Glycoalkaloids, Solarium

The fruit of a number of solanaceous plants, including tomato Lycopersicon esculentum), potato Solanum tuberosum) and eggplant Solarium melongena esculentum), have cholinesterase-inhibiting effects (Krasowski et al. 1997). They contain solanaceous glycoalkaloids o-solanine and o-chaconine, which are triglycosides of solanidine, a steroidal alkaloid derived from cholesterol. They are the only plant chemicals known to inhibit both acetlycholinesterase and butyrylcholinesterase, both in vitro and in vivo. 

The utility of high-performance liquid chromatography (h.p.l.c.) has been demonstrated in the separation of Solarium and Veratrum steroidal alkaloids.50 Methods have been described for the determination of Solarium alkaloids by paper chromatography51 and of crude glycoalkaloids by t.l.c.52... 

Chromatography on a cation-exchange resin has been studied as a means of separating the glycoalkaloids of Solarium laciniatum. Sorption isotherms of the solasodine glycosides a-solamargine, /3-solamargine, and solasonine were measured. ... 

As can be seen from Table XLVI, results concerning production of glycoalkaloids in Solarium cell cultures are variable some authors were unable to detect the glycoalkaloids in cell cultures (e.g.. Ref. 760), others did find production of these compounds in various types of cell and tissue cultures. In fact, Zenk (76/) showed that cell clones of Solarium laciniatum may vary significantly in solasonine (48) content, ranging from 0 to more than 3% dry weight, with a clear maximum in frequency of occurrence at about 0.2%. 

Table 7.3 Steroidal alkaloids (alkamines) alphabetically listed within the different structural types For 41 out of altogether 115 compounds from Solarium spp. (113 compounds), Lycianthes biflora, and Saracha punctata (one compound each) at least one corresponding glycoalkaloid was found and structurally elucidated, i.e., for 36% of the alkamines also corresponding glycosides are known (continued)...

Table 7.5 Most frequent glycoalkaloids in the genus Solarium in the order of frequency listed all alkaloids with an occurrence in >2 species solacauUne added as a rare example for a straight chain (not branched) oligosaccharide moiety... 

Thus, it may be assumed, that steroidal alkaloids, i.e., alkamines and/or glycoalkaloids, represent a common and consistent ttait in the genus Solarium. This was already assumed by Heftmann (1983) ( It is quite possible that they occur in all representatives of this genus ) and Hegnauer (1990) Solatium alkaloids are hardly absent in any species of the genus . 

Provide brief information on major natural toxicants and common allergenic or medicinal properties of the plant. In some cases, it may be relevant to mention similar information from related species e.g. glycoalkaloids in crossable wild relatives of Solarium tuberosum subsp. tuberosum, potato). 

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