3-5-dihydroxy-4--methoxystilbene and pterostilbene

Stilbenes are phytoalexins that become activated when plants are stressed. These compounds exist in foods and are widely consumed. Resveratrol is a grape-derived stilbene, which possesses a wide range of health-promoting activities, including anticancer properties. Several other stilbenes structurally similar to resveratrol are also available in food, but their biological activities remain largely unknown. In this study, we compared the effects of resveratrol and its natural derivatives pterostilbene, trans-resveratrol trimethylether, trans-pinostilbene and trans-desoxyrhapontigenin on androgen-responsive human prostate cancer LNCaP cells. We found that these compounds exert differential effects on LNCaP cell growth, cell cycle and apoptosis. Trans-resveratrol trimethylether appeared to be the most potent compound among the stilbenes tested. Treatment of LNCaP cells with trans-resveratrol trimethylether resulted in G2/M blockage while other compounds, including resveratrol, induced G1/S arrest. Moreover, different from other compounds, trans-resveratrol trimethylether induced apoptosis. At the molecular level, the effects of these compounds on cell cycle correlated with induction of the cyclin-dependent kinase inhibitor 1A and B mRNA levels. Additionally, these compounds also inhibited both androgen- as well as estrogen-mediated pathways. These results provide mechanistic information on how resveratrol and its methylether analogs may act to contribute to potential antiprostate cancer activity.

Topics: Androgen Antagonists; Anticarcinogenic Agents; Antineoplastic Agents, Phytogenic; Apoptosis; Cell Cycle; Cell Line, Tumor; Cell Proliferation; Cyclin-Dependent Kinase Inhibitor p21; Cyclin-Dependent Kinase Inhibitor p27; Dose-Response Relationship, Drug; Estrogen Antagonists; Gene Expression Regulation, Neoplastic; Humans; Intracellular Signaling Peptides and Proteins; Male; Prostate-Specific Antigen; Prostatic Neoplasms; Resveratrol; RNA, Messenger; Stilbenes; Structure-Activity Relationship

Pterostilbene, a naturally occurring analog of resveratrol, has previously shown PPARalpha activation in H4IIEC3 cells and was found to decrease cholesterol levels in animals. In this study, analogs of pterostilbene were synthesized and their ability to activate PPARalpha was investigated. Among analogs that was synthesized (E)-4-(3,5-dimethoxystyryl)phenyl dihydrogen phosphate showed activity higher than pterostilbene and control drug ciprofibrate. Docking of the stilbenes inside PPARalpha showed the presence of important hydrogen bond interactions for PPARalpha activation.

Topics: Animals; Cell Line, Tumor; Drug Design; Ligands; Models, Molecular; Molecular Structure; PPAR alpha; Protein Binding; Rats; Resveratrol; Stilbenes

CYP1A1 and CYP1B1 are the inducible forms of cytochrome P450 expressed in extrahepatic tissues, which are responsible for the biotransformation of polycyclic aromatic hydrocarbons, heterocyclic amines and estradiol to the carcinogenic intermediates. The aim of our research was to determine and compare the inhibitory effect of naturally occurring analogues of trans-resveratrol on the catalytic activities of human recombinant CYP1A1 and CYP1B1. Pinostilbene (3,4'-dihydroxy-5-methoxystilbene), desoxyrhapontigenin (3,5-dihydroxy-4'-methoxystilbene), and pterostilbene (3,5-dimethoxy-4'-hydroxystilbene) appeared to be very potent inhibitors of CYP1A1 catalytic activity with Ki values of 0.13, 0.16 and 0.57 microM, respectively. Results from this study indicate that trans-resveratrol analogues in which the hydroxy groups are substituted by methoxy groups exhibit a remarkably stronger inhibitory effect towards CYP1A1 in comparison to the parent compound. On the contrary, the potency of pinostilbene, desoxyrhapontigenin and pterostilbene towards CYP1B1 with Ki values of 0.90, 2.06 and 0.91 microM, respectively, was comparable to that of resveratrol. It appears that between these analogues, inhibition of CYP1A1 and CYP1B1 catalytic activities does not vary much regardless of the number and position of methylether substitution. The results suggest that the trans-resveratrol analogues: pinostilbene, desoxyrhapontigenin and pterostilbene, which occur in some food plants, might be considered as promising chemopreventive agents.

Topics: Aryl Hydrocarbon Hydroxylases; Cytochrome P-450 CYP1A1; Cytochrome P-450 CYP1B1; Enzyme Inhibitors; Humans; Methyl Ethers; Recombinant Proteins; Resveratrol; Stilbenes