Analysis of Fenugreek sapogenins by gas-liquid chromatography

The chemistry and biological significance of saponins in foods and feedingstuffs

Saponins occur widely in plant species and exhibit a range of biological properties, both beneficial and deleterious. This review, which covers the literature to mid 1986, is concerned with their occurrence in plants and their effects when consumed by animals and man. After a short discussion on the nature, occurrence, and biosynthesis of saponins, during which the distinction between steroidal and triterpenoid saponins is made, the structures of saponins which have been identified in a variety of plants used as human foods, animal feedingstuffs, herbs, and flavorings are described. Many of these compounds have been characterized only during the last 2 decades, and modern techniques of isolation, purification, and structural elucidation are discussed. Particular consideration is given to mild chemical and enzymatic methods of hydrolysis and to recent developments in the application of NMR and soft ionization MS techniques to structural elucidation. Methods currently used for the quantitative analysis of saponins, sapogenols, and glycoalkaloids are critically considered; advances in the use of newer methods being emphasized. The levels of saponins in a variety of foods and food plants are discussed in the context of the methods used and factors affecting these levels, including genetic origin, agronomic, and processing variables, are indicated. Critical consideration is given to the biological effects of saponins in food which are very varied and dependent upon both the amount and chemical structure of the individual compounds. The properties considered include membranolytic effects, toxic and fungitoxic effects, adverse effects on animal growth and performance, and the important hypocholesterolemic effect. A final section deals briefly with the pharmacological effects of saponins from ginseng, since use of this plant is increasing in certain sections of western society as well as being traditional in the Orient.

[Effect of vitamin E and protein quality on the hemolytic effect of Trigonella sapogenins in rats]

The influence of vitamin E (9, 90, 450 mg dl-alpha-tocopherol acetate/100 g diet), protein quality and temperature (70 degrees C for 10 min) on the sapogenin-induced hemolysis was studied in rats fed with diets containing different amounts of fenugreek-seed seedflour. Significant increased hemolysis rates were found in rats on diets with the following protein components: 1/3 Trigonella + 2/3 Cornflour (69.7 +/- 11.6% hemolysis), 100% Trigonella (21.0 +/- 8.6% hemolysis), 1/3 Trigonella + 2/3 Casein (14.1 +/- 10.7% hemolysis). The diets of these groups of animals contained raw Trigonella seeds and 9 mg vitamin E/100 g diet, which covers the requirements of rats on this vitamin. With this tocopherol supplement the applied heat treatment had no influence on the sapogenin effects on the erythrocytes. In the groups with the 10th fold and 50th fold of the vitamin E supplementation no significant hemolysis rate was observed. From these results we conclude that when fenugreek seeds are to be used in animal nutrition, a qualitative good protein supply as well as a sufficient intake of vitamin E should be considered in order to compensate the hemolytic effect of Trigonella sapogenins.