• Journal of the Korean Society of Food Science and Nutrition
• /
• v.16 no.2
• /
• pp.110-117
• /
• 1987

Polyphenol oxidase in Prunus salicina(Red) was extracted, some properties and its partially purification were investigated as follows; Polyphenol oxidase was purified about 15 folds after ammonium sulfate saturation and about 64 folds after Sephadex G-100 column chromatography. Polyphenol oxidase showed optimum pH for activity at 6.5 and optimum temperature at at $35^{\circ}C$ and high affinity to catechol in o-diphenol compounds. Thermal stability were about 85% and 75% of initial polyphenol oxidase activity remained after heating at $50^{\circ}C$ for 5 minutes and 30 minutes respectively. The Michaelis constant of the enzyme was 2.58mM. L-cysteine, glutathione, ascorbic acid and potassium cyanide appeared to be most effective inhibitors. EDTA showed a slight inhibition.

• Korean Journal of Pharmacognosy
• /
• v.39 no.3
• /
• pp.165-173
• /
• 2008

Aldose reductase (AR), the principal enzyme of the polyol pathway, has been shown to play an important role in the diabetic complications, including diabetic cataract. The inhibitors of AR, therefore, would be potential agents for prevention of diabetic complications. As part of our ongoing project directed toward the discovery of preventive and/or treatment for diabetic complications, 48 Korean herbal medicines have been investigated with an in vitro evaluation system using aldose reductase inhibitory activities. Of these, 12 herbal medicines exhibited a significant inhibitory activity against aldose reductase. Particularly, seven herbal medicines, i.e., Eurya japonica, Chrysanthemum indicum, Akebia quinata, Saururus chinensis, Catalpa bignonioides, Lonicera japonica, Vitex rotundifolia showed two times more potent inhibitory activity than the positive control 3.3-tetramethyleneglutaric acid (TMG). In addition, Catalpa bignonioides showed the retardation of cataract-opacification of the lens of the eye under diabetic condition by xylose. Therefore, this result may provide a potential therapeutic approach for preventing and treating diabetic cataracts.

• Journal of Life Science
• /
• v.8 no.5
• /
• pp.604-613
• /
• 1998

The last enzyme of the sesquiterpen phytoalexin capsidiol synthesis in tobacco cell, 5-epi-aristolochene hydro-xylase which convert 5-epi-aristolochene (EAS) to capsidiol, was cloned by a reverse transcription polymerase chain reaction strategy and cDNA library screening. Cloned CYP-B3 contained high probability amino acid matches to known plant cytochrome P450 sequences and open reading frame with the conserved FxxGxRxCxG heme-binding region. Transcripts of CYP-B3 were not detected in control cells, but induced in elicitor-treated cells. Furthermore, CYP-B3 transcripts were induced by fungal extracts and cellulase but not by other stimuli(chilling, heat shock and 2,4-D). Induction of CYP-B3 transcripts by elicitor treatment was not affected by ancymidol and ketoconazole treat-ments suggesting that an inhibition of hydroxylase activity by Cyt P450 inhibitors resulting from post translational processing event.

• YAKHAK HOEJI
• /
• v.38 no.4
• /
• pp.440-450
• /
• 1994

Due to the limited bioavailability of $[D-Ala^6]$LHRH from nonparenteral transmucosal sites of administration, enhancement of mucosal permeability by coadministration of several protease inhibitors and/or penetration enhancers were studied in rabbit mucosa. As a reliable bioassay method for $[D-Ala^6]$LHRH, ovulation-inducing effect were measured after vaginal administration in the rat. The permeation of $[D-Ala^6]$LHRH through the mucosal membrane of rabbit mounted on George-Grass diffusion cells were examined in the presence of polyoxyethylene 9-lauryl ether (POE), ${\beta}$-cyclodextrin$({\beta}-CyD)$ or ethylene diamine tetra acetate disodium salt(EDTA). The vaginal membrane showed higher permeability of $[D-Ala^6]$LHRH than the rectal and nasal membrane. POE and ${\beta}-CyD$ showed a small promoting effect on the membrane permeation of $[D-Ala^6]$LHRH, but EDTA showed significant enhancement. Ovaluation was enhanced by the coadministration of sodium laurate(0.5%), a protease inhibitor but was not enhanced by EDTA, a penetration enhancer. On the other hands, coadministration of sodium tauro 24,25 dihydrofusidate(1%) and EDTA(2%) enhanced the ovulation inducing-effect 2.8 times. These results suggest that the vaginal administration of $[D-Ala^6]$LHRH with STDHF or sodium laurate as a protease inhibitor, and EDTA as a penetration enhancer, may become an elective method for transmucosal delivery of $[D-Ala^6]$ LHRH.

