Photochemical transformation of lipoic acid-based ligands: probing the effects of solvent, ligand structure, oxygen and pH

2018 ◽  
Vol 20 (6) ◽  
pp. 3895-3902 ◽  
Author(s):  
Dinesh Mishra ◽  
Sisi Wang ◽  
Serge Michel ◽  
Goutam Palui ◽  
Naiqian Zhan ◽  
...  
Keyword(s):  
Optical Absorption ◽  
Uv Irradiation ◽  
Lipoic Acid ◽  
Photochemical Transformation ◽  
Ligand Structure

We have combined optical absorption with the Ellman's test to identify the parameters that affect the transformation of the 5-membered dithiolanes to thiols in lipoic acid (LA) and its derivatives during UV-irradiation.

Photochromic Behavior of Spiropyrans: The Effect of Substituent

2014 ◽  
Vol 925 ◽  
pp. 323-328 ◽  
Author(s):  
Najiah Nadir ◽  
Zaharah Wahid ◽  
Mat Tamizi Zainuddin ◽  
Noor Zalikha Mohamed Islam
Keyword(s):  
Optical Absorption ◽  
Absorption Spectra ◽  
Uv Irradiation ◽  
Rate Constant ◽  
Half Life ◽  
Diphenyl Ether ◽  
Life Time ◽  
Optical Absorption Spectra ◽  
Photochromic Behavior ◽  
Photochromic Effect

Spiropyrans are among the most promising organic photochromic dyes. However, spiropyrans are very sensitive dyes and there are many independent factors that can affect the performance of these dyes. The effect of substituent on the optical absorption spectra, fading kinetic, and also the dye stability of spiropyrans in diphenyl ether by UV irradiation has been investigated. The 6-nitro BIPS displayed greater absorbance intensity of 0.740% at 600nm compared to 8-ethoxy-6-nitro BIPS of 0.651% at 620nm. Furthermore, 6-nitro BIPS is less stable as it has higher rate constant of 0.1003s-1and thus lower half-life time (50% decay of the photochromic effect) of 6.9s, in contrast to 8-ethoxy-6-nitro BIPS of 0.0594s-1and 11.7s respectively.

Changes in the Morphology and Optical Absorption of Colloidal Silver Reduced with Formic Acid in the Polymer Matrix under UV Irradiation

1997 ◽  
Vol 101 (41) ◽  
pp. 8129-8132 ◽  
Author(s):  
Andrey L. Rogach ◽  
Gvidona P. Shevchenko ◽  
Zinaida M. Afanas'ev ◽  
Vadim V. Sviridov
Keyword(s):  
Optical Absorption ◽  
Formic Acid ◽  
Uv Irradiation ◽  
Polymer Matrix ◽  
Colloidal Silver

A photochemical transformation of cyclic peptides leading to formation of selenolanthionine bridges

2020 ◽  
Vol 44 (27) ◽  
pp. 11433-11436
Author(s):  
Mateusz Waliczek ◽  
Özge Pehlivan ◽  
Piotr Stefanowicz
Keyword(s):  
Uv Irradiation ◽  
Good Yield ◽  
Cyclic Peptides ◽  
Photochemical Transformation ◽  
Selenium Atom

Peptides with diselenide bridge under UV irradiation eliminate one selenium atom forming selenoether bond with good yield.

scholarly journals Effect of UV Irradiation on Interactions ofα-Lipoic Acid with Free Radicals

2013 ◽  
Vol 2013 ◽  
pp. 1-5
Author(s):  
Paweł Ramos ◽  
Piotr Pepliński ◽  
Barbara Pilawa
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Free Radicals ◽  
Uv Irradiation ◽  
Lipoic Acid ◽  
Electron Paramagnetic Resonance Spectroscopy ◽  
Antioxidant Properties ◽  
Resonance Spectroscopy ◽  
Paramagnetic Resonance ◽  
Pharmacological Substance ◽  
Electron Paramagnetic

Changes of antioxidant properties ofα-lipoic acid (LA) after UV irradiation were studied. LA is the typical drug used in diabetic neuropathy. Quenching of free radicals is an important factor of therapy by using this substance.α-Lipoic acid is exposed to UV irradiation during the storage. The aim of our studies was to examine the effect of UV irradiation on the interactions of LA with free radicals. Theα-lipoic acid was irradiated by UVA 315–400 nm light during 10 to 110 minutes by intervals of 10 minutes. The electron paramagnetic resonance spectroscopy was used as the experimental technique. The antioxidant properties of LA were spectroscopically confirmed. The strong effect of UV irradiation on interactions ofα-lipoic acid with free radicals was observed. It was pointed out that interactions of LA with free radicals decrease after its exposition on UV. The interactions of LA with free radicals were higher after the sample irradiation during 10 minutes than for the samples irradiated longer (20–110 minutes). The results are important for problems connected with photomedicine; they pointed out thatα-lipoic acid should not be stored on UV exposition. Application of electron paramagnetic resonance spectroscopy to characterize interactions of pharmacological substance with free radicals was confirmed.

Effect of the alpha-lipoic acid on apoptosis in HIT-T15 cells induced by high glucose

2010 ◽  
Vol 34 (8) ◽  
pp. S14-S14
Author(s):  
Yi Yang ◽  
Wei‑Ping Wang ◽  
Yi‑Nan Liu ◽  
Ting Guo ◽  
Ping Chen ◽  
...  
Keyword(s):  
Lipoic Acid ◽  
High Glucose ◽  
Alpha Lipoic Acid
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