• Journal of Applied Biological Chemistry
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• v.50 no.2
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• pp.70-73
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• 2007

Antioxidant and anti-diabetic activities of acorn were evaluated by its potential for scavenging stable DPPH free radical, inhibition of lipid peroxidation, reducing power, and inhibiton of ${\alpha}-glucosidase\;and\;{\alpha}-amylase$. The water extract of acorn exhibited strong antioxidant and antidiabetic related activities in the tested model systems. Solvent fractionation of the water extract revealed that the water fraction and the EtOAc fraction had strong antioxidant activity, and inhibitory activity on ${\alpha}-glucosidase\;and\;{\alpha}-amylase$. The water fraction exhibited higher DPPH radical scavenging activity ($EC_{50}=7.19{\mu}g/mL$) than that of ${\alpha}-tocopherol\;(EC_{50}=7.59{\mu}g/mL)$. It is considered that water extract of acorn has the potential for natural antioxidant and anti-diabetic products.

• Archives of Pharmacal Research
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• v.21 no.2
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• pp.120-127
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• 1998

Peroxisome proliferators induce hepatic peroxisome proliferation and hepatic tumors in rodents. These chemicals increase the expression of the peroxisomal $\beta$-oxidation pathway and the cytochrome P-450 4A family, which metabolizes lipids, including eicosanoids. Peroxisome proliferators transiently induce increased cell proliferation in vivo. However, peroxisome proliferators are weakly mitogenic and are not co-mitogenic with epidermal growth factor (EGF) in cultured hepatocytes. Earlier study found that the peroxisome proliferator ciprofibrate is cornitogenic with eicosanoids. In order to study possible mechanisms of the comitogenicity of peroxisome proliferator ciprofibrate and eicosanoids' we hypothesized that the co-mitogenicity may result from synergistic or additive increases of second messengers in mitogenic signal pathways. We therefore examined the effect of the peroxisome proliferator ciprofibrate, prostaglandin $F_2_{\alpha}$($PGF_2{\alpha}$) and the combination of ciprofibrate and $PGF_2{\alpha}$ with or without growth factors on the protein kinase C (PKC) activity, and inositol-1, 4, 5-triphosphate ($IP_{3-}$) and intracellular calcium ($[Ca^{2+}]_i$) concentrations in cultured rat hepatocytes. The combination of ciprofibrate and $PGF_2{\alpha}$ significantly increased particulate PKC activity. The combination of ciprofibrate and $PGF_2{\alpha}$ also significantly increased EGF, transforming growth factor-$\alpha$ ($TGF_2{\alpha}$) and hepatic growth factor (HGF)-induced particulate PKC activity. The combination of ciprofibrate and $PGF_2_\alpha$greatly increased $[Ca^{2+}]_i$. However, the increases of PKC activity and $[Ca^{2+}]_i$ by ciprofibrate and $PGF_2{\alpha}$ alone were much smaller. Neither ciprofibrate or $PGF_2{\alpha}$ alone nor the combination of ciprofibrate and $PGF_2{\alpha}$ significantly increased the formation of $IP_3$. The combination of ciprofibrate and $PGF_2{\alpha}$, however, blocked the inhibitory effect of $TGF-{\beta}$ on particulate PKC activity and formation of $IP_3$ induced by EGF. These results show that co-mitogenicity of the peroxisome proliferator ciprofibrate and eicosanoids may result from the increase in particulate PKC activity and intracellular calcium concentration but not from the formation of $IP_3$.

