Biological activities and therapeutic potential of soy isoflavones: a focus on anticancer activity

Despite major advances in medicine, cancer treatment remains a considerable challenge. The rising incidence of new cases and the frequent resistance to cytostatics suggest that standard therapies may be insufficient. This highlights the need for novel compounds with potential anticancer activity and minimal side effects. Among natural molecules, soy isoflavones appear particularly promising. Soybeans and red clover are abundant in genistein and daidzein - isoflavones which are currently used as dietary supplements to alleviate menopausal symptoms, osteoporosis, and polycystic ovary syndrome. Reports also suggest potential benefits in neurodegenerative, cardiovascular, and metabolic diseases, including non-alcoholic fatty liver disease. Their mechanisms of action are diverse and extend beyond estrogenic activity, including anti-inflammatory, antioxidant, and immunomodulatory effects. In cancer, proposed mechanisms involve modulation of estrogen receptors, copper ion-dependent induction of cell death, promotion of apoptosis, inhibition of angiogenesis and metastasis, regulation of epigenetic processes, and effects on platelet function. Owing to their estrogen receptor interactions, isoflavones have been studied particularly in hormone-dependent cancers such as breast, ovarian, and prostate cancer. Moreover, in vitro and in vivo studies have reported promising results in other malignancies, including gliomas, neuroblastoma, hepatocellular carcinoma, lung and bladder cancers, osteosarcoma, and rhabdomyosarcoma. In summary, soy isoflavones require further investigation, particularly in combination with established chemotherapeutics, to evaluate their potential synergy with standard protocols. Their affordability, availability, and favorable safety profile strengthen their relevance as candidates for adjunctive cancer therapy.