1.D.287.  The Menadione (MEN) Family

Menadione (MEN), a polycyclic aromatic ketone, promotes cell injury by imposing massive oxidative stress (Monteiro et al. 2013). Using native mitochondrial membranes, MEN was found to incorporate into membrane systems composed of various lipids.  The effects of MEN on membrane lipid organization caused increased permeability, monitored by calcein release which  seemed to correlate with the extent of MEN incorporation into membranes. MEN perturbed the physical properties of vesicles composed of dipalmitoylphosphatidylcholine or dipalmitoylphosphatidylethanolamine plus tetraoleoylcardiolipin (at 7:3 molar ratio), as reflected by the downshift of the lipid phase transition temperature and the emergence of a new transition peak in the mixed lipid system. MEN favored the formation of non-lamellar structures. MEN distributed across the bilayer thickness in both model and native mitochondrial membranes. MEN's ability to promote alterations of membrane lipid organization was related with its reported mitochondrial toxicity and promotion of apoptosis, predictably involved in its anti-carcinogenic activity (Monteiro et al. 2013).

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