Efficacy of broccoli and glucoraphanin in COVID-19: From hypothesis to proof-of-concept with three experimental clinical cases

Abstract One clinical case describes COVID-19 in a patient who has proposed the hypothesis that Nuclear factor (erythroid-derived 2)-like 2 (Nrf2)-interacting nutrients may help to prevent severe COVID-19 symptoms. Capsules of broccoli seeds containing glucoraphanin were being taken before the onset of SARS-CoV-2 infection and were continued daily for over a month after the first COVID-19 symptoms. They were found to reduce many COVID-19 symptoms rapidly and for a duration of 6-12 hours by repeated dosing. When the patient was stable but still suffering from cough and nasal obstruction when not taking broccoli, a double-blind induced cough challenge confirmed the speed of onset of the broccoli capsules (less than 10 minutes). A second clinical case with lower broccoli doses carried out during the cytokine storm confirmed the clinical benefits already observed. A third clinical case at the onset of COVID-19 symptoms showed similar effects. In the first clinical trial, we used a dose of under 600 micromoles per day of glucoraphanin but such a high dose may induce some pharmacologic effects that must be studied carefully before any study is carried out. It is likely that the fast onset of action is mediated through TRPA1 channel. These experimental clinical cases represent a proof-of-concept to confirm the hypothesis that Nrf2-interacting nutrients are effective in COVID-19 but cannot be used in practice before more safety data are available. They should be confirmed by proper trials on efficacy and safety.