[Photosensitizing and photoprotective properties of extracts from groups of medicinal plants]

Investigation of photosensitization and photoprotection induced by plant extracts was carried out. A group of plants affected human central nervous system was studied in detail. Efficiency of plants as photoprotectors and photosensitizers was tested in the frame of the influence of their extracts on the yield of photochemiluminescence of Gly-Trp solutions. Photosensitization was studied under irradiation with light lambda > 280 nm and lambda > 320 nm, as well as with monochromatic light lambda=313, 365, 405 and 436 nm. All of the plants studied acted as photoprotectors in low concentration and as photosensitizers in high concentration. The efficiency of photoprotection and photosensitization was evaluated with regard to single dose of plant extracts and their concentration in human organism. The effect decreases in the following consequence of plants: Leonurus > Hypericum > Aralia > Schizandra > Echinopanax > Eleutherococcus > Valeriana > Panax ginseng. Photosensitization is due to the components of plant extracts which have strong absorbtion at the high wavelength range. The mechanism of photosensitization was suggested. Singlet oxygen generated by photoexcited compounds is the main species resulted in chemiluminescence. Superoxide radicals does not contribute significantly to the chemiluminescence formation.