Andras Varga

Piceatannol, an Antitumor Compound from Euphorbia lagascae Seeds

Publisher Summary This chapter appraises the advantages of piceatannol, which is isolated in large quantities from Euphorbia lagascae and is an effective multidrug resistance-associated protein-1 inhibitor. Piceatannol is a stilbene that was first identified in Vouacapoua species and is also present in rhubarb, sugarcane, berries, peanuts, red wine, and the skin of grapes. These are a class of plant polyphenols, biosynthesized via the phenylpropanoid pathway and characterized by the presence of a 1,2-diphenylethylene nucleus, mainly as trans stereoisomers. The majority of them belong to a class of defense molecules called phytoalexins that protect against stress, injury, ultraviolet irradiation, and fungal infection. Piceatannol was also shown to be a strong apoptosis inducer, although its methylated derivatives showed just moderate apoptosis induction activity. It inhibits a variety of tyrosine kinases involved in cell proliferation, in the phosphorylation of DNA transcription factors, and several other tyrosine kinases, which are overexpressed in different types of cancers. Piceatannol and its derivatives 3,5,30,40-tetraacetoxystilbene, 3,5-dihydroxy-30, 40- dimethoxystilbene, and 3,5,30-trihydroxy-40-methoxystilbene were found to be ineffective in the P-glycoprotein-mediated multidrug resistance reversal assay. Furthermore, they exert differential biological effects by modifying multiple cellular targets. These data, together with previous work, point to stilbenes as a group of promising antitumor compounds.