutrition and Health
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• v.47 no.6
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• pp.484-488
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• 2014

Purpose: This study investigated the question of whether the addition of natural ingredients (pear fermented solution, celery powder, vitamin C) in curing agents may influence antioxidant activities and nutritional characteristics of smoked duck. Methods: Smoked duck samples with general or natural curing agent containing three additive ingredients were examined to determine total polyphenol contents, antioxidant activities, pH, TBARS, and food additives residue (nitrite ion, antioxidant, sodium glutamate). Results: Smoked duck with natural curing agent showed a higher level of total polyphenol content and antioxidant activities than smoked duck using general curing agent (p < 0.05). The pH and TBARS of smoked duck were significantly decreased by the addition of natural curing ingredients compared to those of smoked duck using general curing agent (p < 0.05). The residues of food additives were not detected in smoked duck using natural curing agent. Conclusion: Findings suggest that the addition of pear fermented solution, celery powder, and vitamin C in natural duck curing agent may improve the antioxidant activities and nutritional characteristics of smoked duck and provides health benefits.

• Preventive Nutrition and Food Science
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• v.20 no.4
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• pp.276-283
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• 2015

Hydrocolloids have many applications in foods including their use in dysphagia diets. We aimed to evaluate whether hydrocolloids in foods affect the digestibility of starch and protein, and their effects on antioxidant capacity. The thickening hydrocolloids: locust bean gum and carboxymethyl cellulose, and the gel-forming agents: agar agar, konjacglucomannan, and Hot & Soft Plus were blended with corn starch and soy protein, skim milk, or grape juice and were examined for their in vitro-digestability by comparing the reducing sugar and trichloroacetic acid (TCA)-soluble peptide, for antioxidant capacity by total polyphenol contents and the 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity. The hydrocolloids resulted in a decrease in starch digestibility with the gel-forming agents. Hydrocolloids diminished TCA-soluble peptides in skim milk compared to soy protein with the exception of locust bean gum and decreased free radical scavenging capacities and total phenolic contents in grape juice. Our findings may provide evidence for the use of hydrocolloids for people at risk of nutritional deficiencies such as dysphagia patients.

• Journal of Physiology & Pathology in Korean Medicine
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• v.18 no.6
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• pp.1881-1891
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• 2004

Daejowhan-gamibang(DJG) is used to prevention and treatment of cerebrovascular disease, heart disease, dementia, hyperlipdemia circulatory disturbance. Korean traditional herbal prescriptions and herb medicines in neuronal cells, which have been used for the treatment of stroke and brain diseases in Korean traditional medicine were screened to study the antioxidant effects and its mechanism. Daejowhan-gamibang water extract(DJGWE) was tested on their antioxidant activity using radical scavenging effects against ABTS. It showed significant antioxidant capacities at 50㎍ concentration. The antioxidant activity of DJGWE was determined in the different concentration (10㎍, 50 ㎍, and 100㎍). At the same time, the antiperoxidation effects was determined. Lipid peroxidation in brain homogenates induced by NADPH and ADP-Fe/sup 2+/ was significantly inhibited by DJGWE in vitro. DJGWE showed a potent antioxidant and antiperoxidative activity, further investigation, in vitro and in vivo, will be needed for the confirm of possibility as an antioxidant therapeutic agents and their optimal treatment of brain diseases in human. In searching the mechanism of antioxidant effects of DJGWE, it showed the inhibition of activity of JNK, p38, ERK and caspase 3 induced by hypoxia. So, DJGWE should be surveyed for the use of the potential therapeutic prescription for stroke and brain degenerative diseases such as pakinson's disease, dementia.

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

• Culinary science and hospitality research
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• v.23 no.8
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• pp.90-97
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• 2017

This study investigated optimal extraction conditions for application of Hippophae rhamnoides leaves as a natural antioxidant. Hippophae rhamnoides leaves were extracted using ethanol at various concentrations (0, 30, 50, and 70%) and extraction times (4, 8, and 12 hrs) at $70^{\circ}C$ and then evaluated for extraction yield (22.51%), total phenolic contents (84.21~149.25 mg/g), total flavonoid contents (63.10~124.14 mg/g), as well as antioxidant activities DPPH, ABTS radical scavenging activity, reducing power, and FRAP. Antioxidant activities (DPPH, ABTS radical scavenging activity, reducing power) were correlated with total phenolic and flavonoid contents. 70% EtOH extracts for 12 h at $70^{\circ}C$ showed the highest total phenolic and flavonoid contents with strong antioxidant activities, and that the leaves of Hippophae rhamnoides could be considerd as a candidate of new functional antioxidant agents. This extract could be a good source for natural antioxidants and good health food. This work offers would be useful for chemical and biological studies of natural plants and its products.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.11
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• pp.6991-6995
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• 2013

Antioxidant activity, total phenolic, total flavonoid compounds and cytotoxicity to cancer cell lines of propolis extracts from two extraction methods were investigated in this study. Propolis was collected from Phayao province and extracted with 70% ethanol using maceration and sonication techniques. The antioxidant activity was evaluated by DPPH assay. Total phenolic and flavonoid compounds were also determined. Moreover, the cytotoxicity of propolis was evaluated using MTT assay. The percentage propolis yield after extraction using maceration (18.1%) was higher than using sonication (15.7%). Nevertheless, antioxidant and flavonoid compounds of the sonication propolis extract were significant greater than using maceration. Propolis extract from sonication showed antioxidant activity by $3.30{\pm}0.15$ mg gallic acid equivalents/g extract. Total phenolic compound was $18.3{\pm}3.30$ mg gallic acid equivalents/g extract and flavonoid compound was $20.49{\pm}0.62$ mg quercetin/g extract. Additionally, propolis extracts from two extraction methods demonstrated the inhibitory effect on proliferation of A549 and HeLa cancer cell lines at 24, 48 and 72 hours in a dose-dependent manner. These results are of interest for the selection of the most appropriate method for preparation of propolis extracts as potential antioxidant and anticancer agents.

• Korean Journal of Pharmacognosy
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• v.44 no.3
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• pp.224-229
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• 2013

Bromotopsentin (BSM) is a bisindole alkaloid compound, which is recognized as a metabolite of the marine sponge Spongosorites sp. In this study, the antioxidant activity of BSM was investigated. The 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging assay, the trolox equivalent antioxidant capacity (TEAC) assay, the superoxide radical scavenging (NBT) assay, the lipid peroxidation and hydroxyl radical-induced DNA damage assays were carried out to evaluate the antioxidant activity of BSM. It was found that BSM had stronger scavenging activity on the stable free radical DPPH and superoxide radical than L-ascorbic acid with an $IC_{50}$ value of 62 and 64 ${\mu}M$, respectively. The TEAC value which indicated the total antioxidant capacity of BSM was about 0.8, which was also stronger than L-ascorbic acid. About 1.3 ${\mu}M$ of BSM induced 50% inhibition of lipid peroxidation. 60 nM of BSM exhibited a significant protective activity against DNA strand scission by hydroxyl radical on pBR322 DNA. Taken together, we suggest that BSM possesses strong antioxidant activity, and could be a valuable new addition to the list of anti-aging chemotherapeutic agents.