Synthesis, cytotoxic and antioxidant evaluations of amino derivatives from perezone.

A series of eight amino derivatives (3a-h) from perezone 1 were prepared by nucleophilic addition of bioactive amines v.gr. melatonin, acetyl tryptamine, tryptophan and other amino acids esters (valine, leucine and methionine). Their structures were elucidated by spectroscopy data. The cytotoxic evaluation against four human tumor cell lines PC-3, K-562, HCT-15 and SKLU-1 was performed as well as the TBARS assay for antioxidant activity. The results suggest that 1 and its isomer 4 were highly active against all cell lines, 4 was twice as potent than 1 against PC-3 and HCT-15. The derivative 3a (IC(50)=7.5 ± 0.3 µM) was more active than 1 against HCT-15 whereas 3h was selective against K-562 with IC(50)=4.5 ± 0.4 µM. The TBARS assay has shown that 3c with IC(50)=5.564 ± 0.24 µM is a potent antioxidant with superior effect comparing to α-tocopherol and moreover was more active than the precursor molecule 1.

Synthesis and cytotoxic activity of new azepino[3',4':4,5]pyrrolo[2,1-a]isoquinolin-12-ones.

A series of azepino[3',4':4,5]pyrrolo[2,1-a]isoquinolin-12-ones (3a-f), that were conformationally restricted analogs of lead compound 2, were designed as potential cytotoxic compounds and synthesized using a radical oxidative aromatic substitution reaction as the key step. Compounds 3a-f were tested on five tumor cell lines to determine the conformational requirements for biological activity of compound 2. The results show that conformational restrictions on compound 2, generating the derivatives 3a-f, do not appreciably reduce the cytotoxic activity of 2, although compound 3d (R=Br) showed good activity against U-251 cells. Preliminary structure-activity relationship studies with these compounds revealed the importance of halogens bonded to the isoquinoline moiety. Additionally, derivatives 3f (R=NO(2)) and 3b (R=F) were cytotoxic to PC-3 and K-562 cells. However, none of the azepino[3',4':4,5]pyrrolo[2,1-a]isoquinolinones inhibited the enzymatic activity of CDK1/cyclin B, CDK5/p25, or GSK-3.

Synthesis and cytotoxic evaluation of new (4,5,6,7-tetrahydro-indol-1-yl)-3-R-propionic acids and propionic acid ethyl esters generated by molecular mimicry.

Indolones 4 and 5, and indolyl-aminoacids 6a-e, 7a-e, and 8a and 8b were designed by structural modification of lead compound 3. These compounds were tested on six tumor cell lines to determine the role of the azepinone ring and the N-phenyl substituent in the cytotoxicity of 3. Our results show that 4 and 5 have dramatically reduced cytotoxicity, due to the loss of the azepinone moiety of lead compound 3. In contrast, indolyl-aminoacids 6a, 7a, and 8a (N-(L)-cysteine ethyl ester derivatives) inhibited the proliferation of almost all cancer cell lines tested, even though they lack the azepinone ring. In addition, derivative 6c (N-(D)-alanine methyl ester group) was selectively cytotoxic to HCT-15 cells. Preliminary structure-activity relationship (SAR) studies with these compounds revealed the importance of the ethyl ester moiety on the amino acid moiety. Compounds 6a-e, 7a-e, and 8a and 8b were obtained in good yields by a catalytic Paal-Knorr reaction carried out under microwave irradiation using commercially available chiral amino esters or amino acids and 1,4-dicarbonyl compounds.