The ability of cells to control the expression of genes is important for cell survival. Nutrients can alter the gene expression that controls levels of bioactive proteins. Herbs alter gene activity in various ways. Gene transcription, the most important, is the initial step in gene expression.
The pregnane X receptor (PXR receptor) is the target of many herbs. It is a cell’s chemical receptor that binds steroids, toxic bile acids, environmental toxins and prescription drugs. The PXR receptor is activated by hyperforin from St. John’s Wort (SJW), an anti-depressant, and Guggulsterone, an Ayurvedic medication, which alters cholesterol and bile acid metabolism.
Hyperforin is a component of St. John’s Wort that can alter gene expression, resulting in herb-drug interactions. Hyperforin activates gene transcription in the same chemical pathway by which 60% of prescription drugs are metabolized. This increases the breakdown of drugs, causing low blood levels of some drugs.
Soy and red clover, containing isoflavones, were the first foods found to be “endocrine disruptors”, which block normal estrogen activity. For example, sheep that eat clover may have abnormal estrous cycles. Isoflavones are considered to be phytoestrogens, increasing estrogen activity and are important for bone metabolism, cancer and reproduction. The specific gene expression produced depends on the concentration of the isoflavone. Isoflavones bind receptors with less strength than does estradiol.
Resveratrol, from grape peels, grape seeds and wine, is a nuclear receptor activator as well as an anti-oxidant. These two effects may produce the beneficial effects of resveratrol in protecting the brain after a stroke.
The proteolytic (breaking down of protein) activity of the proteosome may alter transcription by altering the half-life and the environment of transcription factors and co-factors. The proteosome is a barrel-shaped structure of many layers of polypeptides with various enzyme activities. The proteosome has a pore by which chemicals enter. Epigallocatechin gallate (EGCG) in green tea inhibits the protein destruction by the proteosome. This alters transcription factor stability in the nucleus of a cell. Since cancers depend on proteosome activity, the amount of EGCG found in the blood of green tea drinkers is enough to stop growth of tumor cells.
Nutritional chemicals are activators of sirtuins, which increase life spans of certain animals. Sirtuins are deacetylation enzymes. Sirtuins are one way that foods can alter gene activity and sirtuin activating chemicals include the stilbenes resveratrol, butein and piceatannol and the flavones luteolin and quercitin. Resveratrol increases sirtuin activity in yeast (Saccharomyces cerevisiae) and increases the cell life span by 70%.
CONCLUSION: Three ways that biologics alter gene function and cell function are as follows: (1) Activation of nuclear receptors. (2) Inhibition of the proteasome. (3) Activation of sirtuins. Various nutritional agents are listed that alter gene function in beneficial ways, which improve cellular health.
NOTE: Gene transcription is the process of transcribing the information in DNA to RNA so that proteins for the body can be made from the appropriate amino acids. Gene expression refers to the production of a specific protein from a specific section of DNA.
Receptors are specific proteins on cell walls, in cytoplasm or on a cell nucleus that can bind a specific chemical. The Pregnane X receptor of the nucleus is able to sense foreign chemicals and initiate the process of detoxification.
Peroxisomes are tiny structures in cells for fatty acid metabolism and to rid the cell of harmful peroxides.
Read about the chemicals from food, polyphenols, which can change the genetics of cancer.
To read the author’s abstract of the article click on the link to the author’s title of the article above.
PMID: 16011469.
Summary #206.
