The Preparation Of Chlorophyll Transition Metal Complexes From Silkworm Faeces And Their Interactions With DNA

Porphyrin and their metal derivatives are strong DNA binders, Some of thesecompounds have been used for radiation sensitization therapy of cancer and are targeted tointeract with cellular DNA, For example, photofrin has been used in clinical trials, soporphyrin has been investigated widely as an DNA target. Chlorophyll is belong to themagnesium porphyrin family, and distributing widely in the world, it is the pigment forcapture and transport of solar energy in photosynthesis. Studies suggested that chlorophyllcan be used as an potent near infrared photosensitizer, based on the hypothesize,In the thesis,we studied the interacation of chlorophyll and DNA.1. Chlorophyll was extracted from silkworm faeces, since chlorophyll itself was notstable and it's transition metal complexes were more stable, so chlorophyll has been preparedto Zinc chlorophyll (Zn-CHL) and copper chlorophyll (Cu-CHL). These two metalderivatives were characterized by UV absorption spectra and Mass Spectra.2.The photocleavage activity of Zn-CHL and Cu-CHL to pBR 322 DNA were studied byagarose gel electrophoresis.The results showed that the optimization cleavage concentrationrange was 343.2-457.6μmol/L for Zn-CHL, in this range pBR 322 DNA was almostcompletely disappear. And for Cu-CHL the optimization cleavage concentration range was178.5-357μmol/L, in the range all the FormⅠDNA was cleavage into FormⅡand FormⅢ,but the DNA was not disappear. As compared the cleavage activities of the two chlorophyllderivatives, when from concentration, copper chlorophyll was better than zinc, but as fromthe cleavage effect, zinc was better than copper chlorophyll.3. By using absorption spectra method, fluorescence spectroscopy, CD and viscositymeasurements for zinc chlorophyll complex and by by using absorption spectra method, CDand viscosity measurements for copper chlorophyll complex, we studied the binding modesof zinc and copper chlorophyll complexes with DNA, The result showed that zinc and copperchlorophylls both through the outside binding mode to interact with ct-DNA.