Scientists have shown the anti-oxidant potential of papaya leaf by comparing the effect of alpha-tocopherol in the lab.
Alpha-tocopherol is a form of Vitamin E. According to the Health Information Fact Sheet of the National Institute of Health,
“…Vitamin E is a fat-soluble antioxidant that stops the production of ROS formed when fat undergoes oxidation. Scientists are investigating whether, by limiting free-radical production and possibly through other mechanisms, vitamin E might help prevent or delay the chronic diseases associated with free radicals.”
A summary of the study:
“This preliminary study indicates the safety and antioxidative stress potential of the juice of C. papaya, which was found to be comparable to the standard antioxidant compound alpha-tocopherol.”
-Mehdipour, S., Yasa, N., Dehghan, G., Khorasani, R., Mohammadirad, A., Rahimi, R. and Abdollahi, M. (2006), Antioxidant potentials of Iranian Carica papaya juice in vitro and in vivo are comparable to α-tocopherol. Phytother. Res., 20: 591–594. doi:10.1002/ptr.1932