Neuroprotective effects of phytoestrogens: A potential alternative to estrogen therapy in Alzheimer's disease patients

Alzheimer's disease (AD) is classified as an age-related neuro-degenerative disorder leading to loss of memory and decline in cognitive abilities, often characterized as dementia. According to the WHO report 2020, out of 50 million people battling with dementia worldwide, 60%–70% cases account for AD. Some researchers have reported two to three times higher incidence of AD among women than men and further confirmed that postmenopausal women are more prone to AD than healthy men of the same age. This hints at the potential neuroprotective role of estrogen hormone, whose level drops to <30 pg/mL postmenopause. Several epidemiological studies also suggest early postmenopausal use of estrogens may contribute to the prevention, attenuation, or even delay in the onset of AD. Collectively, this evidence supports the further development of estrogen-like compounds for the treatment and prevention of AD, with a rising interest in phytoestrogens as potential interventions with lower side effects. This review highlights multiple pathways of estrogen-mediated neuroprotection against neurodegenerative diseases like AD and discusses the role of selective estrogen receptor molecules mainly phytoestrogens, in AD progression so that latter can be considered and used as an alternate therapy for treating Alzheimer patients.