91. “The Secalosides, Novel Tumor Cell Growth Inhibitory Glycosides from a Pollen Extract”
    Jaton, J.-C.; Roulin, K.; Rose, K.; Sirotnak, F. M.; Lewenstein, A.; Brunner, G.; Fankhauser, C. P.; Burger, U.
    J. Nat. Prod. 1997, 60, 356-360.

The pollen of rye (Secale cereale) was shown to contain a biologically highly active family of glycosides called the secalosides. Secalosides A and B (1), both of molecular formula C₄₆H₅₁NO₂₄, were found to be epimeric esters of (2-oxo-3-indolyl)acetic acid (4). They are made up, in addition to this heterocyclic aglycon I (4), of three hexose building blocks and a carbocyclic aglycon II, which is an indan-derived dicarboxylic acid (5). In aqueous solution, secalosides A and B interchanged by epimerization at the chiral center of 4. A further epimeric pair, secalosides C and D (2), contain one additional glucose building block. Secalosides A and B, the racemic aglycon I (4), and 2-oxo-1,2,3,4-tetrahydroquinoline-4-carboxylic acid (3), which results from 4 by hydrolytic rearrangement, exhibited significant antitumor activity against S180 sarcoma in vivo. IC₅₀ values obtained were about 5 μg/mouse for the secalosides and 1 μg/mouse for 3 and 4.

DOI : 10.1021/np9606557 

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