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Japanese Food Natto Might Help in COVID-19 Treatment

Japanese Food Natto Might Help in COVID-19 Treatment

by Saisruthi Sankaranarayanan on Jul 24 2021 3:16 PM
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Highlights:
  • Natto is a fermented soybean dish, traditionally served as a breakfast in Japan
  • Extracts of natto could possibly hold back SARS-CoV-2 from infecting cells
  • Protein-degrading enzymes that affect the spike protein of coronavirus are present in natto extracts
Extracts of natto, a protein-packed Japanese food, could possibly cease the ability of the SARS-Cov-2 virus to infect cells. Researchers from the Tokyo University of Agriculture and Technology now say that purified natto extracts are worth being investigated as antiviral drugs.
"Traditionally, Japanese people have assumed that natto is beneficial for their health. In recent years, research studies have revealed scientific evidence for this belief. In this study, we investigated natto's antiviral effects on SARS-CoV-2, the virus that causes COVID-19, and bovine herpesvirus 1 (BHV-1), which causes respiratory disease in cattle," said Tetsuya Mizutani, director of the Center for Infectious Disease Epidemiology and Prevention Research at the Tokyo University of Agriculture and Technology (CEPiR-TUAT).

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What on Earth is Natto?

Natto is a traditional Japanese food made by fermenting cooked soybeans. The fermentation process is carried out by the bacteria called Bacillus subtilis.

Natto is a gut-friendly, nutrient-rich food that serves as a good source of probiotics, vitamin-K, and minerals. It was previously found to be a diet staple in those who were least likely to die from stroke or cardiac disease. It is also known to promote bone health, heart health, and digestive health.

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What Did Natto Do Against the Viruses?

The researchers prepared extracts of store-bought natto and applied them to the lab-grown SARS-CoV-2 and BHV-1 virus cultures. Later, the mixtures were added to human and cattle cells, respectively. This made the viruses fail from infecting the live human and cattle cells.

Similar effects were observed when the natto extracts were tested against the N501Y variant of SARS-CoV-2, which first originated in the UK.

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How Could Natto Make It?

When the team applied heat-treated natto extracts to the same settings, the viruses were not harmed and were able to infect the cells. Thus, they hypothesized that the heat-sensitive proteases lie behind this antiviral action of natto extracts. Proteases are enzymes that destroy other proteins.

"We found what appears to be a protease or proteases (proteins that metabolize other proteins) in the natto extract directly digests the receptor-binding domain on the spike protein in SARS-CoV-2," Mizutani said, noting that the protease appears to break down in the heat, losing the ability to digest proteins and letting the virus remain infectious.

They further tested their hypothesis by investigating the pattern of degradation of spike proteins through various chemical analyses.

While natto extracts seem to be powerful against SARS-CoV-2, the authors cautioned that their findings do not provide any direct evidence of reduced viral infection simply by eating natto.

"Although there are vaccines for COVID-19, we do not know how effective they may be against every variant. It will also take time to vaccinate everyone, and there are still reports of breakthrough cases, so we need to make treatments for those who develop COVID-19. This work may offer a big hint for such pharmaceutical design," highlighted Mizutani.

The findings of this breakthrough research are published in the journal Biochemical and Biophysical Research Communications.

References
  1. Oba M, Rongduo W, Saito A, Okabayashi T, Yokota T, Yasuoka J, Sato Y, Nishifuji K, Wake H, Nibu Y, Mizutani T. Natto extract, a Japanese fermented soybean food, directly inhibits viral infections including SARS-CoV-2 in vitro. BiochemBiophys Res Commun. 2021 Jul 13;570:21-25. doi: 10.1016/j.bbrc.2021.07.034. Epub ahead of print. PMID: 34271432; PMCID: PMC8276596.
  2. The Nutritional Benefits of Fermented Superfood Natto - (https://www.onegreenplanet.org/natural-health/nutritional-benefits-of-fermented-superfood-natto/)


Source-Medindia


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