news-date">27.05.2022
A chemical found in green vegetables has been shown to slow the growth of COVID-19 and cold viruses. American researchers came to this conclusion in a study published in the “Nature Journal Communications Biology”.
In laboratory experiments, researchers at the Johns Hopkins Children’s Center found a chemical found in abundance in broccoli and other cruciferous vegetables that could be a potentially new and powerful weapon against the viruses that cause COVID-19 and the common cold: sulforaphane.
In a study published March 18 in the Nature journal Communications Biology, the scientists described that sulforaphane, a well-known phytochemical whose anti-cancer effects are already known, inhibits the multiplication of SARS-CoV-2 can inhibit.
Broccoli, collards, kale, and Brussels sprouts contain natural precursors to sulforaphane
The natural precursor to sulforaphane is particularly abundant in broccoli, collards, kale, and Brussels sprouts—veggies that aren’t exactly popular with kids. But this is another argument that it should still be offered to them more often. Previous studies, including those by Johns Hopkins Medicine, have shown that sulforaphane has cancer and infection-preventing properties by interfering with certain cellular processes.
“As the COVID-19 pandemic began, our multidisciplinary research teams conducted our investigations […] to focus on a possible treatment for the new virus,” explained microbiologist Ass. Prof. Dr. Lori Jones-Brando, Ph.D., of Johns Hopkins University School of Medicine and senior paper author.
Sulforaphane effective in mice
In one experiment, the research team first exposed cells to sulforaphane for one to two hours before infecting the cells with SARS-CoV-2 and the common cold coronavirus HCoV-OC43. They found that low micromolar (µM) concentrations of sulforaphane (2.4–31 µM – (micromolar) reduced the multiplication of six SARS-CoV-2 strains, including the delta and omicron variants, as well as that of the HCoV- Reduced OC43 coronavirus by 50% The researchers also observed similar results in cells previously infected with the viruses, in which the protective effect of sulforaphane was also seen in an already established viral infection.
The group also studied the effects of sulforaphane in combination with remdesivir, an antiviral drug used to shorten the recovery time of hospitalized patients with COVID-19 infections. According to their results, remdesivir inhibited 50% of the replication of HCoV-OC43 and SARS-CoV-2 at 22 µM and 4 µM, respectively. In addition, the research team reports that sulforaphane and remdesivir worked synergistically at multiple combination ratios to reduce viral load by 50% in cells infected with HCoV-OC43 or SARS-CoV-2. In this context, synergism means that lower doses of sulforaphane (eg 1.6-3.2 µM) and remdesivir (eg 0.5-3.2 µM) in combination are more effective against the viruses than either used alone.
“In the past we have learned that combining several compounds in one treatment regimen is an ideal strategy for treating viral infections,” says Ass.-Prof. dr Alvaro Ordonez, MD, the paper’s first author from Johns Hopkins University. “The fact that sulforaphane and remdesivir work better together than alone is very encouraging.”
The researchers then conducted studies in a mouse model of SARS-CoV-2 infection. They found that mice given 30 milligrams of sulforaphane per kilogram of body weight before infection with the virus reduced body weight loss. This typically occurs with a viral infection. “Pretreated” mice lost significantly less weight (7.5% less weight loss). In addition, pretreatment resulted in a statistically significant decrease in both viral load, or amount of virus, in the lungs (17% less weight loss) and upper airways (9% decrease) and lung damage (29% decrease) compared to infected mice no sulforaphane was administered. The compound also reduced inflammation in the lungs and protected the cells from an excessive immune response.
“We found that sulforaphane has antiviral activity against HCoV-OC43 and SARS-CoV-2 coronaviruses while helping to control the immune response,” summarized Ordonez. “This multifunctional activity makes it an interesting compound to use against these viral infections as well as those caused by other human coronaviruses.”
The team plans to conduct human trials to evaluate whether sulforaphane may be effective in preventing or treating these infections.
Sources: EurekAlert! Johns Hopkins Medicine, Communications Biology