For making hypocrellins clinically applicable for
phototherapy to
vascular diseases, it is mainly focused onto finding a derivative which can be transported fluently in blood system but without serious loss of the inherent activity of its parents. Based on this consideration, a novel 17-3-amino-1-propane-sulfonic
acid-HB
Schiff-base (NSHB) was designed and synthesized in this work. As expected, NSHB is readily dissolved in
phosphate buffered saline (PBS) or any other aqueous
solvent in a concentration which is suitable for
intravenous injection, while the quite higher partition coefficient (5:1) is beneficial to the affinity to
biological targets. Based on EPR measurements, it is proved that the
photosensitization activity of NSHB to photo-generate
semiquinone anion radicals and
superoxide anion radical (O*(2)(-)) is even higher than its parent HB, while the ability to generate
singlet oxygen ((1)O(2)) is not seriously reduced. In addition, nearly comparable
PDT activity to A549 cells for NSHB and HB confirms that the molecular design is successful and NSHB is readily delivered into target tissues via blood circulation after
intravenous injection. Furthermore, the quantum yield of (1)O(2) for NSHB is as 12.5 times as that for HB under red light (600-700 nm), which is beneficial to
phototherapy to solid
tumors.