Noni juice is known for its high levels of antioxidants. Antioxidants prevent cellular damage caused by molecules called free radicals. Your body requires a healthy balance of antioxidants and free radicals to maintain optimal health. Researchers suspect that the potential health benefits of noni juice are likely related to its powerful antioxidant properties. The main antioxidants in noni juice include beta carotene, iridoids, and vitamins C and E.