The Analgesic Acetaminophen and the Antipsychotic Clozapine can each Redox-Cycle with Melanin.

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TitleThe Analgesic Acetaminophen and the Antipsychotic Clozapine can each Redox-Cycle with Melanin.
Publication TypeJournal Article
Year of Publication2017
AuthorsTemoҫin, Z, Kim, E, Li, J, Panzella, L, Alfieri, MLaura, Napolitano, A, Kelly, DL, Bentley, WE, Payne, GF
JournalACS Chem Neurosci
Date Published2017 Sep 25

Melanins are ubiquitous but their complexity and insolubility has hindered characterization of their structures and functions. We are developing electrochemical reverse engineering methodologies that focus on properties and especially on redox properties. Previous studies have shown that melanins: (i) are redox-active and can rapidly and repeatedly exchange electrons with diffusible oxidants and reductants; and (ii) have redox potentials in mid-region of the physiological range. These properties suggest the functional activities of melanins will depend on their redox context. The brain has a complex redox context with steep local gradients in O2 that can promote redox-cycling between melanin and diffusible redox-active chemical species. Here, we performed in vitro reverse engineering studies and report that melanins can redox-cycle with two common redox-active drugs. Experimentally, we used two melanin models: a convenient natural melanin derived from cuttlefish (Sepia melanin) and a synthetic cysteinyldopamine-dopamine core-shell model of neuromelanin. One drug, acetaminophen (APAP) has been used clinically for over a century and recent studies suggest that low doses of APAP can protect the brain from oxidative stress-induced toxicity and neurodegeneration, while higher doses can have toxic effects in the brain. The second drug, clozapine (CLZ), is a second generation antipsychotic with polypharmacological activities that remain incompletely understood. These in vitro observations suggest that the redox activities of drugs may be relevant to their modes-of-action, and that melanins may interact with drugs in ways that affect their activities, metabolism and toxicities.

Alternate JournalACS Chem Neurosci
PubMed ID28945963