Preparation, biological activity and endogenous occurrence of N6-benzyladenosines

Doležal, Karel; Popa, Igor; Hauserová, Eva; Spíchal, Lukáš; Chakrabarty, Kuheli; Novák, Ondřej; Kryštof, Vladimı́r; Voller, Jiří; Holub, Jan; Strnad, Miroslav

doi:10.1016/j.bmc.2007.03.038

Cited by 97 publications

(75 citation statements)

References 32 publications

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“…There is also clear discrimination of aromatic and isoprenoid cytokinins at the receptor level (Spı´chal et al, 2004). The interaction of aromatic cytokinins with cellular signaling systems also appears to be different to that of isoprenoid cytokinins (Dolezˇal et al, 2006(Dolezˇal et al, , 2007. Only four aromatic cytokinins were detected in the two seaweed species analysed in this study with benzyladenosine (BAR) occurring at relatively high concentrations in both species (Table 1).…”

Section: Discussionmentioning

confidence: 86%

Endogenous cytokinins, auxins and abscisic acid inUlva fasciata(Chlorophyta) andDictyota humifusa(Phaeophyta): towards understanding their biosynthesis and homoeostasis

Stirk

Novák

Hradecká

et al. 2009

European Journal of Phycology

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Hormones are present in seaweeds, but little is known about their biosynthesis and regulation. The aim of this study was to investigate variation in concentration and composition of endogenous cytokinins, auxins and abscisic acid in two seaweeds collected over a 1 year period to gain a more complete picture of the types of hormones present during a range of environmental and developmental conditions. Ulva fasciata (Ulvales, Chlorophyta) and Dictyota humifusa (Dictyotales, Phaeophyta) were collected bimonthly from the inter-tidal zone at Rocky Bay, South Africa. Ethanol extracts of the samples containing a mixture of internal standards were purified using a combined DEAE-Sephadex-octadecylsilica column, followed by immuno-affinity chromatography and analysed by high-performance liquid chromatography -mass spectrometry to quantify different cytokinins, auxins and abscisic acid. cis-Zeatin, isopentenyladenine and their ribotide and riboside conjugates were the main cytokinins present in both U. fasciata and D. humifusa with low concentrations of trans-zeatin, dihydrozeatin and aromatic cytokinins. Very low concentrations of O-glucosides and riboside-O-glucosides and no N-glucosides were detected in any of the samples. Based on the cytokinins detected, we propose that as in higher plants, the ribotides are also the first intermediates formed during de novo biosynthesis in seaweeds and are subsequently converted to free-bases and ribosides. The only indole compounds detected in both species were free indole-3-acetic acid and indole-3-acetamide (IAM), suggesting that IAM is the intermediate in auxin biosynthesis. Endogenous abscisic acid was detected in most samples with levels in U. fasciata generally being higher than those measured in D. humifusa.

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Section: Discussionmentioning

confidence: 86%

Endogenous cytokinins, auxins and abscisic acid inUlva fasciata(Chlorophyta) andDictyota humifusa(Phaeophyta): towards understanding their biosynthesis and homoeostasis

Stirk

Novák

Hradecká

et al. 2009

European Journal of Phycology

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“…Biosynthetic, metabolic and degradation pathways of aromatic cytokinins have yet to be elucidated but evidence suggests they are separate from isoprenoid biosynthesis (Strnad 1997). Aromatic cytokinins have specific receptors with different signal perceptions, transduction and responses to isoprenoid cytokinins so that these two groups of cytokinins have different but overlapping spectra of biological activities in plants (Strnad 1997;Doležal et al 2007) with aromatic cytokinins involved in the regulation of more mature tissues rather than stimulating cell division (Kamínek et al 1987).…”

Section: Cytokinin Biosynthesis In Angiospermsmentioning

confidence: 98%

Flow of cytokinins through the environment

Stirk

Staden

2010

Plant Growth Regul

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Cytokinins are a group of plant growth regulators that elicit a wide range of physiological responses in plants. Cytokinins are not restricted to plants alone but also occur in lower order plants, algae and bacteria as well as in parasitic insects and nematodes. The use of cytokinins, including synthetic cytokinins, in agriculture also contributes to the available cytokinin pool. This review discusses possible ways in which cytokinins move through the environment such as via root exudates, leaf litter and in water systems, thus potentially influencing the growth and development of plants and other organisms. This review highlights the need for a more holistic and ecological approach in order to understand cytokinin regulation and homeostasis in plants.

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“…The precursors (2,6-dichloro-9-isopropylpurine, 2,4-dihydroxybenzylamine hydroiodide, and 2,5-dihydroxybenzylamine hydrochloride) re-quired for synthesizing the possible olomoucine II metabolites were prepared as described previously (Otyepka et al, 2000;Dolezal et al, 2006Dolezal et al, , 2007. The appropriate dihydroxybenzylamine isomers (1 mmol) for the metabolites were then added individually, together with triethylamine (6 mmol), to a suspension of 2,6-dichloro-9-isopropylpurine (1 mmol) in ethyl acetate.…”

Section: Methodsmentioning

confidence: 99%

Interactions of Olomoucine II with Human Liver Microsomal Cytochromes P450

Siller

Anzenbacher²,

Anzenbacherová³

et al. 2009

Drug Metab Dispos

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ABSTRACT:Olomoucine II is a cyclin-dependent kinase inhibitor and a potential antineoplastic agent because it can arrest animal cell cycles. This study examines its interactions with human liver microsomal cytochrome P450 (P450) enzymes. Spectroscopic and high-performance liquid chromatography (HPLC) methods were used to estimate the degree of olomoucine II-mediated inhibition of enzymatic activities of eight drug-metabolizing P450s in vitro. In addition, mass spectrometry coupled with HPLC was used to identify an olomoucine II metabolite (2,5-dihydroxyroscovitine) formed in the reaction mixtures, and CYP3A4 was found to be responsible for the hydroxylation of the N 6 -benzyl ring at position 5, leading to this compound. Olomoucine II significantly inhibited the enzymatic activities of CYP1A2, CYP2C9, and (to a lesser degree) CYP3A4. The results indicate that use of olomoucine II as a drug could affect the activities of CYP3A4, CYP1A2, and CYP2C9 in vivo. Hence, the clinical relevance of these interactions should be carefully evaluated.

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Preparation, biological activity and endogenous occurrence of N6-benzyladenosines

Cited by 97 publications

References 32 publications

Endogenous cytokinins, auxins and abscisic acid inUlva fasciata(Chlorophyta) andDictyota humifusa(Phaeophyta): towards understanding their biosynthesis and homoeostasis

Endogenous cytokinins, auxins and abscisic acid inUlva fasciata(Chlorophyta) andDictyota humifusa(Phaeophyta): towards understanding their biosynthesis and homoeostasis

Flow of cytokinins through the environment

Interactions of Olomoucine II with Human Liver Microsomal Cytochromes P450

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