Phytoestrogens and Phytoestrogen-Containing Ayurvedic Botanicals in Breast Cancer: A Narrative Review of Molecular, Preclinical and Clinical Evidence

Abstract

Phytoestrogens are plant-derived polyphenolic compounds capable of interacting with estrogen receptors. They may exert estrogenic, anti-estrogenic, or selective modulatory effects based on several endogenous factors. In Ayurveda, many herbs contain phytoestrogenic compounds are effectively used in various gynaecological disorders. Breast cancer is the most frequent malignancy in women. Approximately 70–80% of breast cancers are ER-positive and depend partly on estrogen signalling for tumour growth.

This narrative review explores the role of phytoestrogen-containing Ayurvedic herbs in breast cancer. Literature was collected from PubMed, Scopus, Google Scholar, ScienceDirect, and Ayurvedic sources. The review focuses on molecular mechanisms, effects on different breast cancer subtypes, estrogen receptor modulation, receptor-independent pathways, and available clinical evidence supporting their integrative therapeutic potential.

Phytoestrogen-containing Ayurvedic Rasayana herbs such as Ashwagandha (Withania somnifera), Shatavari (Asparagus racemosus), and Yashtimadhu (Glycyrrhiza glabra) exhibit diverse biological activities that may influence breast cancer progression. These herbs act through both estrogen receptor (ER)-dependent and ER-independent mechanisms, modulating pathways involved in cell proliferation, apoptosis, inflammation, oxidative stress, and signal transduction. In ER-positive breast cancer, phytoestrogens may produce either anti-proliferative or proliferative effects depending on dose, receptor subtype balance, and endogenous estrogen status. In ER-negative and triple-negative breast cancers, their actions are primarily mediated through anti-inflammatory, antioxidant, and pro-apoptotic pathways. From an Ayurvedic perspective, these Rasayana drugs support systemic balance, tissue rejuvenation, and metabolic regulation, concepts that align with personalized therapeutic approaches. However, concerns regarding dosage, safety, hormone-sensitive tumours, and herb–drug interactions warrant caution. Further well-designed clinical studies are needed to establish their efficacy and safety in integrative breast cancer care.