Radical scavenging activity was also measured in vitro by the tetrazolium nitroblue assay on a commercial juice, by assessing the potential capacity of the juice to protect cells or lipids from oxidative alteration promoted by superoxide anion radicals (SAR). The SAR scavenging activity of noni juice was times higher than that of vitamin C, times that of pycnogenol, and almost of the same order as that of grape seed powder. 1 New iridoid glucosides isolated from methanol extracts of noni fruits, neolignan, and americanin A were found to be potent antioxidants. 23
Most research on the biological effects of coumestrol has been conducted on animals because of ethical concerns. There is a need for more human studies to better understand potential human health impacts due to exposure.  In addition, further research is required to fully understand the biosynthesis pathway of coumestrol, although it is believed to be similar to that of flavones and isoflavones. Further research is required to understand the exact nature of the relationship between the levels of coumestrol in a plant and the plant's response to pathogens.