• BMB Reports
• /
• v.31 no.3
• /
• pp.269-273
• /
• 1998

The objective of this study was to evaluate the reversal of multi drug resistance of human cell lines by specific inhibitors of ${\alpha}-glycosidase$ and mannosidases that had been reported to be involved in N-linked oligosaccharide processing of glycoproteins. N-methyldeoxynojirimycin, I-deoxynojirimycin, and castanospermine, which were known to be potent inhibitors of both ${\alpha}-glycosidase$ I and II, showed no activity against the multidrug resistant phenotype of the cell lines of SNU1DOX, KB-V1, and MCF-7/ADR. In contrast, I-deoxymannojirimycin, an inhibitor of mannosidase I, resulted in a slight reversal for the vinblastine resistance of the KB-V1 cell line, but did not show any activity toward the other cell lines. Parallel experiments with tunicamycin, an inhibitor of N-linked glycosylation, also resulted in no significant changes in multidrug resistant (MDR) phenotype of the cell lines tested in this work. These observations suggest that the unglycosylation of P-glycoprotein associated with the inhibitor treatments might not be correlated with the reversal of multidrug resistance of the cell lines tested in this study.

• Korean Journal of Pharmacognosy
• /
• v.25 no.3
• /
• pp.226-232
• /
• 1994

An antioxidant activity of Gardenia Fruit (Gardenia jasminoides Ellis) which has been used for food coloring was studied. The antioxidant activity was determined by measuring lipid peroxide produced when a mouse liver homogenate was exposed to the air at $37^{\circ}C$, using 2-thiobarbituric acid (TBA). Both water and methanol extracts of Gardenia Fruit showed the antioxidant activity. On solvent fractionation, the antioxidant activity was removed into the ethyl acetate and butanol soluble fractions. And the final water soluble fraction also showed the antioxidant activity in the low concentration, but it promoted the lipid peroxidation in the high concentration. Two compounds (I and II) having the antioxidant activity were isolated from the butanol fraction, and compound I also occurred in the ethyl acetate fraction. The antioxidant activity of compound II was more potent than that of I. By analyzing data for UV, IR and $^1H-NMR$, compounds I and II were identified as geniposide and crocin, respectively.

• Biomedical Science Letters
• /
• v.17 no.3
• /
• pp.225-230
• /
• 2011

Indirubin is the active ingredient of Danggui Longhui Wan, a mixture of plants that is used in traditional Chinese medicine to treat chronic diseases. In this study we investigated the anti-inflammatory effects of an indirubin derivative, indirubin-3’-monoxime-5-sulphonic acid (I3M-5S, $C_{16}H_{11}N_3O_5S$). We found that I3M-5S inhibits the production of various inflammatory mediators such as nitric oxide (NO) and prostaglandin $E_2$ ($PGE_2$) as well as inflammatory cytokines, tumor necrosis factor-${\alpha}$ and interleukin-6 in lipopolysaccharide (LPS) stimulated murine macrophage, RAW264.7 cells. In addition, the expression of inducible nitric oxide synthase and cyclooxygenase-2, which are essential enzymes to produce NO and $PGE_2$, respectively, was blocked by I3M-5S treatment in LPS-stimulated RAW264.7 cells. Present data suggest that I3M-5S exhibits potent anti-inflammatory activity in cultured macrophages and merit further study as potential therapeutic agents for inflammatory disorders.

• Proceedings of the PSK Conference
• /
• 2002.10a
• /
• pp.155-160
• /
• 2002

A series of modified oligonucleotides containing a phosphorothioate (P=S) backbone and a six-membered azasugar (6-AZS) as a sugar substitute in a nucleotide were synthesized and tested for their ability to inhibit the human immunodeficiency virus type I(HIV-l) in vitro without the aid of any transfecting agents. While P=S oligonucleotides with natural nucleotides had little anti-HIV-l activity, the six-membered azasugar nucleotide (6-AZN)-containing P=S oligonucleotides (AZPSONs) potently inhibited the HIV-l/SHIV replication and syncytium formation (ECso = 0.02-0.2 /lM) without cytotoxicity up to 100 /lM. DBM-2198, the most effective in anti-HIV-l activity among the AZPSONs, consists of random sequence and five 6¬AZNs evenly distributed in 18 nucleotides. DBM-2198 showed strong antiviral activity against, not only laboratory strains, but also primary isolates and even drug-resistant strains of HIV-I. DBM-2198 was much more effective than ddI or ddC in its anti-HIV-l activity in vitro. Particularly noteworthy is that the anti-HIV-l activity of DBM-2198 was better than that of AZT with respect to its long-lasting efficacy after a single treatment. Nevertheless, the antiviral activity of the AZPSONs was very specific to HIV-I. Poliovirus, or even simian immunodeficiency virus (SIV), was not inhibited by the AZPSONs. Taken together, our results strongly suggest that AZPSON can be used as a safe and effective AIDS-therapeutic drug against a broad spectrum of HIV -1 strains.

