• Natural Product Sciences
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• 제17권3호
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• pp.245-249
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• 2011

Eight compounds, squalene (1), friedelin (2), ${\beta}$-sitosterol (3), ${\beta}$-sitosterol-3-O-glucoside (4), ${\alpha}$-tocopherol (5), betulinic acid (6), trilinolein (7) and 1-O-(9Z,12Z-Octadecadienoyl)-3-nonadecanoyl glycerol (8), were isolated from the barks of Tilia amurensis. Their chemical structures were identified by comparing their physicochemical and spectral data with those published in the literature. These isolated compounds were examined for their inhibitory activities against topoisomerase I and II. Compound 7 showed significant inhibition of DNA topoisomerase I and II activities, with percent decreases in activity of 87 and 95%, respectively at a concentration of $100\;{\mu}M$. Compound 6 exhibited cytotoxicity against the human colon adenocarcinoma cell line (HT-29), the human breast adenocarcinoma cell line (MCF-7) and the human liver hepatoblastoma cell line (HepG-2), with $IC_{50}$ values of 20, 59 and $16\;{\mu}M$, respectively.

• Archives of Pharmacal Research
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• 제27권1호
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• pp.77-82
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• 2004

DA-125, a novel derivative of adriamycin, is known for its anti-cancer activity. In this study, the inhibitory mechanism of DA-125 on topoisomerase was investigated in the simian virus 40 (SV40) replicating CV-1 cell by studying the SV40 DNA replication intermediates and DNA-topoisomerase complexes. DNA-protein complexes that were formed in the drug-treated cells were quantitated by using a glass filter assay. SV40 DNA replication intermediates that were accumulated in the drug-treated CV-1 cell were analyzed in a high resolution gel. DA-125 did not accumulate B-dimers of SV40 DNA replication intermediates which were found in the adriamycin-treated CV-1 cells. DA-125 induced a dose-dependent formation of the DNA-protein complexes, while adriamycin did not. When adriamycin and etoposide (VP16) were added to the SV40-infected cells at the same time, adriamycin blocked the formation of the DNA-protein complexes induced by VP16 in a dose-dependent manner. However, DA-125 blocked the formation of the DNA-protein complexes induced by VP16 up to the maximum level of the DNA-protein complexes that were induced by DA-125 alone. Adriamycin and DA-125 did not inhibit the formation of the DNA-protein complexes that were caused by camptothecin, a known topoisomerase I poison. DA-125 is bifunctional in inhibiting topoisomerase II because it simultaneously has the properties of the topoisomerase II poison and the DNA intercalator. As a topoisomerase II poison, DA-125 alone induced dose-dependent formation of the DNA-protein complexes. However, as a DNA intercalator, it quantitatively inhibited the formation of the DNA-protein complexes induced by a strong topoisomerase II poison VP16. Furthermore considering that the levels of the DNA-protein complex induced by VP16 were decreased by DA-125 in terms of the topoisomerase II poison, we suggest that DA-125 has a higher affinity to the drug-binding sites of DNA than VP16 has.

• Bulletin of the Korean Chemical Society
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• 제29권10호
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• pp.1988-1992
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• 2008

A series of new derivatives on the ring A of luotonin A were prepared by Friedländer condensation of 6,7,8,10- tetrahydropyrrolo[2,1-b]quinazoline-6,10-dione and suitably substituted 2-aminobenzaldehydes and 2- aminoacetophenones. Their inhibitory activities on topoisomerases and cytotoxicities against selected human cancer cell lines were evaluated. Among the compounds tested, 8-fluoroluotonin A showed similar inhibitory activity on topoisomerase I comparable to camptothecin while luotonin A and 9-hydroxyluotonin A showed 1.37 and 0.94 times stronger inhibitory activity, respectively, on topoisomerase II compared to etoposide. Some derivatives of luotonin A showed moderate cytotoxicity. The possible relationship between the inhibitory activity on Topo II and the cytotoxicity of luotonin A and its analogues, thus, cannot be ruled out.

• Bulletin of the Korean Chemical Society
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• 제25권4호
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• pp.539-544
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• 2004

The ability of protoberberine alkaloids, berberine and berberrubine, to act as topoisomerase II poisons is linked to the anti-cancer activity. Minor alterations in structure have a significant effect on their relative activity. Berberine, which has methoxy group at the 19-position, is significantly less potent than berberrubine. Several observations support non-specific binding to HP14 by the berberine: (i) nonspecific upfield changes in $^1H$ chemical shift for protons of the berberine; (ii) the broadening of imino protons of HP14 upon binding of the berberine; (iii) very small increases in duplex melting temperature in the presence of the berberine. Our results reveal that substitution of a hydroxyl group to a methoxy group on the 19-position, thereby converting the berberrubine to the berberine is associated with a non-specific DNA binding affinity and a reduced topoisomerase II poisoning. The presence of a bulky 19-methoxy substituent decreases intercalating properties of berberine and makes it inactive as topoisomerase II poison.

