1,5 - Disubstituted Phenyl -1,4 - Pentadiene -3 - Ketones In Biological Activity Screening And Mechanism Of A Preliminary Study

Curcumin has a wide range of bioactivity. It has however some limitations such as poor water solublity, easy oxidation, low absorption rate. At present, the synthesis of the curcumin derivatives with better solubility, higher bioactivity and stronger stability has become an important area of research in field of drug discovery at home and abroard.In order to carry out joint development of curcumin derivatives used for medicine and pesticides, this paper undertook three plant pathogenic fungi of Fusarium graminearum, Fusarium oxysporum, Cytospora mandshurica and three tumor cell lines as models for screening of new curcumin derivatives. In order to investigate further the action mechanism, we selected typical cell strain of PC3 (androgen-independent prostate cancer cell) as experimental model for studying anti-tumor activities of the indentified compounds. The study included: (l)By MTT cell proliferation assay, we analysized inhibition effect of the compounds on PC3 cells growth; (2)By LDH release analysis, we investigated the damage of the compounds to PC3 cell membrane; (3)By AO/EB staining, we observed morphologic changes of PC3 cells and assessed the cytotoxity of the compounds to PC3 cells; (4)By agrose gel electrophoresis of DNA, we evaluated apopotosis-inducing effect of the compounds on PC3 cells; (5)by Western-blot analysis, we determined the inhibition effect of the compounds on the phosphorylation of Cdk2 and Cdk4.Experiment results showed 05245 (1,5-di(2-hydroxyphenyl)-1,4-pentadien-3 -one), a novel synthetic curcumin analog, possessed good antifungal activity. At dose of 500μg/mL, inhibition rate of it on three type of plant pathogenic fungi of Fusarium graminearum, Fusarium oxysporum, Cytospora mandshurica reached 72.98, 71.43%, 79.23% respectively. It also had good inhibition effect on three tumor cell lines of PC3, BGC823 and Bcap37 and IC₅₀ was 1.78μM, 2.90μM, 4.08μM for 72 h respectively. In addition, two compounds of 05279 and cj-10 belonging to the extracts of Jatropha curcas L and acylhydrazone derivatives respectively also showed good anti-tumor activity. MTT cell proliferation assay showed that 05245, 05279, cj-10 inhibited PC3 cell proliferation in concentration-dependent manner. LDH release analysis suggested that three compounds had damage to the cell membrane of PC3 cells. AO/EB staining also indicated that 05245, 05279, cj-10 had cytotoxity on PC3 cells. Agrose gel electrophoresis of DNA showed they did not possess apopotosis-inducing effect on PC3 cells. Western-blot analysis indicated that cj-10, 05245 subtly stimulated the phosphorylation of Cdk2 and Cdk4 which were protein kinases for regulating the cell cycle. 05245 had inhibition effect on the phosphorylation of Cdk2 and Cdk4 at dose of 6μM. This was helpful to explain inhibition effect of it on PC3 cells proliferation.