ABSTRACT
Objective::To select volatile oils from 16 species of plants (Cymbopogon citratus, Pelargonium graveolens, Pinus tabulieformis, Litsea cubeba, Mentha haplocalyx, Zingiber officinale, Syzygium aromaticum, Curcuma longa, Zanthoxylum bungeanum, Cinnamomum cassia, Ocimum basilicum, Rosmarinus officinalis, Zanthoxylum schinifolium, Zanthoxylum armatum, Illicium verum, Myristica fragrans) that have good inhibitory effect on the growth of Aspergillus flavus. Method::Aspergillus flavus was isolated from the surface of Platycladi Semen medicinal materials by plate culture method. The volatile oils of 16 plants were extracted by steam distillation. The colony diameter of Aspergillus flavus was determined by fumigation of filter paper, and the effect of volatile oils on the growth of Aspergillus flavus was systematically studied. Result::Aspergillus flavus was successfully isolated from Platycladi Semen by means of morphological, microscopic and DNA barcoding identification methods, the bacteriostatic rates of the above 16 kinds of volatile oils against Aspergillus flavus were 2.93%, 0.05%, 0.37%, 76.07%, 0.34%, 0.15%, 50.05%, 8.51%, 1.43%, 58.20%, 0.07%, 2.60%, 8.73%, 100.00%, 52.62%, 0.07%, respectively. Conclusion::The volatile oils of 16 plants all have different degrees of antibacterial activities for Aspergillus flavus, and volatile oils of Zanthoxylum armatum, Litsea cubeba and Cinnamomum cassia have good inhibitory effect. This study can provide a theoretical basis for the prevention and control of Aspergillus flavus in the growth and storage of Platycladi Semen, and provide a basis for further research on plant volatile oil as bacteriostatic agents in the storage process of traditional Chinese medicine.
ABSTRACT
The structural composition of the surface fungal community of commercially Platycladi semen was analyzed to reveal the surface fungal biodiversity and structural differences. Platycladi semen was collected from Henan, Shandong and Hong Kong, their DNA was extracted, ITS fragments in DNA were amplified by PCR. Miseq was sequenced on Illumina Hiseq 2500 platform after the PCR products were qualified for quality inspection. The sequence OTU cluster was obtained and bioinformatics analysis was carried out. Microbial communities were not observed in the eyes of the Platycladi semen in the three regions. Sequencing results showed that the surface microbial community had high biodiversity, but there were significant differences in species composition. Seven samples o Platycladi semen obtained 345 947 valid sequences, which were divided into 267 OTUs, 3 phylums. 18 classes, 40 orders, 82 families, 120 genus, 191 species fungi. At the genus level, Aspergillus is the dominant species, accounting for the highest proportion, reaching (93.36 ± 6.01)%. Seven samples were contaminated by Aspergillus flavus, and the pollution levels were 14.58%, 15.98%, 17.64%, 16.44%, 0.97%, 23.39% and 18.86%. Except sample No. 5, Aspergillus cibarius was the most abundant, the other six samples were Aspergillus niger, Aspergillus fumigatus and Aspergillus flavus as the core microflora. By analyzing the diversity of fungi distribution in different habitats, we can fully understand the fungi on the surface of Platycladi semen, lay a foundation for early risk warning of Aspergillus flavus contamination and its aflatoxin contamination, and provide a theoretical basis for the quality and safety of Platycladi semen.