title: Antioxidant and genotoxic properties of South African herbal extracts.
abstract: This study investigated the antioxidant and genotoxic properties of 13 South African herbal extracts. Results from the single-cell gel electrophoresis (Comet) assay indicated that there were profound differences between the plant extracts in their ability to produce DNA damage, which varied from highly genotoxic to protective. Similarly, water and methanol extracts of all the herbal preparations showed variable potencies in scavenging hydroxyl radicals, as measured by means of electron spin resonance spectrometery (ESR) with the spin trap alpha-phenyl-N-tert-butylnitrone (PBN). In general, methanol extracts were better scavengers of hydroxyl radicals than the corresponding water extracts. This was also true of the ability of these extracts to inhibit membrane lipid peroxidation, assessed with diphenyl-1-pyrenylphosphine (DPPP). However, neither methanol nor water extracts had the ability to protect against DNA damage. The results show that further research on South African traditional herbal extracts is imperative to gain understanding of the mechanisms involved in their pharmacological effects. The tests implemented in the present investigation are recommended for screening other herbal extracts.
authors.affiliation: Department of Pharmacology, School of Medicine, Faculty of Health Sciences, University of Pretoria, P.O. Box 2034, Pretoria 0001, South Africa. vsteen@med.up.ac.za
authors.forename: Vanessa
authors.initials: V
authors.lastname: Steenkamp
authors.forename: Heidi
authors.initials: H
authors.lastname: Grimmer
authors.forename: Mpho
authors.initials: M
authors.lastname: Semano
authors.forename: Mary
authors.initials: M
authors.lastname: Gulumian
mesh_terms: D000975:Antioxidants / Q000494:pharmacology*; D020552:Comet Assay; D004247:DNA / Q000187:drug effects*; D004249:DNA Damage; D004578:Electron Spin Resonance Spectroscopy; D016166:Free Radical Scavengers / Q000378:metabolism; D006801:Humans; D017665:Hydroxyl Radical / Q000378:metabolism; D015227:Lipid Peroxidation; D008214:Lymphocytes / Q000187:drug effects* / Q000502:physiology; D016488:Medicine, African Traditional; D009153:Mutagens / Q000494:pharmacology*; D008517:Phytotherapy; D010936:Plant Extracts / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology; D028321:Plant Preparations / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology; D013019:South Africa
chemical_list: D000975:Antioxidants; D016166:Free Radical Scavengers; D009153:Mutagens; D010936:Plant Extracts; D028321:Plant Preparations; D017665:Hydroxyl Radical; D004247:DNA