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Two novel diacylated anthocyanins and two known monoacylated anthocyanins were isolated from violet petals of Petunia hybrida cv. Surfinia Violet Mini. Their structures were elucidated by spectral methods. The major novel pigment was identified as malvidin 3- O -(6- O -(4- O -(4- O -(6- O -caffeoyl- β -d-glucopyranosyl)- p -coumaroyl)- α -l-rhamnosyl)- β -d-glucopyranoside)-5- O - β -d-glucopyranoside and the minor novel pigment was determined as malvidin 3- O -(6- O -(4- O -(4- O -(6- O -caffeoyl- β -d-glucopyranosyl)-caffeoyl)- α -l-rhamnosyl)- β -d-glucopyranoside)-5- O - β - d-glucopyranoside.

An assay of chalcone synthase activity based upon analysis by HPLC has been developed. The method is specific (identification of the product formed), f

Three sucrose ester types were isolated and identified from the leaf surface lipids of Petunia hybrida. They contained both unbranched and branched fatty acids (from C2 to C8). Further, one of these sucrose esters contained malonic acids. The structures of the sucrose esters were 2,3,4-O- tri-acyl -α- d -glucopyranosyl -1-O- malonyl -4-O- acyl -6-O- acetyl -β- d -fructofuranoside , 2,3,4-O- tri-acyl -α- d -glucopyranosyl -4-O- acyl -6-O- acetyl -β- d -fructofuranoside and 2,3,4,6-O- tetra-acyl -α- d -glucopyranosyl -β- d -fructofuranoside .

Two novel diacylated and two known anthocyanins were isolated from violet flowers of Petunia hybrida cv Festival. The new anthocyanins are malvidin 3- O -(6- O -(4- O -(4- O -(6- O -feruloyl-β- d -glucopyranosyl)- E - p -coumaroyl)-α-rhamnosyl)-β- d -glucopyranoside)-5-β- d -glucopyranoside and malvidin 3- O -(6- O -(4- O -(4- O -(6- O - E - p -coumaroyl-β- d -glucopyranosyl)- E - p -coumaroyl)-α-rhamnosyl)-β- d -glucopyranoside)-5-β- d -glucopyranoside. The two known pigments are the 3-caffeoylglucosyl- p -coumaroylrutinoside-5-glucosides of malvidin and petunidin.

Six new ergostane glycosides, designated as petunioside A, petunioside B, 24-epipetunioside B, petunioside C, 24-epipetunioside C and petunioside D, were isolated from the methanolic extract of the fresh aerial parts of Petunia hybrida. Their structures were determined by means of spectroscopic analysis and single crystal X-ray analysis.

Seven new steroids have been isolated from leaves and stems of Petunia hybrida . They are 30-hydroxy petuniasterone A (C-30 epimeric mixture), 1α-acetoxy-1,2-dihydropetuniasterone A (designated petuniasterone E), (22 R ,24 S )-7α,24-dihydroxy-22,25-oxidoergosta-1,4-dien-3-one (petuniasterone F), C-24 epimers of (22 R )-7α,22,24,25-tetrahydroxyergosta-1,4-dien-3-one (petuniasterones G 1 and G 2 and C-24 epimers of (22 R )-1-α-acetoxy-7α,22,24,25-tetrahydroxyergost-4-en-3-one (petuniasterones H 1 and H 2 ). The compounds which have 1-α-acetoxy groups may easily be converted into the corresponding A-ring dienes by mild base. The orthoesters and other side-chain variants may be formed from the 24,25-epoxy compounds which co-occur in the plant.

Zusammenfassung Zusammenfassung—Die Wirkung zweier Chalkone auf die Anthocyansynthese in isolierten Petalen von Petunia hybrida wurde untersucht. Dabei zeigte sowohl das 3,4,2′,4′,6′-Penta-hydroxy- als auch das 4,2′,4′,6′-Tetra-hydroxy-3-methoxy-chalkon-4′-glukosid in Gegenwart von D-Glukose-[1- 14 C] eine substitutionsspezifische Wirkung. Es wird stets die Synthese desjenigen Anthocyans gefordert, das dem eingesetzten Chalkon in der Substitution entspricht. Dies last sich kaum anders als damit erklaren, das die Chalkone zur Synthese der Anthocyane herangezogen werden. Bei der gemeinsamen Futterung von Chalkon und Acetat-[1- 14 C] zeigt nur das 3,4,2′,4′,6′-Pentahydroxy-chalkon-4′-glukosid eine substitutionsspezifische Wirkung.

