Erich Heftmann

Functions of sterols in plants

Sterols have at least three functions in animals: they may act as precursors of other steroids, as hormones and as membrane components. The author advances the hypothesis that sterols have similar functions in plants.

High-pressure liquid chromatography of steroids.

After a brief discussion of the merits and limitations of high-pressure liquid chromatography (HPLC) relative to other chromatographic methods, special problems in the application to steroids are discussed. Publications on HPLC of steroids are then discussed under the headings of individual classes, arranged generally in the order of increasing polarity.

Biogenesis of steroids in solanaceae

Abstract The biogenetic pathways leading to the characteristic steroids of the Solanaceae are reviewed. The experimental data from feeding experiments on members of the Solanaceae are described and, where necessary, pertinent experiments on other plants, such as Veratrum spp. are mentioned. The review covers the simple sterols, the steroidal sapogenins and the steroidal alkaloids found in these plants, and their metabolism as well as biosynthesis are considered.

Identification of estrone in pomegranate seeds

Abstract Estrone was isolated from pomegranate seeds and its identity was confirmed by thin-layer chromatography in three solvent systems and by four color reactions. Three derivatives were prepared and had the same chromatographic characteristics in three solvent systems as the corresponding derivatives from authentic estrone. The biological potency of this material was also comparable to that of estrone. Pomegranate seeds are the richest plant source of steroidal estrogens yet found.

Biosynthesis of Dioscorea sapogenins from cholesterol

Abstract Radioactive cholesterol was converted to the sapogenins diosgenin and kryptogenin by Dioscorea spiculiflora seedlings. The sapogenins were isolated by chromatography and their radiochemical purity established by dilution with carrier material and crystallization to constant specific activity.

In vivo conversion of squalene to β-sitosterol

Abstract Squalene- 14 C was converted to β-sitosterol by Pharbitis nil seedlings. The β-sitosterol was isolated by chromatography and its radiochemical purity established by dilution with carrier material and crystallization to constant specific activity.

Degradation of tomatine to 3β-hydroxy-5α-pregn-16-en-20-one by ripe tomatoes

Abstract Tomatine-4- 14 C was prepared by foliar administration of cholesterol-4- 14 C and silicone oil to tomato plants. Chromatographically homogeneous tomatine-4- 14 C in 96% ethanol, when incubated in whole, ripe tomatoes was rapidly converted to 3β-hydroxy-5α-pregn-16-en-20-one in combined form. The identity of this steroid and its acetyl derivative was established by comparing their TCL mobilities with reference materials and by recrystallizing them to constant specific activity.

Biosynthesis of pregnenolone from cholesterol in Haplopappus heterophyllus

Abstract After administration of cholesterol-4- 14 C (I) to the leaves of a Haplopappus heterophyllus plant, radioactive pregnenolone (II) was isolated and purified to constant specific activity by chromatography and recrystallization of both pregnenolone and its acetate. Cholesterol was identified as a natural constituent of the plant by thin-layer and gas-liquid chromatography.

Progesterone metabolism in Digitalis lanata

Abstract After the administration of progesterone-4- 14 C to a Digitalis lanata plant, the following radioactive metabolites were isolated: digitoxigenin, gitoxigenin, digoxigenin, 5α-pregnane-3,20-dione, 5β-pregnane-3,20-dione, 5α-pregnan-3β-ol-20-one, and Δ 5 -pregnen-3β-ol-20-one. The results suggest that progesterone may be na intermediate in the biosynthesis of cardenolides from pregnenolone.

Caffeine metabolism by Penicillium roqueforti

Abstract A strain of P. roqueforti isolated on caffeine-containing agar from air grew in culture media containing concentrations as high as 0.04 m caffeine as the sole source of nitrogen. Growth was accompanied by complete removal of caffeine from the culture medium. After short incubations of nitrogen-starved inocula of this fungus with caffeine-1-methyl- 14 C or with caffeine-2- 14 C, radioactive theophylline was isolated. It was identified by thin-layer chromatography in three solvent systems and also by reconversion to radioactive caffeine after treatment with dimethyl sulfate. Thus, the first step in the metabolism of caffeine by P. roqueforti involves demethylation in the 7-position.