A combined column-chromatographic and infrared spectrophotometric determination of diosgenin and yamogenin in fenugreek seed

Abstract

A routine procedure is described for the determination of diosgenin and yamogenin in fenugreek seed. A crude extract is obtained by acidic hydrolysis of the seed, neutralisation and extraction of the insoluble matter with light petroleum. By means of column chromatography this extract is freed from fixed oil and other substances, thus yielding a mixture of diosgenin and yamogenin suitable for infrared spectrophotometric analysis. The results calculated for duplicate analyses of 2·5-g samples of commercial Moroccan seed, expressed as a 95 per cent. confidence interval of the mean sapogenin value, are 0·96 ± 0·017 per cent. for diosgenin plus yamogenin, 0·58 ± 0·008 per cent. for diosgenin and 0·38 ± 0·016 per cent. for yamogenin. The procedure has been found to be satisfactory for column loadings of up to 75 mg of diosgenin plus yamogenin in the presence of up to 600 mg of fixed oil, which is approximately three times the weight of extractive from 2·5 g of Moroccan seed.