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Aflatoxin B 1 is an aflatoxin produced by Aspergillus flavus and A. parasiticus.It is a very potent carcinogen with a TD 50 3.2 μg/kg/day in rats. [4] This carcinogenic potency varies across species with some, such as rats and monkeys, seemingly much more susceptible than others.
[11] [12] [13] Adults have a higher tolerance to exposure, but are also at risk. No animal species is known to be immune. Aflatoxins are among the most carcinogenic substances known. [14] After entering the body, aflatoxins may be metabolized by the liver to a reactive epoxide intermediate or hydroxylated to become the less harmful aflatoxin M 1.
A. parasiticus produces aflatoxins B1, B2, G1, and G2, named for the colours emitted under UV light on thin-layer chromatography plates—either blue and green. The numbers refer to the type of compound with 1 being major and 2 being minor. [3] These aflatoxins are carcinogenic mycotoxins which have detrimental effects to humans and livestock. [4]
In toxicology, the median lethal dose, LD 50 (abbreviation for "lethal dose, 50%"), LC 50 (lethal concentration, 50%) or LCt 50 is a toxic unit that measures the lethal dose of a given substance. [1] The value of LD 50 for a substance is the dose required to kill half the members of a tested population after a specified test duration.
The discovery of aflatoxins led to substantial changes in agricultural practices and regulations on how grains and legumes were grown, harvested, and stored. [21] The amount of aflatoxins produced by A. flavus is affected by environmental factors. If other competitive fungal organisms are present on host plants, aflatoxin production is low.
Aflatoxin B 1, the most toxic, is a potent carcinogen and has been directly correlated to adverse health effects, such as liver cancer, in many animal species. [11] Aflatoxins are largely associated with commodities produced in the tropics and subtropics, such as cotton, peanuts, spices, pistachios, and maize.
The median toxic dose encompasses the category of toxicity that is greater than half maximum effective concentration (ED 50) but less than the median lethal dose (LD 50). However, for some highly potent toxins (ex. lofentanil , botulinum toxin ) the difference between the ED 50 and TD 50 is so minute that the values assigned to them may be ...
Aflatoxin B 1 exo-8,9-epoxide is a toxic metabolite of aflatoxin B 1.It's formed by the action of cytochrome P450 enzymes in the liver. [1]In the liver, aflatoxin B 1 is metabolized to aflatoxin B 1 exo-8,9-epoxide by the cytochrome P450 enzymes.