Английская Википедия:Esculeoside A
Esculeoside A is a spirosolane-type glycoside with the molecular formula C58H95NO29.[1] The structure of this product is 3-Ο-β-lycotetraosyl (22S,23S,25S)-23-acetoxy-3β,27-dihydroxy-5α-spirosolane 27-Ο-β-D-glucopyranoside.[1] Fujiwara and colleagues were the first to isolate esculeoside A from the ripe fruit of the Cherry tomato in 2002. Esculeoside A, along with many other steroidal alkaloid glycosides, have been shown to possess cytotoxic activity that could result in a variety of potential health benefits for humans.
Synthesis
This natural product can be obtained using column chromatographies of high-porous polystyrene gels and reversed silica gels from a methanolic extract of many varieties of tomatoes.[2] It will appear as colorless needles when synthesized using this method.
Evidence suggests that α-tomatine is a precursor of esculeoside A.[3] In order for alpha tomatine to be converted to esculeoside A, isomerization of the F-ring is required. The mechanism for this reaction is unclear at this time but research from Iijima and colleagues in 2009 suggest a glycosylation step in the putative pathway from α-tomatine to esculeoside A depends on the plant hormone ethylene.[3][4]
Occurrence
Potatoes, eggplant, and tomatoes are all solanaceous plants that contain unique glycoalkaloids.[4] In the case of tomatoes, one of those unique glycoalkaloids is esculeoside A. A tomato saponin, esculeoside A, is found in quantities four times that of lycopene in ripe tomatoes.[5]
Potential health benefits
Studies have shown esculeoside A may be metabolized into derivatives that perform various beneficial activities in the human body including anti-osteoporosis, anti-menopausal disorder and anti-tumor activities.[5] Recent studies in mice have shown a potential link between esculeoside A and cholesterol levels. In one study, esculeoside A administered to mice reduced serum levels of LDL cholesterol and triglycerides by 25-45% without impacting the rates of HDL cholesterol.[1] The potential health benefits of esculeoside A appear to change with factors such as the age of the tomato fruit, the heat used in processing tomatoes, and the pH used in processing.[6] The highest amounts of esculeoside A were found in the outer skin and wall (pericarp wall) of the tomato fruit. Mature tomatoes tended to show higher amounts of esculeoside A than extracts taken from immature tomatoes. Extracts of esculeoside A in the Katsumata study were shown to be stable when heated until the point of 225 °C. This same study found esculeoside A extracts in water at pH 7-11 were stable throughout the heat sterilization process but unstable under acidic conditions.[6] Research has also shown esculeoside A amounts increase when tomatoes are treated with the phytohormone, ethylene.[4] Collectively, research suggests daily intake of esculeoside A from tomatoes could have many benefits.
References
External links
