title: S-allylcysteine scavenges singlet oxygen and hypochlorous acid and protects LLC-PK(1) cells of potassium dichromate-induced toxicity.
abstract: It has been found that S-allylcysteine (SAC), a garlic-derived compound, has in vivo and in vitro antioxidant properties. In addition, it is known that SAC is able to scavenge different reactive oxygen or nitrogen species including superoxide anion (O(2)(-)), hydrogen peroxide (H(2)O(2)), hydroxyl radical (OH()), and peroxynitrite anion (ONOO(-)) although the IC(5O) values for each reactive species has not been calculated and the potential ability of SAC to scavenge singlet oxygen ((1)O(2)) and hypochlorous acid (HOCl) has not been explored. The purposes of this work was (a) to explore the potential ability of SAC to scavenge (1)O(2) and HOCl, (b) to further characterize the O(2)(-), H(2)O(2), OH(), and ONOO(-) scavenging ability of SAC by measuring the IC(50) values using in vitro assays, and (c) to explore the potential ability of SAC to ameliorate the potassium dichromate (K(2)Cr(2)O(7))-induced cytotoxicity in LLC-PK1 cells in which oxidative stress is involved. The scavenging activity was compared against the following reference compounds: N-acetylcysteine for O(2)(-), sodium pyruvate for H(2)O(2), dimethylthiourea for OH(), lipoic acid and glutathione for (1)O(2), lipoic acid for HOCl, and penicillamine for ONOO(-). It was found that SAC was able to scavenge concentration-dependently all the species assayed with the following IC(5O) (mean+/-SEM, mM): O(2)(-) (14.49+/-1.67), H(2)O(2) (68+/-1.92), OH() (0.68+/-0.06), (1)O(2) (1.93+/-0.27), HOCl (2.86+/-0.15), and ONOO(-) (0.80+/-0.05). When the ability of SAC to scavenge these species was compared to those of the reference compounds it was found that the efficacy of SAC (a) to scavenge O(2)(-), H(2)O(2), OH(), and ONOO(-) was lower, (b) to scavenge HOCl was similar, and (c) to scavenge (1)O(2) was higher. In addition, it was found that SAC was able to prevent K(2)Cr(2)O(7)-induced toxicity in LLC-PK1 cells in culture. It was showed for the first time that SAC is able to scavenge (1)O(2) and HOCl and to ameliorate the K(2)Cr(2)O(7)-induced toxicity.
authors.affiliation: Facultad de Química, Departamento de Biología, Edificio F, Sequndo Piso, Laboratorio 209, Universidad Nacional Autónoma de México (UNAM), Ciudad Universitaria, 04510, D.F., Mexico.
authors.forename: Omar Noel
authors.initials: ON
authors.lastname: Medina-Campos
authors.forename: Diana
authors.initials: D
authors.lastname: Barrera
authors.forename: Sabina
authors.initials: S
authors.lastname: Segoviano-Murillo
authors.forename: Diana
authors.initials: D
authors.lastname: Rocha
authors.forename: Perla D
authors.initials: PD
authors.lastname: Maldonado
authors.forename: Nicandro
authors.initials: N
authors.lastname: Mendoza-Patiño
authors.forename: José
authors.initials: J
authors.lastname: Pedraza-Chaverri
mesh_terms: D000818:Animals; D002470:Cell Survival / Q000187:drug effects; D003545:Cysteine / Q000031:analogs & derivatives* / Q000494:pharmacology; D016166:Free Radical Scavengers; D006861:Hydrogen Peroxide / Q000737:chemistry; D017665:Hydroxyl Radical / Q000737:chemistry; D006997:Hypochlorous Acid / Q000737:chemistry*; D018374:LLC-PK1 Cells; D011192:Potassium Dichromate / Q000037:antagonists & inhibitors* / Q000633:toxicity*; D019289:Pyruvic Acid / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000737:chemistry*; D013481:Superoxides / Q000737:chemistry; D013552:Swine; D008063:Thioctic Acid / Q000378:metabolism; D013890:Thiourea / Q000031:analogs & derivatives / Q000378:metabolism
chemical_list: D016166:Free Radical Scavengers; D017382:Reactive Oxygen Species; D013481:Superoxides; D017665:Hydroxyl Radical; D006997:Hypochlorous Acid; D008063:Thioctic Acid; C065299:S-allylcysteine; D019289:Pyruvic Acid; C038983:1,3-dimethylthiourea; D006861:Hydrogen Peroxide; D013890:Thiourea; D003545:Cysteine; D011192:Potassium Dichromate