title: Effects of humic acids in vitro.
abstract: Humic acids are known for their overall positive health and productivity effects in animal feeding trials and, controversially, as an aetiological factor of cancer. We tried to assess the in vitro effect of humic acids from a selected source in Slovakia when used at recommended prophylactic dosage. We investigated antioxidant properties, enzymatic and non-enzymatic antioxidant defence system in liver mitochondria and cultured cancer cell lines in vitro. We observed a significant decrease in superoxide dismutase activity after humic acids treatment irrespective of dissolving in dimethyl sulphoxide or direct addition to mitochondria suspension in a respiration medium. Activities of other antioxidant enzymes measured, such as glutathione peroxidase and glutathione reductase, showed no significant differences from the control as well as the reduced glutathione content. Percentage of inhibition by humic acids of superoxide radical indicated lower efficacy compared with that of hydroxyl radical. Survival of six different cancer cells lines indicated that only the acute T lymphoblastic leukaemia cell line was sensitive to the tested humic acids. Despite relatively low solubility in aqueous solutions, humic acids from the selected source participated in redox regulation. By recapturing the radicals, humic acids reloaded the antioxidant defensive mechanism. Results from in vitro study conducted with humic acids from the natural source showed potential of these substances as promising immunity enhancing agents.
authors.affiliation: Department of Medical Chemistry, Biochemistry and Clinical Biochemistry, Faculty of Medicine, Pavol Jozef Šafárik University in Košice, Tr. SNP 1, 040 11, Košice, Slovak Republic. janka.vaskova@upjs.sk
authors.forename: Janka
authors.initials: J
authors.lastname: Vašková
authors.forename: Beáta
authors.initials: B
authors.lastname: Veliká
authors.forename: Martina
authors.initials: M
authors.lastname: Pilátová
authors.forename: Ivan
authors.initials: I
authors.lastname: Kron
authors.forename: Ladislav
authors.initials: L
authors.lastname: Vaško
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000378:metabolism / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D006367:HeLa Cells; D006801:Humans; D006812:Humic Substances; D017665:Hydroxyl Radical / Q000378:metabolism; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D013482:Superoxide Dismutase / Q000378:metabolism; D014407:Tumor Cells, Cultured
chemical_list: D000975:Antioxidants; D006812:Humic Substances; D017665:Hydroxyl Radical; D013482:Superoxide Dismutase