Bacteriochlorophyll a and Its Derivatives: Chemistry and Perspectives for Cancer Therapy

The review summarizes the chemistry of the third generation of photosensitizers, namely, the derivatives of natural bacteriochlorophyll a for photodynamic treatment of cancer. The compounds of this class strongly absorb light at λ=770-850 nm. This unique property opens new therapeutic opportunities due to deeper tissue penetration of light, thereby increasing the photodamage for tumor eradication. Analyzed are the modifications of bacteriochlorophyll a that improve physico-chemical characteristics of compounds and enhance accumulation in tumors. Focusing on the delivery of photosensitizers to the tumor site and to specific intracellular compartments, we describe the conjugates of bacteriochlorophyll a derivatives with carbohydrate and protein carriers. Boronated bacteriochlorins can be used in both photodynamic and boron neutron capture therapy.