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Mechanisms involved in the chemoprotective effects of rosemary extract studied in human liver and bronchial cells

Identifier

017758

Type of Spiritual Experience

Background

Aspergillus flavus is a saprotrophic and pathogenic fungus with a cosmopolitan distribution. It is best known for its colonisation of cereal grains, legumes, and tree nuts. Postharvest rot typically develops during harvest, storage, and/or transit. A. flavus infections can occur while hosts are still in the field (preharvest), but often show no symptoms (dormancy) until postharvest storage and/or transport. In addition to causing preharvest and postharvest infections, many strains produce significant quantities of toxic compounds known as mycotoxins, which, when consumed, are toxic to mammals A. flavus is also an opportunistic human and animal pathogen, causing aspergillosis in immunocompromised individuals.

Aflatoxin B1 is an aflatoxin produced by Aspergillus flavus and A. parasiticus. It is arguably the most potent carcinogen known, and is up to twice as carcinogenic as an equitoxic dose of X-rays.

Benzo[a]pyrene is a polycyclic aromatic hydrocarbon found in coal tar with the formula C20H12. Its metabolites are mutagenic and highly carcinogenic, and it is listed as a Group 1 carcinogen by the IARC. The compound is one of the benzopyrenes, formed by a benzene ring fused to pyrene, and is the result of incomplete combustion at temperatures between 300 °C (572 °F) and 600 °C (1,112 °F).

In the 18th century, young British chimney sweeps who climbed into chimneys suffered from chimney sweeps' carcinoma, a scrotal cancer peculiar to their profession, and this was connected to the effects of soot in 1775, in the first work of occupational cancer epidemiology and also the first connection of any chemical mixture to cancer formation. Frequent skin cancers were noted among fuel industry workers in the 19th century. In 1933, benzo[a]pyrene was determined to be the compound responsible for these cases, and its carcinogenicity was demonstrated when skin tumors occurred in laboratory animals repeatedly painted with coal tar. Benzo[a]pyrene has since been identified as a prime carcinogen in cigarette smoke. When the body attempts to metabolise benzo[a]pyrene, the resulting diol epoxide reacts and binds to DNA, resulting in mutations and eventually cancer.

A description of the experience

Cancer Lett. 1997 Mar 19;114(1-2):275-81.

Mechanisms involved in the chemoprotective effects of rosemary extract studied in human liver and bronchial cells.

Offord EA1, Macé K, Avanti O, Pfeifer AM.

  • 1Nestlé Research Centre, Lausanne, Switzerland. elizabeth.offord-cavin@chlsnr.nestrd.ch

Abstract

Natural polyphenols found in rosemary have not only potent antioxidant activities but also anticarcinogenic properties. We have studied some of the molecular mechanisms involved in their chemopreventive action using in vitro human liver and bronchial cell models.

Rosemary extract, or its active components, carnosol or carnosic acid are potent inhibitors of DNA adduct formation induced by benzo(a)pyrene or aflatoxin B1. At least two mechanisms are involved in the anticarcinogenic action of rosemary extract: (i) inhibition of the metabolic activation of procarcinogens catalysed by the phase I cytochrome P450 enzymes; (ii) induction of the detoxification pathway catalysed by the phase II enzymes such as glutathione S-transferase.

PMID:  9103309

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PubMed

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