Radioprotection (uv and gamma rays) of DNA molecule by indole and indole- derivatives

Journal Article · Sun Dec 31 23:00:00 EST 1972 · Z. Naturforsch., c, v. 28c, no. 7/8, pp. 379-385

OSTI ID:4387673

Tomicic, I; Pieber, M; Romero, C; Soto, A; Toha, J C

The radioprotective ability of L-tryptophan, tryptamine, 3indoleacetic acid, and indole (10/sup -4/ M), on uv- and gamma-irradiated DNA (10/sup -4/ M) is studied. UV radioprotection is accomplished in the following order of efficiency: L-tryptophan and 3-indoleacetic acid> indole and tryptamine. The corresponding DRF (dose reduction factor) measured as absorbancy loss at 260 nm, were: L-tryptophan and 3-indoleacetic acid around 3 and tryptamine and indole around 1. When absorbancy loss plus changes in the patterns of the absorbancy curve were considered the DRF was: Ltryptophan 2.53, 3-indoleacetic acid 1.54, indole 1.22, and tryptamine 0.75, respectively. For gamma radiation damage the order of radioprotection found was: indole, L-tryptophan and tryptamine > 3- indoleacetic acid. The DRF when comparing the absorbancy loss at 260 nm was: L- tryptophan, indole, and tryptamine around 11 and 3-indoleacetic acid around 4. When evaluating total changes in absorbancy the DRF were: indole and L-tryptophan around 6.5, tryptamine 3.7, and 3-indoleacetic 2.1. These data were correlated with measurements of the degree of molecular interactions of DNA and protectors studied by: Spectrophotometry, m.p. determinations, circular dichroism and oriented circular dichroism, viscosity, and rate of dialysis. Also data of fluorescence and phosphorescence were considered. For gamma radioprotection a mechanism based in radical trapping, local radical trappingg, and partial recovery of radioprotectors is proposed. UV radioprotection is discussed considering: The close interaction of L-tryptophan with DNA which might impede dimer formation, its proton and electron donor ability. A possible (triplet- triplet) energy transfer from excited DNA to indole derivative is discussed on the basis of acetone competition and a dimer excision process considered. (auth)

• Research Organization: Chile Univ., Santiago
• NSA Number: NSA-29-005280
• OSTI ID: 4387673
• Journal Information: Z. Naturforsch., c, v. 28c, no. 7/8, pp. 379-385, Journal Name: Z. Naturforsch., c, v. 28c, no. 7/8, pp. 379-385; ISSN ZNFCA
• Country of Publication: Germany
• Language: English

Related Subjects

*DNA-- CHEMICAL RADIATION EFFECTS
*INDOLES-- RADIOSENSITIVITY EFFECTS
*TRYPTAMINES-- RADIOSENSITIVITY EFFECTS
*TRYPTOPHAN-- RADIOSENSITIVITY EFFECTS
GAMMA RADIATION
IN VITRO
IRRADIATION
N48110* --Life Sciences--Radiation Effects on Biochemicals-- In-Vitro
PHOTON BEAMS
RADIOPROTECTIVE SUBSTANCES
RESPONSE MODIFYING FACTORS
ULTRAVIOLET RADIATION