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The inhibitory effect of neem ( Azadirachta indica ) leaf extracts on aflatoxin synthesis in Aspergillus parasiticus
Author(s) -
Bhatnagar Deepar,
McCormick Susan P.
Publication year - 1988
Publication title -
journal of the american oil chemists' society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.512
H-Index - 117
eISSN - 1558-9331
pISSN - 0003-021X
DOI - 10.1007/bf02660575
Subject(s) - azadirachta , aspergillus parasiticus , aflatoxin , mycelium , azadirachtin , aspergillus flavus , chemistry , biosynthesis , aspergillus , food science , botany , biology , horticulture , biochemistry , pesticide , enzyme , agronomy
The effect of neem ( Azadirachta indica ) leaf extracts on Aspergillus parasiticus growth and aflatoxin biosynthesis was investigated. The extracts were prepared by blending 50 g (wet weight) of fresh leaves in one 1 of 10 mM potassium phosphate (pH 7.0) or by boiling the leaves in the buffer. Extracts were added to fungal growth media at 1, 5, 10, 20 and 50% (vol/vol) concentrations prior to inoculation. The formulations did not affect fungal growth (i.e., mycelial dry weight) but essentially blocked (>98%) aflatoxin biosynthesis at concentrations greater than 10% (vol/vol). The inhibitory effect was somewhat diminished (60–70%) inhibition) in heated leaf extracts. Volatile components of the extracts were analyzed using capillary gas chromatography/mass spectrometry; the major volatile component was 3‐methyl 2‐buten‐1‐ol. However, volatiles from blended leaf extracts did not affect either aflatoxin synthesis or fungal growth. The neem‐mediated inhibition appears to involve regulation of secondary metabolism, because once secondary biosynthesis was initiated the inhibitory effect of the neem leaf constituents was lost.