Biosynthesis of cyanidin in cell cultures of Haplopappus gracilis

-Dihydroquercetin proved to be a good precursor for light-stimulated cyanidin biosynthesis in cell suspension cultures of Haplopappus gracilis. Wit     

Induction of anthocyanin formation and of enzymes related to its biosynthesis by UV light in cell cultures of Haplopappus gracilis

Only UV light below 345 nm stimulates anthocyanin formation in dark grown cell suspension cultures of Haplopappus gracilis. A linear relationship between UV dose and flavonoid accumulation, as found previously with parsley cell cultures, was not observed with the H. gracilis cells. Only continuous irradiation with high doses of UV was effective. Drastic increases in the activities of the enzymes phenylalanine ammonia-lyase, chalcone isomerase and flavanone synthase were observed under continuous UV light. The increase in enzyme activities paralleled anthocyanin formation.     

Biosynthesis of morindone and alizarin in intact plants and cell suspension cultures of Morinda citrifolia

Chrysophanol (1,8-dihydroxy-3-methylanthraquinone) is an acetate-derived anthraquinone which is substituted in both benzenoid rings. Morindone (1,5,6-trihydroxy-2-methylanthraquinone) is also substituted in both rings but is shown to be derived from shikimic acid via o-succinoylbenzoic acid.     

Partial purification and characterization of geissoschizine dehydrogenase from suspension cultures of Catharanthus roseus

The characterization and partial purification of geissoschizine dehydrogenase from Catharanthus roseus cell suspension cultures are described. The 35-fold purified enzyme removes the 21α-hydrogen of geissoschizine in a NADP⁺-dependent reaction. NAD⁺, FAD or FMN cannot act as cofactors for the dehydrogenation. Structurally related indole alkaloids are not dehydrogenated. In comparison to enzymes of the ajmalicine pathway, geissoschizine dehydrogenase shows an extremely low specific activity.     

Phenolic synthesis in Perilla cell suspension cultures

Suspension cultures of Perilla ocymoides accumulate caffeic acid, both in free and ester forms, as the only phenylpropanoid end metabolite. Increased levels of growth substances influenced the levels of PAL activity and phenolic accumulation so that cytokinin stimulated, while auxin repressed both parameters. The regulatory role of caffeyl compounds is discussed in relation to their accumulation during the early exponential phase of culture growth.     

Increases in enzyme levels during the formation of phenolic acids in carrot cell cultures

The levels of glutamic acid dehydrogenase (GDH), phenylalanine ammonia-lyase (PAL), cinnamic acid 4-hydroxylase (CAH) and O-methyltransferase (OMT) were measured during the formation of phenolic acids in carrot cells in suspension culture. Caffeic, ferulic and p-hydroxybenzoic acids were always present as the culture proceded. Total content of these acids increased at the early logarithmic and linear phases. GDH showed high activity at the early logarithmic and stationary phases. PAL activity was much enhanced at the linear and stationary phases. CAH activity was found in actively growing cells, especially at the early and late logarithmic phases OMT behaved similarly to PAL. The increases in GDH and CAH might be responsible for the rapid synthesis of phenolic acid at the early logarithmic phase. The increase in phenolic acid at the linear phase would certainly be due to enhancements of both PAL and OMT. On the other hand, the accumulation of vanillic acid was observed in cells which were transferred and cultured on an agar medium, but not in cells in suspension culture. This accumulation is related to increases in OMT levels and also to changes in the degree of β-oxidation.     

Induction of benzoquinone formation by activated carbon in Lithospermum erythrorhizon cell suspension cultures

Cultured cells of Lithospermum erythrorhizon which were capable of producing red naphthoquinone (shikonin) derivatives on Linsmaier-Skoog's agar medium stopped synthesizing these compounds when grown in liquid medium without agar. However, when the liquid medium was supplemented with a small amount of activated carbon, the cells produced a new orange benzoquinone derivative, echinofuran B, which may be considered an abnormal metabolite of geranylquinol, the key intermediate in the biosynthesis of shikonin. A similar effect of activated carbon was also observed with a variant cell line incapable of producing shikonin derivatives even on the agar medium. By contrast, the callus cultures grown on the agar medium as well as the dried roots of the intact plant were found to contain a small amount of echinofuran C, another new benzoquinone related to echinofuran B, in addition to shikonin derivatives.     

Production of ferruginol by cell suspension cultures of Salvia miltiorrhiza

The time-course production of ferruginol, a diterpene, was examined during growth of Salvia miltiorrhiza in cell culture. Ferruginol was produced in the lag and stationary phases of growth and so production of this secondary metabolite was inversely related to active cell division. The effects of auxins and light on ferruginol production were also examined.     

Light induced changes in anthocyanin concentration,activity of phenylalanine ammonia-lyase and flavanone synthase and some of their properties in Brassica oleracea

Seedlings of red cabbage, Brassica oleracea cv Red Danish, germinated in the dark, rapidly produced anthocyanins upon illumination. The anthocyanin production increased up to six days of illumination time. The activity of phenylalanine ammonia-lyase increased rapidly in illuminated seedlings to a maximum at 8 hr and declined thereafter to dark levels. During this period the activity of flavanone synthase, the first enzyme responsible for the establishment of C₁₅ flavonoid skeleton, paralleled that of the anthocyanin concentration. The crude flavanone synthase has a pH optimum at around 8, a molecular weight of ca 120 000, and is able to utilize only p-coumaryl-CoA as co-substrate for the production of flavonoids.     

