Natural Trichothecene Mycotoxins from a Rotten Moldy Apple Core-Derived Trichothecium roseum: Occurrence, Identification, and Potential Transfer to Commercial Apple Juice

Abstract

Trichotherosin A (1), a new trichothecene precursor derivative, along with six known trichothecene mycotoxins (2− 7), was isolated from Trichothecium roseum KIB-093, a plant pathogenic fungus associated with a rotten moldy apple core. Their structures were elucidated based on their HRMS (high-resolution mass spectrometry) and NMR (nuclear magnetic resonance) data as well as theoretical calculations. Trichothecene mycotoxins are widely recognized for their potent toxicity. Compounds 1−7 were all active in a cytotoxicity screening, with no selectivity toward either normal human cell lines or human cancer cell lines. Among them, 2 was the most cytotoxic, with the smallest IC 50 value being 33 nM. T. roseum is recognized as one of the main pathogenic fungi causing apple core rot. It is of great possibility for infected apples to be utilized in the apple-based beverage industry. According to the cytotoxicity results, qualitative determination of compounds 2−7, the isolated members characterized by a 12,13epoxytrichothec-9-ene (EPT) core skeleton with certain cytotoxic effects, was performed using HPLC-HR-ESI-Q-TOF-MS (highperformance liquid chromatography-high resolution-electrospray ionization-quadrupole-time-of-flight-mass spectrometry) in 10 different commercial apple juices. All compounds 2−7 were detectable, with the detection rates ranging from 13.33 to 80%, indicating the potential contamination of trichothecene mycotoxins in certain apple juices, which could pose health risks to consumers.