Degradation of phorbol 12,13-diacetate in aqueous solution by gamma irradiation

Phorbol esters (PEs) are highly toxic compounds that cause skin irritation, inflammation, and tumor promotion upon contact with humans or animals. These compounds are naturally present in Jatropha curcas L To promote the use of J. curcas seed oil in bio-diesel production industries and reduce environmental concerns, it is necessary to find methods of degrading PEs. In this study, the degradation of phorbol 12,13-diacetate (PDA), as a representative PE, in aqueous solution at a concentration of 10 mg/L by Co-60-gamma-irradiation was investigated. The results demonstrate that PDA was effectively degraded by this treatment and the degradation efficiency increased with the absorbed dose within the range of 0.5-3 kGy. Complete degradation of PDA was achieved at a dose of 3 kGy. In the presence of radical scavengers (i.e., methanol, tert-butanol, 2-propanol), reactive species from water radiolysis were scavenged, and significant inhibition of PDA degradation was observed at absorbed doses less than 1 kGy. In the presence of nitrous oxide, the generation of hydroxyl radicals (center dot OH) was promoted during gamma irradiation and PDA degradation was drastically enhanced. (C) 2014 Elsevier Ltd. All rights reserved.