An improved column-chromatographic quantitative isolation of diosgenin and yamogenin from plant crude extracts prior to their determination by infrared spectrophotometry

Abstract

A previously described routine procedure involving the use of a silica gel column in determining diosgenin and yamogenin has been improved by using water-containing solvents. The advantages are that there is less variation between duplicate results, that each column can be used at least five times and that component bands are eluted in predictable volumes of solvents. An apparatus and solvent sequence is described that allows twelve columns to be developed simultaneously.

The method has been successfully applied to crude extracts from Dioscorea deltoidea tuber and to oily crude extracts from the seeds of Trigonella foenumgraecum(fenugreek) and Balanites aegyptiaca. The over-all error of the procedure, including sampling, extraction and infrared spectrophotometric determination for duplicate analyses of 2·5-g samples of the fenugreek seed used, expressed as a 95 per cent. confidence interval of the mean sapogenin value, was 1·04 ± 0·025 per cent. for diosgenin plus yamogenin, 0·64 ± 0·019 per cent. for diosgenin and 0·40 ± 0·023 per cent. for yamogenin.

As the method does not permit the separation of tigogenin from diosgenin nor that of neotigogenin from yamogenin, the results indicate maximum yields for diosgenin and yamogenin in fenugreek seed. The results exclude sterols, steryl esters, dihydroxysapogenins and spirostadienes.