Photodynamic activity of anthra and Napthoquinones from thespesia Populnea and ervatamia coroneria Plants and some synthetic coumarins

Abstract

Photodynamic therapy has emerged as one of the modalities in the newlinetreatment of malignant and non malignant diseases Basically this technique newlineinvolves the combined action of photosensitizer light photons and molecular newlineoxygen through the formation of biologically active species singlet oxygen newlinethat are resulting cellular necrosis and or apoptosis Current limitations of newlineporphyrin based photosensitizers have promoted search for more ideally newlinesuited sensitizers In recent years increasing attention has also been paid newlineto the photodynamic action of quinones With quinones as photosensitizer newline singlet oxygen resulting from energy transfer from the triplet newlinestate sensitizer Type II photo mechanism to ground state molecular oxygen newlineis believed to be the phototoxic agent in the photodynamic action Electron newlinetransfer from the photoexcited sensitizers to oxygen to form superoxide anion newlineis a Type I photo mechanism newline newline