• Journal of Microbiology and Biotechnology
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• v.20 no.3
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• pp.563-568
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• 2010

The Val289 residue in the $\alpha$-amylase of Bacillus amyloliquefaciens, which is equivalent to the Ala289 and Val286 residues in the $\alpha$-amylases of B. stearothermophilus and B. licheniformis, respectively, was studied by site-directed mutagenesis. This residue was substituted with 10 different amino acids by random substitution of the Val codon. In these mutant $\alpha$-amylases, Val289 was substituted with Ile, Tyr, Phe, Leu, Gly, Pro, Ser, Arg, Glu, and Asp. Compared with the wild-type $\alpha$-amylase, the mutant $\alpha$-amylase Val289Ile showed 20% more hydrolytic activity, whereas Val289Phe and Val289Leu showed 50% lesser activity. On the other hand, the mutant $\alpha$-amylases Val289Gly, Val289Tyr, Val289Ser, and Val289Pro showed less than 15% activity. The substitution of Val289 with Arg, Asp, or Glu resulted in complete loss of the $\alpha$-amylase activity. Interestingly, the mutant $\alpha$-amylase Val289Tyr had acquired a transglycosylation activity, which resulted in the change of product profile of the reaction, giving a longer oligosaccharide.

• Journal of Applied Biological Chemistry
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• v.58 no.1
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• pp.1-3
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• 2015

This study investigated the inhibitory activities of 2-hydroxyquinoline and its analogs against ${\alpha}$-glucosidase and ${\alpha}$-amylase. Based on the $IC_{50}$ values of 2-hydroxyquinoline analogs tested against ${\alpha}$-glucosidase and ${\alpha}$-amylase, 2-hydroxyquinoline had potent inhibitory activity (64.4 and $130.5{\mu}g/mL$, respectively), while 2-methyl-8-hydroxyquinoline showed weakly inhibitory activity (90.7 and $215.4{\mu}g/mL$, respectively). 2-Methylquinoline demonstrated no activity against ${\alpha}$-glucosidase and ${\alpha}$-amylase. In conclusion, 2-hydroxyquinoline analogs, with the existence of a methyl group and hydroxyl on quinoline, can be useful as a new diabetes treatment.

• Microbiology and Biotechnology Letters
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• v.24 no.4
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• pp.427-429
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• 1996

We have already cloned an extracellular $\alpha$-glucosidase gene from Aspergillus niger with oligonucleotide probe synthesized on the basis of the peptide sequences determined previously. The DNA sequence revealed an open reading frame of 895 amino acids split by three introns. We are attempting to construct an A. niger strain deficient in the $\alpha$-glucosidase enzyme activity, which would be useful for the glucoamylase production without contamination by the industrially undesirable $\alpha$-glucosidase. For destruction of the $\alpha$-glucosidase gene, we try to make transformations. A cloned partial $\alpha$-glucosidase gene was introduced into Aspergillus niger, and transformants with suppressed $\alpha$-glucosidase activity were isolated. The transformants were cultured on YPD medium which contained Hygromycin B at 30$\circ$C. The activity of $\alpha$-glucosidase of the suppressed transformants was compared to that of wild type activity. As shown by southern-hybridization, we detected that the transformant was a heterocaryon.

• Asian-Australasian Journal of Animal Sciences
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• v.16 no.3
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• pp.342-347
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• 2003

The enzyme $20{\alpha}$-hydroxysteroid dehydrogenase ($20{\alpha}$-HSD) catabolizes progesterone to $20{\alpha}$-dihydroprogesterone ($20{\alpha}$-OHP), and is appeared in rat corpora luteal and placenta. A polled samples of 10-15 placental and ovarian tissues collected from each individual rat were subjected to measurement of $20{\alpha}$-HSD activity. A $20{\alpha}$-HSD activity in the cytosol fraction was based on the generation of NADPH. In this study, it is designed to study cytosolic $20{\alpha}$-HSD activity in rat ovarian and placenta during pregnancy, and its relationship to embryonic mortality. It was found that from days 5 to 18 of pregnancy the $20{\alpha}$-HSD activities steady by decreased but at parturition time rapidly increased in ovary. On the other hand, placental cytosolic $20{\alpha}$-HSD activities were high detected from days 8 to 10 of pregnancy, not detectable from days 11 to 20 of pregnancy, but again very high at the time of parturition. Analysis of DEAE column chromatography revealed that two different types of $20{\alpha}$-HSD (HSD-1 and HSD-2) were found with similar activity in the placental cytosol on day 10 of pregnancy. The number of fetuses on day 10 of pregnancy was 15.4 and decreased significantly to 12.9 on day 12. The results suggested that expression of $20{\alpha}$-HSD in the placental tissues seems to be related the number of fetal survived in the specific time (days 11 and 12) which spontaneous fetal loss occurs.

