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| | Aflatoxins Basic information |
| Product Name: | Aflatoxins | | Synonyms: | Aflatoxins | | CAS: | | | MF: | | | MW: | 0 | | EINECS: | | | Product Categories: | | | Mol File: | Mol File | ![Aflatoxins Structure]() |
| | Aflatoxins Chemical Properties |
| | Aflatoxins Usage And Synthesis |
| Description | Aflatoxins are a group of polyketide metabolites produced
mainly by strains of the fungus Aspergillus flavus and the
closely related species A. parasiticus. The most biologically
active aflatoxin is B1; it is considered the most potent
naturally occurring carcinogen known. | | Agricultural Uses | Aflatoxin refers to a group of highly toxic polynuclear moulds (mycotoxins.) They are designated as B1,B2,G1,G2,M1and M2, and are produced chiefly by fungus Aspergillusflavus, which is a natural contaminant of fruits, vegetables and cereal grains. Aflatoxins are toxic to many animals including fish and birds. The B2and G1 strains are carcinogens.
Aflatoxins fluoresce strongly under UV light. They
are soluble in methanol, acetone and chloroform, but
only slightly soluble in water and hydrocarbon solvents.
Prevention of mould growth is the most effective
protection against aflatoxins. Removal or inactivation is
possible by physical and chemical means (solvent
refining or hand picking). FDA (Food and Drug
Administration) does not allow any aflatoxin content in
foods or feeds, although its presence up to 20 ppb does
not attract penalty. | | Enzyme inhibitor | These mycotoxins (FWB1 = 312.30 g/mol; CAS 1162-65-8; FWB2 = 314.29
g/mol; CAS 7220-81-7; FWG1 = 328.27 g/mol; CAS 1165-39-5; FWG2 =
330.29 g/mol; CAS 7241-98-77; FWM1 = 328.27 g/mol; CAS 6795-23-9;
FWM2 = 330.29 g/mol; CAS 6885-57-0), produced by the fungus
Aspergillus flavus, A. parasiticus, A. oryzae, and some Penicillium strains,
are a set of closely related metabolites that are known carcinogens. The B
and G designations in the name refer to the blue or green fluorescence,
respectively, that are exhibited by the mycotoxins (aflotoxins B and G are
22
dihydro derivatives of B1 and G1 that are less toxic). The M series of
aflatoxins are hydroxylated derivatives of the B series toxins isolated from
the milk of cows that ingested aflatoxin-contaminated feed. Initially
innocuous forms are bioactivated by members of the cytochrome p450
family into mutagenic and carcinogenic intermediates. Aflatoxin-B1, for
example, is converted into aflatoxin B1-78,9 exo-epoxide, which is in turn
converted into the 8,9-dihydroxy-8-N-guanyl-9-hydroxy aflatoxin B1
adduct. This adduct is metabolized into aflatoxin B1 formaminopyrimidine
adduct. It is these adducts that prove to be strongly mutagenic and often
carcinogenic. Chronic hepatitis B virus (HBV) infection and persistent
AFB? exposure are major risk factors for developing hepatocellular
carcinogenesis, suggesting synergy in the action of these agents. Nucleic
Acid Interactions: Aflatoxins have dimensions and so-called bay region
aromatic characteristics that allow them to intercalate between base-pairs in
DNA and double-stranded segments of RNA. Major groove recognition of
DNA by proteins also relies the variation in hydrogen-bond donor/acceptor
content to makes DNA base-pairs distinguishable from one another, and
aflatoxins may mimic major groove-binding proteins. Aflatoxins also
inhibit RNA biosynthesis, transcription, and protein biosynthesis.
CAUTION: Aflatoxin B1 is a highly potent mutagen and carcinogen. Avoid
direct exposure to the skin or eyes as well as inhalation. Target (s) : RNA
polymerase; DNase-I (deoxyribonuclease I), by Aflatoxin B2a >
Aflatoxin G2a;; electron transport; nucleoside transport;
oxidative phosphorylation, uncoupled; b-galactoside a-2,6-
sialyltransferase, inhibited by Aflatoxins B1, B2a, and G1; glycoprotein
sialyltransferase; acetylcholinesterase, inhibited by Aflatoxin B1;
aminopeptidase B. | | Metabolism | Under optimum conditions, aflatoxin can be produced
by A. flavus within 24 to 36 hours; a significant amount
can be produced in a few days. Increases in aflatoxins
of 200 to more than 2,000 parts per billion (ppb) have
been reported in three days when recently harvested field
corn was stored at high moisture levels. Aflatoxins may
increase in truckloads of contaminated corn at a rate of up
to 6% per hour. | | Toxicity evaluation | Aflatoxins are both toxic and carcinogenic. They have
been shown to produce cancer in all species tested;
epidemiologic evidence suggests that they are involved
in human liver cancer in some parts of the world. In
general, the toxicity of aflatoxins is ofmore concern than its
carcinogenicity in domestic animals. Regular or occasional
consumption by farm animals of aflatoxin-containing feed,
of less than 100 ppb to several hundred parts per million
(ppm), results in lowered feed consumption, poor feed
conversion, reduced growth, and decreased production.
Reduced growth and productivity may be accompanied by
liver damage, hemorrhage, and suppression of natural
immunity to parasites. Once damage has occurred,
animals do not fully recover when returned to a toxinfree
ration. Growers who produce homegrown feed must
be aware of the local aflatoxin hazard and, if necessary,
have grain checked for aflatoxins before making it into
feed (7–11). |
| | Aflatoxins Preparation Products And Raw materials |
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