Inhibition of growth and mycotoxin production of Aspergillus flavus and Aspergillus parasiticus by extracts of Agave species.
In this work, the effect of ethanolic, methanolic and aqueous extracts of Agave asperrima and Agave striata on growth and production of aflatoxin (in A&M medium) and cyclopiazonic acid (CPA; in Czpaek-Dox medium) and on growth in corn under storage conditions was determined. Aspergillus strains were inoculated (10(6) conidia per ml of medium or per 6 g of corn), then plant extracts were added and incubated without shaking at 28 degrees C for 8 days (for aflatoxin-producing analysis) or for 12 days (for CPA-producing analysis). Aflatoxin was assayed by HPLC and cyclopiazonic acid by absorbance at 580 nm using the Erlich reagent. The extracts that most effectively inhibited growth were those from the flowers of both plants. These exhibited an MIC from 0.5 to 2 mg/ml in culture media. Extracts from scape showed an MIC from 15 to 30 mg/ml in culture media. The MIC of the flower extracts was higher (>30 mg/g) when examined in corn. However, concentrations lower than the MIC drastically inhibited production of aflatoxins in culture medium or in corn. Half of the MIC inhibited 99% of the production of aflatoxins and 85% of cyclopiazonic acid.
Sánchez
Eduardo
E
Facultad de Ciencias Biologicas, Universidad Autónoma de Nuevo León, Apdo. Postal 124-F, San Nicolás, N.L. 66451, México.
Heredia
Norma
N
García
Santos
S
D000348:Aflatoxins / Q000032:analysis / Q000096:biosynthesis*; D027882:Agave / Q000737:chemistry*; D001230:Aspergillus / Q000187:drug effects* / Q000254:growth & development* / Q000378:metabolism; D001231:Aspergillus flavus / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism; D002851:Chromatography, High Pressure Liquid; D015169:Colony Count, Microbial; D003470:Culture Media / Q000737:chemistry; D004305:Dose-Response Relationship, Drug; D005516:Food Microbiology; D007211:Indoles / Q000032:analysis; D008826:Microbial Sensitivity Tests; D010936:Plant Extracts / Q000494:pharmacology*; D013997:Time Factors
D000348:Aflatoxins; D003470:Culture Media; D007211:Indoles; D010936:Plant Extracts; C000543:cyclopiazonic acid