Spring 2012 Biomedical Seminar Series
Friday, April , 2012
Studies have linked high-flavanoid rich diets with improved cardiovascular health. Cocoa contains a large amount of flavonoids particularly the subtype known as flavanols. Epicatechin, a flavanol in chocolate has been shown to have cardioprotective capabilities. One study looked at the effects of epicatechin in the setting of myocardial ischemia-reperfusion. In this study, epicatechin was administered to rats prior to an ischemia-reperfusion injury (IR). Results showed that epicatechin decreased infarct size and preserved the heartÂs structure and function. Here, we wish to study the mechanism by which epicatechin exerts cardioprotective effects. The extent to which cardiac tissue survive IR injury depends on the viability of the mitochondria. Thus, we hypothesize that epicatechin protects the heart by preserving mitochondrial structure and function during IR. The effectiveness of epicatechin on preserving the mitochondria was measured using a temperature controlled oxygen-electrode, a calcium fluorescent probe and an electron microscope.
Photooxidation of the antioxidant trans-resveratrol Angela Guerrero, MARC U*STAR Scholar Abstract: Resveratrol has received much attention as a polyphenolic antioxidant capable of removing free radicals. However, its reactivity with other reactive oxygen species such as singlet dioxygen, has been unexplored. We present an investigation of the chemistry of trans-resveratrol with singlet oxygen, an electrophilic reactive oxygen species. We found two reactivity channels, namely [2+2] addition followed by cleavage of the resveratrol trans double bond leading to the corresponding aldehydes, and [4+2] addition leading to endoperoxide formation. Trans-resveratrol removes singlet oxygen efficiently with a rate constant of 1.5 x 106 M-1sec-1. The fraction of the total singlet oxygen removal rate that leads to products was determined by determined competition experiments with known singlet oxygen traps. The implications of this kinetic data will be discussed.