Research Interests
Free radicals, especially oxygen centered ones, cause damage to natural systems such as lipids in human phospholipid membranes and the effects are implicated in various degenerative diseases such as cancer and heart disease. Natural antioxidants, such as vitamin E, will trap these radicals, and we have discovered synthetic phenolic antioxidants more active than the natural ones.
Recent research has shown that certain natural compounds such as DNA bases, and urocanic acid initiate photo-oxidation of lipids and this has relevance to the initiation of skin cancer. This research is being applied to natural fluids such as human blood plasma where a reactive form of oxygen, singlet oxygen, can be the damaging species.
A variety of natural substances such as flavonoids from many plants are used by humans as “antioxidants” to trap and deactivate damaging oxygen-centred radicals. The bile pigments, bilirubin and biliverdin, are present in human blood from natural catabolism of haemoglobin. We are currently studying the antioxidant activities of such compounds and of synthetic model compounds by quantitative kinetic methods to evaluate their antioxidant efficacy.
“Bilirubin as an Antioxidant in Micelles and Lipid Bilayers: Its Contribution to the Total Antioxidant Capacity of Human Blood Plasma”. Patricia D. MacLean, Emily C. Drake, and L. Ross C. Barclay. Free Radical Biol. & Med. 43, 600-609 (2007).
"Radically Different Antioxidants: Thermally Generated Carbon-Centered Radicals as Chain-Breaking Antioxidants" Mathieu Frenette, Patricia D. MacLean, L. Ross C. Barclay, and Juan C. Scaiano. J. Am. Chem. Soc., 128, 16432-16433 (2006).
"Polypyrroles as Antioxidants: Kinetic Studies on Reactions of Bilirubin and Biliverdin Dimethyl Esters and Synthetic Model Compounds with Peroxyl Radicals in Solution. Chemical Calculations on Selected Typical Structures" Leonid L. Chepelev, Cory S. Beshara, Patricia D. MacLean, Gillian L. Hatfield, Amy A. Rand, Alison Thompson, James S. Wright, and L. Ross C. Barclay. J. Org. Chem., 71, 22-30 (2006).
"The
L-Type Calcium Channel Blockers, Hantzsch 1,4-Dihydropyridines, Are
Not Peroxyl Radical- Trapping, Chain-Breaking Antioxidants" Peter
Mulder, Grzegorz Litwinienko, Shuqiong Lin, Patricia
D. Maclean, L. Ross C. Barclay, and K. U. Ingold. Chem. Res. Toxicol.,
19, 79-85 (2006).