No abstract

A new dimeric isocoumarin, bireticulol, was isolated from the terrestrial Streptomyces sp. and characterized as a 5-5¢ dimer of reticulol. In addition, reticulol and 8-hydroxy-6,7-dimethoxy-3-methyl isocoumarin, together with other known polyketides piericidin A, 2¢-(2-hydroxyphenyl)-2,4¢-bibenzoxazole-4-carboxylic acid methyl ester (UK-1) and 3-benzyl-4-hydroxy-5-methyldihydrofuran-2-one were also obtained. Bireticulol exhibited cytotoxic effects against KB (human epidermoid carcinoma, ATCC CCL-17) and NCI-H187 (human small cell lung cancer, ATCC CRL-5804) cell lines with IC 50 values of 24.4 and 8.31 lg ml À1 , respectively.

Bireticulol, a Bioactive Isocoumarin Dimer from Streptomyces sp. BCC24731. -Bireticulol (I), a new dimeric isocoumarin, exhibits cytotoxic effects against KB and NCI-H187 cell lines. -(BOONLARPPRADAB*, C.; SURIYACHADKUN, C.; SUPHOTHINA, S.; TOBWOR, P.; J. Antibiot. 64 (2011) 3, 267-270, http://dx.