A handful of cashew nuts contains about 20 mg anacardic acid, a substance that has an anti-oestrogenic effect, molecular biologists at the University of Louisville discovered. They also discovered that the anacardic acid killed hormone sensitive breast cancer cells in their test tubes.
A handful of cashew nuts contains about 20 mg anacardic acid, a substance that has an anti-oestrogenic effect, molecular biologists at the University of Louisville discovered. They also discovered that the anacardic acid killed hormone sensitive breast cancer cells in their test tubes.
A handful of cashew nuts contains about 20 mg anacardic acid, a substance that has an anti-oestrogenic effect, molecular biologists at the University of Louisville discovered. They also discovered that the anacardic acid killed hormone sensitive breast cancer cells in their test tubes.
A handful of cashew nuts contains about 20 mg anacardic acid, a substance that has an anti-oestrogenic effect, molecular biologists at the University of Louisville discovered. They also discovered that the anacardic acid killed hormone sensitive breast cancer cells in their test tubes.
What? Did we just say that anacardic acid is a substance? That’s not quite accurate. Anacardic acid is a collective name for a number of compounds. The basic structure of anacardic acid is shown on the right above. The diagram below is of an analogue found in foods containing cashew nuts. Chemists have identified dozens of variants of anacardic acid in cashew nuts, which happen to be the best nutritional source of anacardic acid.
Products containing cashew apple juice probably contain considerably more of the stuff, going by the concentrations of anacardic acid that chemists have found in the cashew apple. [Food Chem Toxicol. 2006 Feb;44(2):188-97.]
Molecular researchers have been performing experiments with anacardic acid for a few years and have reported encouraging results. They discovered for example that anacardic acid protects the lungs of lab animals against the harmful particles in diesel exhaust fumes [Evid Based Complement Alternat Med. 2013;2013:549879.], and kills prostate cancer cells in test tubes. [Chin J Cancer Res. 2012 Dec;24(4):275-83.]
In the study that this post refers to, the researchers also did experiments with cancer cells. With breast cancer cells to be precise. The MCF-7 cell line is sensitive to estradiol; the MDA-MB-231 line is not.
The figure below shows that anacardic acid boosted the number of mono- and oligonucleosomes in the estradiol sensitive cells. In plain English: the genetic material in the oestrogen-sensitive cancer cells was destroyed when exposed to anacardic acid. The cells died.
The researchers discovered that anacardic acid didn’t force estradiol out of its socket in the receptor protein. Nor did anacardic acid speed up the breakdown of the estradiol receptor by the cell.
What the substance did do is shown in the figure below. The bar chart shows you how many signals the estradiol receptor passed on to the cell’s DNA.
E2 = estradiol; AnAc = anacardic acid.
As you can see, anacardic acid got in the way of estradiol, once it had attached itself to its receptor, stimulating the DNA.
The researchers do not venture an opinion on the extent to which you might be able to deactivate estradiol by including cashew nuts in your diet. The effect of 30 g cashew nuts eaten daily might just be very, very small, we fear. But who knows, maybe the effect would be strengthened if combined with other nutritional factors that have approximately the same effect, but work in a slightly different way.
Ginkgo might be such a factor. Like anacardic acid, ginkgo inhibits the functioning of the estradiol receptor. [J Steroid Biochem Mol Biol. 2006 Aug;100(4-5):167-76.] Or kelp. Or quercetin.
Anacardic acid inhibits estrogen receptor alpha-DNA binding and reduces target gene transcription and breast cancer cell proliferation.
Schultz DJ, Wickramasinghe NS, Ivanova MM, Isaacs SM, Dougherty SM, Imbert-Fernandez Y, Cunningham AR, Chen C, Klinge CM.
Abstract
Anacardic acid (AnAc; 2-hydroxy-6-alkylbenzoic acid) is a dietary and medicinal phytochemical with established anticancer activity in cell and animal models. The mechanisms by which AnAc inhibits cancer cell proliferation remain undefined. AnAc 24:1(omega5) was purified from geranium (Pelargonium x hortorum) and shown to inhibit the proliferation of estrogen receptor alpha (ERalpha)-positive MCF-7 and endocrine-resistant LCC9 and LY2 breast cancer cells with greater efficacy than ERalpha-negative primary human breast epithelial cells, MCF-10A normal breast epithelial cells, and MDA-MB-231 basal-like breast cancer cells. AnAc 24:1(omega5) inhibited cell cycle progression and induced apoptosis in a cell-specific manner. AnAc 24:1(omega5) inhibited estradiol (E(2))-induced estrogen response element (ERE) reporter activity and transcription of the endogenous E(2) target genes pS2, cyclin D1, and cathepsin D in MCF-7 cells. AnAc 24:1(omega5) did not compete with E(2) for ERalpha or ERbeta binding, nor did AnAc 24:1(omega5) reduce ERalpha or ERbeta steady-state protein levels in MCF-7 cells; rather, AnAc 24:1(omega5) inhibited ER-ERE binding in vitro. Virtual screening with the molecular docking software Surflex evaluated AnAc 24:1(omega5) interaction with ERalpha ligand binding (LBD) and DNA binding (DBD) domains in conjunction with experimental validation. Molecular modeling revealed AnAc 24:1(omega5) interaction with the ERalpha DBD but not the LBD. Chromatin immunoprecipitation experiments revealed that AnAc 24:1(omega5) inhibited E(2)-ERalpha interaction with the endogenous pS2 gene promoter region containing an ERE. These data indicate that AnAc 24:1(omega5) inhibits cell proliferation, cell cycle progression, and apoptosis in an ER-dependent manner by reducing ER-DNA interaction and inhibiting ER-mediated transcriptional responses.
PMID: 20197399 [PubMed – indexed for MEDLINE] PMCID: PMC2837512
