Baicalin Inhibits the Fenton Reaction by Enhancing Electron Transfer from Fe²⁺ to Dissolved Oxygen

Abstract

Sho-saiko-to is an herbal medicine that is known to have diverse pharmacological activities and has been used for the treatment of various infectious diseases. Here, we examined the effects of baicalin, a compound isolated from Sho-saiko-to, and the effects of the iron chelator quinolinic acid on the Fenton reaction. The control reaction mixture contained 0.1 M 5,5-dimethyl-1-pyrroline N-oxide (DMPO), 0.2 mM H 2 O 2, 0.2 mM FeSO 4( NH 4)2 SO 4, and 40 mM sodium phosphate buffer (pH 7.4). Upon the addition of 0.6 mM baicalin or quinolinic acid to the control reaction mixture, the ESR peak heights of DMPO/OH radical adducts were measured as 32% ± 1% (baicalin) and 166% ± 27% (quinolinic acid) of that of the control mixture. In order to clarify why baicalin and quinolinic acid exerted opposite effects on the formation of hydroxyl radicals, we measured oxygen consumption in the presence of either compound. Upon the addition of 0.6 mM baicalin (or quinolinic acid) to the control reaction mixture without DMPO and H 2 O 2, the relative oxygen consumption rates were found to be 449% ± 40% (baicalin) and 18% ± 9% (quinolinic acid) of that of the control mixture without DMPO and H 2 O 2, indicating that baicalin facilitated the transfer of electrons from Fe (2+) to dissolved oxygen. Thus, the great majority of Fe (2+) turned into Fe (3+), and the formation of hydroxyl radicals was subsequently inhibited in this reaction.

Role of catalytic iron and oxidative stress in nitrofen-induced congenital diaphragmatic hernia and its amelioration by Saireito (TJ-114)

“…Cinnamon in Goreisan and Baicalin in Sho-saikoto have also been reported to inhibit the Fenton reaction catalysed by copper or iron. ( 40 , 41 ) These may be the chemicals responsible for the effectiveness of Saireito. In ESR studies, Goreisan played a major role.…”

Role of Flavonoids in the Treatment of Iron Overload

“…The antioxidation and iron chelation properties of baicalin may be related to the following reasons: baicalin promotes the transfer of electrons from Fe 2+ to dissolved oxygen, so that most of the Fe 2+ is transformed into Fe 3+ , subsequently inhibiting the formation of hydroxyl radicals ( Nishizaki and Iwahashi, 2015 ). In addition, baicalin positively regulates the expression of divalent metal transporter 1 and negatively regulates the expression of ferroportin 1, which reduces the accumulation of iron in different brain regions ( Xiong et al, 2012 ; Guo et al, 2014 ).…”

Huaier suppresses pancreatic cancer progression via activating cell autophagy induced ferroptosis

“…According to the most recent study, the excessive production of ROS is important to induce ferroptosis (17). Excessive levels of iron induce oxidative stress via Fenton and redox reactions, resulting in increased production of ROS (35). Therefore, we examined the effect of Huaier on ROS production and found that Huaier upregulated ROS levels in a concentration-dependent manner.…”