Hypericin is a photosensitizing plant pigment from Hypericum perforatum with multiple modes of light-induced biological activities due to production of singlet oxygen and/or excited-state proton transfer with consequent pH drop in the hypericin environment. In the present work, we studied the effects of three inhibitors of crucial mechanisms responsible for intracellular pH (pHi) regulation on ...

Cell death triggered by photodynamic therapy can occur through different mechanisms: apoptosis, necrosis or autophagy. However, recent studies have demonstrated the existence of other mechanisms with characteristics of both necrosis and apoptosis. These new cell death pathways, collectively termed regulated necrosis, include a variety of processes triggered by different stimuli. In this study, ...

Abstract Photodynamic therapy (PDT) is a promising cancer treatment with fewer side effects, and it eliminates tumors in target tissues reactive oxygen species produced by photosensitizers (PS) light. In this study, we isolated methyl pheophorbide A, which induces photodynamic cell death the U937 SK-HEP-1 cells, from perilla leaves. Its potential as material for development of new PS was also e...

Keloid is a common and refractory disease characterized by abnormal fibroblast proliferation and excessive deposition of extracellular matrix components. Hypocrellin B (HB) is a natural perylene quinone photosensitizer. In this experiment, we studied the effects of photodynamic therapy (PDT) using yellow light from light-emitting diode (LED) combined with HB on keloid fibroblasts (KFB) in vitro...

The present studies were undertaken to characterize further the potential role of protein kinase C (PKC) in the regulation of apoptosis in HL-60 promyelocytic leukemia cells. The capacity of acute exposure to specific and nonspecific pharmacological inhibitors of PKC to promote apoptotic DNA fragmentation was examined both quantitatively and qualitatively and correlated with effects on cellular...

Hypericin is a pigment present in the widely distributed medicinal plant Hypericum perforatum L. (Hypericaceae). In our research, hypericin was found to be an inhibitor of NADPH/Fe 2+ induced microsomal lipid peroxidation and NADPH-dependent lucigenin chemiluminescence emission in vitro. Hypericin also inhibited the microsomal CYP1Adependent 7-ethoxyresorufin O-deethylase (EROD) which participa...

PURPOSE Ocular neovascularization is a leading cause of blindness in ischemic retinopathies. Hypericin is an active ingredient in the medical herb St. John's Wort (SJW). Because hypericin inhibits intracellular signaling pathways that are believed to participate in the regulation of angiogenesis, we investigated the actions of hypericin and SJW in retinal neovascularization, using a mouse model...