Photoprotective Effect of the PlantCollaea argentinaagainst Adverse Effects Induced by Photodynamic Therapy

Leandro Mamone,Adriana Casas,Pablo Vallecorsa,Daniel Sáenz,Gabriela Di Venosa,Alcira Batlle

doi:10.1155/2014/436463

Abstract

Photodynamic therapy (PDT) is a treatment modality for tumours and other accessible lesions based on the combination of light and a photosensitizer (PS) accumulated in the target tissue. The main disadvantage of PDT is PS retention after treatment during long time periods that conduces to cutaneous damage. It is believed that singlet oxygen is responsible for that skin photosensitization. The aim of this work was to evaluate the photoprotective activity of the methanolic extract of the Argentinian plantCollaea argentinaagainst PDT under several treatments and employing different PSs.C. argentinaexhibited photoprotective activity against aminolevulinic acid- (ALA-) PDT in the LM2 murine adenocarcinoma cell line. The photoprotection was dependant on the extract concentration and the incubation time, being detectable from 40 μg/mL onwards and at least after 3 h exposure of the cells.C. argentinaextract protects these mammalian tumor cells against PDT effects, and it interferes with the oxygen singlet production from PSs during PDT treatment. We propose that it will be a promising agent to protect cells against PDT-induced skin sensitivity.

Highlights

Photodynamic therapy (PDT) is a treatment modality for tumors and other accessible lesions
Two molecules of Aminolevulinic acid (ALA) are converted into porphobilinogen, reaction mediated by porphobilinogen synthase, and 5 other enzymes, 3 cytosolic and 2 mitochondrial, which lead to the formation of protoporphyrin IX (PpIX), which is a very efficient photosensitizer
We evaluated the effect of C. argentina extract to abrogate aminolevulinic acid- (ALA-)PDT induced phototoxicity in LM2 cells (Figure 3), employing ALA-PDT conditions taken from previous work [15]

Summary

Introduction

Photodynamic therapy (PDT) is a treatment modality for tumors and other accessible lesions. It is based on the combination of light and a photosensitizer (PS), which is a lightsensitive drug selectively accumulated in the target tissue [1]. The cytotoxic effect of these species, through its reaction with cellular targets such as proteins, lipids, and DNA, is the rationale for the use of PDT in the treatment of cancer. While ALA itself is neither fluorescent nor a photosensitiser, it can induce the biochemical formation of protoporphyrin IX (PpIX). Two molecules of ALA are converted into porphobilinogen, reaction mediated by porphobilinogen synthase, and 5 other enzymes, 3 cytosolic and 2 mitochondrial, which lead to the formation of PpIX, which is a very efficient photosensitizer. Photodynamic action of PpIX is mainly induced by the generation of singlet oxygen in a type

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