乌檀的化学成分研究

从珍稀药用植物乌檀(Nauclea officinalis)的枝叶中分离得到1个甾醇类、3个三萜类、2个酚类和1个生物碱类化合物。通过光谱分析,分别鉴定为豆甾-4-烯-3-酮(1)、铁冬青酸(2)、常春藤皂苷元(3)、3-羰基奎诺瓦酸(4)、2,5-二甲氧基苯甲酸(5)、3,4,5-三甲氧基苯甲酸(6)和Strictosamide(7)。7个化合物均是首次从乌檀中得到。     

Hypaphorine, an indole alkaloid from Erythrina velutina, induced sleep on normal mice

An indole alkaloid (hypaphorine (1)) was isolated from Brazilian medicinal plant, Erythrina velutina (Leguminosae). This compound was investigated for sleep promoting effects in mice, and the results showed that it significantly increased non-rapid eye movement (NREM) sleep time during the first hour after its administration. The NREM sleep time was enhanced by 33% in the experimental mice when compared to that of the controls. This study therefore confirmed its sleep promoting property.     

棕色扁海绵中的吡咯生物碱

从中国南海棕色扁海绵Phakellia fusca Schimidt的乙醇浸提物中,分离得到3个吡咯生物碱,结合理化性质,波谱分析,文献检索,确定其结构分别为4,5-二溴-1H-吡咯-2-甲酸甲酯(1)、4,5-二溴-3-氰-1H-吡咯-2-甲酸甲酯(2)、4,5-二溴-1H-吡咯-2-甲酰氨(3)。其中化合物(2)未见文献报道。     

中坝鹅掌叶附子中的生物碱成分

从中坝鹅掌叶附子(Aconitum carmichaeli Debx．)的块根中分离得到6个二萜生物碱,根据波谱方法分别鉴定为：songoramine(1)、次乌头碱(hypaconitine,2)、karakanine(3)、宋果灵(songorine,4)、尼奥宁(neoline,5)、附子灵(fuzline,6)。其中化合物3为首次从该植物的块根中分离鉴定。     

Metabolism of purine bases, nucleosides and alkaloids in theobromine-forming Theobroma cacao leaves

We examined the purine alkaloid content and purine metabolism in cacao (Theobroma cacao L.) plant leaves at various ages: young small leaves (stage I), developing intermediate size leaves (stage II), fully developed leaves (stage III) from flush shoots, and aged leaves (stage IV) from 1-year-old shoots. The major purine alkaloid in stage I leaves was theobromine (4.5 μmol g^–1 fresh weight), followed by caffeine (0.75 μmol g^–1 fresh weight). More than 75% of purine alkaloids disappeared with subsequent leaf development (stages II–IV). In stage I leaves, ¹⁴C-labelled adenine, adenosine, guanine, guanosine, hypoxanthine and inosine were converted to salvage products (nucleotides and nucleic acids), to degradation products (ureides and CO₂) and to purine alkaloids (3- and 7-methylxanthine, 7-methylxanthosine and theobromine). In contrast, ¹⁴C-labelled xanthine and xanthosine were not used for nucleotide synthesis. They were completely degraded, but nearly 20% of [8-¹⁴C]Xanthosine was converted in stage I leaves to purine alkaloids. These observations are consistent with the following biosynthetic pathways for theobromine: (a) AMP → IMP → 5′-xanthosine monophosphate → xanthosine → 7-methylxanthosine → 7-methylxanthine → theobromine; (b) GMP → guanosine → xanthosine → 7-methylxanthosine → 7-methylxanthine → theobromine; (c) xanthine → 3-methylxanthine → theobromine. Although no caffeine biosynthesis from ¹⁴C-labelled purine bases and nucleosides was observed during 18 h incubations, exogenously supplied [8-¹⁴C]Theobromine was converted to caffeine in young leaves. Conversion of theobromine to caffeine may, therefore, be slow in cacao leaves. No purine alkaloid synthesis was observed in the subsequent growth stages (stages II–IV). Significant degradation of purine alkaloids was found in leaves of stages II and III, in which [8-¹⁴C]Theobromine was degraded to CO₂ via 3-methylxanthine, xanthine and allantoic acid. [8-¹⁴C]Caffeine was catabolised to CO₂ via theophylline (1,3-dimethylxanthine) or theobromine.     

Occurrence of theobromine synthase genes in purine alkaloid-free species of <Emphasis Type="Italic">Camellia</Emphasis> plants

Caffeine (1,3,7-trimethylxanthine) and theobromine (3,7-dimethylxanthine) are purine alkaloids that are present in high concentrations in plants of some species of Camellia. However, most members of the genus Camellia contain no purine alkaloids. Tracer experiments using [8-¹⁴C]adenine and [8-¹⁴C]theobromine showed that the purine alkaloid pathway is not fully functional in leaves of purine alkaloid-free species. In five species of purine alkaloid-free Camellia plants, sufficient evidence was obtained to show the occurrence of genes that are homologous to caffeine synthase. Recombinant enzymes derived from purine alkaloid-free species showed only theobromine synthase activity. Unlike the caffeine synthase gene, these genes were expressed more strongly in mature tissue than in young tissue. The nucleotide sequence data reported here have been deposited in the GenBank database under the accession numbers AB297451 (CjCS1), AB362882 (CgCS1), AB362883 (CgCS2), AB362884 (CkCS1), AB362885 (ClCS1), and AB362886 (CcCS2).     

Pyrinadines B-G, new bis-pyridine alkaloids with an azoxy moiety from sponge Cribrochalina sp

Six new cytotoxic bis-3-alkylpyridine alkaloids with an azoxy moiety, pyrinadines B–G (1–6), have been isolated from an Okinawan marine sponge Cribrochalina sp., and the structures were elucidated by spectroscopic data and chemical means.     

刈割对栽培长春花(Catharanthus roseus)生活史型转变的影响

为了提高栽培长春花（Catharanthus roseus）的生物碱产量,应用植物生活史型的理论和方法,研究了刈割对栽培长春花生活史型转变及其生物碱代谢的影响。运用主成分分析法（Principal Component Analysis, PCA）对刈割后的长春花后生活史型变化进行定量和定性划分,发现在对照栽培环境下生长的长春花处于DE生境,定性划分结果为SV生活史型,定量划分结果为V_0.3638S_0.6174C_0.0187,属于SV型。刈割使长春花的生活史型转变为V0.2847S0.6684C0.0469,属于SC型。同时,对两种生活史型的长春花中长春碱及其前体文朵灵和长春质碱的含量进行了检测分析,发现刈割后的SC型长春花不同叶位叶片中的生物碱含量均显著提高（p<0.05）,可以为提高栽培长春花生物碱含量提供科学指导,也进一步验证了生活史型理论。     

番茄生物碱粗提物抑菌作用的研究

本文研究了番茄生物碱粗提物对食品中常见腐败菌的抑菌效力,发现它对细菌和酵母菌具有较强的抑制作用,但对霉菌的抑菌作用较弱。番茄生物碱在中性环境中抑菌作用显著,经过121℃的高温处理仍具有较强的抑菌效力,且比苯甲酸钠的抑菌作用强。