• Bulletin of the Korean Chemical Society
• /
• v.35 no.12
• /
• pp.3627-3631
• /
• 2014

In this study we examined two ester-containing cross-links, hex-2-enyl acetate and hex-2-enyl propionate, as new cross-linking systems for helix stabilization of short peptides. We demonstrated that these hexenyl ester cross-links can be readily installed via a ruthenium-mediated ring-closing metathesis reaction of L-aspartic acid 4-allyl ester or L-glutamic acid 5-allyl ester at position i and (S)-2-(4'-pentenyl)alanine at position i+4 using second generation Hoveyda-Grubbs catalyst at $60^{\circ}C$. Between these two cross-links, we found that the hex-2-enyl propionate significantly stabilizes the ${\alpha}$-helical conformations of short model peptides. The helix-stabilizing effects of the hex-2-enyl propionate tether appear to be as powerful as Verdine's i,i+4 all-hydrocarbon stapling system, which is one of the most widely used and the most potent helix-stabilizing cross-linking systems. Furthermore, the hex-2-enyl propionate bridge is reasonably robust against non-enzymatic hydrolytic cleavage at a physiological pH. While extended studies for probing its chemical scopes and biological applications are needed, we believe that this new helix-stabilizing system could serve as a useful chemical tool for understanding protein folding and designing conformationally-constrained peptide drugs.

• Journal of applied mathematics & informatics
• /
• v.27 no.5_6
• /
• pp.1493-1499
• /
• 2009

Let $A_1$ and $A_2$ be nonzero complex idempotent and tripotent matrix, respectively. Denote a linear combination of the two matrices by A = $c_1A_1$ + $c_2A_2$, where $c_1,\;c_2$ are nonzero complex scalars. In this paper, under an assumption of $A_1A_2$ = $A_2A_1$, we characterize all situations in which the linear combination is tripotent. A statistical interpretation of this tripotent problem is also pointed out. Moreover, In [2], Baksalary characterized all situations in which the above linear combination is idem-potent by using the property of decomposition of a tripotent matrix, i.e. if $A_2$ is tripotent, then $A_2$ = $B_1-B_2$, where $B^2_i=B_i$, i = 1, 2 and $B_1B_2=B_2B_1=0$. While in this paper, by utilizing a method different from the one used by Baksalary in [2], we prove the theorem 1 in [2] again.

• Biomolecules & Therapeutics
• /
• v.17 no.1
• /
• pp.62-69
• /
• 2009

Roots of Astragalus membranaceus (A. membranaceus) (Astragali Radix, AR) has been used as a herbal medicine for gastrointestinal disorders in China, Korea, Japan, and other Asia countries. In this study we investigated the effects of the AR 70% ethanol extract and compounds isolated from AR on gastritis in rats and growth of human gastric cancer cells. AR 70% ethanol extract showed the potent acid-neutralizing capacities and partly cytotoxicity of Helicobacter pylori and human AGS gastric cancers cell. Astragaloside I and daucosterol, which were isolated from AR, significantly inhibited HCl/ethanol-induced gastric lesions. In addition, daucosterol increased the mucus content to almost the same as the positive control. The results of this study suggest that astragaloside I and daucosterol may be good candidates for the development of new drugs or neutraceuticals which can be used for the treatment or prevention of gastritis.

• Archives of Pharmacal Research
• /
• v.26 no.6
• /
• pp.466-470
• /
• 2003

Nine diarylheptanoids (1-9), one triterpene (10), one sesquiterpenoid (11), one naphthoquinone (12), four tetralones (13-16), one naphthalene carboxylic acid glucoside (17) and six naphthalenyl glycosides (18-23) were isolated from the roots of Juglans mandshurica Maximowicz (Juglandaceae), and their structures determined from the chemical and spectral data. Here, we report the inhibitory effects, on the DNA topoisomerases I and II activities, of all these compounds. Compounds 10 and 23 showed more potent inhibitory effects, on the DNA topoisomerases I and II (94.0 and 86.0% inhibitions at the concentration of 5 $\mu$ g/mL, respectively), than the positive control compounds, camptothecin and etoposide.

• Journal of Physiology & Pathology in Korean Medicine
• /
• v.17 no.4
• /
• pp.991-995
• /
• 2003

The purpose of this research was to investigate the effects of unripened fruits and ripened fruits of Rubus coreanus Miquel on murine peritoneal macrophages. The 70% ethyl alcohol extracts (20 or 100 mg/kg) of unripened fruits (RCE-I) and of ripened fruits (RCE-II) were administered p.o. once a day for 7 days to mice. RCE-I and RCE-II decreased the phagocytic activity of murine peritoneal macrophages and the production of nitric oxide. Also, RCE-I and RCE-II increased the production of tumor necrosis factor- a from peritoneal macrophages. In general, the immuno-suppressive action of RCE-I on macrophages was more potent than those of RCE-II. These results suggest that the fruits of Rubus coreanus Miquel regulates the non-specific immune response via decrease of phagocytic activity and increase of production of tumor necrosis factor- a from murine peritoneal macrophages.

• Food Science and Biotechnology
• /
• v.17 no.5
• /
• pp.1110-1114
• /
• 2008

$\beta$-Glucuronidases of intestinal bacteria are capable of retoxifying compounds that have been detoxified by liver glucuronidation, which is one of the most important detoxication processes in the liver. Therefore, this enzyme is known to accelerate colon cancer invasion and metastasis. Two bromophenols, 2,4,6-tribromophenol (I) and 2,4-dibromophenol (II), were purified from the red alga Grateloupia elliptica. $IC_{50}$ values of bromophenol I and II against Escherichia coli $\beta$-glucuronidase were 5.4 and 8.5 mg/mL, respectively. Hence, bromophenols of G. elliptica, a potent $\beta$-glucuronidase inhibitor, can be used as a novel pharmaceutical agent for the prevention and treatment of colon cancer.