Iron is the most abundant transition metal in the brain, participating in essential and diverse brain activities, such as the synthesis of neurotransmitters, myelination, and mitochondrial function (
15). Excessive iron accumulation in neurons and glial cells is a serious pathogenetic mechanism in the formation of many neurodegenerative diseases such as AD, PD, and Huntington’s disease (HD) (
16). Iron overload has been reported by in vivo MRI in patients with AD (
17). Iron deposition plays a very active role in the formation of amyloid-β aggregation (
18). Alzheimer’s disease patients have an abnormally high increase in iron levels in neurons in the putamen, thalamus, red nucleus, hippocampus, and temporal cortex (
15). Iron accumulation in the globus pallidus and putamen, the head of the caudate nucleus, increases with age (
15). The cause of brain iron accumulation with aging is uncertain (
15). Iron accumulation in nerve tissues increases further during the progression of AD (
15). Iron accumulation in the hippocampus and basal ganglia in rodents leads to marked impairments in spatial and aversive memory and recognition memory. Ferroptosis is an iron-dependent cell death, which is different from apoptosis, necrosis, autophagy, and other forms of cell death (
19). Ferroptosis and its cell death are observed in AD, HD, and PD, as well as degenerative diseases such as carcinogenesis, stroke, intracerebral hemorrhage, and traumatic brain injury, ischemia-reperfusion injury. Iron changes the valence state in biochemistry between the ferrous Fe
2+ and the ferric Fe
3+ species. While this property is vital in physiology, it can also be deleterious as a source of oxidative stress, especially in an obligate aerobic environment. Thus, iron is tightly regulated in the brain, where both deficiency and overload of iron may cause dysfunction of the brain (
15).