Chemical analysis and biological activities of fatty acids from the liver of x-ray irradiated rabbit, the antitumor agent so-called OX.

Chemical and biological characteristics of the unsaturated fatty acids from the liver of irradiated and non-irradiated animals and some unsaturated fatty acids in sale have been described. The unsaturated fatty acid fractions from the rabbit liver taken after irradiating animal with x-ray show hardly any difference from those of non-irradiated animal in each component. But the former were distinguished from the latter in the increased rate of velocity of autoxidation. Similar characteristics were observed on the unsaturated fatty acids irradiated in vitro. They developed less labile free radicals with the shift of the double bonds to the carboxylic group and the conjugated double bonds, dienoic and trienoic acids. Biologically, the fatty acids from the irradiated animal suppressed the growth of bacteria requiring unsatturated fatty acid. And they are slightly stronger in the activity of uncoupling effect for the oxidative phosphorylation and the swelling of mitochondria comparing to those of general fatty acids, oleic and linoleic acids. They showed a strong lytic activity on the cell membrane as in the case of general fatty acids, linoleic, oleic, and some long chain unsaturated fatty acids. Tumor cells surviving through the treatment with unsaturated fatty acids changed the cell characteristics temporarily, with a slow-down of the ascites development and the cell growth. ∗PMID: 4221888 [PubMed indexed for MEDLINE] Copyright c ©OKAYAMA UNIVERSITY MEDICAL SCHOOL Acta Meet Okayama 19, 59 -72, (1965) CHEMICAL ANALYSIS AND BIOLOGICAL ACTIVITIES OF FATTY ACIDS FROM THE LIVER OF X-RAY IRRADIATED RABBIT, THE ANTITUMOR AGENT SO-CALLED OX* Satimaru SENO, and Michio YAMAMOTO Department of Pathology and Department of Radiation Medicine, Okayama University Medical School, Okayama, Japan Received for publication, March 20, 1965 The antitumor activity of the unsaturated fatty acid fraction from the liver of x-ray-irradiated rabbit has been found through the experiments on the BrownPearce sarcoma of rabbie, Ehrlich ascites tumor in solid form, and several human carcinomas• In several cases of human tumor treated With the fatty acids from the irradiated rabbit the tumors disappeared completely or extremely reduced in size by local application. The striking effects were observed on some of the squamous cell carcinomas of the skin and on some of rectum adenocarcinomass, to which the fatty acids could effectively come in contact at high concentration. Ehrlich ascites tumor moderately developed in subcutaneous tissue became necrotic and disappeared after the injections of the fatty acids into the surrounding tissues• Since then chemical analysis and biological properties of the fatty acids have been exhaustively studied by us with the collaboration of colleagues for the purpose to reveal the mechanism of the antitumor activity.. In this paper the chemical, biological and morphological findings obtained through our experiments for the last two years are summarized. CHEMICAL ANALYSIS Unsaturated fatty acid fraction was obtained from the liver of rabbit which had received a whole body irradiation with x-ray, 3,000 r at one time, 24 hours before the liver was harvested. Fatty acids were obtained with fresh liver homogenate or dried liver powder by the method of FOLcH et a/"., and unsatturated fatty acid fraction was obtained by urea abduct method. Chemical analysis proved that the refractory index n~ was 1. 4715, acid value 25.4, saponification value 179.1, iodine number 90 to 150, peroxide value 30.7, unsaponifiable substance 17 .5 %, conjugated dienoic acid 1.279 %, conjugated trienoic acid 0.033 %, negative Ninhydrin reaction, negative biuret reaction, negative Molish reaction and positive Liebermann reaction• *Supported by a grant (CA 06146-03) from the National Institute for Cancer, National Institute of Health, United Stats Public Health Service, Department of Health, Education and Welfare. U. S. A.