Polyacetylenic lipids

Rooney, F. and Capon, R.J. (1998) Callyspongynes A and B new polyacetylene lipids from a Southern Australian marine sponge, Callyspongia sp. Lipids, 33, 639-642. 

Further, ginseng constituents are polysaccharides, essential oil constituents, polyacetylenes, peptides, and other lipids (7). Ginseng is included in the pharmacopeias of several countries such as China, Germany, and the United Kingdom (113). Modern therapeutic claims refer to vitality, immune function, cancer, cardiovascular diseases, and sexual function (114,115). More than 500 studies have been published on the pharmacological activity of ginseng (7,80). 

The involvement of desaturase-type enzymes in the biosynthesis of some important lipidic antifeedants now has been firmly established (Fig. Ic) (7). An instructive example of this phenomenon is the production of ricinoleate (a purgative) by a desaturase homolog found in the castor plant. Here, a subtle variation in mechanistic pathway is responsible for the introduction of a C-12 hydroxyl group rather than a 12,13-double bond (7). Another interesting case features the putative dehydrogenation of a cyclopropyl fatty acid to produce sterculate, a potent inhibitor of the mammalian but not the plant A desaturase (8). Finally, the biosynthesis of polyacetylenes with antifungal properties such as falcarindiol is thought to involve a sequence of unique desaturase-mediated oxidations (9). 

De novo fatty acid synthesis (FAS) supplies fatty acids for a large variety of lipids, including membrane lipids, epiticular waxes and cutin, neutrcd storage lipids, and many natural products, such as acyl salicylates, polyacetylenes or macrocyclic lactones. Many of these specific lipids are found in highly differentiated plant cells, where they can often represent a major part of cell dry weight. The regulation of FAS, which in most cases supplies the same fatty acids (palmitic eind oleic acids) for different end products, is therefore a key question. 

Glaser coupling methodologies have also been instrumental in the synthesis of cyclic polyacetylenes linked to porphyrins, lipids, carbohydrates, cyclophane ethers (e.g., 77, dicationic aromatic... 

Biopolymers, like nucleic acids (DNA and RNA), proteins, polysaccharides, lipids, and so on. have fundamental significance in life processes. Since the mid-1980s, highly conducting polymers, like doped different polyacetylenes (1) and (2) (SN) (3), or the TCNQ-TTF system (4) and (5), with quasi-one-dimensional alternating stacks of the two different types of molecule embedded in a three-dimensional molecular crystal, and PPV (6), have become objects of extensive experimental investigations because they are also candidates for the discovery of new physical phenomena, such as solitons, polarons and bipolarons, and superconductivity with higher transition temperatures (T ). 

Gavagnin, M., Castelluccio, F., Antonelli, A., Templado, J., and Cimino, G. (2004) Unusual C21 linear polyacetylenic alcohols from an Atlantic ascidian. Lipids, 39, 681-685. 

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