Diethylene glycol disulfide from castor bean cell suspension cultures

Diethylene glycol disulfide was isolated from castor bean cell suspension cultures. Incubation of suspension cultures with Na₂³⁵SO₄ resulted in the incorporation of radioactivity into the isolated diethylene glycol disulfide. Diethylene glycol disulfide was detected in cells (430 nmol/g cells) and in cell-free growth medium (41.5 nmol/ml).     

Behaviour of phenylalanine ammonia-lyase in carrot cells in suspension cultures

The high PAL activity in carrot cells in suspension culture was found at the linear and early stationary phases, with concomitant increases in phenylal     

Medium- and light-induced formation of serpentine and anthocyanins in cell suspension cultures of Catharanthus roseus

By irradiation with fluorescent light, medium-induced cell cultures of Catharanthus roseus accumulated anthocyanins and the indole alkaloid serpentine. The formation of both compounds was inhibited by phosphate and nitrogen-containing mineral salts and stimulated by high sucrose concentrations. The accumulation of serpentine was preceded by an increase and subsequent decrease of its biogenetic precursor ajmalicine, which was the predominant alkaloid of medium-induced cultures in the dark. High concentrations of serpentine or anthocyanins were observed only in a small proportion of all cells present in a medium-induced culture. The aglycones of the anthocyanins were identified as petunidin, malvidin and hirsutidin.     

Induction of shikonin formation by agar in Lithospermum erythrorhizon cell suspension cultures

Cultured cells of Lithospermum erythrorhizon capable of producing red naphthoquinone (shikonin) derivatives on Linsmaier-Skoog agar medium ceased s     

Flavonoid constituents of Eupatorium odoratum

Isosakuranetin and a new chalcone, odoratin, have been isolated from the leaves of Eupatorium odoratum. The structure of odoratin has been shown to be 2′-hydroxy-4,4′,5′,6′-tetramethoxy chalcone.     

Myricetin and quercetin methyl ethers from Haplopappus integerrimus var. Punctatus

Nine flavonoids including two new myricetin derivatives, myricetin 3′,4′-dimethyl ether and myricetin 3,3′, 4′-trimethyl ether, were obtained from Haplopappus integerrimus var. punctatus. The known compounds are quercetin 7,3′-dimethyl ether, querectin 3,3′-dimethyl ether, isorhamnetin, quercetin 3,7-dimethyl ether, quercetin 3-methyl ether, quercetin and quercetin 3-β-d-glucoside.     

Two phenolic acids from Lithospermum erythrorhizon cell suspension cultures

Two phenolic acids isolated from colourless cell cultures of Lithospermum erythrorhizon were identified as rosmarinic acid and lithospermic acid. However, these compounds were not detected in pigmented cell cultures producing shikonin derivatives.     

Flavonoid glycosides from illuminated cell suspension cultures of Petroselinum hortense

Twenty-four different flavonoid glycosides were isolated from illuminated cell suspension cultures of parsley (Petroselinum hortense). The chemical structures of fourteen of these compounds were further characterized. The aglycones identified were the flavones apigenin, luteolin and chrysoeriol, and the flavonols quercetin and isorhamnetin. The flavones occurred either as 7-O-glucosides or as 7-O-apioglucosides, while the flavonols were 3-O-monoglucosides or 3,7-O-diglucosides. One-half of these glycosides were electrophoretically mobile and substituted with malonate residues.     

Glucosylation of phenolic compounds by Datura innoxia suspension cultures

Datura innoxia grown in suspension cultures can glucosylate simple phenols. Three isomers of dihydroxybenzene (hydroquinone, resorcinol and catechol) were readily converted into their corresponding mono-β-glucosides. Both salicyl alcohol and salicylaldehyde fed to the cells were transformed specifically to isosalicin instead of salicin. Furthermore, the analysis of the cells treated with salicylic acid suggested the formation of its glucose ester in addition to the corresponding monoglucoside. Feeding experiments showed that the cultured cells possess a remarkably high capacity for glucosylation of hydroquinone, which was totally converted into arbutin within 10 hr after administration. The in vitro glucosylation of hydroquinone carried out by the cell-free extract demonstrated that this enzymic reaction requires the presence of UDPG as a high energy donor of glucose.     

Phenolic constituents of Artemesia tridentata spp. Vaseyana

Ten coumarins and four flavonoids have been isolated from a single collection of Artemesia tridentata ssp. vaseyana (Rydb.) Beetle. The coumarins are 7-methylesculin, esculin, umbelliferone, skimmin, cichoriin, isoscopoletin, scopoletin, scoparon, esculetin and a new natural product, artelin (5,6,7,8-tetramethoxy coumarin). The flavonoids are luteolin, luteolin-7-glucoside, axillarin and eupafolin.