Assessment of the Microbiome and Potential Aflatoxin Associated With the Medicinal Herb Platycladus orientalis

Abstract

Platycladi Semen, which is derived from the dried ripe seed of Platycladus orientalis, has been used for the treatment of insomnia and constipation in China for 2000 years. However, it is susceptible to fungal and aflatoxin contamination under proper humidity and temperature during storage. Although aflatoxin contamination in Platycladi Semen has been reported preliminarily, few studies have been conducted on fungal infection and aflatoxin contamination simultaneously. Thus, this work aims to provide an indepth understanding of fungal contamination in Platycladi Semen, and information on aflatoxin contamination. We focused on a comparison of the difference in fungal diversity between aflatoxin-contaminated and aflatoxin-free Platycladi Semen samples. First, aflatoxin levels in 11 Platycladi Semen samples, which were collected from local herbal markets in Shandong, Anhui, and Hebei provinces throughout China, were determined by IAC-HPLC-FLD, and positive confirmation of detected samples was performed by LC-MS/MS. The samples were divided into two groups, based on production or nonproduction of aflatoxin. We then used the Illumina MiSeq PE250 platform, and targeted the internal transcribed spacer two sequences to analyze the diversity and composition of the fungal microbiome, as well as to assess the presence of potential mycotoxinproducing fungi. Results showed that five samples were contaminated with aflatoxins, one of which exceeded the legal limits of Chinese Pharmacopeia Commission (2015). At the phylum level, the Ascomycota was the most dominant in all tested samples, with a relative abundance of 83.04-99.46%. Aspergillus (27.88-97.28%), Xerochrysium (0-28.49%), and Xeromyces (0-22.24%) were the three predominant genera. Furthermore, differences in fungal composition between the aflatoxin-contaminated and aflatoxin-free groups, as well as between different provinces were observed. A total of 74 species were identified, and four potential mycotoxin-producing fungi were detected in all samples, namely Aspergillus flavus, Aspergillus fumigatus, Fusarium poae, and Penicillium steckii. In conclusion, we report the great diversity of fungi associated with Platycladi Semen, highlight the risk to consumers of ingesting potent aflatoxin, and provide a reference for the safe application and quality improvement of Platycladi Semen.

Analysis of Fungal Microbiomes in Edible Medicinal Morindae Officinalis Radix and Alpiniae Oxyphyllae Fructus Using DNA Metabarcoding

“…In general, Penicillium and Cladosporium were the dominant genera. In our previous studies, the predominant genus in four seed herbs (Platycladi Semen, Myristicae Semen, and Cassiae Semen) was Aspergillus [ 33 , 34 , 35 ]. The relationship between dominant fungi and herbs has not been well explained, owing to the complex factors that influence the fungal community.…”

“…It could be used as an effective tool for the simultaneous characterization of numerous microbial species. In previous studies, DNA metabarcoding has been successfully applied in the investigation of fungal contamination in Platycladi Semen [ 33 ], Myristicae Semen [ 34 ], and Cassiae Semen [ 35 ]. In the present study, DNA metabarcoding efficiently analyzed the fungal microbiomes in MOR and AOF.…”

Revealing the Impact of the Environment on the Ginsenosides in American Ginseng from Three Scales: Bioclimatic Factors, Soil Physicochemical Properties and Microbial Communities

“…Characteristics of soil microbial communities of American ginseng in three geographical regions High-throughput sequencing has provided new prospects to the research of microbial diversity. It was used to analyse the abundance and richness of lowabundance microorganisms in environmental samples, multiple samples can be sequenced simultaneously, greatly saving time, overcoming the limitations of culture-based methods in isolation [53].…”

Metal–Organic Frameworks (MOFs) Based Analytical Techniques for Food Safety Evaluation

“…There are many other contaminants that bring risks to food safety and human health, including environmental organic contaminants, mycotoxins among many others [67,68]. Here we selected a few representatives for a brief introduction (Table 3).…”