• Fisheries and Aquatic Sciences
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• v.16 no.4
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• pp.237-242
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• 2013

We investigated the antioxidant and angiotensin I converting enzyme (ACE) inhibitory activities of red snow crab Chionoecetes japonicas shell (RSCS) hydrolysate by enzymatic hydrolysis and its molecular weight cut-off fractions. The RSCS hydrolysate was fractionated through two ultrafiltration membranes of 3 and 10 kDa cut-offs. Three fractions (<3 kDa, 3-10 kDa, and >10 kDa) were evaluated for total amino acid composition, antioxidant activities using 2'-azino-bis[3-ethylbenzthiazoline-6-sulfonic acid] ($ABTS^+$) radical scavenging and superoxide dismutase (SOD)-like activities and reducing power assays, and ACE inhibitory activity using Hou's method. Although all fractions showed activity, the <3 kDa fraction of RSCS hydrolysate exhibited the greatest $ABTS^+$ radical scavenging, SOD-like and ACE inhibitory activities. However, these fractions exhibited low reducing power. These results suggest that the low-molecular-weight enzymatic hydrolysate of RSCS could be used as a functional ingredient to control oxidative stress and ACE activity.

• Natural Product Sciences
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• v.12 no.4
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• pp.210-213
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• 2006

A 4,5-dioxoaporphine type alkaloid, cepharadione B (1), a phenolic acid, protocatechuic acid (2), and flavonols, quercetin (3), afzelin (4), and quercitrin (5), were isolated from the EtOAc-soluble extract of the whole plants of Houttuynia cordata. All the isolates (1-5) were subjected to in vitro bioassays to evaluate advanced glycation end products (AGEs) formation and rat lens aldose reductase (RLAR) inhibitory activity. The three flavonols 3-5 exhibited a significant inhibitory activity on AGEs formation with $IC_{50}$ values of 66.9, 58.9, and $32.3{\mu}M$, respectively. While the two flavonol rhamnosides 4 and 5 showed a remarkable inhibitory activity against RLAR with $IC_{50}$ values of 0.81 and $0.16{\mu}M$, respectively.

• Natural Product Sciences
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• v.17 no.2
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• pp.108-112
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• 2011

Several isoquinoline alkaloids (1 - 18), which have basic chemical structures as protoberberine and aporphine skeletones, were evaluated for their inhibitory activities on AChE and BuChE. Among them, compounds 3, 4, 6, 8 and 12 showed the potent AchE activity with the $IC_{50}$ values ranging from $10.2{\pm}0.5\;{\mu}M$ to $24.5{\pm}1.6\;{\mu}M$, meanwhile, compound 14 - 17 exhibited strong inhibitory activity with $IC_{50}$ values from $2.1{\pm}0.2$ to $5.5{\pm}0.3\;{\mu}M$. Compounds 14 - 17 exhibited selective inhibition for AChE compared with BuChE. The isoquinoline alkaloid possesses aromatic methylenedioxy groups and quaternary nitrogen atoms are crucial for the anti-cholinesterase inhibitory activity.

• Korean Journal of Pharmacognosy
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• v.42 no.2
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• pp.161-168
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• 2011

Advanced glycation end products (AGEs) has been shown to play an important role in the development of the diabetic complications. The AGEs inhibitors or cross-link breakers attenuate various functional and structural manifestations of diabetic complications. In this study, 69 China herbal medicines have been investigated with an in vitro evaluation system using AGEs inhibitory activity. Of these, 28 herbal medicines $IC_{50}$=<50 ${\mu}g/ml$) were found to have stronger AGEs inhibitory activity compared with aminoguanidine ($IC_{50}$=59.77 ${\mu}g/ml$). Particularly, 5 herbal medicines, Camptotheca acuminata (stem, leaf), Eurya groffii (stem, leaf), Cornus Capitata (leaf), Mucuna birdwoodiana (root), Nelumbo nucifera (fruit, seed) showed more potent inhibitory activity (approximately 6-27 fold) than the positive control aminoguanidine.

• Electrical & Electronic Materials
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• v.14 no.12
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• pp.3-6
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• 2001

In common globular proteins, the native form is n its most stable state. However, the native form of inhibitory serpins (serine protease inhibitors) and some viral membrane fusion proteins is in a metastable state. Metastability in these proteins is critical to their biological functions. Our previous studies revealed that unusual interactions, such as side-chain overpacking, buried polar groups, surface hydrophobic pockets, ad internal cavities are the structural basis of the native metastability. To understand the mechanism by which these structural defects regulate protein functions, cavity-filling mutations of $\alpha$1-antitrypsin, a prototype serpin, were characterized. Increasing conformational stability is correlated with decreasing inhibitory activity. Moreover, the activity loss appears to correlate with the decrease in the rate of the conformational switch during complex formation with a target protease. We also increased the stability of $\alpha$1-antitrypsin greatly via combining various stabilizing single amino acid substitutions that were distributed throughout the molecule. The results showed that a substantial increase of stability, over 13 kcal/mol, affected the inhibitory activity with a correlation of 11% activity loss per kcal/mol. The results strongly suggest that the native metastability of proteins is indeed a structural design that regulates protein functions and that the native strain of $\alpha$1-antitrypsin distributed throughout the molecule regulates the inhibitory function in a concerted manner.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• v.16 no.2
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• pp.96-118
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• 2003

