There are numerous phytochemicals that have potential to be of benefit in battling COVID-19. Phytochemicals are, of course, found in plants. One food that contains several phytochemicals of interest is citrus: lemons, limes, oranges, and grapefruits.

Constituents of citrus appear to be among the most potent of food-derived natural substances to inhibit the SARS-CoV-2 (the novel coronavirus). Some of these phytochemicals that have a molecular structure suggesting potential benefit in battling this coronavirus include hesperidin, naringenin, naringin, hesperitin, neohesperitin, a-glucosyl hesperidin, tangeritin, and nobiletin. These phytochemicals have multiple ways they may target the coronavirus. For example, several of these bind to the spike protein of SARS-CoV-2 thereby blocking the key that the virus uses to gain entry to human cells.

Several studies have been published that provide data on the plant substances with greatest potential activity against different targets of SARS-CoV-2 infection. Hesperidin seems to be particularly powerful. A study examined the ability of various phytochemicals to bind three key SARS-CoV-2 proteins important for its infectivity. Hesperidin was the most effective in binding all three of these proteins. It had greater binding activity than the two antiviral drugs that were used for comparison

A number of these active phytochemicals are available in supplemental form. Stellar-C is a vitamin C supplement that contains hesperidin. It also contains quercetin, another phytochemical that is being studied in COVID-19.

A variety of different plant foods should be consumed on a regular basis for optimal health. When it comes to COVID-19, citrus should be at the top of the list.