title: The alkaloid brachycerine is induced by ultraviolet radiation and is a singlet oxygen quencher.
abstract: The effects of ultraviolet (UV) radiation on chlorophyll content and accumulation of the anti-inflammatory monoterpene-indole alkaloid brachycerine in plants and calli of Psychotria brachyceras (Rubiaceae) were investigated. In this study, we also investigated a protective role for brachycerine against stress conditions. Calli and tip cuttings incubated in nutrient media were daily supplemented with 4 or 16 h of UV. High-performance liquid chromatography analyses of methanolic extracts showed only traces of brachycerine in irradiated aseptic cultures, with no alkaloid being observed in control calli. In cuttings, a 10-fold increase in brachycerine content was seen after exposure for 16 h to UV-C, whereas a 4 h daily supplementation doubled the amount of the alkaloid in leaves. Exposure to a UV-B source also doubled the alkaloid yield. In vitro brachycerine was able to quench singlet oxygen. The data indicate a potential protective role for brachycerine against UV radiation, acting as a UV filter (absorption peaks are within the UV range) and a reactive oxygen species scavenger. In addition, UV radiation may be used to increase yields of this compound of pharmaceutical interest.
authors.affiliation: Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil.
authors.forename: Tatiana S
authors.initials: TS
authors.lastname: Gregianini
authors.forename: Vivian C
authors.initials: VC
authors.lastname: da Silveira
authors.forename: Diogo D
authors.initials: DD
authors.lastname: Porto
authors.forename: Vitor A
authors.initials: VA
authors.lastname: Kerber
authors.forename: Amelia T
authors.initials: AT
authors.lastname: Henriques
authors.forename: Arthur G
authors.initials: AG
authors.lastname: Fett-Neto
mesh_terms: D007211:Indoles / Q000378:metabolism*; D039821:Monoterpenes / Q000378:metabolism*; D032069:Psychotria / Q000737:chemistry / Q000528:radiation effects*; D026082:Singlet Oxygen / Q000737:chemistry*; D014466:Ultraviolet Rays
chemical_list: D007211:Indoles; D039821:Monoterpenes; C433964:brachycerine; D026082:Singlet Oxygen