Role of Phytoestrogens in Post Menopausal Disorders: A Review

Phytoestrogens are polyphenolic non-steroidal secondary metabolite phytoconstituents having oestrogenic potential due to the structural similarities with the endogenous oestrogen 17β-estradiol in mammals. They can be classified into flavanols, isoflavones, lignans, Ellagic tannins, Coumestans and Stilbenes based on the differences in their chemical structure. They are known to alleviate the climacteric changes such as hormone-related tumors, Osteoporosis, Atherosclerosis, Alzheimer’s, etc of the post menopausal state, which arises due to low levels of endogenous oestrogen hormone. All Phytoestrogens except stilbenes are biosynthesized through Shikimic acid pathway, either from the aromatic amino acids or the important intermediates in the pathway and mimic estrogen activities by various cell signalling pathways acting on multiple molecular targets in mediating various pharmacological responses. Stilbenes are phytoalexins produced in response to stress by various biotic and abiotic factors. They are known to exhibit both oestrogenic and activities based on the concentration of the phytoestrogen and their ability to bind with various oestrogen receptors in synergizing or antagonising the pharmacological response. Apart from the oestrogenic activity, phytoestrogens are known to exhibit various pharmacological responses like antioxidant, anti-inflammatory, cardiovascular disorders, anti-cancer, age-related cognitive decline etc. Dietary sources of phytoestrogen include fruits (blueberry, strawberry raspberry), vegetables (broccoli, garlic, carrot, spinach, legumes), flax seed, soybean, green tea, black tea, red clover.