Simultaneous determination of α-lipoic acid and its reduced form by high-performance liquid chromatography with fluorescence detection

Selective and sensitive determination of lipoyllysine (protein-bound α-lipoic acid) in biological specimens by high-performance liquid chromatography with fluorescence detection

“…The optimization of the reductive labeling reaction of LLys was next studied. TECP is reported as an effective reducing agent from disulfide (-S-S-) to thiol (-SH) [14,31,32]. In the case of the reduction of LLys, a disulfide in the structure was selectively converted to two thiol groups by TCEP.…”

Simultaneous determination of lipoic acid (LA) and dihydrolipoic acid (DHLA) in human plasma using high-performance liquid chromatography coupled with electrochemical detection

“…It is a cofactor for mitochondrial alphaketo-acid dehydrogenase, crucial prosthetic group of various cellular enzymes, chelating agent for heavy metals poisoning, and a scavenger of various free radicals such as hydroxyl radicals, hypochlorous acid, peroxyradicals, superoxide radicals, and singlet oxygen [1,2,5,[7][8][9][10][11]. Lipoic acid restores others antioxidants of the body antioxidant network including glutathione, coenzyme Q10 and vitamins C and E to their reduced state and maintains body antioxidant capacity [4,12,13]. It is an effective therapeutic agent in so many diseases including diabetes, mitochondrial cytopathies, cardiovascular diseases, hepatitis, cataract, radiation damage, HIV infections, heavy metal poisoning, neurodegenerative disorders, and neurovascular abnormalities associated with diabetic neuropathy [3,14].…”

Simultaneous Determination of the Endogenous Free α-Lipoic Acid and Dihydrolipoic Acid in Human Plasma and Erythrocytes by RP-HPLC with Electrochemical Detection

“…Similarly, very few methods [17][18][19][20][21][22][23] are available for simultaneous determination of the total a-LA and its reduced form, DHLA, in biological samples after oral administration. But to our knowledge, no single method has been reported so far that is capable of determining the endogenous free a-LA and DHLA simultaneously.…”

“…Moreover, the problem with these methods is that they do not differentiate clearly between total and free LA as drastic hydrolysis conditions have been used for their extraction that are able to extract covalently bound LA but degrade the free LA, and these available methods also are not simple and reliable because these molecules do not possess strong chromophores to permit the use of conventional ultraviolet-visible (UV-vis) or florescence (FL) detectors. To overcome these problems, few derivatization reagents have been used to determine them by FL detection [18,19]. However, such derivatization is laborious and expensive.…”