title: Generation of ROS mediated by mechanical waves (ultrasound) and its possible applications.
abstract: The thermal decomposition of 9,10 diphenylanthracene peroxide (DPAO2) generates DPA and a mix of triplet and singlet molecular oxygen. For DPAO2the efficiency to produce singlet molecular oxygen is 0.35. On the other hand, it has shown that many thermal reactions can be carried out through the interaction of molecules with ultrasound. Ultrasound irradiation can create hydrodynamic stress (sonomechanical process), inertial cavitation (pyrolitic process) and long range effects mediated by radicals or ROS. Sonochemical reactions can be originated by pyrolytic like process, shock mechanical waves, thermal reactions and radical and ROS mediated reactions. Sonolysis of pure water can yield hydrogen or hydroxyl radicals and hydrogen peroxide (ROS). When DPAO2in 1,4 dioxane solution is treated with 20 or 24kHz and different power intensity the production of molecular singlet oxygen is observed. Specific scavengers like tetracyclone (TC) are used to demonstrate it. The efficiency now is 0.85 showing that the sonochemical process is much more efficient that the thermal one. Another endoperoxide, artemisinin was also studied. Unlike the concept of photosensitizer of photodynamic therapy, in spite of large amount of reported results in literature, the term sonosensitizer and the sonosensitization process are not well defined. We define sonosensitized reaction as one in which a chemical species decompose as consequence of cavitation phenomena producing ROS or other radicals and some other target species does undergo a chemical reaction. The concept could be reach rapidly other peroxides which are now under experimental studies. For artemisinin, an important antimalarian and anticancer drug, was established that ultrasound irradiation increases the effectiveness of the treatment but without any explanation. We show that artemisinin is an endoperoxide and behaves as a sonosensitizer in the sense of our definition.
authors.affiliation: Dpto. de Química, Facultad de Ciencias Exactas Físico Químicas y Naturales, Universidad Nacional de Río Cuarto, Ruta 36 km 601, CP 5800 Río Cuarto, Argentina.
authors.forename: Walter
authors.initials: W
authors.lastname: Duco
authors.affiliation: Dpto. de Química, Facultad de Ciencias Exactas Físico Químicas y Naturales, Universidad Nacional de Río Cuarto, Ruta 36 km 601, CP 5800 Río Cuarto, Argentina.
authors.forename: Viviana
authors.initials: V
authors.lastname: Grosso
authors.affiliation: Dpto. de Fisica, Facultad de Ciencias Exactas Físico Químicas y Naturales, Universidad Nacional de Río Cuarto, Ruta 36 km 601, CP 5800 Río Cuarto, Argentina.
authors.forename: Daniel
authors.initials: D
authors.lastname: Zaccari
authors.affiliation: Dpto. de Química, Facultad de Ciencias Exactas Físico Químicas y Naturales, Universidad Nacional de Río Cuarto, Ruta 36 km 601, CP 5800 Río Cuarto, Argentina. Electronic address: asolterman@exa.unrc.edu.ar.
authors.forename: Arnaldo T
authors.initials: AT
authors.lastname: Soltermann
mesh_terms: D000873:Anthracenes / Q000737:chemistry; D000970:Antineoplastic Agents / Q000737:chemistry / Q000627:therapeutic use; D037621:Artemisinins / Q000737:chemistry*; D005609:Free Radicals / Q000737:chemistry; D006801:Humans; D006861:Hydrogen Peroxide / Q000737:chemistry*; D017665:Hydroxyl Radical / Q000737:chemistry* / Q000528:radiation effects; D017382:Reactive Oxygen Species / Q000737:chemistry* / Q000528:radiation effects; D026082:Singlet Oxygen / Q000737:chemistry; D000069453:Ultrasonic Waves
chemical_list: D000873:Anthracenes; D000970:Antineoplastic Agents; D037621:Artemisinins; D005609:Free Radicals; D017382:Reactive Oxygen Species; C075429:9,10-diphenylanthracene endoperoxide; D026082:Singlet Oxygen; D017665:Hydroxyl Radical; C031327:artemisinin; D006861:Hydrogen Peroxide; C034020:anthracene
keywords: Cancer treatment; Cavitation phenomena; Endoperoxides; Singlet molecular oxygen; Sonodynamic effect; Sonosensitizer