Cytotoxic Activities of Aspergillin PZ and Trichoderone B from an Isolate of Aspergillus flavipes sp. Against NCI-60 Human Tumor Cell Lines

In the process of piloting a new approach to natural product discovery from microorganisms isolated from systematically determined geographic sites in the State of Texas, USA, two previously identified and structurally similar bioactive pentacyclic aspochalasins, aspergillin PZ (1) and trichoderone B (2), were rediscovered from a single isolate of Aspergillus flavipes sp.. While the antimicrobial activity and cytotoxic activity of 1 had been documented in several publications, nothing was known about the bioactivities of 2. After a large laboratory-scale fermentation and activity-guided purification, both 1 and 2 were enrolled in the NCI-60 Human Tumor Cell Lines Screen program. A preliminary single-dose assay of two natural products shows a similar cytotoxic profile and a low potency against human tumor cell lines with few exceptions at the 10 mu M dosage level.