Antimutagenic and antioxidant activity of a protein fraction from aerial parts of Urtica dioica

Abstract

Context: Urtica dioica L. (Urticaceae), stinging nettle, has been employed as a folklore remedy for a wide spectrum of ailments, including urinary disorders, prostatic hyperplasia, and liver diseases. It has been also used traditionally for cancer treatment.

Object: To evaluate the potential chemopreventive properties of a protein fraction from the aerial part of Urtica dioica (namely UDHL₃₀).

Materials and methods: UDHL₃₀ has been tested for the antimutagenic activity in bacteria (50–800?μg/plate; Ames test by the preincubation method) and for the cytotoxicity on human hepatoma HepG2 cells (0.06–2?mg/mL; 24 and 48?h incubation). Moreover, the antioxidant activity of UDHL₃₀ (0.1–1200?μg/mL; ABTS and superoxide-radical scavenger assays) was evaluated as potential protective mechanisms.

Results: UDHL₃₀ was not cytotoxic on HepG2 cells up to 2?mg/mL; conversely, it exhibited a strong antimutagenic activity against the mutagen 2-aminoanthracene (2AA) in all strains tested (maximum inhibition of 56, 78, and 61% in TA98, TA100, and WP2uvrA strains, respectively, at 800?μg/plate). In addition, a remarkable scavenging activity against ABTS radical and superoxide anion (IC₅₀ values of 19.9?±?1.0?μg/mL and 75.3?±?0.9?μg/mL, respectively) was produced.

Discussion and conclusions: UDHL₃₀ possesses antimutagenic and radical scavenging properties. Being 2AA a pro-carcinogenic agent, we hypothesize that the antimutagenicity of UDHL₃₀ can be due to the inhibition of CYP450-isoenzymes, involved in the mutagen bioactivation. The radical scavenger ability could contribute to 2AA-antimutagenicity. These data encourage further studies in order to better define the potential usefulness of UDHL₃₀ in chemoprevention.