New potential antitumoral fluorescent tetracyclic thieno[3,2-<it>b</it>]pyridine derivatives: interaction with DNA and nanosized liposomes
<p>Abstract</p> <p>Fluorescence properties of two new potential antitumoral tetracyclic thieno[3,2-<it>b</it>]pyridine derivatives were studied in solution and in liposomes of DPPC (dipalmitoyl phosphatidylcholine), egg lecithin (phosphatidylcholine from egg yolk; Egg-P...
| Main Authors: | , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
SpringerOpen
2011-01-01
|
| Series: | Nanoscale Research Letters |
| Online Access: | http://www.nanoscalereslett.com/content/6/1/379 |
| Summary: | <p>Abstract</p> <p>Fluorescence properties of two new potential antitumoral tetracyclic thieno[3,2-<it>b</it>]pyridine derivatives were studied in solution and in liposomes of DPPC (dipalmitoyl phosphatidylcholine), egg lecithin (phosphatidylcholine from egg yolk; Egg-PC) and DODAB (dioctadecyldimethylammonium bromide). Compound <b>1</b>, pyrido[2',3':3,2]thieno[4,5-<it>d</it>]pyrido[1,2-<it>a</it>]pyrimidin-6-one, exhibits reasonably high fluorescence quantum yields in all solvents studied (0.20 ≤ Φ<sub>F </sub>≤ 0.30), while for compound <b>2</b>, 3-[(<it>p</it>-methoxyphenyl)ethynyl]pyrido[2',3':3,2]thieno[4,5-<it>d</it>]pyrido[1,2-<it>a</it>]pyrimidin-6-one, the values are much lower (0.01 ≤ Φ<sub>F </sub>≤ 0.05). The interaction of these compounds with salmon sperm DNA was studied using spectroscopic methods, allowing the determination of intrinsic binding constants, <it>K</it> <sub>i </sub>= (8.7 ± 0.9) × 10<sup>3 </sup>M<sup>-1 </sup>for compound <b>1 </b>and <it>K</it> <sub>i </sub>= (5.9 ± 0.6) × 10<sup>3 </sup>M<sup>-1 </sup>for <b>2</b>, and binding site sizes of <it>n </it>= 11 ± 3 and <it>n </it>= 7 ± 2 base pairs, respectively. Compound <b>2 </b>is the most intercalative compound in salmon sperm DNA (35%), while for compound <b>1 </b>only 11% of the molecules are intercalated. Studies of incorporation of both compounds in liposomes of DPPC, Egg-PC and DODAB revealed that compound <b>2 </b>is mainly located in the hydrophobic region of the lipid bilayer, while compound <b>1 </b>prefers a hydrated and fluid environment.</p> |
|---|---|
| ISSN: | 1931-7573 1556-276X |