The antiproliferative effect of spectinabilins from Streptomyces spectabilis on hepatocellular carcinoma cells in vitro and in vivo

Spectinabilin (1), spectinabilin derivative (2), and a new analogue, 2-demethyl-spectinabilin (3) were isolated from the fermentation broth of a soil-borne Streptomyces spectabilis strain. The structure of the new compound was elucidated by a detailed spectroscopic data analysis including data from CD spectra. Spectinabilin (1) demonstrated cytotoxicity against five human cancer cell lines, with IC50 values ranging from 18.7 ± 3.1 to 34.6 ± 4.7...