Oxidative Stress Protection and Anti-Inflammatory Activity of Polyphenolic Fraction from Urtica dioica: In Vitro...

Area of Science:

• Dermatology and Cosmetology
• Phytochemistry
• Cell Biology

Background:

• Polyphenols offer antioxidant and anti-inflammatory benefits, crucial for combating skin aging (inflammaging).
• Urtica dioica (stinging nettle) is recognized as a rich source of polyphenolic compounds.
• Potential applications in cosmetology and dermatology exist for Urtica dioica extracts.

Purpose of the Study:

• To evaluate the antioxidant and anti-inflammatory activities of polyphenol-rich fractions from Urtica dioica leaves (UdLs) and flowers (UdFs).
• To assess these fractions' effects on human skin cells under oxidative stress and lipopolysaccharide (LPS) stimulation.

Main Methods:

• Accelerated solvent extraction and solid-phase extraction were used to isolate and purify polyphenol-rich fractions.
• Chemical composition was analyzed using Ultra-Performance Liquid Chromatography with Diode Array Detection and Mass Spectrometry (UPLC-DAD-MS).
• Biological activities were assessed via cytotoxicity assays, antioxidant capacity tests (DPPH, ABTS, FRAP, CUPRAC, TPC, H₂DCFDA), antioxidant enzyme activity (SOD, CAT), lipid peroxidation (MDA), and cytokine production (IL-1β, IL-6, IL-10).

Main Results:

• Both UdL and UdF fractions were rich in polyphenols, with chlorogenic acid predominant. UdLs were higher in phenolic acids, while UdFs contained more flavonoids (isorhamnetin derivatives).
• Fractions were non-cytotoxic and demonstrated strong radical scavenging potential, with UdL slightly more effective.
• Both fractions significantly reduced intracellular reactive oxygen species (ROS), enhanced antioxidant enzyme activity, attenuated lipid peroxidation, and decreased pro-inflammatory cytokine secretion in stimulated skin cells.

Conclusions:

• Polyphenolic fractions from Urtica dioica leaves and flowers possess significant antioxidant and anti-inflammatory properties.
• These findings support the use of Urtica dioica extracts as multifunctional ingredients in anti-aging and skin-protective cosmetic formulations.
• The study validates the potential of Urtica dioica for dermatological and cosmetic applications due to its rich polyphenol content.