Stinging nettles are a family of plants known for their tiny, distinctive spikes on stems and leaves that can sting and irritate the skin. But science is increasingly discovering how there is so much more to this seeming nuisance weed than meets the eye. Sure, they sting, but they’re also edible and boast a wealth of health and even medicinal qualities that have been known to humans since at least the Bronze Age.
Researchers today are busy exploring innovative ways to make the most of stinging nettles’ more positive properties. Forget skin rashes—scientists now know that these plants can be used as a natural food preservative. A nettle-based solution has been found to boost chicken’s immune systems and help improve overall farm animal health. Those are just a few examples of the nettle’s newfound potential. Now, scientists are figuring out how to use stinging nettle extract to make a type of biodegradable plastic that can keep fruit fresh for longer.
Seven biomolecular scientists from India, Saudi Arabia, and Egypt say they are exploring ways to manufacture biopolymers—a fancy term for biodegradable plastics—that can do more than simply help you carry produce and degrade in a landfill later. In new research published in the journal Biomolecules, these researchers describe how they’ve synthesized metal oxide nanoparticles using stinging nettle extract, then took this solution and applied it to films of chitosan-based bioplastics, to see what would happen (https://www.mdpi.com/2218-273X/11/2/224).
Separate studies have shown that applying nettle extract directly to fruits and vegetables can inhibit spoilage and lengthen storage time. But could applying the extract to plastic bags have the same effect on food stored in those bags? Apparently, yes—this latest study realized the same antioxidizing and antimicrobial effects on fruits by coating biodegradable plastics with the extract instead. The nettle extract even made the bioplastics they tested more durable and clearer. So, the nettle extract not only improved the functionality of the bioplastics but also made the plastic look better. “The incorporation of these [nanoparticles] in chitosan films improved the physical characteristics of the films,” Kalia et al. reported. “Additionally, fruits packaged with nanocomposite films were reported with the least microbial load and spoilage in comparison with unpackaged fruits.”
They found these features especially useful for packaging and storing guava, a serious concern in India. The study notes that Indian farmers grow over 4 million tons of guava each year, but that not all of it makes it to households. Guava “is highly perishable with a shelf life of approximately one week at ambient temperature and two weeks at 6 to 8 degrees Celsius,” the research team points out. “Hence, it suffers from substantial post-harvest losses during storage and transportation.” Putting guava fruits into biodegradable plastic bags laced with their nettle extract adds an extra week to the fruits’ shelf life, they report.
“This plant species needs thorough research for its utilization in human health.”
New research directions
Croatian scientists say they are discovering that liquid nettle extract can be used to fertilize crops while further enhancing the iron accumulation of those same crops, making them more nutritious. Other scientists, an Indian-Italian research team, say they can concentrate the health benefits of stinging nettles by freeze-drying the plant’s leaves and then processing them into a powder. Adding this powder to any dish can probably enrich a variety of foods, helping to fight against malnutrition, they say, though cautioning that much more research is necessary to determine just how beneficial nettle powder as a food additive could be.
Scientists in India also figure prominently in research on stinging nettles. Dr. Vasudha Pant, principal investigator at Green Hills Trust in Uttarakhand, perhaps put it best in his 2019 assessment published in The Journal of Ethnobiology and Traditional Medicine
“Nettle has been found to be a rich source of protein, calcium, magnesium, potassium, and iron,” Pant wrote. “This plant species needs thorough research for its utilization in human health.”
At Grow Further, we’re excited by the possibilities of supporting work on both indigenous and cutting-edge uses of stinging nettle.
— Grow Further
Photo credit: Stinging nettles, iStock Photos, Getty Images