The interplay of Ashwagandha with hormonal dynamics and gut microbiota in women with breast cancer: a tri-axial perspective.

Ashwagandha (Withania somnifera), a traditional Ayurvedic adaptogen, is increasingly investigated in hormone-sensitive malignancies such as breast cancer. Its bioactive constituents, particularly withaferin A, exhibit diverse effects relevant to hormonal regulation, tumor suppression, and systemic balance. This review explores Ashwagandha's tri-axial roles in hormonal modulation, gut microbiota interaction, and direct anticancer activity across breast cancer subtypes. Preclinical findings show that withaferin A suppresses estrogen receptor alpha (ERα), inhibits STAT3 and NF-κB signaling, induces ROS-mediated apoptosis, and alters epigenetic regulators. In HER2-positive and triple-negative models, it reduces cancer stem cell activity, epithelial-to-mesenchymal transition (EMT), and pro-inflammatory mediators. Ashwagandha also influences the hypothalamic-pituitary-gonadal axis, raising LH, FSH, estrogen, and progesterone, while lowering cortisol and normalizing thyroid function. Immunologically, it enhances CD8⁺ T cell activity, reduces myeloid-derived suppressor cells (MDSCs) and tumor-associated macrophages (TAMs), and may synergize with checkpoint inhibitors. Effects on gut microbiota suggest additional roles in estrogen metabolism and inflammatory regulation. Toxicity data indicate high tolerability (LD₅₀ > 2000 mg/kg), though rare hepatic and thyroid adverse events occur. Regulatory oversight remains inconsistent, with limited phytochemical standardization. Ashwagandha shows multidimensional promise but requires rigorous, standardized clinical validation.