Photostability of bacteriochlorophyll „a“ and bacteriopheophytin „a“ against UV-A, UV-B and visible light treatments in methanol solutions

Bacteriochlorins as the porphyrins derivatives are well known photosensitizers with great potential for use in various fields of pharmacy and medicine. Photostability of selected bacteriochlorins, bacteriochlorophyll a and bacteriopheophytin a, in different methanol solutions (with and without lipids) during continual UV-A, UV-B and visible light treatments were studied using absorption UV-VIS spectroscopy providing kinetic analysis. Applied irradiation treatments resulted in irreversible degradation of both selected bacteriochlorins obeying the first order of kinetics. Bacteriopheophytin a showed significantly higher photostability in comparison to bacteriochlorophyll a for all applied irradiation treatments, for about one to three orders of magnitude. Photochemical degradation of bacteriochlorins is energy dependant process, governed by photons energy input.Lipid environment play stability role for both bacteriochlorins against all, UV-A, UV-B and visible light treatments. Bacteriopheophytin a induced lipid peroxidation processduring UV-A irradiation treatment.