Design, synthesis and in vitro and in vivo antitumor activities of novel bivalent ß-carbolines.

A series of bivalent ß-carbolines with a spacer of three to ten methylene units between the indole nitrogen was synthesized and evaluated as antitumor agents. The results demonstrated that compounds 18c, 21b, 25a and 31b exhibited strong cytotoxic activities with IC(50) value of lower than 20 µM against four tumor cell lines. Acute toxicities and antitumor efficacies of the selected compounds in mice were also evaluated, compounds 18b, 21b, 26a and 31b exhibited potent antitumor activities with tumor inhibition rate of over 40% in animal models. Preliminary structure-activity relationships analysis indicated that (1) the spacer length affected antitumor potencies, and four to six methylene units were more favorable; (2) the introduction of appropriate substituent into position-1 of ß-carboline facilitated antitumor potencies.

Synthesis and biological evaluation of 1,9-disubstituted ß-carbolines as potent DNA intercalating and cytotoxic agents.

A series of novel 1,9-disubstituted ß-carbolines was designed, synthesized and evaluated as cytotoxic and DNA intercalating agents. Compounds 7b, 7c, 8b and 8c exhibited the most potent cytotoxic activities with IC(50) values of lower than 20 µM against ten human tumor cell lines. The results indicated that (1) the 3-chlorobenzyl and 3-phenylpropyl substituents in position-9 of ß-carboline nucleus were the suitable pharmacophoric group giving rise to significant antitumor agents; (2) the length of the alkylamino side chain moiety affected their cytotoxic potencies, and three CH(2) units were more favorable. In addition, these compounds were found to exhibit remarkable DNA intercalating effects.

WITHDRAWN: Discovery of 5-benzylidene(thio) barbiturates as a new class of mushroom tyrosinase inhibitors.

This article has been withdrawn at the request of the authors. The Publisher apologizes for any inconvenience this may cause. The full Elsevier Policy on Article Withdrawal can be found at http://www.elsevier.com/locate/withdrawalpolicy.

Synthesis and cytotoxic evaluation of 1-carboxamide and 1-amino side chain substituted ß-carbolines.

The condensation of alkylenediamine with ethyl ß-carboline-1-carboxylate and 1-bromo-ß-carboline gave ß-carboline-1-carboxamides and 1-amino-ß-carbolines, respectively. Some of these ß-carbolines were active against a panel of human tumor cell lines, and 1-amino derivatives were more potent than their 1-carboxamide congeners. In particular, among the 1-amino-ß-carbolines, the N(9)-arylated alkyl substituted ß-carbolines exhibited the most interesting cytotoxic activities with IC(50) value of lower than 20 µM. The preliminary structure-activity relationships (SARs) analysis suggested that (1) 1-amino substituents were the advisable pharmacophoric group for enhanced cytotoxic activities; (2) the introduction of appropriate arylated alkyl groups into position-9 of ß-carboline facilitated their cytotoxic potencies.

Synthesis, cytotoxic activities and DNA binding properties of ß-carboline derivatives.

In a continuing effort to develop novel ß-carbolines endowed with better pharmacological profile, a series of water-soluble ß-carbolines bearing a flexible amino side chain was designed and synthesized, and the cytotoxic activities in vitro of these compounds were evaluated. The N(9)-arylated alkyl substituted ß-carbolines represented the most interesting cytotoxic agents, and compounds 4c and 4d were found to be the most potent compounds with IC(50) values lower than 10 µM against ten human tumor cell lines. The results confirmed that the N(9)-arylated alkyl substituents of ß-carboline played a very important role in the modulation of the cytotoxic potencies. In addition, the interaction with DNA of these compounds was also investigated, these compounds were found to exhibit significant DNA binding affinity.

Synthesis of novel beta-carbolines with efficient DNA-binding capacity and potent cytotoxicity.

A series of water-soluble beta-carbolines, bearing a flexible amino side chain, was prepared and evaluated in vitro against a panel of human tumor cell lines. The N(9)-arylated alkyl substituted beta-carbolines represented the most interesting cytotoxic activities, and compound 7b was found to be the most potent antitumor agent with IC(50) values lower than 10microM against eight human tumor cell lines. The results confirmed that the N(9)-arylated alkyl substituents of beta-carboline nucleus played an important role in the modulation of the cytotoxic potencies. In addition, these compounds were found to exhibit significant DNA-binding affinity.

Synthesis and biological evaluation of novel beta-carbolines as potent cytotoxic and DNA intercalating agents.

A series of novel water-soluble beta-carbolines bearing a flexible amino side chain was designed, synthesized and evaluated as potent cytotoxic and DNA intercatalating agents. The N(9)-arylated alkyl substituted beta-carbolines represented the most interesting cytotoxic activities. The results suggested that (1) the N(9)-arylated alkyl substituents of beta-carboline nucleus played a very important role in the modulation of the cytotoxic potencies; (2) the length of the alkylamino side chain significantly affected their cytotoxic potency, and N,N-dimethylaminopropylamino substituent were more favorable. In addition, these compounds were found to exhibit significant DNA intercalating potencies.

Design, synthesis and 3D-QSAR of beta-carboline derivatives as potent antitumor agents.

In a continuing effort to develop novel beta-carbolines endowed with better pharmacological profiles, a series of beta-carboline derivatives were designed and synthesized based on the previously developed SARs. Cytotoxicities in vitro of these compounds against a panel of human tumor cell lines were also investigated. The results demonstrated that the N2-benzylated beta-carbolinium bromides 56-60 represented the most potent compounds with IC50 values lower than 10 microM. The application of 3D-QSAR to these compounds explored the structural basis for their biological activities. CoMFA (q2=0.513, r2=0.862) and CoMSIA (q2=0.503, r2=0.831) models were developed for a set of 47 beta-carbolines. The results indicated that the antitumor pharmacophore of these molecules were marked at position-1, -2, -3, -7 and -9 of beta-carboline ring.

Synthesis and cytotoxic evaluation of N2-benzylated quaternary beta-carboline amino acid ester conjugates.

The beta-carboline alkaloids have been characterized as a class of potential antitumor agents. To further enhance the cytotoxic potency and improve water solubility of beta-carboline, a series of new beta-carboline amino acid ester, beta-carboline amino acid and N(2)-benzylated quaternary beta-carboline amino acid ester conjugates were designed and synthesized, and the cytotoxic activities of these compounds were evaluated using a panel of human tumor cell lines. The N(2)-benzylated quaternary beta-carboline amino acid ester conjugates represented the most interesting cytotoxic activities. Particularly, compounds 8b and 8g were found to be the most potent compounds with IC(50) values lower than 20 microM against all human tumor cell lines investigated. These results confirmed that the N(2)-benzyl substituent on the beta-carboline ring played an important role in the modulation of the cytotoxic potencies.