Efficient synthesis of methyl lycotetraoside, the tetrasaccharide constituent of the tomato defence glycoalkaloid α-tomatine

Bioactivities of glycoalkaloids and their aglycones from Solanum species

Potatoes, tomatoes, and aubergines are all species of the Solanum genus and contain a vast array of secondary metabolites including calystegine alkaloids, phenolic compounds, lectins, and glycoalkaloids. Glycoalkaloids have been the subject of many literature papers, occur widely in the human diet, and are known to induce toxicity. Therefore, from a food safety perspective further information is required regarding their analysis, toxicity, and bioavailability. This is especially important in crop cultivars derived from wild species to prevent glycoalkaloid-induced toxicity. A comprehensive review of the bioactivity of glycoalkaloids and their aglycones of the Solanum species, particularly focused on comparison of their bioactivities including their anticancer, anticholesterol, antimicrobial, anti-inflammatory, antinociceptive, and antipyretic effects, toxicity, and synergism of action of the principal Solanum glycoalkaloids, correlated to differences of their individual molecular structures is presented.

Interaction of the Glycoalkaloid Tomatine with DMPC and Sterol Monolayers Studied by Surface Pressure Measurements and Brewster Angle Microscopy

The interaction of the glycoalkaloid tomatine with monolayers of dimyristoylphosphatidylcholine (DMPC) and cholesterol, as well as other selected sterols, has been investigated using surface pressure measurements at constant area and Brewster angle microscopy (BAM). The interaction of tomatine with sterol monolayers is found to vary with the structure of the sterol. The interaction of tomatine with cholesterol-containing monolayers results in a surface pressure increase accompanied by the appearance of a mottled texture. Morphological changes are observed that suggest the formation of tomatine-cholesterol complexes that aggregate at the water-air interface. No morphology change observable by BAM is observed for monolayers containing epicholesterol, suggesting that the stereochemistry of hydrogen bonding between the sterol and the sugar units on tomatine is of particular significance. Strong interactions are observed with cholestanol- and coprostanol-containing monolayers, and BAM reveals formation of spiked aggregates upon interaction with 7:3 mole ratio DMPC/coprostanol mixed monolayers. More modest surface pressure changes are observed for cholestenone- and epicoprostanol-containing monolayers. A much smaller surface pressure increase is observed when tomatine is injected beneath a pure DMPC monolayer.