Saccharoquinoline, a Cytotoxic Alkaloidal Meroterpenoid from Marine-Derived Bacterium sp.

A cytotoxic alkaloidal meroterpenoid, saccharoquinoline (), has been isolated from the fermentation broth of the marine-derived bacterium sp. CNQ-490. The planar structure of was elucidated by 1D, 2D NMR, and MS spectroscopic data analyzes, while the relative configuration of was defined through the interpretation of NOE spectroscopic data. Saccharoquinoline () is composed of a drimane-type sesquiterpene unit in combination with an apparent 6,7,8-trihydroxyquinoline-2-carboxylic acid. This combination of biosynthetic pathways was observed for the first time in natural microbial products. Saccharoquinoline () was found to have cytotoxicity against the HCT-116 cancer cell line by inducing G1 arrest, which leads to cell growth inhibition.