A Clean Sweep: Can hemp, mushrooms fight COVID on surfaces?

While the pandemic pushed most people to pause in 2020, it had the opposite effect on Leonard Williams, Ph.D., director, professor and researcher at the Center for Excellence in Post-Harvest Technologies in the College of Agriculture and Environmental Sciences at North Carolina Agricultural and Technical State University.

Williams was declared an “essential worker” by the university, which allowed him to continue to work during the campus lockdown brought on by the pandemic. While in his lab, he wondered how to use his skills as a food microbiologist, and his extensive research experience, to fight the virus.

“I wanted to capitalize on our infrastructure here at the center,” said Williams. “We have some high-end equipment, and I wanted to do what I could to help. This is what forward-thinking researchers do.”

COVID-19 perplexed everyone in mid-2020. Daily newscasts showed its rapid spread as the worldwide death count rose, and more and more schools, businesses and facilities closed. Scientists focused on curing the disease, but Williams felt the need to explore other options as well.

He and a team of other CAES researchers wondered if there might be synthetic and natural sources to combat the replication, transcription and transmission of COVID-19. Knowing that hemp and mushrooms have antiviral and anti-inflammatory properties, they wondered if both, or either, might effectively kill the SARS-Corona Virus 2 and stop the spread of COVID-19. And if hemp or mushrooms were usable, what would the end-product look like? Would it be easy to use and readily available, and how effective could it be?

Additionally, they wanted to know if hemp and mushroom extracts could serve as an alternative to conventional disinfectants that could be used on contact surfaces, like polyvinyl chloride (PVC), stainless steel, cardboard and copper. These were the surfaces most often touched by food handlers and other essential workers, and if the virus was active, it could easily be spread from person to person on these surfaces. Both are also natural products that are safe around food, humans and animals, and are environmentally friendly.

With funding through the Evans-Allen program from the National Institutes of Food and Agriculture, they developed a project to:

• Establish the most efficient extraction method from the hemp and mushroom crude extract with maximum phenolic and flavonoid contents and antioxidant activities using different solvents;
• Determine the antiviral activities of hemp and mushroom extract against novel SARS-CoV-2 in an in vitro cell culture assay;
• Measure the transfer rates of SARS-CoV-2 on different contact surfaces treated with hemp or mushroom extracts and compare its efficacy to conventional commercial disinfectants (hydrogen peroxide and sodium hypochlorite).

Janak Khatiwada, Ph.D., a food nutritional biochemist, added his research acumen to the team led by Williams.

Williams pulled together a multidisciplinary team from across campus: Janak Khatiwada, Ph.D., a food nutritional biochemist; Omoanghe Isikhuemhen, Ph.D., a mycologist with extensive experience in the cultivation of medicinal mushrooms; Guochen Yang, Ph.D., a horticulture specialist with expertise in hemp, plant propagation, tissue culture and micropropagation; and Salam Ibrahim, Ph.D., a food safety specialist and microbiologist with experience in the use of probiotics for controlling foodborne pathogens.

Since the mushrooms needed time to grow, the group started with hemp, which is known as a superfood because of its multiple uses in food, fiber, medicine, paints and varnishes, soaps and edible oils. Hemp has been shown to be effective in reducing other immunomodulatory conditions, like airway hyper-responsiveness, airway inflammation and coughs. other anti-inflammatory and anti-tussive responses. Because of COVID-19’s effects on the respiratory system, the group considered hemp an excellent candidate for further study.

The group selected three varieties of hemp to test with COVID-19 isolates, provided by the National Institute of Health Biodefense and Emerging Infectious Research Resources Repository. Most of the work was done at the Center for Excellence Post-Harvest Technologies, which is a U.S. Centers for Disease Control (CDC) Certified Select Agent Biosafety Level 3 (Bsl-3) lab. All other safety precautions were used, Williams said, since this work was done in 2020 at the height of the pandemic when little was known about how it was spread.

The group’s first objective was to establish the most efficient extraction method. The hemp plants were washed, shade-dried and cut into a fine powder using an elective stainless-steel grain grinder mill. The crude plant powder was decanted, freeze-dried and tested for alkaloids, flavonoids, glycosides, saponins, protein and carbohydrates. The material was further treated, filtered, rinsed, put in a centrifuge, freeze-dried and stored.

Then, the plant extracts were tested for phytochemicals, or key plant-derived chemicals, that have potential antiviral properties, using specialized equipment to determine which could be isolated from the plant extracts.

Leonard Williams, Ph.D., right, director, professor, and researcher at the Center for Excellence in Post-Harvest Technologies in the CAES, stops by the University Farm to officially return a hemp plant that he previously removed for research. John Ivey, the research specialist for the university’s industrial hemp research project, receives the plant for proper disposal.

The second process was to determine the antiviral activities of hemp against novel SARS-CoV-2 in an in-vitro cell culture assay. For this study, the team measured the transfer rates of SARS-CoV-2 to different contact surfaces treated with hemp, and compared the results to conventional disinfectants. Different surfaces were tested in separate experiments. The hard surfaces were washed with warm water and liquid soap, rinsed with tap water and soaked in bleach and ethanol. They were then wrapped in aluminum foil and autoclaved. Once the surfaces were dry, they were swabbed, exposed to SARS-CoV-2 and then decontaminated with hemp.

What they discovered, Williams said, was that some of the crude extracts from the different hemp varieties were able to help reduce the proliferation of SARS-CoV-2 cells

“These are preliminary results, but we were pleased with our positive findings,” he said. “We are looking at what’s next.”

That question will be answered using the mushroom extracts to see if they get the same or similar response. Additionally, they will determine if variants of SARS-CoV-2 will produce the same results.

Williams and the team are also working on manuscripts that will appear in peer-reviewed journals, and they are preparing to file a patent application. A patent will pave the way for them to work with an entity interested in using the knowledge to develop products the public can buy. This could be a disinfectant spray akin to other mass-produced disinfectants, or maybe even clothing with the product included in the material.

“In addition to helping to solve a problem and being safe to use, this research could be profitable for hemp farmers,” Williams said. “This is just the beginning. There are so many other markets where this research could be used.”