TY - JOUR
T1 - A quantum chemical study on the free radical scavenging activity of tyrosol and hydroxytyrosol
AU - Galano, Annia
AU - Alvarez-Idaboy, Juan Raúl
AU - Francisco-Márquez, Misaela
AU - Medina, Manuel E.
N1 - Funding Information:
We gratefully acknowledge the Laboratorio de Visualización y Cómputo Paralelo at Universidad Autónoma Metropolitana-Iztapalapa and Dirección General de Cómputo y de Tecnologías de Información y Comunicación (DGCTIC) at Universidad Nacional Autónoma de México. M. E. M. thanks CONACYT for postdoctoral fellowship No. 48363. This work was partially supported by a grant from the DGAPA UNAM (PAPIIT-IN209812), and projects SEP-CONACyT 167491 and 167430.
PY - 2012/3
Y1 - 2012/3
N2 - The free radical scavenging activity of hydroxytyrosol (HTyr) and tyrosol (Tyr) has been studied in aqueous and lipid solutions, using the density functional theory. Four mechanisms of reaction have been considered: single electron transfer (SET), sequential electron proton transfer (SEPT), hydrogen transfer (HT), and radical adduct formation. It was found that while SET and SEPT do not contribute to the overall reactivity of HTyr and Tyr toward ·OOH and ·OCH3 radicals, they can be important for their reactions with ·OH, ·OCCl3, and ·OOCCl3. The ·OOH-scavenging activity of HTyr and Tyr was found to take place exclusively by HT, and it is also predicted to be the main mechanism for their reactions with ·OCH3. HT is proposed as the main mechanism for the scavenging activity of HTyr and Tyr when reacting with other ·OR and ·OOR radicals, provided that R is an alkyl or an alkenyl group. The major products of reaction are predicted to be the phenoxyl radicals. In addition, Tyr was found to be less efficient than HTyr as free radical scavenger. Moreover, while HTyr is predicted to be a good peroxyl scavenger, Tyr is predicted to be only moderately for that purpose.
AB - The free radical scavenging activity of hydroxytyrosol (HTyr) and tyrosol (Tyr) has been studied in aqueous and lipid solutions, using the density functional theory. Four mechanisms of reaction have been considered: single electron transfer (SET), sequential electron proton transfer (SEPT), hydrogen transfer (HT), and radical adduct formation. It was found that while SET and SEPT do not contribute to the overall reactivity of HTyr and Tyr toward ·OOH and ·OCH3 radicals, they can be important for their reactions with ·OH, ·OCCl3, and ·OOCCl3. The ·OOH-scavenging activity of HTyr and Tyr was found to take place exclusively by HT, and it is also predicted to be the main mechanism for their reactions with ·OCH3. HT is proposed as the main mechanism for the scavenging activity of HTyr and Tyr when reacting with other ·OR and ·OOR radicals, provided that R is an alkyl or an alkenyl group. The major products of reaction are predicted to be the phenoxyl radicals. In addition, Tyr was found to be less efficient than HTyr as free radical scavenger. Moreover, while HTyr is predicted to be a good peroxyl scavenger, Tyr is predicted to be only moderately for that purpose.
KW - Branching ratios
KW - Mechanism of reaction
KW - Rate constant
KW - UV-vis spectra
UR - http://www.scopus.com/inward/record.url?scp=84857491229&partnerID=8YFLogxK
U2 - 10.1007/s00214-012-1173-3
DO - 10.1007/s00214-012-1173-3
M3 - Artículo
SN - 1432-881X
VL - 131
SP - 1
EP - 12
JO - Theoretical Chemistry Accounts
JF - Theoretical Chemistry Accounts
IS - 3
M1 - 1173
ER -