New potential antitumoral fluorescent tetracyclic thieno[3,2-b]pyridine derivatives: interaction with DNA and nanosized liposomes

Fluorescence properties of two new potential antitumoral tetracyclic thieno[3,2- b ]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). Comp...

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Published in:Nanoscale research letters 2011-05, Vol.6 (1), p.379-379, Article 379
Main Authors: Castanheira, Elisabete MS, Carvalho, Maria Solange D, Rodrigues, Ana Rita O, Calhelha, Ricardo C, Queiroz, Maria-João RP
Format: Article
Language:English
Subjects:
11th Trends in NanoTechnology International Conference (TNT2010)
Chemistry and Materials Science
Materials Science
Molecular Medicine
Nano Express
Nanochemistry
Nanoscale Science and Technology
Nanotechnology
Nanotechnology and Microengineering
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Summary:Fluorescence properties of two new potential antitumoral tetracyclic thieno[3,2- b ]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 1 , pyrido[2',3':3,2]thieno[4,5- d ]pyrido[1,2- a ]pyrimidin-6-one, exhibits reasonably high fluorescence quantum yields in all solvents studied (0.20 ≤ Φ F ≤ 0.30), while for compound 2 , 3-[( p -methoxyphenyl)ethynyl]pyrido[2',3':3,2]thieno[4,5- d ]pyrido[1,2- a ]pyrimidin-6-one, the values are much lower (0.01 ≤ Φ F ≤ 0.05). The interaction of these compounds with salmon sperm DNA was studied using spectroscopic methods, allowing the determination of intrinsic binding constants, K i = (8.7 ± 0.9) × 10 3 M -1 for compound 1 and K i = (5.9 ± 0.6) × 10 3 M -1 for 2 , and binding site sizes of n = 11 ± 3 and n = 7 ± 2 base pairs, respectively. Compound 2 is the most intercalative compound in salmon sperm DNA (35%), while for compound 1 only 11% of the molecules are intercalated. Studies of incorporation of both compounds in liposomes of DPPC, Egg-PC and DODAB revealed that compound 2 is mainly located in the hydrophobic region of the lipid bilayer, while compound 1 prefers a hydrated and fluid environment.
ISSN:1556-276X
1931-7573
1556-276X
DOI:10.1186/1556-276X-6-379