title: Cucurbitacin glucosides: antioxidant and free-radical scavenging activities.
abstract: The cucurbitacins are of great interest because of the wide range of biological activities they exhibit in plants and animals. We studied the antioxidant properties of cucurbitacin B + E glucosides (cucurbitacin glucoside combination, CGC) and their direct free-radical scavenging properties, using ESR spectroscopy. Antioxidant activity was measured by the ability of the CGC to reduce preformed ABTS*+ into its native form and to inhibit MDA formation during the oxidation of linoleic acid. In both methods, the CGC exhibited antioxidant activity in a dose-dependent manner as expected from antioxidants. Using ESR spectroscopy, we found that the CGC inhibited *OH-dependent DEPMPO-OH adduct formation, O2*--dependent DEPMPO-OOH adduct formation, and the 1O2-dependent TEMPO adduct generated in the photoradiation-porphin system. The IC50 values were 0.38, 8, and 11 mM, respectively. Together, these data demonstrate that the CGC exhibits antioxidant properties, probably through the involvement of a direct scavenging effect on several free radicals.
authors.affiliation: The Mina & Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan 52900, Israel.
authors.forename: Tehila
authors.initials: T
authors.lastname: Tannin-Spitz
authors.forename: Margalit
authors.initials: M
authors.lastname: Bergman
authors.forename: Shlomo
authors.initials: S
authors.lastname: Grossman
mesh_terms: D000975:Antioxidants / Q000494:pharmacology*; D054728:Cucurbitacins / Q000494:pharmacology*; D004578:Electron Spin Resonance Spectroscopy; D016166:Free Radical Scavengers / Q000494:pharmacology*; D005960:Glucosides / Q000494:pharmacology*; D017665:Hydroxyl Radical / Q000737:chemistry; D019787:Linoleic Acid / Q000737:chemistry; D010084:Oxidation-Reduction; D026082:Singlet Oxygen / Q000737:chemistry; D013481:Superoxides / Q000737:chemistry; D014315:Triterpenes / Q000494:pharmacology
chemical_list: D000975:Antioxidants; D016166:Free Radical Scavengers; D005960:Glucosides; D014315:Triterpenes; C041246:cucurbitacin B; D013481:Superoxides; D026082:Singlet Oxygen; D017665:Hydroxyl Radical; D054728:Cucurbitacins; D019787:Linoleic Acid; C102326:cucurbitacin E