17 毒化バイ貝Babylonia Japonicaよりの新有毒成分Neosurugatoxinの分離及び構造決定

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A new toxin, named Neosurugatoxin, was isolated from the toxic Japanese Ivory Shell and its structure was determined by X-ray crystallographic analysis. The space group of the crystal is orthorhombic P2_12_12_1 with four molecules in a unit cell. The cell dimension are a=21.595(10), b=13.964(7), c=10.659(5)A. A number, of 2476 reflexions were measured on a Philips 4-circle diffractometer using CuKα radiation. The crystal structure was determined by the heavy atom method and refined by the block-diagonal least-squares method. The final R value was 0.051 including hydrogen atoms. The molecular structure and bond lengths are shown in Fig.4. The molecule is a glycoside with a pentacyclic aglycone, which is constructed from two planar parts, 6-bromo-2-oxindole (D,E ring) and a heterocyclic system(B,C ring) including a dioxopyrimidine ring(A ring). The saccharide is O-β-D-xylopyranosyl(1→5)myoinositol. Several structural feature common to both Neosurugatoxin and Surugatoxin are: both have an oxindole, a dioxopyrimidine, myoinositol, and other functional groups. Neosurugatoxin at a concentration of 1×10^<-9>g/ml inhibited the contractile response of isolated guinea pig ileum to 3×10^<-5>g/ml of nicotine and evoked mydriasis in mice at a minimum dose of 3ng/g.
天然有機化合物討論会の論文
1981-09-10