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Pyrolytic conversion of gummiferin into atractyloside. Chemical and biological evidence
Author(s) -
Defaye G.,
Vignais P.M.,
Vignais P.V.
Publication year - 1972
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(72)80515-5
Subject(s) - pyrolytic carbon , citation , physics , chemistry , library science , computer science , organic chemistry , pyrolysis
The thistle A tractylis gummifera L. contains two toxic glucosides which can crystallize as potassium salts. The first one, named by Lefranc [l] atractylic acid, is now currently called atractyloside. The second one, isolated for the first time in 1964 and called gummiferin [2] has been identified with 4-carboxyatractyloside [3] (fig. 1); the presence of such a compound in extracts of A fractylis gummifera L. has been independently established by another group [4]. While atractyloside (ATR) and gummiferin (GUM) are both specific inhibitors of adenine nucleotide translocation in mitochondria, striking differences in their inhibitory effects are encountered: competitivity (ATR) and non competitivity (GUM) with ADP, saturation of sites and strong homotropic interaction exclusively in the case of GUM binding [ 51. A single difference in the genin structure (a supplementary carboxyl group in GUM) is responsible for these different properties, substantiating our earlier conclusion [6] that the atractyligenin moiety of ATR was responsible for the inhibition of ADP translocation and could play a role of allosteric effector. In this note, the biological effects of decarboxyGUM are compared with those of authentic ATR and GUM. Two possible isomeric decarboxylated compounds could be expected: one with the carboxyl axial like the methyl on Cl0 (fig. 2a), the other one with the carboxyl equatorial (fig. 2b). The two corresponding aglycones have been described and called by Piozzi et al. [7] atractyligenin and 4-epi-atractyligenin, respectively. The chemical and biological tests presented below show that ATR and decarboxy-GUM are identical. This finding confirms the structure I for GUM. Work is in progress to isolate the C4 -stereoisomer of ATR; this compound should be a new supplementary tool to analyze the topography of the binding site in the inner mitochondrial membrane.