Inactivation ofPlasmodium falciparumby Photodynamic Excitation of Heme‐Cycle Intermediates Derived from δ‐Aminolevulinic Acid

Abstract

Transfusion-transmitted malaria (TTM), especially that caused by Plasmodium falciparum, is of great concern in malaria-endemic areas. As a result of increased international travel, migration, and the spread of drugresistant parasites, TTM is also a growing problem in industrialized nations. An effective and inexpensive means of inactivating malaria parasites in blood products would represent an important advance. In this report, we demonstrate that photoactivation of plasmodial heme-cycle intermediates, derived from supplemental d-aminolevulinic acid (ALA), by exposure to simple white light in the presence of ALA, reduces P. falciparum in culture to levels that are undetectable by light microscopy or lactate dehydrogenase assay. Photodynamic excitation of presumed heme-cycle intermediates, which was revealed by fluorescence microscopy, did not appear to adversely affect the viability of erythrocytes. These data suggest that this pathogeninactivation strategy, which uses inexpensive reagents and white light, may represent an appropriate means of inactivating malaria parasites in blood products in resource-poor settings.

Photodynamic therapy based on 5‐aminolevulinic acid and its use as an antimicrobial Agent

“…) . It would seem that each of these biosynthetic pathways has the potential for exploitation by ALA‐based PDT and consistent with this observation, a recent in vitro study demonstrated that the technique was able to induce the accumulation of endogenous porphyrins in P. falciparum when present in parasitized erythrocytes with inactivation of the organism resulting . It was suggested by these latter authors that ALA‐based PDT should be further tested for the potential to act as a blood decontaminant not only for malaria parasites but also for other parasitic threats such Babesia spp, Toxoplasma gondii, Trypanosoma cruzi, and Leishmania spp.…”

Photoantimicrobials and Photodynamic Antimicrobial Therapy in Search of Antibiotics

“…Akuatik ekosistemde parazit kontrolünü sağlamak için klorofil türevleri kullanılmış ve bu bileşiğin sinek larvaları üzerine öldü-rücü etki gösterdiği saptanmıştır (16) . Bundan başka kan ürünlerinden Malaria etkeninin inaktive edilmesinde de FDAT yararlanıla-bileceği belirtilmektedir (44) .…”

Light based anti-infectives: ultraviolet C irradiation, photodynamic therapy, blue light, and beyond

“…Phthalocyanines (one of the most effective, HOSiPcOSi(CH,),(CH,),N(CH,), (Pc 4) ), illuminated by red light, manifested the photoinactivation of P. falciparum parasitized in red cells in a dose-dependent manner and could be used to make blood components safe [151]. Another study demonstrated that ALA-induced inactivation of plasmodial heme-cycle intermediates, by exposure to white light, reduced P. falciparum in culture to levels such that they were not detectable by light microscopy nor by lactate dehydrogenase assay [152]. …”