Search results for "b-carbolines"
showing 3 items of 3 documents
Intra- and extra-cellular DNA damage by harmine and 9-methyl-harmine
2014
It is known that b-carbolines are able to produce photosensitized damage in cell-free DNA, but there is little information on their effects on cellular DNA. Therefore, we have analyzed the DNA damage produced by harmine and 9-methyl-harmine under UVA irradiation in V79 cells, together with the associated generation of micronuclei and photocytotoxicity. The results indicate that the most frequent photoproducts generated in the cellular DNA are modified purines such as 8-oxo-7,8-dihydroguanine. Only relatively few single-strand breaks were observed. CPDs were absent, although they were generated in cell-free DNA irradiated under the same conditions. The overall extent of DNA damage in the cel…
Mechanisms of DNA damage by photoexcited 9-methyl-β-carbolines
2013
It has been well documented that β-carboline alkaloids, particularly the 9-methyl derivatives, are efficient photosensitizers. However, structure–activity relationships are missing and the photochemical mechanisms involved in the DNA photodamage still remain unknown. In the present work, we examined the capability of three 9-methyl-β-carbolines (9-methyl-norharmane, 9-methyl-harmane and 9-methylharmine) to induce DNA damage upon UVA excitation at physiological pH. The type and extent of the damage was analyzed together with the photophysical and binding properties of the β-carboline derivatives investigated. The results indicate that even at neutral pH most of the DNA damage is generated fr…
Albumin-Folate Conjugates for Drug-targeting in Photodynamic Therapy.
2016
Photodynamic therapy (PDT) is based on the cytotoxicity of photosensitizers in the presence of light. Increased selectivity and effectivity of the treatment is expected if a specific uptake of the photosensitizers into the target cells, often tumor cells, can be achieved. An attractive transporter for that purpose is the folic acid receptor α (FRα), which is overexpressed on the surface of many tumor cells and mediates an endocytotic uptake. Here, we describe the synthesis and photobiological characterization of polar β-carboline derivatives as photosensitizers covalently linked to folate-tagged albumin as the carrier system. The particles were taken up by KB (human carcinoma) cells within …