Steroidal glycoalkaloid profiling and structures of glycoalkaloids in wild tomato fruit.
Steroidal glycoalkaloids (SGAs) constitute one of the main groups of secondary metabolites in tomato fruit. However, the detailed composition of SGAs other than α-tomatine, dehydrotomatine and esculeoside A, remains unclear. Comparative SGA profiling was performed in eight tomato accessions, including wild tomato species by HPLC-Fourier transform ion cyclotron resonance mass spectrometry (HPLC-FTICR/MS). On the basis of molecular formulae obtained from accurate m/z and fragmentation patterns by multistage MS/ MS (MS(n)), 123 glycoalkaloids in total were screened. Detailed MS(n) analysis showed that the observed structural diversity was derived from various chemical modifications, such as glycosylation, acetylation, hydroxylation and isomerization. Total SGA content in each tomato accession was in the range of 121-1986 nmol/gfr.wt. Furthermore, the compositional variety of SGA structures was distinctive in some tomato accessions. While most tomato accessions were basically categorized as α-tomatine-rich or esculeoside A-rich group, other specific SGAs also accumulated at high levels in wild tomato. Here, five such SGAs were isolated and their structures were determined by NMR spectroscopic analysis, indicating three of them were presumably synthesized during α-tomatine metabolism.
Department of Nutrition and Life Science, Kanagawa Institute of Technology, 1030 Shimo-ogino, Atsugi, Kanagawa 243-0292, Japan; Kazusa DNA Research Institute, Kazusa-Kamatari 2-6-7, Kisarazu, Chiba 292-0818, Japan. Electronic address: iijima@bio.kanagawa-it.ac.jp.
Yoko
Y
Iijima
Bunta
B
Watanabe
Ryosuke
R
Sasaki
Makiko
M
Takenaka
Hiroshi
H
Ono
Nozomu
N
Sakurai
Naoyuki
N
Umemoto
Hideyuki
H
Suzuki
Daisuke
D
Shibata
Koh
K
Aoki
D005638:Fruit / Q000737:chemistry*; D006027:Glycosides / Q000737:chemistry / Q000302:isolation & purification*; D018551:Solanum lycopersicum / Q000737:chemistry*; D015394:Molecular Structure; D010840:Phytosterols / Q000737:chemistry / Q000302:isolation & purification*; D010936:Plant Extracts / Q000737:chemistry*; D012991:Solanaceous Alkaloids / Q000737:chemistry / Q000302:isolation & purification*
D006027:Glycosides; D010840:Phytosterols; D010936:Plant Extracts; D012991:Solanaceous Alkaloids
Esculeoside A; HPLC-FTICR/MS; Metabolic profiling; Solanaceae; Solanum lycopersicum; Steroidal glycoalkaloids; Wild tomato; α-Tomatine