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.

Esculeoside A
Names
IUPAC name
(2aS,2'S,3'S,4S,5'S,6aS,6bS,8aS,8bR,9S,11aS,12bR)-4-(((2R,3R,4R,5R,6R)-3,4-dihydroxy-5-(((2S,3R,4S,5R,6R)-5-hydroxy-6-(hydroxymethyl)-3-(((2S,3R,4S,5S,6R)-3,4,5-trihydroxy-6-(hydroxymethyl)tetrahydro-2H-pyran-2-yl)oxy)-4-(((2S,3R,4S,5R)-3,4,5-trihydroxytetrahydro-2H-pyran-2-yl)oxy)tetrahydro-2H-pyran-2-yl)oxy)-6-(hydroxymethyl)tetrahydro-2H-pyran-2-yl)oxy)-6a,8a,9-trimethyl-5'-((((2R,3R,4S,5S,6R)-3,4,5-trihydroxy-6-(hydroxymethyl)tetrahydro-2H-pyran-2-yl)oxy)methyl)octadecahydrospiro[naphtho[2',1':4,5]indeno[2,1-b]furan-10,2'-piperidin]-3'-yl acetate
Identifiers
3D model (JSmol)
ChEBI
ChemSpider
UNII
  • InChI=1S/C58H95NO29/c1-21-36-30(88-58(21)35(79-22(2)64)11-23(14-59-58)19-77-51-45(74)41(70)38(67)31(15-60)81-51)13-28-26-6-5-24-12-25(7-9-56(24,3)27(26)8-10-57(28,36)4)80-53-47(76)43(72)48(34(18-63)84-53)85-55-50(87-54-46(75)42(71)39(68)32(16-61)82-54)49(40(69)33(17-62)83-55)86-52-44(73)37(66)29(65)20-78-52/h21,23-55,59-63,65-76H,5-20H2,1-4H3/t21-,23-,24-,25-,26+,27-,28-,29+,30-,31+,32+,33+,34+,35-,36-,37-,38+,39+,40+,41-,42-,43+,44+,45+,46+,47+,48-,49-,50+,51+,52-,53+,54-,55-,56-,57-,58-/m0/s1 ☒N
    Key: VSQBWNYALURFOT-ZSFCQSFNSA-N ☒N
  • InChI=1/C58H95NO29/c1-21-36-30(88-58(21)35(79-22(2)64)11-23(14-59-58)19-77-51-45(74)41(70)38(67)31(15-60)81-51)13-28-26-6-5-24-12-25(7-9-56(24,3)27(26)8-10-57(28,36)4)80-53-47(76)43(72)48(34(18-63)84-53)85-55-50(87-54-46(75)42(71)39(68)32(16-61)82-54)49(40(69)33(17-62)83-55)86-52-44(73)37(66)29(65)20-78-52/h21,23-55,59-63,65-76H,5-20H2,1-4H3/t21-,23-,24-,25-,26+,27-,28-,29+,30-,31+,32+,33+,34+,35-,36-,37-,38+,39+,40+,41-,42-,43+,44+,45+,46+,47+,48-,49-,50+,51+,52-,53+,54-,55-,56-,57-,58-/m0/s1
    Key: VSQBWNYALURFOT-ZSFCQSFNBT
  • C[C@@]12[C@](CC[C@]3([H])[C@]2([H])CC[C@@]4(C)C3C[C@@]5([H])[C@]4([H])[C@H](C)[C@]6(NC[C@@H](CO[C@H]7[C@H](O)[C@@H](O)[C@H](O)[C@@H](CO)O7)C[C@@H]6OC(C)=O)O5)([H])C[C@@H](O[C@]8([H])O[C@H](CO)[C@H](O[C@@]9([H])[C@H](O[C@@]%10([H])[C@H](O)[C@@H](O)[C@H](O)[C@@H](CO)O%10)[C@@H](O[C@@]%11([H])[C@H](O)[C@@H](O)[C@H](O)CO%11)[C@H](O)[C@@H](CO)O9)[C@H](O)[C@H]8O)CC1
Properties
C58H95NO29
Molar mass 1270.376 g·mol−1
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Solanum lycopersicum

Synthesis

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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

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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

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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

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  1. ^ a b c Nohara, Toshihiro; Ono, M.; Ikeda, T.; Fujiwara, Y.; El-Aasr, M. (2010). "The Tomato Saponin, Esculeoside A". Journal of Natural Products. 73 (10): 1734–1741. doi:10.1021/np100311t. PMID 20853874.
  2. ^ Fujiwara, Y.; Takaki, A.; Uehara, Y.; Ikeda, T.; Okawa, M.; Yamauchi, K.; Ono, M.; Yoshimitsu, H.; Nohara, T. (2004). "Tomato steroidal alkaloid glycosides, esculeosides A and B, from ripe fruits". Tetrahedron. 60 (22): 4915–4920. doi:10.1016/j.tet.2004.03.088.
  3. ^ a b Yamanaka, T.; Vincken, J.; Zuilhof, H.; Legger, A.; Takada, N.; Gruppen, H. (2009). "C22 Isomerization in a-Tomatine-to-Esculeoside A Conversion during Tomato Ripening Is Driven by C27 Hydroxylation of Triterpenoidal Skeleton". Journal of Agricultural and Food Chemistry. 57 (9): 3786–3791. doi:10.1021/jf900017n. PMID 19415927.
  4. ^ a b c Iijima, Y.; Fujiwara, Y.; Tokita, T.; Ikeda, T.; Nohara, T.; Aoki, K.; Shibata, D. (2009). "Involvement of Ethylene in the Accumulation of Esculeoside A during Fruit Ripening of Tomato (Solanum lycopersicum)". Journal of Agricultural and Food Chemistry. 57 (8): 3247–3252. doi:10.1021/jf8037902. PMID 19284799.
  5. ^ a b Manabe, H.; Murakami, Y.; El-Aasr, M.; Ikeda, T.; Fujiwara, Y.; Ono, M.; Nohara, T. (2010). "Content variations of the tomato saponin Esculeoside A in various processed tomatoes". Journal of Natural Medicine. 65 (1): 176–179. doi:10.1007/s11418-010-0443-4. PMID 20652644. S2CID 26835692.
  6. ^ a b Katsumata, A.; Kimura, M.; Saigo, H.; Aburaya, K.; Nakano, M.; Ikeda, T.; Fujiwara, Y.; Nagai, R. (2011). "Changes in Esculeoside A Content in Different Regions of the Tomato Fruit during Maturation and Heat Processing". Journal of Agricultural and Food Chemistry. 59 (8): 4104–4110. doi:10.1021/jf104025p. PMID 21395308.
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