2010 年 33 巻 5 号 p. 905-908
The relationship of chemical structures of 6-formylpterin (6FP) and its derivatives with scavenging activity of singlet oxygen (1O2) was examined. First, effects of pterin derivatives on 1O2 released from activated human neutrophils were examined. The neutrophils, stimulated with opsonized zymosan, released 1O2 that was detected by chemiluminescence using a 1O2 specific probe, trans-1-(2′-methoxyvinyl)pyrene. 6FP and its derivatives suppressed the 1O2 release. 6FP and other commercially available pterin derivatives, such as biopterin and neopterin, which have different substitutions at the 6-position, suppressed the 1O2 release with similar extent. On the other hand, newly synthesized pterin derivatives, which have different substitutions at the 2- and/or 3-position, such as 2-amino-6-formyl-3-methylpteridin-4-one, suppressed the 1O2 release in a dose-dependent manner and more potently than 6FP. Then, the 1O2 scavenging activity of pterin derivatives was examined photochemically by direct analysis of near-infrared luminescence at 1270 nm, the most sensitive method for the detection of 1O2. When rose Bengal, a photosensitizer, in D2O solution, was irradiated by 514 nm laser beam, the emission spectrum of 1O2 was observed. 6FP suppressed this emission spectrum of 1O2, and the newly synthesized pterin derivatives with different substituent at the 2- and/or 3-position suppressed the spectrum more potently than 6FP. The order of potency was similar to that obtained from biological assays. These findings indicate that the substitutions at the 2- and/or 3-position play an important role in 1O2 scavenging activity of pterin derivatives.
