Verticillins are a group of epipolythiodioxopiperazine alkaloids that have displayed potent cytotoxicity. To evaluate their potential further, a larger supply of these compounds was needed for both in vivo studies and analogue development via semisynthesis. To optimize the biosynthesis of these secondary metabolites, their production was analyzed in two different fungal strains (MSX59553 and MSX79542) under a suite of fermentation conditions. These studies were facilitated by the use of the droplet-liquid microjunction-surface sampling probe (droplet probe), which enables chemical analysis in situ directly from the surface of the cultures. These experiments showed that the production of verticillins was greatly affected by growth conditions; a significantly higher quantity of these alkaloids was noted when the fungal strains were grown on an oatmeal-based medium. Using these technologies to select the best among the tested growth conditions, the production of the verticillin analogues was increased while concomitantly decreasing the time required for fermentations from 5 weeks to about 11 days. Importantly, where we could previously supply 5–10 mg every 6 weeks, we are now able to supply 50–150 mg quantities of key analogues per month via laboratory scale fermentation.

High grade serous ovarian cancer (HGSOC) is the most lethal gynecological malignancy in women worldwide and the fifth most common cause of cancer related deaths among U.S. women. New therapies are needed to treat HGSOC particularly since most patients develop resistance to current frontline therapies. Many natural product and fungal metabolites exhibit anti-cancer activity and represent an untapped reservoir of potential new agents with unique mechanism(s) of action. Verticillin A, an epipolythiodioxopiperazine (ETP) alkaloid, is one such compound and our recent advances in fermentation and isolation are now enabling evaluation of its anti-cancer activity. Verticillin A demonstrated cytotoxicity in HGSOC cell lines in a dose-dependent manner with a low nM IC 50 . Furthermore, treatment with verticillin A induced DNA damage and caused apoptosis in HGSOC cell lines OVCAR4 and OVCAR8. RNA-Seq analysis of verticillin A treated OVCAR8 cells revealed an enrichment of transcripts in the apoptosis signaling and the oxidative stress response pathways. Mass spectrometry histone profiling confirmed reports that verticillin A caused epigenetic modifications with global changes in histone methylation and acetylation marks. To facilitate in vivo delivery of verticillin A and to monitor its ability to reduce HGSOC tumor burden, verticillin A was encapsulated into an expansile nanoparticle (verticillin A-eNP) delivery system. In an in vivo human ovarian cancer xenograft model, verticillin A-eNPs decreased tumor *

The chemistry of nature can be beautiful, inspiring, beneficial and poisonous, depending on perspective.