Pyropheophorbide A Methyl Ester is a chlorophyll (C379815) analog for studies of photosynthesis. Methyl pyropheophorbide a (Pyropheophorbide-a methyl ester), a chlorophyll-a derivative, and is a potent photosensitizer that can be used in photodynamic therapy (PDT) of cancer. Methyl pyropheophorbide a has photodynamic activity and can induce apoptosis and inhibit tumor growth.