The incorporation of shikimate-[ 14 C] and cinnamate-[ 14 C] into 3′,4′- and 3′,4′,5′-hydroxy substituted anthocyanins was studied in isolated petals of Petunia hybrida . According to the dilution values, the incorporation of shikimate-[ 14 C] was about 3–6 times better than that of cinnamate-[ 14 C]. However a comparison of the incorporation of the 2 precursors on a relative basis showed no significant differences in the relative proportions of the specific activities of the 3′,4′-dihydroxysubstituted cyanidin-3-monoglucoside and the 3′,4′,5′-trihydroxysubstituted delphinidin-3-monoglucoside. This result and the [ 14 C]-incorporation behaviour of the 3′-methoxy-4′-hydroxysubstituted peonidin-3-monoglucoside do not support the hypothesis that there are alternative pathways of flavonoid biosynthesis.

From leaves of Petunia parodii were isolated four epoxy group-bearing petuniasterones. These were shown to be (22 R ,24 R )-7α-acetoxy-4β,5β-epoxy-17β,22,24,25-tetrahydroxyergost-1-en-3-one 22,24,25-[(methylthio)carbonyl]orthoacetate (petuniasterone I); (22 R ,24 R )-7α,12α-diacetoxy-4β,5β-epoxy-22,24,25-trihydroxyergost-1-en-3-one 22,24,25-orthoacetate (petuniasterone J); (22 R ,24 R )-7α-acetoxy-16β,17β-epoxy-22,24,25-trihydroxyergosta-1,4-dien-3-one 22,24,25-orthoacetate (petuniasterone K); and (22 R ,24 R )-7α-acetoxy-16β,17β-epoxy-22,24,25-trihydroxy-ergosta-1,4-dien-3-one 22,24,25-[(methylthio)carbonyl]orthoacetate (petuniasterone L). From leaves of Petunia integrifolia were isolated (22 R ,24 R )-7α,12ξ-diacetoxy-11β,22,24,25-tetrahydroxyergosta-1,4-diene-3-one 22,24,25-orthoacetate (12ξ-acetoxy-11-β-hydroxypetuniasterone D 7-acetate); (22 R ,24 R )-7α,12ξ-diacetoxy-11β,22,24,25-tetrahydroxyergosta-1,4-dien-3-one 22,24,25-orthopropionate (12ξ-acetoxy-11β-hydroxypetuniasterone M 7-acetate); (22 R ,24 R )-7α,22,24,25-tetrahydroxyergosta-1,4-dien-3-one 22,24,25-orthopropionate (petuniasterone M); and (22 R , 24 R )-12α-acetoxy-7α,22,24,25-tetrahydroxyergosta-1,4-diene-3-one 22,24,25-orthopropionate (12α-acetoxypetuniasterone M). From leaves of Petunia hybrida were isolated 30-hydroxypetuniasterone A 7-acetate and petuniasterone C 7-acetate.

A 3′, 4′-dihydroxy or a 3′, 4′, 5′-trihydroxy substitution pattern of dihydroflavonols is required for their conversion into the corresponding anthocyanins in a white flower of Petunia hybrida . The presence of a 5-hydroxyl group is not required. B-ring methylated dihydroflavonols were not converted into the corresponding anthocyanins. In case of a 4′-methoxy substituted dihydroflavonol a 4′-hydroxyanthocyanin is obtained, suggesting demethylation of this compound. The conversion of synthetic (±)- trans -2,3-dihydroflavonols into anthocyanins proceeded almost as well as with natural compounds. The results demonstrate that the cinnamic acid starter hypothesis for the origin of B-ring substituents is not correct for B-ring methylation.

Phytic acid has been identified by paper electrophoresis and NMR spectroscopy in extracts of pollen from Petunia hybrida. In this species pollen wa

3,4,2′,4′,6′-Pentahydroxychalcone 4′-glucoside, which is specific for B-ring substitution, triggers an incorporation of [1- 14 C]acetate into cyanidin 3-monoglucoside in Petunia hybrida , at a stage when anthocyanin accumulation is linear and intensive. This incorporation could not be specifically prevented by adding either transcriptive or translational antimetabolites. Sodium diethyldithiocarbaminate, which specifically complexes with Cu 2+ ions, produces the same effect. This similarity in action suggests that both reagents affect those enzymes of the anthocyanin pathway which require bivalent metal ions as co-factors.

Cybrids with nuclei of Nicotiana tabacum and chloroplasts from Petunia hybrida in general accumulate higher amounts of nicotine and (1 S ,2 E ,4 R ,6 R ,7 E ,11 E )-and(1 S ,2 E ,4 S ,6 R ,7 E ,11 E )-2,7,11-cembratriene-4,6-diol than do ordinary tobacco plants. The composition of the cembranic diterpenoids present in the cuticular wax of the cybrid leaves, was, with one exception, found to be similar to that encountered in the leaves of N. tabacum .

The incorporation of phenylalanine-[ 14 C] into anthocyanins of petals of Petunia hybrida is greater than that of cinnamic acid-[ 14 C]. Moreover, there is a preferential incorporation of phenylalanine-[ 14 C] into delphinidin 3-monoglucoside, as compared with the incorporation into cyanidin and peonidin 3-monoglucosides.