• Journal of Ginseng Research
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• v.12 no.2
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• pp.128-134
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• 1988

The effect of the saponin fraction extracted from Panax ginseng C.A. Meyer on the antioxidant activity of $\alpha$-tocopherol was investigated in vitro as well as in vivo. Microsomal preparation of rat(Winter, 180-200g) liver was incubated in the mixture containing NADPH, $Fe^{3+}$, ATP, $\alpha$-tocopherol with and/or without ginseng saponin fraction for 30 minutes and the malondialdehyde formed was assayed and found that the saponin fraction stimulated the antioxidant activity of $\alpha$-tocopherol cooperatively. It was also realized that the cooperative stimulation of the antioxidant activity of $\alpha$-tocopherol was most eminent when the concentration of the saponin fraction was around $10^{-5}$% in the reaction mixture. Alcoholic suspension of $\alpha$-tocopherol with and f or without ginseng saponin fraction was administered orally to rats in which the lipid preoccupation was induced by ethanol administration and the lipid peroxide contents of the liver were assayed at certain periods of time after $\alpha$-tocopherol administration in this animal. From the previous work and present experimental results, it seemed that the saponin fraction accelerated the absorption of $\alpha$-tocopherol and therefore stimulated the antioxidant activity of $\alpha$-tocopherol more effectively in the animal body.

• The Korean Journal of Physiology
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• v.29 no.2
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• pp.203-216
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• 1995

The effects of ${\alpha}_1-adrenergic$ receptor stimulation on membrane potential, intracellular $Na^+$ activity, and twitch force were investigated in ventricular muscles from guinea-pig hearts. Action potentials, intracellular $Na^+$ activity, and twitch force of ventricular papillary muscles were measured simultaneously under various experimental conditions. Stimulation of the ${\alpha}_1-adrenergic$ receptor by phenylephrine produced variable changes in action potential duration, a slight hyperpolarization of the diastolic membrane potential, a decrease in intracellular $Na^+$ activity, and a biphasic inotropic response in which a transient negative inotropic response was followed by a sustained positive inotropic response. These changes were blocked by prazosin, an antagonist of the ${\alpha}_1-adrenergic$ receptor, but not by atenolol, an antagonist of the ${\beta}-adrenergic$ receptor. This indicates that the changes in membrane potential, intracellular $Na^+$ activity, and twitch force are mediated by stimulation of the ${\alpha}_1-adrenergic$ receptor, but not by stimulation of ${\beta}-adrenergic$ receptor. The decrease in intracellular $Na^+$ activity was not observed in quiescent muscles, depending on the rate of the action pontentials in beating muscles. The intracellular $Na^+$ activity decrease was substantially inhibited by tetrodotoxin. However, the decrease in intracellular $Na^+$ activity was not affected by an inhibition of the $Na^+-K^+$ pump. Therefore, the decrease in intracellular $Na^+$ activity mediated by the ${\alpha}_1-adrenergic$ receptor appears to be due to a reduction of $Na^+$ influx during the action potential, perhaps through tetrodotoxin sensitive $Na^+$ channels. Our study also revealed that the decrease in intracellular $Na^+$ activity might be related to the transient negative inotropic response. The intracellular $Na^+$ activity decrease could lower intracellular $Ca^{2+}$ through the $Na^+-Ca^{2+}$ exchanger and thereby produce a decline in twitch force.

