The photosensitization activity of a water-soluble carboxylate of hypocrellin B

Based on theoretical prediction of the molecular polarity, water-soluble sodium HB-14-carboxylate (SCHB) was prepared and its photosensitization activity was evaluated. SCHB shows not only very good amphiphilicity but also much stronger absorption at 620 nm than its parents. In DMSO-PBS (3:1 by volume) solution (pH 7.4) of SCHB, the photosensitization generated the semiquinone anion radicals (SCHB−) under anaerobic condition or superoxide anion radicals (O2−) in the presence of oxygen. In the oxygenated PBS solution of SCHB, hydroxyl radicals (OH) were photogenerated. In addition, SCHB could also be photosensitized to generate singlet oxygen (1O2) with a quantum yield about 0.26. These findings suggest that SCHB can exert photodynamic action via photosensitization.