Researchers from UCLA and China have found that catalase, a naturally occurring enzyme, holds potential as a low-cost therapeutic drug to treat COVID-19 symptoms and suppress the replication of coronavirus inside the body. A study detailing the research was published in Advanced Materials. Catalase is produced naturally and used by humans, animals and plants. Inside cells, the antioxidant enzyme kick starts the breakdown of hydrogen peroxide, which can be toxic, into water and oxygen. The enzyme is also commonly used worldwide in food production and as a dietary supplement.