Sterols of Delphinium ajacis; Production and Metabolic Relationships in Whole Plants and Callus Tissue*

Abstract

Sterols from whole nonsterile Delphinium ajacis plants and from sterile tissue cultures (callus) were identified and determined quantitatively. The major sterols in the whole plant tissues were sitosterol, campesterol and stigmasterol, whereas those in the callus tissue were stigmastanol, 24-ethylidenelophenol and Δ⁷-stigmastanol. Of the 21 compounds identified in callus tissue, 5 were not present in the whole plant, most notably Δ⁷-stigmastanol. For both sources of tissue, the sterol predominating in one was a minor component in the other (whole plant/tissue cultures: sitosterol 57%/5%; stigmastanol 2%/35%). On a tissue dry-weight basis, the amount of sterols isolated from callus tissue culture was ten to twenty times that obtained from the whole plant. Qualitatively the sterols from both sources fit into a metabolic scheme which proceeds from cycloartenol through 4,4-dimethylsterols and 4-methylsterols to sterols. A proposed metabolic pathway shows the differences in accumulation of sterols in the two types of tissue. The increase in sterol production in cultured cells, especially when favored by growth conditions, has promise for industrial application and in organic synthesis.

Key Word Index

Delphinium ajacis - Ranunculaceae - Sterols - Triterpenoids - Callus Tissue Culture - Plant Metabolism - Mass Spectrometry