Abstract
In order to develop a new molecular species of compounds with antibiotical activities by the application of radiation-chemical reaction, a study was made on the alterations of antibiotical activity of chloramphenicol after gamma-irradiation of its aqueous solution. The results suggested that the gamma-irradiation over 6.25×106 R of aqueous chloramphenicol solution resulted in the formation of new substance (s) that had an inhibitory activity of protein biosynthesis in Ehrlich ascites tumor cells, to the same extent as the activity of chloramphenicol before irradiation, although the antibacterial and protein biosynthesis-inhibiting actions on E. coli cells were markedly destroyed by irradiation. Furthermore, when chloramphenicol solution irradiated at a dose of 6.25×105 R was separated into five fractions by Sephadex G-10 gel filtration, some new substances, which were distinctly different from chloramphenicol in both Rf values on thin-layer chromatograms and antibiotical activities, appeared in the fractions 1, 4 and 5. However, the chemical nature of these products have not been characterized till now.
