Hyperglycemia has been considered as a major health topic recently. Studies showed it may alter steroidogenesis also affect animal or human physiology. Steroid hormones are required to keep normal animal physiology, thus if steroidogenesis is altered due to oxidative stress induced by hyperglycemia, it can be important issues. Quercetin, a phytochemical that extracted from plants, has been identify with anti-oxidant, anti-inflammatory and anti-carcinoma function. In this project, we aim to investigate the molecular mechanism of how hyperglycemia induced oxidative stress alter steroidogenesis and test the anti-oxidant ability of quercetin.