The effect of Glycyrrhizae Radix water extract, known as depigmenting agent, on melanin biosynthesis was investigated in cellular level by using B16 mouse melanoma cells. The inhibitory effect of Glycyrrhizae Radix water extract on melanogenesis was determined by mushroom tyrosinase assay traditionally using in vitro screening test. To determine whether Glycyrrhizae Radix water extract suppress melanin synthesis in cellular level, B16 mouse melanoma cells were cultured in the presence of different concentrations of Glycyrrhizae Radix water extract. Effects on cell proliferation, melanin biosynthesis, tyrosinase activity, DOPAchrome tautomerase activity, and expression level of mRNA for tyrosinase were examined. The maximum concentration of Glycyrrhizae Radix water extract that was not inhibitory to growth of the cells was 2 mgml. At that concentration, melanin synthesis was significantly inhibited without cytotoxicity after 5 days, compared with untreated cells. The treatment with Glycyrrhizae Radix water extract reduced tyrosinase and DOPAchrome tautomerase activity in a dose-dependent manner. However, the treatment with Glycyrrhizae Radix water extract did not affect significantly mRNA levels for tyrosinase. These results suggest that the inhibitory effect of Glycyrrhizae Radix water extract on melanogenesis is correlated with the suppression of tyrosinase and DOPAchrome tautomerase activity more than altering mRNA levels of tyrosinase.

• Preventive Nutrition and Food Science
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• v.19 no.4
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• pp.274-280
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• 2014

The purpose of this study was to investigate the biological activities of cultivated Angelica gigas Nakai (CAG) and wild Angelica gigas Nakai (WAG) extracts prepared by extraction with water, 30% ethanol, 60% ethanol, or 90% ethanol. The electron donating ability of the WAG extracts was higher than that of the CAG extracts and 0.1% and 1.0% solutions of the comparative substance, L-ascorbic acid. The superoxide dismutase-like activity of the CAG extracts was higher than that of WAG extracts. Superoxide dismutase-like activity was highest (33.95%) in the CAG water extract. The total polyphenol content was highest in the 60% ethanol extracts of WAG. The nitrite scavenging ability of the CAG and WAG extracts was highest at a pH of 1.2. The tyrosinase inhibitory effect was highest (43.72%) in the water extract of WAG. The angiotensin converting enzyme inhibitory activity was highest (83.84%) in the 60% ethanol extract of WAG. The results of the present study will be useful for understanding the antioxidant and angiotensin-converting enzyme inhibitory activities of Angelica gigas Nakai extracts.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.11a
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• pp.3-6
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• 2001

In common globular proteins, the native form is in its most stable state. However, the native form of inhibitory serpins (serine protease inhibitors) and some viral membrane fusion proteins is in a metastable state. Metastability in these Proteins is critical to their biological functions. Our previous studies revealed that unusual interactions, such as side-chain overpacking, buried polar groups, surface hydrophobic pockets, and internal cavities are the structural basis of the native metastability. To understand the mechanism by which these structural defects regulate protein functions, cavity-filling mutations of ${\alpha}$1-antitrypsin, a prototype serpin, were characterized. Increasing conformational stability is correlated with decreasing inhibitory activity. Moreover, the activity loss appears to correlate with the decrease in the rate of the conformational switch during complex formation with a target protease. We also increased the stability of ${\alpha}$1-antitrypsin greatly via combining various stabilizing single amino acid substitutions that were distributed throughout the molecule. The results showed that a substantial increase of stability, over 13 kcal/mol, affected the inhibitory activity with a correlation of 11% activity loss per kcal/mol. The results strongly suggest that the native metastability of proteins is indeed a structural design that regulates protein functions and that the native strain of e 1-antitrypsin distributed throughout the molecule regulates the inhibitory function in a concerted manner.

• Korean Journal of Korean Medical Institute of Dermatology and Aesthetics
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• v.1 no.1
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• pp.91-97
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• 2005

(1) Objectives: To discover natural skin-lightening agents, we have evaluated the inhibitory activity of EtOH extracts from 20 medicinal plants against mushroom tyrosinase. (2) Methods: Tyrosinase activity was determined by the dopachrome method using L-tyrosine as the substrates. (3) Results: Of the plant extracts tested, the extracts of 4 plants, Albizzia julibrissin, Curcuma longa, Anethum graveolens and Sophora flavescens, exhibited potent inhibitory activity (> 50%) in mushroom tyrosinase assay. Four plant extract, extracts of Agrimonia pilosa, Paeonia moutan, Magnolia obovata and Eugenia caryophyllata also showed relatively strong inhibitory (> 40%) against mushroom tyrosinase. (4) Conclusion: These active medicinal plants may be useful for the development of skin-whitening agents. Since the active medicinal plants may contain effective tyrosinase inhibitors even more than kojic acid, further study to identify the active constituents from the plants is expected.

• Korean Journal of Pharmacognosy
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• v.44 no.3
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• pp.305-311
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• 2013

Advanced glycation end products (AGEs) have been postulated to play a central role in the development of diabetic complications. A variety of different agents that inhibit AGEs have been under investigation. In this study, 54 herbal medicines from China have been investigated with an in vitro evaluation system using AGEs formation inhibitory activity. Of these, 6 herbal medicines ($IC_{50}&lt;5{\mu}g/ml$) were found to have significant AGEs formation inhibitory activity. Particularly, herbal medicines Punica granatum (peels), Terminalia chebula (fruits), Rheum palmatum (roots), Oxyria digyna (stems and leaves), Anisodus luridus (roots) and Quercus schottkyana(stems and leaves) showed more potent inhibitory activity (approximately 9-43 fold) than the positive control aminoguanidine ($IC_{50}=77.04{\mu}g/ml$).