Toxicity of imine-iminium dyes and pigments: electron transfer, radicals, oxidative stress and other physiological effects.
Although conjugation is well known as an important contributor to color, there is scant recognition concerning involvement of imine and iminium functions in the physiological effects of this class of dyes and pigments. The group includes the dyes methylene blue, rhodamine, malachite green, fuchsin, crystal violet, auramine and cyanins, in addition to the pigments consisting of pyocyanine, phthalocyanine and pheophytin. The physiological effects consist of both toxicity and beneficial aspects. The unifying theme of electron transfer-reactive oxygen species-oxidative stress is used as the rationale in both cases. Toxicity is frequently prevented or alleviated by antioxidants. The apparent dichotomy of methylene blue action as both oxidant and antioxidant is rationalized based on similar previous cases. This mechanistic approach may have practical benefit. This review is important in conveying, for the first time, a unifying mechanism for toxicity based on electron transfer-reactive oxygen species-oxidative stress arising from imine-iminium.
Department of Chemistry and Biochemistry, San Diego State University, San Diego, CA, USA.
Peter
P
Kovacic
Ratnasamy
R
Somanathan
D000818:Animals; D001576:Benzophenoneidum / Q000737:chemistry / Q000633:toxicity; D004396:Coloring Agents / Q000737:chemistry / Q000633:toxicity*; D004195:Disease Models, Animal; D004579:Electron Transport; D006801:Humans; D007097:Imines / Q000737:chemistry / Q000633:toxicity*; D007211:Indoles / Q000737:chemistry / Q000633:toxicity; D054833:Isoindoles; D008751:Methylene Blue / Q000737:chemistry / Q000633:toxicity; D018384:Oxidative Stress / Q000187:drug effects*; D010674:Pheophytins / Q000737:chemistry / Q000633:toxicity; D011710:Pyocyanine / Q000737:chemistry / Q000633:toxicity; D017382:Reactive Oxygen Species / Q000378:metabolism*; D012235:Rhodamines / Q000737:chemistry / Q000633:toxicity; D012394:Rosaniline Dyes / Q000737:chemistry / Q000633:toxicity; D014320:Triphenylmethyl Compounds / Q000737:chemistry / Q000633:toxicity
D004396:Coloring Agents; D007097:Imines; D007211:Indoles; D054833:Isoindoles; D010674:Pheophytins; D017382:Reactive Oxygen Species; D012235:Rhodamines; D012394:Rosaniline Dyes; D014320:Triphenylmethyl Compounds; C005095:malachite green; D001576:Benzophenoneidum; C046945:triphenylmethane; D011710:Pyocyanine; D008751:Methylene Blue; C013647:phthalocyanine
dyes; electron transfer; imine-iminium; physiological effects; pigments; radicals