title: Antioxidant potential of natural and synthesised polyprenylated hydroquinones.
abstract: The metabolites 2-octaprenyl-1,4-hydroquinone (1) and 2-(24-hydroxy)-octaprenyl-1,4-hydroquinone (2), isolated from the sponge Ircinia spinosula, along with a series of synthetic derivatives, were evaluated for their antioxidant capacity, in order to establish a potential relationship between structural characteristics and antioxidant activity. The antioxidant potential of both natural and synthesised compounds was evaluated in vitro by their ability: (1) to interact with the stable free 1,1-diphenyl-2-picrylhydrazyl radical (DPPH) and (2) to inhibit the peroxidation, induced by the Fe(++)/ascorbate system, of heat inactivated hepatic microsomal membrane lipids. Metabolite 1 presented a strong interaction with DPPH and had a moderate effect on lipid peroxidation, while metabolite 2 interacted extensively with DPPH and exhibited a significant effect against lipid peroxidation. All derivatives retaining the free 1,4-hydroquinone system maintained fully or partly the free radical scavenging capacity.
authors.affiliation: School of Pharmacy, Department of Pharmacognosy, University of Athens, Panepistimiopolis Zografou, 157 71, Athens, Greece.
authors.forename: Leto-A
authors.initials: LA
authors.lastname: Tziveleka
authors.forename: Angeliki P
authors.initials: AP
authors.lastname: Kourounakis
authors.forename: Panos N
authors.initials: PN
authors.lastname: Kourounakis
authors.forename: Vassilios
authors.initials: V
authors.lastname: Roussis
authors.forename: Constantinos
authors.initials: C
authors.lastname: Vagias
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000138:chemical synthesis / Q000302:isolation & purification / Q000494:pharmacology*; D001713:Biphenyl Compounds; D002070:Butadienes; D005260:Female; D005609:Free Radicals / Q000037:antagonists & inhibitors; D006873:Hydroquinones / Q000138:chemical synthesis / Q000302:isolation & purification / Q000494:pharmacology*; D007700:Kinetics; D015227:Lipid Peroxidation / Q000187:drug effects; D010851:Picrates / Q000037:antagonists & inhibitors; D011161:Porifera / Q000737:chemistry*; D051381:Rats; D011916:Rats, Inbred F344; D013329:Structure-Activity Relationship
chemical_list: D000975:Antioxidants; D001713:Biphenyl Compounds; D002070:Butadienes; D005609:Free Radicals; D006873:Hydroquinones; D010851:Picrates; C004931:1,1-diphenyl-2-picrylhydrazyl