• Preventive Nutrition and Food Science
• /
• v.5 no.4
• /
• pp.184-188
• /
• 2000

HMG-CoA reductase is th rate-limiting enzyme of cholesterol biosynthesis. As intracellular levels of cholesterol should be regulated elaborately in response to external stimuli an internal needs, the expression of the HMG-CoA reductase gene is regulated intricately at several different levels from transcription to post-translational modification. In this study, we investigated the regulatory mechanism of HMG-CoA reductase gene expression at the post-transcriptional/pre-translational levels in a baby hamster kidney cell line, C100. when 25-hydroxycholesterol was added to cells cultured in medium containing 5% delipidized fetal bovine serum and 25$\mu$M lovastatin, the levels of HMG-CoA reductase mRNA decreased rapidly, which seemed to be due to the increased degradation of reductase mRNA. These suppressive effects of 25-hydroxycholesterol on MG-CoA reductase mRNA levels were blocked by a translation inhibitor, cycloheximide. Similarly, actinomycin D and 5,6-dichloro-1-$\beta$-D-ribofuranosylbenzimidazole, transcription inhibitors, blocked the 25-hydroxycholesterol-mediated degradation of HMG-CoA reductase mRNA. These results indicate that new protein/RNA synthesis is required for the degradation of HMG-CoA reductase mRNA. In addition, data from the transfection experiments shows that cis-acting determinants, regulating the stability of reductase mRNA, were scattered in the sequence corresponding to 1766-4313 based on the sequence of Syrian hamster HMG-CoA reductase cDNA. Our data suggests that sterol-mediated destabilization of reductase mRNA might be one of the important regulatory mechanism of HMG-CoA reductase gene expression.

• Biomedical Science Letters
• /
• v.13 no.4
• /
• pp.279-285
• /
• 2007

Although retinoic acid has been known as either anti-inflammatory or pro-inflammatory molecule, depending on the cell type, its exact role in mature human neutrophils has not been fully explored. In this study, we investigate the effects of retinoic acid on neutrophil apoptosis and the associated mechanism and found that 9-cis retinoic acid (9CRA) significantly inhibits the spontaneous apoptosis of neutrophils. Its effect is increased by co-treatment with $TNF-\alpha$ (P<0.05). The 9CRA-induced inhibition is blocked by the following enzyme inhibitors: Ly 294002, phosphoinoside (PI)-3 kinase inhibitor, U73122, a phospholipase C (PLC) inhibitor, PP2, Src family protein inhibitor, SB202190, p38 MAPK inhibitor, and BAY-11-7085, NF-kB inhibitor. This study also demonstrates that all-trans retinoic acid suppresses spontaneous apoptosis, similar to the mechanism of inhibition exhibited by 9CRA. Phosphorylation of p38 MAPK decreases by 9CRA treatment. $Ik-B{\alpha}$ is degraded until 30 minutes after a time-dependent 9CRA treatment, but degradation can be inhibited by Ly 294002. These results indicate that 9CRA decreases p38 MAPK activation, induces NF-kB activation via PI-3 kinase, and also blocks cleavage of caspase 3. As these findings suggest, 9CRA has a molecular mechanism which may help pro-inflammatory response by blocking neutrophil apoptosis.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.41 no.1
• /
• pp.7-12
• /
• 2008

To develop a whitening agent, cytotoxicity of the soluble collagen isolated from Todarodes pacificus (CIT) was evaluated. CIT tested for cytotoxicity on human dermal fibroblast (CCD-986sk) was exhibited very low cytotoxicity. Because tyrosinase is the key enzyme for melanin biosynthesis, the use of various tyrosinase inhibitors is a common practice for whitening purpose in cosmetics. Tyrosinase inhibitory activity and melanin production assay were measured to confirm the whitening effect. The inhibitory effect of MMP-1 in UV-irradiated human dermal fibroblast was also performed. CIT showed strong inhibition potency on tyrosinase by 51.5% at 0.2 mg/mL which increased the inhibition by increasing the concentration of CIT, and showed 69.1% inhibition at 1.0 mg/mL. CIT showed strong inhibition effect on melanin production with 82% at 1.0 mg/mL. The CIT also reduced about 76% expression of MMP-1 in UV-irradiated CCD-986sk cell at 1.0 mg/mL. From the preliminary observations, we suggest that the collagen isolated from CIT could be a potential source of natural skin-whitening and anti-aging agents for the photo-damaged skin.

