Puerarin, a key bioactive ingredient of Radix Puerariae, inhibits oxidative stress and protects against homocysteine-induced cardiac injury via PI3K/Akt/Nrf2/HO-1 signaling

Abstract

Elevated plasma homocysteine (Hcy) levels are a major contributor to the risk factor for the developing cardiovascular diseases (CVDs). This study explored the protective efficacy of puerarin (Pue), a key bioactive ingredient derived from Radix Puerariae, against cardiac damage induced by Hcy, along with its underlying molecular mechanisms. Using H9c2 cardiomyocytes and a guinea pig model of hyperhomocysteinemia (HHcy), we demonstrated that Pue attenuated Hcy-induced cardiotoxicity, oxidative stress, mitochondrial dysfunction and apoptosis. The cardioprotective effects of Pue were exerted by activating the PI3K/Akt/Nrf2/HO-1 signaling axis. In vitro, Pue pretreatment markedly enhanced cell viability, diminished the release of lactate dehydrogenase (LDH), lowered reactive oxygen species (ROS) and malondialdehyde (MDA) levels, and elevated superoxide dismutase (SOD) activities in Hcy-injured H9c2 cardiomyocytes. Furthermore, Pue upregulated Nrf2 and HO-1 expression, two key regulators of the antioxidant response, and alleviated Hcy-induced mitochondrial dysfunction and apoptosis. These beneficial effects were abrogated by the HO-1 inhibitor Znpp and the PI3K inhibitor LY294002, indicating the contribution of the PI3K/Akt/Nrf2/HO-1 axis. In vivo, Pue treatment significantly reduced serum Hcy levels, decreased serum biomarkers of myocardial injury, lowered MDA levels, and increased SOD activities in HHcy guinea pigs. Additionally, Pue improved cardiac remodeling and attenuated myocardial apoptosis, accompanied by upregulation of Nrf2 and HO-1 expression and an increased p-Akt/Akt ratio within myocardial tissues. Overall, these findings suggest that Pue protects against Hcy-induced cardiac injury via the PI3K/Akt/Nrf2/HO-1 signaling axis, offering a potential therapeutic approach for the prevention and management of CVDs associated with elevated Hcy levels.