Anti-tumor substances isolation

C52H76O24, Mr 1085.16, yellow cryst., mp. 180-183 °C. A. belongs to the substance class of the chromomycins which exhibit anti-tumor activity. It is isolated from Streptomyces argillaceus and S. tana-shiensis. It cannot be used clinically on account of its toxicity. 

With more than 350 original structures, almost all of which contain nitrogen, Didemnidae may be regarded as the richest family of the class Ascidiacea, with several molecules that are undergoing clinical trials for their antiviral and anti-tumor activity. Most of the structures isolated from Didemnidae derive from only three genera, Didemnum, Trididemnum and Lissoclinum, which each contain families of active substances (didemnins, eudis-tomins, lamellarins, lissoclinamides and Hssodimides). Table 28.3 shows the main types of structure encountered in the main genera of the order. 

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