Juglanin, a natural product isolated and purified from the herbs of Phymatopteris hastate with antioxidant activity, shows protective effects on fructose-induced hepatitis by inhibiting inflammation and apoptosis through TLR4 and JAK2/STAT3 signaling pathways in fructose-fed rats, and can lead to G2/M phase arrest, induce apoptosis as well as autophagy through the ROS/JNK signaling pathway in human breast cancer cells, it may be a promising candidate for development of anti-tumor drugs targeting breast cancer.