Compounds found in turmeric — a condiment commonly used in Indian cuisine — can help prevent and treat stomach cancer, scientists claim.
Researchers Federal University of Sao Paulo (UNIFESP) and the Federal University of Para (UFPA) in Brazil identified possible therapeutic effects of curcumin — the yellow powder derived from the roots of the turmeric plant.
“We undertook a vast review of the scientific literature on all nutrients and bioactive compounds with the potential to prevent or treat stomach cancer and found that curcumin is one of them,” Danielle Queiroz Calcagno, a professor at UFPA. According to Calcagno, compounds such as cholecalciferol (a form of vitamin D), resveratrol (a polyphenol) and quercetin can prevent or combat stomach cancer because they are natural regulators of histone activity.
Histones are proteins in cell nuclei that organise the DNA double helix into structural units called nucleosomes, according to a study published in the journal Epigenomics.
Each nucleosome is made of DNA coiled like a spool around eight histone proteins (a histone octamer) to compact the DNA so that it fits in the cell, where it is packaged into chromatin.
Posttranslational chemical modification of the amino acid chain in these proteins, such as acetylation (introduction of an acetyl group) or methylation (addition of a methyl group), can affect chromatin compaction and hence gene expression.
“If the histones are acetylated, for e
xample, the chromatin will be less condensed, and a gene in a region of the DNA segment inside it will be available to be expressed. In contrast, if the histones aren’t acetylated, the chromatin will be more condensed, and the gene won’t be expressed,” Calgano said.
Researchers studied histone acetylation patterns in stomach cell samples from healthy individuals and patients diagnosed with stomach cancer.
They found that the cells from stomach cancer patients displayed alterations in the pattern of expression of histone acetyltransferases (HATs) and histone deacetylases (HDACs). These alterations are epigenetic and affect the structure and integrity of the genome in many tumors, including stomach cancer.
Recent research has also shown that nutrients and bioactive compounds can regulate the activity of HATs and HDACs, the scientists at UNIFESP and UFPA set out to identify any that might influence histone acetylation and hence help prevent stomach cancer or even treat the disease.
In addition to curcumin, other compounds found to play a key role in modulating histone activity were cholecalciferol, resveratrol (present mainly in grape seeds and red wine), quercetin (abundant in apples, broccoli and onions), garcinol (isolated from the bark of the kokum tree, Garcinia indica), and sodium butyrate (produced by gut bacteria via fermentation of dietary fiber).
“These compounds can favor the activation or repression of genes involved in the development of stomach cancer by promoting or inhibiting histone acetylation,” Calcagno said.