2,3-Dimethoxy-5-methyl-p-benzoquinone

2,3-Dimethoxy-5-methyl-p-benzoquinone, also known as coenzyme Q0, is a key intermediate in the synthesis of coenzyme Q, coenzyme Q10, other ubiquinones, and vitamin E. It inhibits the growth of SKOV-3, A2780, and A2870/CP70 human ovarian carcinoma cells (IC50s = 26.6, 27.3, and 28.4 µM, respectively) with a cytotoxic concentration of greater than 40 µM for non-cancerous ovarian surface epithelial cells. It halts the cell cycle at the G2/M phase, increases the production of reactive oxygen species (ROS), and induces autophagy and apoptosis in SKOV-3 cells. 2,3-Dimethoxy-5-methyl-p-benzoquinone downregulates the protooncogene HER-2 and decreases the protein levels of phosphorylated AKT and mTOR in SKOV-3 cells. It also decreases the incidence of tumors and tumor burden in a SKOV-3 human ovarian carcinoma mouse xenograft model when administered at a dose of 2.5 mg/kg every four days.