title: Examination of the potential genotoxicity of pure capsaicin in bacterial mutation, chromosome aberration, and rodent micronucleus tests.
abstract: There is widespread dietary exposure to capsaicin in the form of chili peppers, while capsaicin's analgesic qualities have led to increased use of a topical herbal remedy in various impure forms. Most recently, injection of pure capsaicin has been proposed as a means of relieving a variety of debilitating diseases, in which case tissues would receive relatively high and direct exposure. The purpose of the present study, where a series of standard assays were performed in accordance with the Organisation for Economic Cooperation and Development guidance, was to clarify earlier conflicting reports concerning potential genotoxicity of capsaicin prior to administering it to patients in an injectable form. The results confirm the absence of genotoxic activity of high-purity capsaicin in the bacterial mutation and chromosome aberration tests. In addition, no evidence of cytotoxicity or genotoxicity was seen in the rat bone marrow micronucleus test, where systemic exposure to pure capsaicin was achieved using the subcutaneous route and a rising dose toleration protocol. It is concluded that pure capsaicin is not active in the standard battery of genotoxicity assays recommended by the International Conference on Harmonisation for evaluation of new medicines; earlier reported in vitro genotoxic activity is probably associated with mutagenic impurities in commercial grades of the material.
authors.affiliation: CTBR Bio-Research Inc., Montreal, Canada. rproudlock@ctbr.com
authors.forename: Raymond
authors.initials: R
authors.lastname: Proudlock
authors.forename: Crista
authors.initials: C
authors.lastname: Thompson
authors.forename: Eric
authors.initials: E
authors.lastname: Longstaff
mesh_terms: D000818:Animals; D001853:Bone Marrow / Q000187:drug effects; D002211:Capsaicin / Q000633:toxicity*; D002869:Chromosome Aberrations; D002876:Chromosomes, Bacterial / Q000235:genetics*; D004926:Escherichia coli / Q000187:drug effects* / Q000235:genetics; D006801:Humans; D008297:Male; D015162:Micronucleus Tests; D009152:Mutagenicity Tests; D009153:Mutagens / Q000633:toxicity*; D009154:Mutation; D051381:Rats; D017207:Rats, Sprague-Dawley; D012486:Salmonella typhimurium / Q000187:drug effects* / Q000235:genetics
chemical_list: D009153:Mutagens; D002211:Capsaicin