Syntheses and cytotoxic properties of the curcumin analogs 2,6-bis(benzylidene)-4-phenylcyclohexanones

Diarylpentanoids with antitumor activity: A critical review of structure-activity relationship studies

Diarypentanoids are commonly considered as monocarbonyl analogues of curcumin. Since the discovery of this compound in 1962, twenty one diarylpentanoids have been isolated and almost 600 synthetic analogues with antitumor activity have been synthesized. This review reports the exploitation of diarylpentanoids to develop curcumin analogues with improved antitumor activity over the last two decades. The mechanism of action and structure-activity relationship (SAR) studies are also highlighted. More importantly, structural features for the antitumor activity that may guide the design of new and more effective diarylpentanoids are also proposed.

Design, synthesis, and cytotoxicity of novel 3-arylidenones derived from alicyclic ketones

Forty-four novel chalcone-inspired analogs having a 3-aryl-2-propenoyl moiety derived from alicyclic ketones were designed, synthesized, and investigated for cytotoxicity against murine B16 and L1210 cancer cell lines. The analogs belong to four structurally divergent series, three of which (series g, h, and i) contain differently substituted cyclopentanone units and the fourth (series j) contains a 3,3-dimethyl-4-piperidinone moiety. Of these, the analogs in series j showed potential cytotoxic activity against murine B16 (melanoma) and L1210 (lymphoma) cells. The most active compounds 5j, 11j, 15j, and 12h produced IC(50) values from 4.4 to 15 μm against both cell lines. A single-crystal X-ray structure analysis and molecular modeling studies confirmed that these chalcones have an E-geometry about the alkene bond and possess a slightly 'twisted' conformation similar to that of combretastatin A-4. At a concentration of 30 μm, compounds 5j, 11j, and 15j did not cause microtubule depolymerization in cells, suggesting that they have a different mechanism of action.

E-2-[3-(3,4-dichlorophenyl)-1-oxo-2-propenyl]-3-methylquinoxaline-1,4-dioxide: a lead antitubercular agent which alters mitochondrial respiration in rat liver

A series of 2-(3-aryl-1-oxo-2-propenyl)-3-methylquinoxaline-1,4-dioxides 1a-l and 2-acetyl-3-methylquinoxaline-1,4-dioxide 2 were evaluated against Mycobacterium tuberculosis H(37)Rv. With the exception of the 4-nitro analog 1k, significant antitubercular potencies were observed in series 1 and 2 which have IC(50) values in the range of 1-23 microM. Negative correlations were noted between the IC(50) values of 1a-j, l towards M. tuberculosis and both the sigma and pi constants of the substituents in the benzylidene aryl ring. In particular, 1h emerged as a lead compound having IC(50) and IC(90) figures of 1.03 microM and 1.53 microM, respectively. This molecule affected respiration in rat liver mitochondria which is likely one way that 1h and the bioactive analogs exert their antitubercular properties. The quinoxaline 2, which lacks an alpha,beta-unsaturated group, has no effect on mitochondrial respiration using concentrations which inhibit the growth of M. tuberculosis.

1,5-diaryl-3-oxo-1,4-pentadienes: a case for antineoplastics with multiple targets

A number of organic molecules which contain the 1,5-diaryl-3-oxo-1,4-pentadienyl group, referred to hereafter as the dienone moiety, have antineoplastic properties. Emphasis is made on the attachment of this structural moiety to several molecular scaffolds, namely piperidines, N-acylpiperidines, cycloalkanes and 3,4-dihydro-1H-napthalenes. Many of these compounds are potent cytotoxins having micromolar and nanomolar IC(50) values towards a wide range of neoplastic and transformed cells. On occasions, greater toxicity towards neoplasms than normal cells has been demonstrated. A number of these compounds have in vivo anticancer properties and in general excellent tolerability in rodents is demonstrated. The way in which a number of physicochemical properties such as redox potentials, torsion angles, atomic charges and logP values govern cytotoxic potencies are presented. The importance of the shapes of different compounds as determined by molecular modeling in contributing to antineoplastic properties is outlined. Arguments are presented in favour of designing antineoplastics which have multiple sites of action in contrast to those bioactive molecules which have only one molecular target. A number of compounds which possess the dienone group have different modes of action some of which are chronicled in this review, such as inducing apoptosis, affecting respiration in mitochondria, inhibiting macromolecular biosynthesis and both inhibiting and stimulating certain enzymes. Other important properties of these compounds are discussed including their anti-angiogenic, MDR-revertant and antioxidant properties. It is hoped that this eulogy of the importance of the dienone group will encourage researchers to consider incorporating this structural unit into candidate cytotoxins in the future.