• Bulletin of the Korean Chemical Society
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• 제32권10호
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• pp.3566-3570
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• 2011

A series of 2,4,6-tripyridyl pyridines were synthesized, and evaluated for their antitumor cytotoxicity, topoisomerase I and II inhibitory activity. From the eighteen prepared compounds, compounds 10-12 have shown better or similar cytotoxicity against several human cancer cell lines as compared to 2,2':6',2"-terpyridine and doxorubicin. Especially, compound 10 exhibited the most potent cytotoxicity better than positive controls. Structure-activity relationship study indicated that 2,2':6',2"-terpyridine skeleton has an important role in displaying significant cytotoxicity against several human cancer cell lines.

• Natural Product Sciences
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• 제13권4호
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• pp.359-364
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• 2007

Three known ${\alpha}$-amyrin triterpenoids, ursolic acid (1), $2{\alpha},3{\alpha}$-dihydro xyurs-12-ene-28-oic acid (2) and euscaphic acid (3), and ${\beta}$-amyrin triterpenoid, $3{\beta}$-hydroxyolean-5,12-diene (4), and ${\alpha}$-spinasterol (5) have been isolated from the fractionated n-butanol extracts of the spikes of Prunella vulgaris var. lilacina, guided by DNA topoisomerases I and II inhibitory activities and cytotoxic activity against human cancer cells. Their structures were elucidated on the basis of spectroscopic and chemical methods. Compound 4 exhibited significant cytotoxic activity against human colon adenoblastoma (HT-29), and 5 showed DNA topoisomerase I and II inhibitions.

• Bulletin of the Korean Chemical Society
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• 제29권8호
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• pp.1605-1608
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• 2008

• 대한약학회:학술대회논문집
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• 대한약학회 2002년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.2
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• pp.315.1-315.1
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• 2002

DNA topoisomerases I (topo I) and II are essential enzymes that relax DNA supercoiling and relieve torsional strain during DNA processing. including replication. transcription. and repair. Topo I relaxes DNA by cleaving one strand of DNA by attacking a backbone phosphale with a catalytic lyrosine (Tyr723. human topo I). This enzyme has recently been investigated as a new target for antineoplastic drugs. Inhibitors to the enzyme intercalate between the DNA base pairs. interfering religation of cleaved DNA, therefore inhibit the activity of topo I. (omitted)

• Archives of Pharmacal Research
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• 제27권8호
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• pp.829-833
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• 2004

The bioactivity-guided fractionation of the methylene chloride extract of the sclerotium of Poria cocos led to the isolation of (S)-(＋)-turmerone (1), ergosterol peroxide (2), polyporenic acid C (3), dehydropachymic acid (4), pachymic acid (5), and tumulosic acid (6). Compounds 4-6 exhibited moderate cytotoxicities, with $IC_{50}$ values of 20.5, 29.1, and $10.4{\;}\mu\textrm{m}$, respectively, against a human colon carcinoma cell line. However, 3-6 not only showed inhibitory activities as potent as etoposide used as a positive control on DNA topoisomerase II (36.1, 36.2, 43.9 and 66.7％ inhibition at a concentration of $20{\;}\mu\textrm{m}$, respectively), but also inhibition of DNA topoisomerase I (55.8, 60.7, 43.5, and 83.3％ inhibition at a concentration of $100{\;}\mu\textrm{m}$, respec-tively).

• Bulletin of the Korean Chemical Society
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• 제30권7호
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• pp.1463-1469
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• 2009

Eleven novel oxiranyl and thiiranyl phenolic compounds were synthesized as potential antitumor agents using epichlorohydrin and epithiohydrin in the presence of $K_2CO_3$. Cytotoxicities were found in range of I$C_{50}$ values of 2.5-14.8 $\mu$M, which was partially attributed to topoisomerase II inhibition. Bis-thiiranyl anthraquinone analog, 19 showed more cytotoxicity against MDA-MB-231 (breast cancer cell) and PC3 (prostate cancer cell) after 24 and/or 48 h and more potent topoisomerase II inhibitory activity than etoposide.