Enzymic release of monohydroxysapogenins from the seed of Trigonella foenumgraecum L.

Abstract

The furostanol glycosides, the precursors of steroidal sapo-genins, and other constituents of fenugreek (Trigonella foenumgraecum, L) and methods of assay for steroidal sapogenin, are reviewed. A GLC method for assying yields of monohydroxysapogenins (mainly diosgenin and yamogenin) was adopted and the reliability of the method wan established. No free sapogenins are present in the need. Methods of obtaining a good yield of sapogenins have been explored. The sapogenins are made available by endogenous and exogenous enzymic hydrolysis with and without acid hydrolysis on the whole seed, powdered need, defatted powdered need, these being autoclaved when necessary to exclude endo-genos enzymic hydrolysis. The results obtained by acid hydrolysis can be much improved by prior enzymic hydrolysis without germination. The conditions of enzymic hydrolysis were examined. A temperature of 45°, with initial pH 4.0, with aeration by shaking in plugged flasks, for a period of 4 days, followed by acid hydrolysis, frequently gave result 100% higher than those by acid hydrolysis alone, Naringinase D and cellulase are amongst the cheaper alternatives to emulsin. The results vary from whole seed and powdered need, the latter giving a peculiarly low result with acid hydrolysis alone but giving a high result in a short time when enzymes functioned before acid hydrolysis. Powdering of the seed to allow defatting given edible oil and facilitates subsequent crystallization of the sapogenin. The yield of monohydroxysapogenin from autoclaved methanol extract of defatted powdered need wan also markedly improved by the use of exogenous enzymes. Other studies decribed include a simple method of preparation of a cruie enzyme from the seed for its use in the isolation of the sapogenin and the successful use of this crude enzyme and of, e.g., Naringinase D in an immobilized form, as calcium alginate pellets. The yields of monohydroxysapogenins are discussed in relation to linkages between the 3- and 26- sugar units of the precursor furostanol glycosides and components of the cell wall and membranes. The result may have implications for improving the assay or yield of aglycones other than those of steroidal sapogenins.

Date of Award	1980
Original language	English
Awarding Institution	University of Bath