Fermentation of Common Nettle Extracts by Ligilactobacillus salivarius: New Avenue for the Development of Added-Value Bioactive Products

Every year, the medicinal plant industry discards 30 million tons of by-products—most of it just thrown away. But what if we could turn that waste into health-boosting ingredients?

The common nettle, Urtica dioica, is a nutritional powerhouse—rich in polyphenols, vitamins, and essential fatty acids—but its by-products are often left to rot. Researchers decided to change that by giving these leftovers a second life through fermentation. They used green extraction techniques to create aqueous and ethanolic extracts from nettle tea by-products and flowers, then fermented them with Ligilactobacillus salivarius, a beneficial probiotic bacterium. The results were striking: fermentation significantly boosted the phenolic content and antioxidant activity of the extracts. Chlorogenic acid levels jumped up to 4-fold, while caffeic acid derivatives increased up to 2.5-fold. Even better, the probiotic bacteria remained alive and viable throughout the process. This means we can produce both high-value extracts and probiotic biomass from what was once considered waste. This low-energy, environmentally friendly approach offers a sustainable way to transform nettle by-products into functional ingredients, turning a waste problem into a wellness opportunity.

Key Points

• Fermentation boosts phenolic content and antioxidant activity.
• Chlorogenic acid increases up to 4-fold, caffeic acid derivatives 2.5-fold.
• Probiotic bacteria stay viable, enabling added-value products.