Min Hu ¹ Lulu Wang ¹ Dapeng Su ¹ Qing-Song Yuan ¹ Chenghong Xiao ¹ Lanping Guo ² Meidan Wang ³ Chuanzhi Kang ² Tao Zhou ^1* Jinqiang Zhang ^1*

• ¹ Guizhou University of Traditional Chinese Medicine, Guiyang, Guizhou Province, China
• ² State Key Laboratory of Dao-di Herbs, National Resource Center for Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing, China
• ³ Faculty of Biology, University of Freiburg, Freiburg, Germany

Medicinal herbs have been increasingly used for therapeutic purposes against a diverse range of human diseases worldwide. However, inevitable contaminants, including mycotoxins, in medicinal herbs can cause serious problems for humans despite their health benefits. The increasing consumption of medicinal plants has made their use a public health problem due to the lack of effective surveillance of the use, efficacy, toxicity, and quality of these natural products. Radix Dipsaci is commonly utilized in traditional Chinese medicine and is susceptible to contamination with mycotoxins. Here, we evaluated the mycotoxins, mycobiota and toxigenic fungi in the traditional medicine Radix Dipsaci. A total of 28 out of 63 Radix Dipsaci sample batches (44.4%) were found to contain mycotoxins. Among the positive samples, the contamination levels of AFB1, AFG1, AFG2, and OTA in the positive samples ranged from 0.52 to 32.13 μg/kg, 5.14 to 20.05 μg/kg, 1.52 to 2.33 μg/kg, and 1.81 to 19.43 μg/kg respectively, while the concentrations of ZEN and T-2 were found to range from 2.85 to 6.33 μg/kg and from 2.03 to 2.53 μg/kg, respectively. More than 60% of the contaminated samples were combined with multiple mycotoxins. Fungal diversity and community were altered in the Radix Dipsaci contaminated with various mycotoxins. The abundance of Aspergillus and Fusarium increased in the Radix Dipsaci contaminated with aflatoxins (AFs) and ZEN. A total of ninety-five strains of potentially toxigenic fungi were isolated from the Radix Dipsaci samples contaminated with mycotoxins, predominantly comprising Aspergillus (73.7%), Fusarium (20.0%), and Penicillium (6.3%). Through morphological identification, molecular identification, mycotoxin synthase gene identification and toxin production verification, we confirmed that AFB1 and AFG1 primarily derive from A. flavus, OTA primarily derives from A. westerdijkiae, ZEN primarily derives from F. oxysporum, and T-2 primarily derives from F. graminearum in Radix Dipsaci. These data can facilitate our comprehension of prevalent toxigenic fungal species and contamination levels in Chinese herbal medicine, thereby aiding the establishment of effective strategies for prevention, control, and degradation to mitigate the presence of fungi and mycotoxins in Chinese herbal medicine.