• Journal of Microbiology and Biotechnology
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• v.12 no.4
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• pp.610-616
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• 2002

The growth-inhibiting effects of Pinus densiflpora leaf-derived materials on nine human intestinal bacteria were investigated using the impregnated paper disk method, and their activities were compared with those of 13 commercially available terpenes. The biologically active constituent of the extract of P densiflora leaf was characterized as the monoterpene (1R)-(+)-$\alpha$-pinene by various spectroscopic analyses. Responses varied according to bacterial strain, chemicals, and dose. At 10 mg/disk, limonene and (1R)-(+)-$\alpha$-pinene strongly inhibited the growth of Clostridium perfringens, Staphylococcus aureus, and Escherichia coli, without adverse effects on the growth of five lactic acid-bacteria (Bifidobacterium adolescentis, B. bifidum, B. longum, Lactobacillus acidophilus, and L. casei). Little or no inhibition against seven bacteria was observed with anethole, borneol, camphor, caryophyllene, 1,8-cineole, estragole, linalool, and $\alpha$-terpineol. Structure-activity relationship revealed that (1R)-(+)-$\alpha$-pinene had more growth-inhibiting activity against C. perfringens than (1R)-(+)-$\beta$-, (1S-(-)-$\alpha$-, and (1S-(-)-$\beta$-pinenes. Furthermore, the growth-inhibition against L. casei was much more pronounced in (1R)-(+)-$\beta$- and (In-(-)-$\beta$-pinenes than (1R)-(+)-$\alpha$- and (1S)-(-)-$\alpha$-pinenes. These results indicate that the (+)-$\alpha$ form seems to be required against C. perfringens and $\beta$ form against L. casei for growth-inhibiting activity. Morphologically, most strains of C. perfringens were damaged and disappeared at 5 and 2 mg/disk of (1R)-(+)-$\alpha$-pinene. Morphological study revealed that (1R)-(+)-$\alpha$-pinene had more growth-inhibiting activity against C. perfringens than (1R)-(+)-$\beta$-, (1S)-(-)-$\alpha$-, and (1S)-(-)-$\beta$-pinenes. As naturally occurring growth-inhibiting agents, the Pinus leaf-derived materials described above could be useful preventive agents against diseases caused by harmful intestinal bacteria such as clostridia.

• Biomolecules & Therapeutics
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• v.22 no.5
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• pp.414-419
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• 2014

Matrix metalloproteinases (MMPs) are zinc-dependent endopeptidases that regulate cell-matrix composition and are also involved in processing various bioactive molecules such as cell-surface receptors, chemokines, and cytokines. Our group recently reported that MMP-3, -8, and -9 are upregulated during microglial activation and play a role as proinflammatory mediators (Lee et al., 2010, 2014). In particular, we demonstrated that MMP-8 has tumor necrosis factor alpha (TNF-${\alpha}$)-converting enzyme (TACE) activity by cleaving the prodomain of TNF-${\alpha}$ and that inhibition of MMP-8 inhibits TACE activity. The present study was undertaken to compare the effect of MMP-8 inhibitor (M8I) with those of inhibitors of other MMPs, such as MMP-3 (NNGH) or MMP-9 (M9I), in their regulation of TNF-${\alpha}$ activity. We found that the MMP inhibitors suppressed TNF-${\alpha}$ secretion from lipopolysaccharide (LPS)-stimulated BV2 microglial cells in an order of efficacy: M8I>NNGH>M9I. In addition, MMP inhibitors suppressed the activity of recombinant TACE protein in the same efficacy order as that of TNF-${\alpha}$ inhibition (M8I>NNGH>M9I), proving a direct correlation between TACE activity and TNF-${\alpha}$ secretion. A subsequent pro-TNF-${\alpha}$ cleavage assay revealed that both MMP-3 and MMP-9 cleave a prodomain of TNF-${\alpha}$, suggesting that MMP-3 and MMP-9 also have TACE activity. However, the number and position of cleavage sites varied between MMP-3, -8, and -9. Collectively, the concurrent inhibition of MMP and TACE by NNGH, M8I, or M9I may contribute to their strong anti-inflammatory and neuroprotective effects.