Terpenoids and glycolipids from euphorbiaceae.
The family Euphorbiaceae is widely distributed throughout both hemispheres and ranges in morphological form from large desert succulents to trees and even small herbaceous types. Many species contain a milky juice which is more or less toxic, especially for cold-blooded animals, and can produce a dermatitis similar to that from poison ivy. Separation procedures and characterization of the less polar fractions of the plant extracts have been widely described in the literature for their content in diterpene derivatives. In the continuing research on biologically active compounds from Euphorbiaceae, a series of studies on the isolation and structure elucidation of glyceroglycolipids (GGLs) and glycosphingolipids (GSLs) have been carried out in order to develop the novel medicinal resources from natural Euphorbiaceae products. Glyceroglycolipids are major constituents of the chloroplast membrane in the plant kingdom. Recently, glycolipids were found to possess antitumor-promoting activity while glyceroglycolipids isolated from Euphorbiaceae have shown an interesting anti-inflammatory activity in vivo. Glycosphingolipids are present at the outer layer of the lipid-bilayer in biological membranes and are thought to participate in antigen-antibody reactions and transmission of biologically informations. Sphingolipid breakdown products, sphingosine and lysosphingolipids, inhibit protein kinase C, a pivotal enzyme in cell regulation and signal transduction. Sphingolipids and lysosphingolipids affect significantly cellular responses and exhibit antitumor promoter activities in various mammalian cells. These molecules may function as endogenous modulators of cell function and possibly as second messengers.