Tag Archives: oxygen species

Grapes may protect us from UV rays

1 Reply

A study by researchers from the University of Barcelona and the CSIC (Spanish National Research Council) has indicated that some compounds found in grapes help to protect skin cells from the sun’s ultraviolet radiation.

Ultraviolet (UV) rays emitted by the sun are the leading environmental cause of skin complaints, causing skin cancer, sunburn and solar erythema, as well as premature ageing of the dermis and epidermis. Now, a Spanish study has proven that some substances in grapes can reduce the amount of cell damage caused in skin exposed to this radiation.

UV rays act on the skin by activating ‘reactive oxygen species’ (ROS). These compounds in turn oxidise macromolecules such as lipids and DNA, stimulating certain reactions and enzymes (JNK and p38MAPK) that cause cell death.

Grapes

Grapes

A group of scientists from the University of Barcelona and the CSIC have shown that some polyphenolic substances extracted from grapes (flavonoids) can reduce the formation of ROSs in human epidermis cells that have been exposed to long-wave (UVA) and medium-wave (UVB) ultraviolet radiation.

“These polyphenolic fractions inhibit the generation of the ROSs and, as a result, the subsequent activation of the JNK and p38 enzymes, meaning they have a protective effect against ultraviolet radiation emitted by the sun,” Marta Cascante, a biochemist at the University of Barcelona (Spain) and director of the research project, tells SINC.


The researchers found that the higher the degree of the flavonoids’ polymerisation and formation of compounds containing gallic acid, the greater their photoprotective capacity.

The study has been published in the Journal of Agricultural and Food Chemistry.

Excess copper and iron link to Alzheimer’s

1 Reply

The exact causes of neuro-degenerative disorders like Alzheimer’s and Parkinson’s disease are unknown, but scientists say excess of copper and iron in the human brain may be one of the influencing factors.

Another is DNA damage by reactive oxygen species, highly destructive molecules usually formed as a byproduct of cellular respiration.

Researchers from the University of Texas Medical Branch at Galveston have discovered how these two pieces of the neuro-degenerative disease puzzle fit together, the Journal of Alzheimer’s Disease reports.

“Reactive oxygen species cause the majority of the brain cell DNA damage that we see in Alzheimer’s and Parkinson’s disease, as well as most other neuro-degenerative disorders,” said post-doctoral fellow Muralidhar Hegde, who led the study.

Alzheimer's disease

Alzheimer's disease

Alzheimer’s sufferers may repeat statements and questions over and over, forget chats, appointments or events, routinely misplace possessions, often putting them in illogical locations. Eventually they forget the names of family members and everyday objects.

Humans ordinarily have small amounts of iron and copper in their bodies – in fact, the elements are essential to health, according to a Texas statement.

But some people’s tissues contain much larger quantities of iron or copper, which overwhelm the proteins that normally bind the metals and sequester them for safe storage.


The result — so-called ‘free’ iron or copper ions circulating in the blood are able to initiate chemical reactions that produce reactive oxygen species.

A high level of copper or iron, they say, can function as a “double whammy” in the brain by both helping generate a large numbers of the DNA-attacking reactive oxygen species and interfering with the machinery of DNA repair that prevents the deleterious consequences of genome damage.