Research Interests: Chemistry, Photochemistry, Photosynthesis, Cyanobacteria, Carotenoids, and 15 moreMedicine, Biological Sciences, Crystal structure, Sequence alignment, Animals, CHEMICAL SCIENCES, Carotenoid, Singlet Oxygen, Amino Acid Sequence, Photoprotection, Binding Site, Light Harvesting, Molecular Structure, Dimerization, and Molecular Sequence Data
Research Interests: Chemistry, Photochemistry, Fluorescence, DNA damage, Medicine, and 14 moreBiological Sciences, DNA, Physical sciences, Intercalation Chemistry, CHEMICAL SCIENCES, Agarose Gel Electrophoresis, Photochemistry and Photobiology, Absorbance, Quinolines, Acridine Orange, "Intercalating Agents", Ethidium bromide, Ultraviolet Rays, and Agarose
Carotenoids are present in many biological systems, often decreasing the formation of products of oxidative damage to biological molecules. In the macula their concentration is so high that it has been believed that the yellow color... more
Carotenoids are present in many biological systems, often decreasing the formation of products of oxidative damage to biological molecules. In the macula their concentration is so high that it has been believed that the yellow color filters out damaging blue light. Recent reports that dietary lutein reduces the risk of cataract in the eye lens suggested that the antioxidant action of carotenoids, which has been inferred from decreased oxidative damage, warranted further direct investigation. Superoxide and hydroxyl radical scavenging by lutein and zeaxanthin (retinal carotenoids), beta-carotene, lycopene, lutein esters (from marigolds), and a commercial mixture of soy carotenoids were compared to scavenging by ascorbate and ascorbyl palmitate. Radical scavenging was measured with a chemiluminescent assay (luminol) and by electron spin resonance, ESR. Inhibitory concentrations, IC(50), were determined with the luminescent assay. All of the carotenoids scavenged both superoxide (in ES...
Research Interests:
Research Interests: Engineering, Chemistry, Physical Chemistry, Water, Photochemistry, and 14 moreMagnetic Resonance Spectroscopy, Medicine, Circular Dichroism, Chlorophyll, Physical sciences, Luminescence, The, CHEMICAL SCIENCES, Oxygen, Time Factors, Solutions, Sensitivity and Specificity, Aqueous Solution, and Physicochemical Properties
Research Interests:
We report the quantum yields for singlet oxygen production by a series of porphyrazines (pz) of the form M[pz(An;B4-n)] (Scheme 1), where the peripheral substituent A is [S-R]2 with R = (CH2CH2O)3H, B is a fused... more
We report the quantum yields for singlet oxygen production by a series of porphyrazines (pz) of the form M[pz(An;B4-n)] (Scheme 1), where the peripheral substituent A is [S-R]2 with R = (CH2CH2O)3H, B is a fused alpha,alpha'-dialkoxybenzo group and M = 2H, Mg or Zn. These compounds show intense near-IR absorbance/emission (longest wavelength emission, approximately 830 nm). Their solubilities vary with R, whereas their optical properties do not. We show that singlet oxygen sensitization by these luminescent compounds can be "tuned" from essentially off to on by varying n and selection among M = 2H, Mg or Zn. The quantum yields vary ca 60-fold within the set of compounds studied, from phidelta = 0.007 for compound 3 to phidelta = approximately 0.4 for compound 11.