Quantitative estimation of diosgenin in Dioscorea tubers by densitometric thin-layer chromatography

Microdetermination of diosgenin from fenugreek (Trigonella foenum-graecum) seeds

Sulfuric acid hydrolysis of steroidal glycosides of Amber fenugreek was studied by capillary gas chromatographic analysis of diosgenin [(25R)-spirost-5-en-3-ol] and isomeric spirostadiene artifacts from 100 mg samples of seed material. Following extraction with 80% ethanol, highest recoveries of diosgenin occurred when hydrolyses were conducted in sulfuric acid, prepared at 1 molar (M) concentration in water containing 60-80% 2-propanol. Compared to a previous method with aqueous hydrochloric acid, the selected conditions of hydrolysis at 100 degrees C for 2 h with sulfuric acid in 70% 2-propanol reduced diene formation but did not completely eliminate these artifacts. Extraction of steroidal saponins with various alcohol/water mixtures prior to sulfuric acid hydrolysis gave similar recoveries of diosgenin. Application of the quantitative method to experimental samples of Amber, Quatro, and ZT-5 fenugreek, using 10 mg subsamples of crushed seed that had been defatted with petroleum ether and dried at 60 degrees C, gave diosgenin levels of 0.55, 0.42, and 0.75%, respectively. Levels of smilagenin and sarsasapogenin were very low in hydrolyzed seed extracts from ZT-5, a Canadian breeder line of fenugreek.

Homogeneous enzyme immunoassay of diosgenin and its glycosides

Homogeneous enzyme immunoassay has been used as a tool for the determination of diosgenin and its glycosides in plants. Diosgenin antisera was found to inhibit the activity of diosgenin hemisuccinate-horseradish peroxidase conjugate which was reversed by the addition of free diosgenin or its glycosides. The increase of enzyme activity was proportional to the quantity of the hapten over a certain range of hapten concentration. Thus, a minimum of 2.5 micrograms/ml of diosgenin and 11.5 micrograms/ml of diosgenin glycosides could be determined by this method. The results were comparable with those obtained by high-performance liquid chromatography and gravimetric methods.

Evaluation of chemical analysis for the determination of solasodine in Solanum laciniatum

A detailed study of a method for solasodine analysis has been carried out and the suitability of chemical analysis for solasodine determination in plant material evaluated. A number of problems with the analytical isolation of solasodine and its subsequent colorimetric determination have been highlighted: oven drying of plant material greater than 100 degrees leads to solasodine loss; cell disruption of the dry plant material is required if complete and rapid extraction of solasodine is to take place; hydrolysis of plant extract residues in greater than 1 N acid leads to solasodine loss; the colorimetric procedure is more temperamental than past methods have indicated, especially with regard to the specificity of the reaction and the instability of the complex.

A quantitative gas-liquid chromatographic method for the estimation of hecogenin and tigogenin in the leaves, juice and sapogenin concentrates of Agave sisalana

A gas-liquid chromatographic method has been devised for the routine estimation of the hecogenin [3beta-hydroxy-(25R)-5beta-spirostan-12-one] and tigogenin [ (25R)-5beta-spirostan-3beta-ol] contents of Agave sisalana leaf and juice samples and of the crude sapogenin concentrates known as "coffee grounds". Because of partial degradation of the sapogenins in the GLC system it was found necessary to acetylate the compounds prior to their estimation. In East African samples the tigogenin proportion of the total sapogenin content is usually about 10%. At this level, the 95% inverse tolerance limits on predicted tigogenin weights are approximately +/- 7%.