Monitoring changes in anthocyanin and steroid alkaloid glycoside content in lines of transgenic potato plants using liquid chromatography/mass spectrometry

Transgenic potato plants overexpressing and repressing enzymes of flavonoids biosynthesis were created and analyzed. The selected plants clearly showed the expected changes in anthocyanins synthesis level. Overexpression of a DNA encoding dihydroflavonol 4-reductase (DFR) in sense orientation resulted in an increase in tuber anthocyanins, a 4-fold increase in petunidin and pelargonidin derivatives. A significant decrease in anthocyanin level was observed when the plant was transformed with a corresponding antisense construct. The transformation of potato plants was also accompanied by significant changes in steroid alkaloid glycosides (SAG) level in transgenic potato tuber. The changes in SAGs content was not dependent on flavonoid composition in transgenic potato. However, in an extreme situation where the highest (DFR11) or the lowest (DFRa3) anthocyanin level was detected the positive correlation with steroid alkaloid content was clearly visible. It is suggested that the changes in SAGs content resulted from chromatin stressed upon transformation. A liquid chromatography/mass spectrometry (LC/MS) system with electrospray ionization was applied for profiling qualitative and quantitative changes of steroid alkaloid glycosides in tubers of twelve lines of transgenic potato plants. Except alpha-chaconine and alpha-solanine, in the extracts from dried tuber skin alpha-solamargine and alpha-solasonine, triglycosides of solasonine, were identified in minor amounts, triglycosides of solanidine dehydrodimers were also recognized.     

Identification of Harman as the Antibiotic Compound Produced by a Tunicate-Associated Bacterium

The alkaloid harman, previously reported from some marine invertebrates, was identified as the antibiotic substance of the tunicate-associated bacterium Enterococcus faecium. It exhibited antibacterial activity (MIC, 0.017 mM) against the ichthyopathogenic strain Vibrio anguillarum.     

Beilschglabrines A and B: Two new bioactive phenanthrene alkaloids from the stem bark of Beilschmiedia glabra

Two new phenanthrene alkaloids, beilschglabrines A (1) and B (2) were isolated from the stem bark of Beilschmiedia glabra, together with lupeol, taraxerol, and 24-methylenelanosta-7,9-diene-3β-15α-diol. The structures of the isolated compounds were elucidated by extensive spectroscopic data analysis and comparison with respective literature data. The compounds were tested for DPPH radical scavenging, acetylcholinesterase and lipoxygenase inhibitory activities. Compound 1 displayed considerable activity in the acetylcholinesterase (IC₅₀ 50.4 μM), the DPPH radical scavenging (IC₅₀ 115.9 μM) and the lipoxygenase (IC₅₀ 32.8 μM) assays.     

An alkaloid from Haplophyllum tuberculatum

A new alkaloid (+)-tuberine was isolated from Haplophyllum tuberculatum. Physicochemical and spectral evidence established its structure and stereochemistry as N- benzoyl-4′-[(2″S,3″S,6″S)-(+)-7″-acetoxy-2″-hydroxy-3″,7″-dimethyl-3″,6″-epoxyoctyloxy]phenethylamine.     

(+)-5,17-dehydromatrine N-oxide,a new alkaloid in Euchresta japonica

A new lupin alkaloid, (+)-5,17-dehydromatrine N-oxide, was isolated from the fresh aerial parts of Euchresta japonica. Its structure was confirmed by spectrometric data and by direct comparison with a synthetic sample, prepared from (+)-sophoranol ((+)-5-hydroxymatrine). It was also concluded that (+)-5,17-dehydromatrine N-oxide and (+)-matrine N-oxide possess the same configuration with respect to the asymmetric nitrogen by NMR spectra.     

Anti-inflammatory and antiproliferative prenylated carbazole alkaloids from Clausena vestita

Twelve prenylated carbazole alkaloids, containing a novel prenylated carbazole alkaloid, named as clausevestine (1), and 11 known prenylated carbazole alkaloids (2–12), were isolated and identified from the stems and leaves of Clausena vestita, which is a Chinese endemic plant. The chemical structure of 1 was established by means of comprehensive spectroscopic data analyses and the known compounds were determined via comparing their NMR and MS data as well as optical rotation values with those reported in literature. Especially, clausevestine (1) is an unusual prenylated carbazole alkaloid possessing an unprecedented carbon skeleton holding 20 carbon atoms. The anti-inflammatory effects and antiproliferative activities of those isolated prenylated carbazole alkaloids were tested. Prenylated carbazole alkaloids 1–12 displayed remarkable inhibitory effects on NO (nitric oxide) production with IC₅₀ values equivalent to that of the positive control (hydrocortisone). Meanwhile, prenylated carbazole alkaloids 1–12 exhibited remarkable antiproliferative activities against diverse human cancer cell lines in vitro holding the IC₅₀ values ranging from 0.32 ± 0.04 to 18.76 ± 0.18 µM. These findings indicate that these prenylated carbazole alkaloids possessing remarkable anti-inflammatory effects and antiproliferative activities could be meaningful to the discovery of new anti-inflammatory and anti-tumor candidate drugs.     

Structure and carcinogenicity of Dibenzo(c,g)carbazole derivatives

The carcinogenicity of several groups of carcinogens is evoked with particular reference to Dibenzo(c,g)carbazole derivatives. The activity of these derivatives is discussed with respect to their species and organ specificity. The enzymatic equipment is decisive as to whether the compounds formed can react with DNA or are simply detoxified and eliminated. All these carcinogens are complete carcinogens, i.e. they have the property of both initiation and promotion.     

一株假单胞菌(Pseudomonas sp.)石油脱有机氮分析

为了探讨咔唑降解菌在石油中的脱氮性能, 从研究咔唑降解菌Pseudomonas sp. XLDN4-9在双液相系统中降解咔唑的性能出发, 分别考察了XLDN4-9休止细胞体系对原油、润滑油及柴油的脱氮效果, 并借助于GC-MS分析了柴油中咔唑及其衍生物的降解状况。结果表明, 正十四烷-水系统有利于咔唑的降解; 以低氮柴油代替正十四烷, 2 g/L咔唑可在15 h内降解95.2%; XLDN4-9休止细胞体系对原油、润滑油、柴油均有显著脱氮效果。在柴油脱氮过程中, 发现3 天后, 99%的咔唑被降解, 四种单甲基咔唑的降解率为63.4%~87.6%, 二甲基咔唑共降解了15%。     

C19-、C20-二萜生物碱抗肿瘤活性研究进展

二萜生物碱具有较高的药理活性和药用价值,一直以来为药理学家和临床医生所重视,但对于其抗肿瘤作用的报道却并不多见,主要集中于 C19-、C20- 二萜生物碱。综述近 10 年来 C19-、C20- 二萜生物碱抗肿瘤作用的基础及临床研究进展,并对当前研究存在的不足提出见解,为进一步研究及应用提供参考。