Occurrence and Characterization of Fungi and Mycotoxins in Contaminated Medicinal Herbs

Abstract

Traditional medicinal herbs are widely used and may be contaminated with mycotoxigenic fungi during cultivation, harvesting, and storage, causing spoilage and mycotoxin production. We evaluated the predominant mycoflora and extent of mycotoxin contaminations in 48 contaminated samples of 13 different medicinal herbs. In total, 70.8% of herbs were slightly contaminated with aflatoxins (<5 μg kg^-1). <i>Codonopsis</i> radix samples contained ochratoxin A (OTA) (360-515 μg kg^-1), and Scutellariae radix samples contained OTA (49-231 μg kg^-1) and citrinin (15-53 μg kg^-1). Forty samples (83.3%) contained fungal contamination. Sixty-nine strains were characterized via morphological and molecular identification. The predominant mycoflora comprised four genera, <i>Aspergillus</i> spp. (26.1%), <i>Penicillium</i> spp. (24.6%), <i>Rhizopus</i> spp. (14.5%), and <i>Trichoderma</i> spp. (11.6%). Aflatoxins, OTA, and citrinin were detected in 37 cultures by high-performance liquid chromatography-tandem mass spectrometry. Approximately 21.6% of <i>Aspergillus</i> and <i>Penicillium</i> isolates produced mycotoxins. One <i>Penicillium polonicum</i> strain isolated from <i>Scutellariae</i> radix synthesized citrinin. Multiplex PCR analysis showed that three <i>Aspergillus flavus</i> strains harbored aflatoxin biosynthesis genes. One <i>Aspergillus flavus</i> strain isolated from <i>Amomi</i> fructus produced AFB₁ and AFB₂. To the best of our knowledge, the citrinin production by <i>Aspergillus chevalieri</i> and <i>Penicillium sacculum</i> was first reported in this study, which poses a potential risk of mycotoxin contamination in medicinal herbs.