Laboratory of Synthesis of Molecules with Biological Interest, University of Frères Mentouri Constantine 1, Constantine, Algeria.
Phytochemistry. 2021 Dec;192:112950. doi: 10.1016/j.phytochem.2021.112950. Epub 2021 Sep 13.
Carnosic acid (CA), a phenolic diterpene and abietane-type compound, is a potent natural antioxidant with medical benefits. The present paper elucidates, for the first time, the kinetics and the exact mechanism of the peroxyl radical scavenging activity of CA in the gas phase and under physiological conditions. According to the obtained results, the reaction of CA with HOO is significantly faster in aqueous solution than in the gas phase and nonpolar environments. The abstraction of the hydrogen atom from 2-OH is the decisive mechanism in the gas phase and nonpolar media, while both hydrogen abstraction (15%) and electron transfer (85%) mechanisms can take place in aqueous solution. The overall rate coefficient in water (4.73 × 10 M s) is about 36 times higher than that of the reference antioxidant Trolox (1.30 × 10 M s), suggesting that CA is a potent scavenger of peroxyl radicals in polar media.
迷迭香酸（CA）是一种酚类二萜和松香烷型化合物，具有医疗益处，是一种有效的天然抗氧化剂。本文首次阐明了 CA 在气相中和生理条件下清除过氧自由基活性的动力学和确切机制。根据所得结果，CA 与 HOO 的反应在水溶液中明显快于气相中和非极性环境。从 2-OH 中提取氢原子是气相和非极性介质中的决定性机制，而在水溶液中可以发生氢原子提取（15%）和电子转移（85%）机制。在水中的总速率系数（4.73×10 M s）约比参考抗氧化剂 Trolox（1.30×10 M s）高 36 倍，这表明 CA 是极性介质中过氧自由基的有效清除剂。
