melphalan and lipoamide

In order to determine the role of glutathione reductase (GR) in protection against Alphtalocyanine tetrasulfonate-sensitized human erythrocyte photolysis, we have studied the effects of antitumour alkylating agents that inactivate GR, on photohemolysis rate. The rates of inactivation of reduced GR decreased in order BCNU > pharanox (N-p-[bis-(2-chloroethyl)-amino]-phenylacetic acid N-oxide) > phenalol (N-p-[bis-(2-chloroethyl)-amino]-phenylacetyl-L- phenylalanine) > o-F- and p-F-lophenal (o- and p-isomers of N-p-[bis-(2-chloroethyl)-amino]-phenylacetyl-D,L-fluorophenylalanine) > D,L-melphalan. As supposed, erythrocyte photolysis was accelerated by BCNU and pharanox, however, it was slowed down by phenylalanine mustards. The latter effect was explained by singlet oxygen quenching and/or photooxidation reactions of these compounds. This points out to a possibility of certain phenylalanine derivatives to neutralize the side-effects of photodynamic therapy.

Topics: Alkylating Agents; Carmustine; Glutathione Reductase; Hemolysis; Humans; Kinetics; Light; Melphalan; Oxidation-Reduction; Oxygen; Oxygen Consumption; Phenylacetates; Photolysis; Photosensitizing Agents; Singlet Oxygen; Thioctic Acid