Photochemical interaction of cyanocobalamin and hydroxocobalamin with cysteine

Qadeer, Kiran; Arsalan, Adeel; Ahmad, Iqbal; Fatima, Kaneez; Anwar, Zubair; Ahmed, Sofia; Khattak, Saif ur Rehman; Mahmud, Shaukat

doi:10.1016/j.molstruc.2020.129441

Cited by 2 publications

(4 citation statements)

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“…Different vitamin B 12 forms undergo different photodegradation mechanisms. Upon light exposure, the cyanide ligand in CNCbl is replaced with an OH − group to form OHCbl (in neutral or alkaline solutions) or with water to form H 2 OCbl + (in acidic solutions) [122,163,164]. MeCbl and AdoCbl undergo photoreduction to vitamin B 12 r, which is quickly oxidized to OHCbl or H 2 OCbl + , depending on the pH [159,165,166].…”

Section: Ph Of the Solutionmentioning

confidence: 99%

“…MeCbl and AdoCbl undergo photoreduction to vitamin B 12 r, which is quickly oxidized to OHCbl or H 2 OCbl + , depending on the pH [159,165,166]. Under the influence of light, OHCbl is irreversibly degraded to unknown corrin ring oxidation products [122,163].…”

Section: Ph Of the Solutionmentioning

confidence: 99%

“…Therefore, the instability of vitamin B 12 in the presence of ascorbic acid, which was first discussed by Gakenheimer and Feller in 1949 [129], is the most known vitamin B 12 incompatibility. Some reducing agents with the thiol functional group, including cysteine, homocysteine, N-acetyl-cysteine, cysteamine, pentafluorophenylthiolate, glutathione, and dithiothreitol form molecular complexes with vitamin B 12 [163,[169][170][171][172][173][174]. However, more in general, reducing agents, such as ascorbic acid, reducing sugars, thiols, formaldehyde, mercaptide ion, NaHSO 3 or FeSO 4 , typically cause a reduction in the cobalt ion from Co(III) to Co(II), yielding vitamin B 12 r by the cleavage of the β-ligand [122,163,[175][176][177].…”

Section: Presence Of Oxidizing and Reducing Agentsmentioning

confidence: 99%

“…Some reducing agents with the thiol functional group, including cysteine, homocysteine, N-acetyl-cysteine, cysteamine, pentafluorophenylthiolate, glutathione, and dithiothreitol form molecular complexes with vitamin B 12 [163,[169][170][171][172][173][174]. However, more in general, reducing agents, such as ascorbic acid, reducing sugars, thiols, formaldehyde, mercaptide ion, NaHSO 3 or FeSO 4 , typically cause a reduction in the cobalt ion from Co(III) to Co(II), yielding vitamin B 12 r by the cleavage of the β-ligand [122,163,[175][176][177]. In the presence of air, the vitamin B 12 r thus formed is oxidized to OHCbl [122,130].…”

Section: Presence Of Oxidizing and Reducing Agentsmentioning

confidence: 99%

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Vitamin B12 in Foods, Food Supplements, and Medicines—A Review of Its Role and Properties with a Focus on Its Stability

et al. 2022

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Vitamin B12, also known as the anti-pernicious anemia factor, is an essential micronutrient totally dependent on dietary sources that is commonly integrated with food supplements. Four vitamin B12 forms—cyanocobalamin, hydroxocobalamin, 5′-deoxyadenosylcobalamin, and methylcobalamin—are currently used for supplementation and, here, we provide an overview of their biochemical role, bioavailability, and efficacy in different dosage forms. Since the effective quantity of vitamin B12 depends on the stability of the different forms, we further provide a review of their main reactivity and stability under exposure to various environmental factors (e.g., temperature, pH, light) and the presence of some typical interacting compounds (oxidants, reductants, and other water-soluble vitamins). Further, we explore how the manufacturing process and storage affect B12 stability in foods, food supplements, and medicines and provide a summary of the data published to date on the content-related quality of vitamin B12 products on the market. We also provide an overview of the approaches toward their stabilization, including minimization of the destabilizing factors, addition of proper stabilizers, or application of some (innovative) technological processes that could be implemented and contribute to the production of high-quality vitamin B12 products.

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