dehydrodiconiferyl-alcohol and pinoresinol

A candidate gene for phenylcoumaran benzylic ether reductase in Arabidopsis thaliana encodes a peptide with predicted functional activity and plays a crucial role in secondary metabolism. Phenylcoumaran benzylic ether reductase (PCBER) is thought to be an enzyme crucial in the biosynthesis of 8-5'-linked neolignans. Genes of the enzyme have been isolated and characterized in several plant species. In this study, we cloned cDNA and the 5'-untranslated region of one PCBER candidate gene (At4g39230, designated AtPCBER1) from Arabidopsis thaliana. At the amino acid level, AtPCBER1 shows high sequence identity (64-71 %) with PCBERs identified from other plant species. Expression analyses of AtPCBER1 by reverse transcriptase-polymerase chain reaction and histochemical analysis of transgenic plants harboring the 5'-untranslated region of AtPCBER1 linked with gus coding sequence indicate that expression is induced by wounding and is expressed in most tissues, including flower, stem, leaf, and root. Catalytic analysis of recombinant AtPCBER1 with neolignan and lignans in the presence of NADPH suggests that the protein can reduce not only the 8-5'-linked neolignan, dehydrodiconiferyl alcohol, but also 8-8' linked lignans, pinoresinol, and lariciresinol, with lower activities. To investigate further, we performed metabolomic analyses of transgenic plants in which the target gene was up- or down-regulated. Our results indicate no significant effects of AtPCBER1 gene regulation on plant growth and development; however, levels of some secondary metabolites, including lignans, flavonoids, and glucosinolates, differ between wild-type and transgenic plants. Taken together, our findings indicate that AtPCBER1 encodes a polypeptide with PCBER activity and has a critical role in the biosynthesis of secondary metabolites in A. thaliana.

Topics: Arabidopsis; Arabidopsis Proteins; Biocatalysis; Flavonoids; Furans; Gene Expression Profiling; Gene Expression Regulation, Enzymologic; Gene Expression Regulation, Plant; Glucosinolates; Lignans; Metabolomics; Oxidoreductases; Phenols; Phylogeny; Plants, Genetically Modified; Principal Component Analysis; Reverse Transcriptase Polymerase Chain Reaction; Tandem Mass Spectrometry

To study the chemical constituents of Eucommia ulmoides in Guizhou Province.. Silica gel, Sephadex LH-20, RP-18, MCI and semi-preparative HPLC were used to study the chemical constituents of Eucommia ulmoides, and the chemical structures were elucidated by application of spectral data.. 16 compounds were isolated from the bark of Eucommia ulmoides. Their structures were identified as β-sitosterol (1), cycloeucalenol (2), betulinic acid (3), 24-methylenecycloartenone (4), cycloeucalenone (5), salicifoliol (6), pinoresinol (7), genipin (8) , alternariol (9), balanophonin (10), eucommidiol (11), pinoresinol-4'-O-β-D-glucopyranoside (12), eucommiol (13), deoxyeucommiol (14), 8-hydroxypinoresinol (15), and dehydrodiconiferyl alcohol -γ'-O-β-D-glucopyranoside (16).. Seven compounds, including compounds 2,4 - 6,9, 10 and 15 are isolated from Eucommia ulmoides for the first time, and compound 14 is isolated from the bark of Eucommia ulmoides for the first time.

Topics: Betulinic Acid; Chromatography, High Pressure Liquid; Eucommiaceae; Furans; Lignans; Pentacyclic Triterpenes; Phenols; Phytochemicals; Plant Bark; Sitosterols; Triterpenes