Solanesol structure

In the mid-1950s, the determination of the molecular weight of compounds with a molecular weight above 300 to 400 was difficult and often inaccurate. As a result, Rowland et al. were unable to precisely define the molecular weight of solanesol and therefore its structure. Originally, they had intended to report that solanesol was either a C45 compound (I, n = 8 in Figure II.A-1) or a C50 compound (I, n = 9 in Figure... 

The structure of the unsaturated C45 polyisoprenoid alcohol, solanesol, was established in 1956 by Rowland et al. (3359). Despite the fact that solanesol was one of the major individnal components of the extractable waxes from tobacco, its pyrolysis was not reported until 1962. While Lam (2255) favored the satnrated hydrocarbons as the major precursors in tobacco of PAHs in smoke, Wynder (4294) considered both the satnrated hydrocarbons and the phytosterols to be the major precnrsors. Wright (4282) proposed that the phytosterols and other terpenoids snch as solanesol were the major precursors in tobacco of PAHs in smoke. In spite of their differences of opinion on the relative importance of these tobacco components in their contribntion to smoke PAHs, they collaborated on several stndies in the late 1950s (4355, 4356). Snbseqnently, the satnrated hydrocarbons, the phytosterols, and other terpenoids snch as solanesol were shown to be important in the formation of PAHs in tobacco smoke (3251, 3269, 3291, 3616). 

The references cited for a parficular tobacco and/or tobacco smoke component may deal with its identification or with a variety of topics pertinent to the particular component. Topics may include such simple items as the isolation and identification of a component, its characterization by classical chemical means, for example, the definition of the structure of solanesol isolated from flue-cured tobacco by Rowland et al. (3359), or the characterization of a component by spectrographic means, for example, UV, IR, NMR, MS, and chromatographic retention time. One example is the identification by Snook et al. of many PAHs (3756-3758) and aza-arenes (3750) in cigarette mainstream smoke (MSS). Many references cited herein describe the search for and elucidation of the precursor in tobacco of a particular component in cigarette MSS (3616), for example, the saturated aliphatic hydrocarbon precursors of the PAHs, including benzo[fl]pyrene (B[a]P) the quantitation of the component on a per gram of tobacco basis or on its per cigarette MSS... 

The characterization of the component by classical chemical means, for example, the definition of the structure of solanesol isolated from flue-cured tobacco by Rowland et al. (3359), the characterization of a component by spectrographic means such as UV, IR, NMR, MS, and chromatographic retention time, for example, the identification by Snook et al. of numerous PAHs (3756-3758) and aza-arenes (3750) in cigarette MSS. 

Rao and Chakraborty (1988) have studied the effects of solvent extractions on the chemical composition of tobacco. Water extractions significantly reduced the levels of nicotine, reducing sugar and polyphenols. Extractions with methanol reduced the content of solanesol, neophytadiene, hydrocarbons, and steroids. The solvent extractions did not alter the structural identity of the tobacco. There were no significant cellular changes. 

MHz. Oligomers of natural isoprene that consist of 9-23 isoprene units, referred to as polyprenol, can be a good model for structural analysis of naturally-occurring polyisoprenes. Polyprenol is categorized into three classes al -trans (Solanesol-type), two-trans and poly-cw (Betulaprenol-type), and thiee-trans and poly-cw (Ficaprenol-type). Surprisingly, a polyprenol of all-cw configuration has not been reported. ... 

Undecaprenol (bactoprenol) from Salmonella contains eleven isoprene units, and two irons and nine cis double bonds In the form of undecaprenyl phosphate, it acts as a carrier of carbohydrate residues in the biosynthesis of bacterial antigenic polysaccharides synthesis of Murein (see) also depends on undecaprenyl phosphate. In eukaryotes the Dolichol phosphates (see) function in the transfer of carbohydrate residues in the synthesis of glycoproteins and glycoli-pids. Probably the long lipid chains of these P serve to anchor them in membranes, while the phosphate group acts as a carrier by protruding into the cytoplasm. It is not known whether all P. function as carbohydrate carriers. The structural relationship between solanesol and plastoquinone-9 and ubiquinone-9, and the joint occurrence of these compounds suggest a precursor role for P. Biosynthesis of P. proceeds from mevalonic acid and the conformation of all double bonds is predetermined in early precursors. 

A short-hand convention to describe structures of polyprenols has been suggested (392). Abbreviations a> (co-isoprene residue), T (/A flrA25 -isoprene residue), C (c/5-isoprene residue), and S (saturated isoprene residue) are used to designate a structure. Thus, the all- / aA25 -nonaprenol, solanesol, the first polyprenol to be isolated from nature, can be represented as cu-T-T-[T]5-T-OH. 

Polyprenols of higher plants have mostly been isolated from leaves solanesol (C45) was first obtained in 1956 from tobacco leaves. However, their occurrence in certain woody tissues has been demonstrated. Silver birch (Betula verrucosa) wood has been shown to contain fatty acid esters of betulaprenols -6 to -9 the major polyprenol, betulaprenol-7 has the structure cu-T-T-C-[C]2-C-OH (573) the poli renols from the leaves were free, and the major component had 11 isoprene units (188, 256). 

---