Organic Letters | Spotlight

Drinking to your health

Research shows that the benefits of wine, grapes are more complicated


Antioxidant is an enzyme or other organic substance that is capable of counteracting the damaging effects of oxidation in living organisms.

Singlet oxygen is a reactive oxygen species form when some light-absorbing molecules interact with oxygen molecules. It is the lowest excited state of the dioxygen molecule, and a highly reactive oxidant. The detection of singlet oxygen luminescence (in the near infrared) is possible using sensitive laser spectroscopy. For details: /

Free radical is an atom or molecule that bears an unpaired electron and is extremely reactive—capable of engaging in rapid chain reactions that damage or destroy other molecules and generate many more free radicals: in the body, the free radicals are scavenged by antioxidants, uric acid, and certain enzyme activities.

Reactive oxygen species (ROS) are highly reactive molecules or ions containing oxygen. ROS damage a variety of biomolecules, including DNA bases, some amino acids, as well as unsaturated fats and lipids. On the other hand, they contribute to the microbicidal activity of phagocytes, regulation of signal transduction and gene expression. Free radicals and superoxide are ROS, as is singlet oxygen.

Links to reference:

Organic Letters (vol. 13, no. 18, 2011):

National Institutes of Health:

Matthias Selke’s background:

MARC Program:

MORE Programs:

Department of Chemistry and Biochemistry at CSULA:

College of Natural and Social Sciences at CSULA: :

Picture of Professor Selke and research team. Pictured: (l-r) Angela Guerrero, Professor Matthias Selke and Dong Zhang in a chemistry lab, located in Wing B of the Wallis Annenberg Integrated Sciences Complex on the CSULA campus.

Antioxidants from wine grapes, red wine and grape juice have been known to provide health benefits, including cardio-protective, anti-aging and anti-tumor effects.

Now, a team of Cal State L.A. researchers reveals that the mysterious benefits of wine are more complicated. The study indicates that trans-resveratrol, a molecule found in grapes and red wine, can and does react with singlet oxygen and make other interesting biomolecules.

In fact, one of the major products is a molecule which, upon heating, is transformed into a completely different compound found in root bark of a certain tree (morus alba) used in traditional Chinese medicine.

“This compound is called Moracin M,” said CSULA’s Professor of Chemistry Matthias Selke. “This new chemistry is a very convenient way of making Moracin M in the laboratory. At the same time, we note that the chemistry of antioxidants goes beyond the simplistic assumption that all they do is remove free radicals.”

Selke and CSULA alumnus Jeff Celaje led the study, which was recently published by the American Chemical Society journal, Organic Letters. The study, funded by the National Institutes of Health, also concluded that resveratrol is much less efficient in removing singlet oxygen compared to other antioxidants, such as Vitamin E and beta-carotene. The results are available here:

Benefits of trans-resveratrol

Singlet oxygen sample in a glass tube. Sample of a dye that makes singlet oxygen in a glass cuvette.

There has been a huge amount of research into what the trans-resveratrol molecule actually does. The benefits are often attributed to resveratrol’s ability of removing so-called reactive oxygen species (ROS), which damage all kinds of biomolecules in living organisms.

According to Celaje, “Resveratrol is the substance in red wine that is responsible for the so-called ‘French paradox’ (the apparently contradictory observations that the French have a lower incidence of coronary heart disease despite having a diet that is higher in saturated fats).”

He added, “Resveratrol continues to be the focus of intense research because of its many health benefits.”

So-called ROS are often and somewhat incorrectly equated with free radicals resulting in some confusion.

“Actually, free radicals are one type of ROS,” said Selke, “but there are other reactive oxygen species as well. The ROS we looked at is singlet oxygen, generated from light-absorbing molecules, light and oxygen. It is well known that singlet oxygen destroys DNA and some amino acids.”

The research team

Co-authors on the paper with Selke and Celaje were CSULA chemistry and biochemistry major Angela Guerrero and post-doctoral researcher and lab manager Dong Zhang.

A CSULA faculty member since 1998, Selke is an expert in organic chemistry, bioorganic chemistry and the role of metals in biology. He was one of only nine scientists across the nation to receive the prestigious Henry Dreyfus Foundation Teacher-Scholar Award in 2004.

Picture of Jeff Celaje. Jeff Celaje

Celaje, who attributes Selke for his passion in chemistry, said, “My experiences at CSULA as a biochemistry student were very pleasant. The Chemistry and Biochemistry department—with the help of programs that fund students’ research, such as the Minority Opportunities in Research (MORE) programs—does a great job preparing students for graduate school. I am now pursuing a doctoral degree in organic chemistry at the University of Southern California.”

A participant in the University’s Minority Access to Research Careers (MARC) undergraduate research training program, Guerrero said, “I had a really great experience conducting research in Dr. Selke’s lab. I hope one day to contribute to bridging the gap between science and medicine as a physician scientist.”

Timothy Dong of UCLA, Ali Jabalameli of CSULA, and Errol Mathias of CSULA also provided valuable experimental assistance for the published research.