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

Antimutagenic activity of proteins (lectins) fraction from herb of Nettle

Plant lectins are non-enzymic and non-immune origin proteins that specifically recognize and bind to various sugar structures and possess the activity to agglutinate cells and/or precipitate polysaccharides and glycoconjugates. The emerging evidences showed that plant lectins contribute not only to tumour cell recognition but also to cell adhesion and localization, to signal transduction, to mitogenic cytotoxicity and apoptosis. The aim of the study was to evaluation the antimutagenicity and the cytotoxicity of a lectin-enriched fraction from Nettle herb. The antimutagenicity was studied in a bacterial reverse mutation assay (Ames test), both in the absence and presence of an exogenous metabolic activator S9 (the liver postmitochondrial supernatant of rats treated with the mixture phenobarbital/β-naphthoflavone to induce the hepatic microsomal enzymes). Cytotoxicity was determined by the tetrazolium dye (MTT) colorimetric assay in HepG2 human hepatoblastoma cell line. The fraction did not display any significant reduction in the cell viability of HepG2 cells. Conversely, it inhibited the antimutagenic effect of the mutagen 2AA (2-aminoanthracene) in all strains tested

Antimutagenic activity of proteins (lectins) fraction from herb of Nettle.

Plant lectins are non-enzymic and non-immune origin proteins that specifically recognize and bind to various sugar structures and possess the activity to agglutinate cells and/or precipitate polysaccharides and glycoconjugates. The emerging evidences showed that plant lectins contribute not only to tumour cell recognition but also to cell adhesion and localization, to signal transduction, to mitogenic cytotoxicity and apoptosis. The aim of experiment. Evaluation of antimutagenicity and cytotoxicity of a lectin-enriched protein fraction from Nettle herb. Material and methods. Lectin-enriched protein fraction was obtained from the herb of Urtica dioica L. The antimutagenicity was studied in a bacterial reverse mutation assay (Ames test), both in the absence and presence of an exogenous metabolic activator S9 (the liver postmitochondrial supernatant of rats treated with the mixture phenobarbital/ β-naphthoflavone to induce the hepatic microsomal enzymes). A set of three strains, S. typhimurium TA98 (hisD3052galbiochl1008rfa1001 ΔuvrBpKM101), S. typhimurium TA100 (hisG56galbiochl1005rfa1004ΔuvrB pKM101) and E. coli WP2uvrA (trpE65ΔuvrA), was used. Cytotoxicity was determined by the tetrazolium dye (MTT) colorimetric assay in HepG2 human hepatoblastoma cell line. Results. Lectin-enriched protein fraction did not display any significant reduction in the cell viability of HepG2 cells, neither after 24 h nor after 48 h of treatment. Lectin-enriched protein fraction showed antimutagenic effect against 2AA (2-aminoanthracene), which reached, at the highest concentration tested, the maximal inhibition of 56%, 78% and 61% in TA98, TA100 and WP2uvrA strains, respectively. In contrast, lectin-enriched fraction produced no significant antimutagenic effects (maximal inhibition < 25%) against 2NF (2-nitrofluorene), SA (sodium azide), MMS (methyl methanesulfonate). Conclusions. Lectin-enriched protein fraction did not inhibited the cell proliferation in tumour hepatic HepG