Aldoximes and nitriles as intermediates in the biosynthesis of cyanogenic glucosides

Young sorghum shoots have been shown to convert tyrosine, p-hydroxyphenylacetaldoxime and p-hydroxyphenylacetonitrile to dhurrin, the cyanogenic glucoside characteristic of this plant. Evidence for the in vivo formation of p-hydroxyphenylacetaldoxime but not p-hydroxyphenylacetonitrile from tyrosine has been obtained from a 'trapping experiment.'     

Lobodirin: Ein neues chromonglucosid aus Lobodirina cerebriformis

From the lichen Lobodirina cerebriformis (Mont.) Follm. Roccellaceae) a new chromone glucoside lobodirin (I) has been isolated. The structure, 7-0-β-d-triacetylglucosyl-isoeugenitol, was established by hydrolysis to glucose isoeugenitol by synthesis of acetyllobodirin from α-acetobromoglucose and isoeugenitol with subsequent acetylation.     

Metabolic formation and occurrence of gibberellin A1-3-0-β-D-glucopyranoside in immature fruits of Phaseolus coccineus L.

Endogenous pools of presumptive gibberellin (GA) glucosyl conjugates of Phaseolus coccineus were metabolically labelled by feeding of [³H]GA₁ to immature fruits. The [³H]GA₁ glucoside fraction was isolated and the main constituent tentatively identified by enzymic hydrolysis, ion exchange chromatography and elution volume on HPLC-RC as GA₁-3-0--D-glucopyranoside.     

Formaldehyde Production by Cells of a Mutant of Candida boidinii S2 Grown in Methanol-limited Chemostat Culture

Formaldehyde production was investigated with cells of a mutant, AOU-1, of a methanol yeast, Candida boidinii S2 grown in methanol-limited chemostat culture. The highest productivity was shown with cells from the culture at a dilution rate of 0.075 hr^-1, when cells had the highest activity of alcohol oxidase and almost minimum activity of formaldehyde dehydrogenase. Under optimal reaction conditions, 950 mm formaldehyde was produced in 10-hr reaction with the cells. By the chemostat culture, not only formaldehyde productivity but also cell productivity was improved in comparison with batch culture. A maximum cell productivity of 0.2 g · liter^-1 · hr^-1 and a cell yield of 47% were obtained.     

Cytotoxic activity of butane type of 1,7-seco-2,7′-cyclolignanes and apoptosis induction by Caspase 9 and 3

All stereoisomers of methoxybutane and fluorobutane type of 1,7-seco-2,7′-cyclolignane were synthesized and cytotoxic activities of these compounds were compared with those of all stereoisomers of butane and butanol type compounds. Both enantiomers of butane type secocyclolignane showed higher cytotoxic activity (IC₅₀ = 16–20 μM) than methoxy type compounds, whereas none was observed for all the stereoisomers of butanol type secocyclolignane, however, (−)-Kadangustin J showed stereospecific cytotoxic activity (IC₅₀ = 47–67 μM). Since (R)-9′-fluoro derivative 23 was most potent (IC₅₀ = 19 μM) among the corresponding fluoro stereoisomers, (R)-9′-alkyl derivatives were synthesized, hydrophobic 9′-heptyl derivative 27 showing highest activity (IC₅₀ = 3.7 μM against HL-60, IC₅₀ = 3.1 μM against HeLa) in this experiment. Apoptosis induction caused by Caspase 3 and 9 for (R)-9′-heptyl derivative 27 was observed in the research on the mechanism. A degradation of DNA into small fragments was also shown by DNA ladder assay.     

云木香化学成分研究Ⅱ

从丽江产云木香（ＳａｕｓｒｅａｌａｐｐａＣ．Ｂ．Ｃｌａｒｋｅ）根中分离得到的另外７个化合物,它们分别是＿孕甾烯醇酮（ｐｒｅｇｎｅｎｏｌｏｎｅ）（１）,β－谷甾醇（β－ｓｉｔｏｓｔｅｒｏｌ）（２）,葫萝卜甙（ｄａｕｃｏｓｔｅｒｏｌ）（３）,苯丙素甙（ｓｙｒｉｎｇｉｎ）（４）,木质素甙（１－ｈｙｄｒｏｘｙｐｉｎｏｒｅｓｉｎｏｌ－１－β－Ｄ－ｇｌｕｃｏｐｙｒａｎｏｓｉｄｅ）（５）,油酸［（ｚ,ｚ）－９,１２－ｏｃｔａｄｅｃａｄｉｅｎｏｉｃａｃｉｄ］（６）和油酸－１,３－甘油二酯［（ｚ,ｚ）－９,１２－ｏｃｔａｄｅｃａｄｉｅｎｏｉｃａｃｉｄ－２－ｈｙｄｒｏｘｙ－１,３－ｐｒｏｐａｎｅｄｉｎｙｌｅｓｔｅｒ］（７）．它们的结构通过波谱和化学的方法得到鉴定。其中化合物１作为天然产物首次从植物中分离得到,化合物３,４,５和７为首次从该植物中分离得到。     

Grayanotoxin-XVIII and grayanoside B,a new a-nor-b-homo-ent-kaurene and its glucoside from Leucothoe grayana

From Leucothoe grayana a new grayanoid (diterpene) and its glucoside have been isolated. The structures of these new natural compounds have been established by chemical and spectroscopic means and by correlation with a known compound.     

Genetic engineering of shikonin biosynthesis hairy root cultures of Lithospermum erythrorhizon transformed with the bacterial ubiC gene

The biosynthetic pathway to 4-hydroxybenzoate (4HB), a precursor of the naphthoquinone pigment shikonin, was modified in Lithospermum erythrorhizon hairy root cultures by introduction of the bacterial gene ubiC. This gene of Escherichia coli encodes chorismate pyruvate-lyase (CPL), an enzyme that converts chorismate into 4HB and is not normally present in plants. The ubiC gene was fused to the sequence for a chloroplast transit peptide and placed under control of a constitutive plant promoter. This construct was introduced into L. erythrorhizon by Agrobacterium rhizogenes-mediated transformation.The resulting hairy root cultures showed high CPL activity. 4HB produced by the CPL reaction was utilized for shikonin biosynthesis, as shown by in vivo inhibition of the native pathway to 4HB with 2-aminoindan-2-phosphonic acid (AIP), an inhibitor of phenylalanine ammonia-lyase. A feeding experiment with [1,7-13C2]shikimate showed that in the absence of AIP the artificially introduced CPL reaction contributed ca. 20% of the overall 4HB biosynthesis in the transgenic cultures. ubiC transformation did not lead to a statistically significant increase of shikonin formation, but to a 5-fold increase of the accumulation of menisdaurin, a nitrile glucoside which is presumably related to aromatic amino acid metabolism.     

长鞭红景天中一个新的葡萄糖甙

从云南怒江产的长鞭红景天(Rhodiola fastigiata (Hook. f. et Thoms.) S. H. Fu)根茎中分离得到13个化合物,它们的结构通过波谱和化学方法得到鉴定.其中,化合物1被鉴定为新的葡萄糖甙(2-O-β-D-吡喃葡糖基-3-甲基-戊酸甲酯),命名为长鞭红景天素甲,化合物2和 5～9首次从该植物中分离得到.