• The Korean Journal of Physiology and Pharmacology
• /
• v.1 no.4
• /
• pp.393-402
• /
• 1997

In the present study, we characterized the angiotensin II (AII)-induced relaxations in the phenylephrine-precontracted rabbit mesenteric arteries with endothelium. 1) AII-induced relaxation was consistently observed in the rabbit mesenteric arteries with and without endothelium, but not in the aortic segment with endothelium. 2) AII-induced endothelium-dependent relaxation was markedly inhibited by $N^w-nitro-L-arginine$ (L-NNA, $100\;{\mu}M$), methylene blue ($10\;{\mu}M$) and LY83583 ($10\;{\mu}M$), respectively. 3) Inhibition of cyclooxygenase with indomethacin ($10\;{\mu}M$) strongly decreased the vasorelaxant response to AII irrespective of the presence of endothelium. 4) 7-Ethoxyresorufin ($1\;{\mu}M$) and clotrimazole ($1\;{\mu}M$), inhibitors of cytochrome P-450-dependent arachidonic acid metabolism, greatly attenuated the vasodilator response to AII. 5) Carbacyclin, arachidonic acid and prostaglandin $F_{2{\alpha}}$ ($PGF_{2{\alpha}}$) caused concentration-dependent relaxations in the mesenteric artery with endothelium, which were inhibited by L-NNA and methylene blue. 6) AII and $PGF_{2{\alpha}}$ significantly stimulated cyclic GMP formation in the mesenteric arteries with endothelium, which was inhibited by L-NNA and methylene blue, respectively. 7) AII enhanced synthesis of $PGF_{2{\alpha}}$ and 6-keto $PGF_{1{\alpha}}$ from the arterial segments with endothelium, which was inhibitable by indomethacin, but not by L-NNA. In conclusion, the vasorelaxant responses to AII of the rabbit mesenteric artery with endothelium are subserved by arachidonic acid and its metabolites produced via activation of cyclooxygenase and cytochrome P-450 enzyme as well as by nitric oxide.

• Korean Journal of Pharmacognosy
• /
• v.42 no.2
• /
• pp.175-181
• /
• 2011

Oxidative stress or accumulation of reactive oxygen species (ROS) leads neuronal cellular death and dysfunction, and it contributes to neuronal degenerative disease such as Alzheimer's disease, Parkinson's disease and stroke. Glutamate is one of the major excitatory neurotransmitter in the central nervous system (CNS). Glutamate contributes to fast synaptic transmission, neuronal plasticity, outgrowth and survival, behavior, learning and memory. In spite of these physiological functions, high concentration of glutamate causes neuronal cell damage, acute insults and chronic neuronal neurodegenerative diseases. Heme oxygenase-1 (HO-1) enzyme plays an important role of cellular antioxidant system against oxidant injury. NNMBS020, the water-insoluble fraction of the 70% EtOH extract of root barks of Dictamnus dasycarpus, showed dominant neuroprotective effects on glutamate-induced neurotoxicity in mouse hippocampal HT22 cells by induced the expression of HO-1 and increased HO activity. In mouse hippocampal HT22 cells, NNMBS020 makes the nuclear accumulation of Nrf2 and stimulates extracellular signal-regulated kinase (ERK) pathway. The ERK MAPK pathway inhibitor significantly reduced NNMBS020-induced HO-1 expression, whereas the JNK and p38 inhibitors did not. In conclusion, the water-insoluble fraction of the 70% EtOH extract of root barks of D. dasycarpus (NNMBS020) significantly protect glutamate-induced oxidative damage by induction of HO-1 via Nrf2 and ERK pathway in mouse hippocampal HT22 cells.

• Biomolecules & Therapeutics
• /
• v.23 no.5
• /
• pp.434-441
• /
• 2015

Histone deacetylase (HDAC) inhibitors are considered novel agents for cancer chemotherapy. We previously investigated MHY219, a new HDAC inhibitor, and its potent anticancer activity in human prostate cancer cells. In the present study, we evaluated MHY219 molecular mechanisms involved in the regulation of prostate cancer cell migration. Similar to suberanilohydroxamic acid (SAHA), MHY219 inhibited HDAC1 enzyme activity in a dose-dependent manner. MHY219 cytotoxicity was higher in LNCaP ($IC_{50}=0.67{\mu}M$) than in DU145 cells ($IC_{50}=1.10{\mu}M$) and PC3 cells ($IC_{50}=5.60{\mu}M$) after 48 h of treatment. MHY219 significantly inhibited the HDAC1 protein levels in LNCaP and DU145 cells at high concentrations. However, inhibitory effects of MHY219 on HDAC proteins levels varied based on the cell type. MHY219 significantly inhibited LNCaP and DU145 cells migration by down-regulation of matrix metalloprotease-1 (MMP-1) and MMP-2 and induction of tissue inhibitor of metalloproteinases-1 (TIMP-1). These results suggest that MHY219 may potentially be used as an anticancer agent to block cancer cell migration through the repression of MMP-1 and MMP-2, which is related to the reduction of HDAC1.