phytochlorin and chlorin

Nine new chlorin derivatives containing maleimide functional group and amino acid residue with chlorin e6 scaffold (compounds 1-6) or pheophorbide a scaffold (compounds 7-9) were synthesised from chlorophyll a. The all nine derivatives demonstrated increased photo cytotoxic activity in HepG2 cell (IC50 3.2-20.5 μM) comparing with chlorin e6 and its trimethyl ester. Their photo cytotoxicities were approximately dependent on their abilities to produce singlet oxygen ((1)O2) in the cells.

Topics: Cell Survival; Dose-Response Relationship, Drug; Hep G2 Cells; Humans; Maleimides; Molecular Conformation; Photosensitizing Agents; Porphyrins; Structure-Activity Relationship

The porphyrin and chlorin parent compounds constitute the base of many potent photosensitizers aimed to be utilized in photodynamic therapy (PDT). However, the photosensitizers available on the market today are not ideal for use in PDT; many of them suffering from drawbacks such as long-lasting photosensitization or absorption at wavelengths below the optimal tissue penetration. This has emphasized the need of new photosensitizers with improved photodynamic properties. In the present study we have used density functional theory based methods to design new chlorin compounds with conjugated substituents such as vinyl groups and carboxylic acids, aiming for strong absorption in the therapeutic window of PDT. The specific substituent positions were found to have a significant effect on the spectra. A chlorin with four propenoic acids was able to red-shift the absorption the most compared with non-substituted chlorin, generating the red-most absorption at 755 nm, and with significantly enhanced oscillator strengths. The results from the present study constitute a useful starting point for further design of tetrapyrrole derivatives as improved photosensitizers.

Topics: Absorption; Chlorophyllides; Mesoporphyrins; Photosensitizing Agents; Porphyrins

The use of photoactivated disinfection has had a significant medical and technological effect in bacterial inactivation, as an alternative to conventional antimicrobial methods. The main goal of this study was to investigate the effect of photoactivated disinfection on Streptococcus mutans, when Radachlorin(®) was used as a photosensitizer.. Streptococcus mutans samples of two different initial concentrations were treated with Radachlorin(®) gel (0.1%), irradiated by the light of a He-Ne laser (633nm), with energy density of 6J/cm(2), and cell viability was evaluated after culturing.. It was observed that the combination of Radachlorin(®) and laser was more effective than Radachlorin(®) or laser alone (p<0.05), in reduction of S. mutans and Radachlorin(®) was cytotoxic, in the dark, only for the lower concentration of bacteria. Lower concentration of S. mutans resulted in higher amount of killing, in the case of using Radachlorin(®) with or without laser.. The photoactivation of Radachlorin(®) using a He-Ne laser could inactivate S. mutans to a significant level. In addition Radachlorin(®) might be cytotoxic in the dark, for the lower concentration of bacteria.

Topics: Anti-Bacterial Agents; Bacterial Load; Chlorophyllides; Darkness; Disinfection; Drug Combinations; Humans; Lasers, Gas; Materials Testing; Microbial Viability; Photosensitizing Agents; Porphyrins; Radiation Dosage; Streptococcus mutans

Under the influence of electric pulses cells undergo membrane electroporation (EP), which results in increased permeability of the membrane to exogenous compounds. EP is applied in oncology as a method to enhance delivery of anticancer drugs. For that reason it was essential to combine photodynamic tumor therapy (PDT)--the cancer treatment method based on the use of photosensitizers that localize selectively in malignant tumors and become cytotoxic when exposed to light, and EP, with the aim to enhance the delivery of photosensitizers into the tumor and therefore to increase the efficacy of PDT. Thus, the aim of study was to evaluate the cytotoxic effect of PDT in combination with EP. A Chinese hamster lung fibroblast cell line (DC-3F) was used. The cells were affected by photosensitizers chlorin e(6) (C e(6)) at the dose of 10 mug/ml and aluminium phthalocyanine tetrasulfonate (AlPcS4) at the dose of 50 microg/ml. Immediately after adding of photosensitizers the cells were electroporated with 8 electric pulses at 1200 V/cm intensity, 0.1 ms duration, 1 Hz frequency. Then, after 20 min of incubation the cells were irradiated using a light source--a visible light passing through a filter (KC 14, emitted light from 660 nm). The fluence rate at the level of the cells was 3 mW/m(2). Cytotoxic effect on cells viability was evaluated using MTT assay. Our in vitro data showed that the cytotoxicity of PDT in combination with EP increases fourfold on the average. Based on the results we suggest that EP could enhance the effect of PDT.

Topics: Animals; Cell Line; Cell Survival; Chlorophyllides; Cricetinae; Electroporation; Indoles; Neoplasms; Photochemotherapy; Porphyrins