Inhibitory effect of Capsicum chinense and Piper nigrum fruits, capsaicin and piperine on aflatoxins production in Aspergillus parasiticus by downregulating the expression of aflD, aflM, aflR, and aflS genes of aflatoxins biosynthetic pathway

• Published in: Journal of environmental science and health. Part B, Pesticides, food contaminants, and agricultural wastes Vol. 55; no. 9; pp. 835 - 843
• Main Authors: Buitimea-Cantúa, Génesis V., Buitimea-Cantúa, Nydia E., Rocha-Pizaña, María del Refugio, Hernández-Morales, Alejandro, Magaña-Barajas, Elisa, Molina-Torres, Jorge
• Format: Journal Article
• Language: English
• Published: Philadelphia Taylor & Francis 01.09.2020; Taylor & Francis Ltd
• Subjects: Aflatoxins; Aflatoxins biosynthesis; Aspergillus parasiticus; biochemical pathways; Biosynthesis; Capsaicin; Capsicum chinense; carcinogenicity; Carcinogens; dose response; environmental science; Fruits; Fungicides; Gene expression; Genes; growth retardation; Metabolites; multigene family; Mycotoxins; Piper nigrum; Piperine; quantitative polymerase chain reaction
• ISSN: 0360-1234; 1532-4109; 1532-4109
• DOI: 10.1080/03601234.2020.1787758

Aflatoxins produced by Aspergillus parasiticus are toxic and carcinogenic metabolites. The biosynthesis of this mycotoxins is a complex process and involves at least 30 genes clustered within an approximately 82 kB gene cluster. In the present study, the effect of Capsicum chinense and Piper nigrum fruits on Aspergillus parasiticus growth and aflatoxin production were studied in relation to the expression of aflD, aflM, aflR, and aflS four; key genes of aflatoxins biosynthesis pathway. GC-EIMS analysis identified capsaicin (66,107 µg g −1 ) and piperine (1,138 µg g −1 ) as the most abundant compounds in C. chinense and P. nigrum fruits, respectively. The antifungal and anti-aflatoxigenic assays showed that C. chinense, P. nigrum, capsaicin, and piperine inhibited A. parasiticus growth and aflatoxins production in a dose-dependent manner. The piperine at 300 µg mL −1 produced higher radial growth inhibition (89%) and aflatoxin production inhibition (69%). The expression of aflatoxin biosynthetic genes was evaluated by quantitative real-time PCR (qRT-PCR) and revealed that aflatoxin inhibition occurring via downregulating the aflS and aflR, and subsequently aflD and aflM genes. These results will improve our understanding of the mechanism of aflatoxin regulation by C. chinense, P. nigrum, capsaicin, and piperine, and provides a reference for further study.