Gentian isoflavones, also known as genistein, are polyphenolic compounds found in plants such as soybeans and red clover. Their molecular structure is similar to 17β-estradiol, and they possess antioxidant properties and a high affinity for estrogen receptors. They can inhibit the activity of tyrosine protein kinase (PTK) and topoisomerase II, and have effects such as inducing programmed cell death, enhancing the efficacy of anticancer drugs, and inhibiting angiogenesis. They are a type of flavonoid (also called isoflavones). They are often found together with isoflavones called genistein, and they are collectively known as soy isoflavones. The health benefits of these compounds have been extensively studied, and they are promising cancer chemopreventive agents with significant effects in preventing cancer and other diseases. Genistein is currently the main phytoestrogen being studied.