Identification of an active principle of antitumor antibiotic jawaharene with a mixture of long chain fatty acids.

Abstract

Jawaharenel' an antitumor antibiotic complex was obtained from the mycelia of a strain of Aspergillus niger. Its antitumor2-7), antiviral1,8) and antimicrobial9,10' properties were studied in detail. In the present study, jawaharene has been fractionated by silica gel column chromatography and an antitumor active fraction designated JF1 has been obtained. This fraction shows a single spot in thin-layer chromatorgram (TLC) using different solvent systems. JF1 has been found by others to inhibit Ehrlich ascites carcinoma (EAC) and sarcoma-180 (S-180) ascites tumor in Swiss mice. It also inhibits the oxygen uptake and glucose uptake by EAC and S-180 cells, in vitro. The results will be published in a separate communication.The methyl esters of JF1 were made with diazomethane11) and the ester-mixture was purified by silica gel column chromatography and preparative TLC. All the eluates were concentrated and dried in: vacuo.The indication that JF1 is a mixture of long chain fatty acids was obtained from its various spectral data. The IR spectrum suggested the presence of carboxylic acid groups, long methylene chains and olefinic double bonds. The same conclusions could be drawn from the NMR spectrum of the methyl esters of JF1. The mass spectrum of the methyl ester preparation indicated it to be a mixture of methyl esters of straight chain aliphatic acids.The molecular ion peaks corresponding to the constituent fatty acid methyl esters were observed at m/z 214, 242, 268, 270, 296 and 298. Finally the methyl esters of the fatty acids constituting JF1 were quantitatively determined by GLC in Pye Unicam, GCDchromatograph, using a 15 % DEGS column on Gaschrom Z (80100 mesh). Methyl esters of fatty acids were identified by comparison with authentic samples. The peaks 1, 2, 3, 4, 5 and 6 corresponding to lauric, myristic, palmitic, palmitoleic, stearic and oleic acid were observed ( Fig. 1) with their relative abundance of 0.2. 0.86, 43.26, 2.0, 11.6 and 42.5 %, respectively.Thus JF, the antitumor active fraction of jawaharene, has been found to consist of six different long chain fatty acids of which palmitic (43.26 %) and oleic (42.5 %) are the major consti-