Raymond D. Bennett

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.

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.

Pregnenolone metabolism in Digitalis lanata

Abstract After the administration of pregnenolone-4- 14 C to a Digitalis lanata plant, the following radioactive metabolites were isolated: digitoxigenin, gitoxigenin, digifologenin, 5β-pregnane-3,20-dione, and progesterone.

Biosynthesis of tomatidine from cholesterol in Lycopersicon pimpinellifolium

Abstract After administration of cholesterol-4-14C (I) to the leaves and flowers of growing Lycopersicon pimpinellifolium plants, radioactive tomatidine (II) was isolated. The radiochemical purity of tomatidine was established by chromatography, crystallization, and oxidation to tomatidin-3-one.

Biosynthesis of limonoids in Citrus seedlings

Abstract Radioactive tracer work showed that nomilinoate A-ring lactone was the predominant, if not the only, limonoid biosynthesized and accumulated in seedlings of lemon, Valencia orange, grapefruit and tangerine. Lemon seedlings were excellent tools for biosynthetic preparation of [14C]nomilin.

Progesterone: Biosynthesis from Pregnenolone in Holarrhena floribunda

After administration of pregnenolone-4-C14 to Holarrhena floribunda leaves, radioactive progesterone was isolated and purified to constant specific activity by chromatography, conversion to a derivative, and recrystallization. The result suggests that the biogenetic sequence leading to progesterone is the same in plants as in animals.

Cytokinins Inhibit Abscisic Acid Biosynthesis in Cercospora Rosicola

Summary The fungus Cercospora rosicola produces the plant hormone, abscisic acid (ABA), as a secondary metabolite. We developed C. rosicola into a convenient system to determine the effects of compounds on the biosynthesis of ABA. Another important group of plant hormones, the cytokinins, inhibited ABA biosynthesis in C. rosicola. The inhibition of ABA biosynthesis was concentration dependent and, in studies using farnesyl-[1-14C]pyrophosphate, appeared to be specific rather than resulting from a general blocking of terpenoid biosynthesis. Inhibitors of ABA biosynthesis have not previously been reported. Knowledge that cytokinins have the ability to inhibit ABA biosynthesis in this fungal system indicates the need for further studies to determine if cytokinin inhibition of ABA biosynthesis occurs in plants and is an element of the hormonal action of cytokinins.