大萼香茶菜乙素和己素的化学结构

从大萼香茶菜［Ｒａｂｄｏｓｉａ ｍ ａｃｒｏｃａｌｙｘ（Ｄｕｎｎ） Ｈａｒａ］叶的乙醇提取物中又分得两种二萜类成分,经ＩＲ、ＭＳ、１ Ｈ－１Ｈ ＣＯＳＹ、１３Ｃ－１ Ｈ ＣＯＳＹ 和ＮＯＥ等光谱分析及衍生物制备,确证其化学结构为新型二萜,分别命名为大萼香茶菜乙素和己素     

大萼香茶菜辛素的化学结构

大萼香茶菜（Ｒａｂｄｏｓｉａｍａｃｒｏｃａｌｙｘ（Ｄｕｎｎ）Ｈａｒａ）系唇形科（Ｌａｂｉａｔａｅ）香茶菜属植物,民间用于治疗肿瘤等疾病。我们曾报道了它的具有抗菌和细胞毒活性的７个新二萜成分：大萼香茶菜甲素、乙素、丙素、丁素、戊素、己素和庚素［１—５］。进一步研究又分得３个结晶单体。其中,结晶Ⅰ鉴定为新化合物,命名为大萼香茶菜辛素;结晶Ⅱ和Ⅲ鉴定为已知化合物ｏｒｉｄｏｎｉｎ和ｅｎｍｅｎｏｌ。大萼香茶菜辛素（Ⅰ）　Ｃ２２Ｈ３４Ｏ８,ｍｐ２３０℃,［α］２２Ｄ－４１．８（ｃ０．２２,ＭｅＯＨ）。ＩＲ不…     

大萼变型丁素的化学结构

继大萼变型甲素和乙素之后,从大萼香茶菜变型 Rabdosia macrocalyx(Dunn.)Haraform 干叶的乙醇提取物中又分离出一种新的二萜,命名为大萼变型丁素。初步的药理试验表明其具有明显的细胞毒作用和较强的抑菌作用。根据光谱和化学证据,确定了大萼变型丁素的结构为(Ⅲ)式。     

大萼香茶菜庚素的化学结构

从大萼香茶菜（Ｒａｂｄｏｓｉａ ｍ ａｃｒｏｃａｌｙｘ （Ｄｕｎｎ） Ｈａｒａ）叶的乙醇提取物中又分离到３ 个二萜成分（结晶Ⅰ、Ⅱ、Ⅲ）,通过ＩＲ、ＭＳ、１Ｈ－１Ｈ ＣＯＳＹ、１３Ｃ－１Ｈ ＣＯＳＹ和ＮＯＥ等光谱分析及衍生物的制备,确定结晶Ⅰ的结构为ｅｎｔ－７β－２０－ｅｐｏｘｙ－６α, ７α,１４α,１５α,１６α－ｐｅｎｔａｈｙｄｒｏｋａｕｒａｎｅ－１７－ａｃ－ｅｔａｔｅ,为新的二萜化合物,命名为大萼香茶菜庚素;结晶Ⅱ和Ⅲ为已知化合物ｒａｂｄｏｐｈｙｌｌｉｎ Ｈ和ｐｏｎｉｃｉｄｉｎ。     

毛叶香茶菜素的结构订正

我们从安徽省黄山产的大萼香茶菜（Ｒａｂｄｏｓｉａｍａｃｒｏｃａｌｙｘ（Ｄｕｎｎ）Ｈａｒａ）中分得一结晶,其元素分析和１３Ｃ－ＮＭＲ与毛叶香茶菜素［１］完全一致,故推定为毛叶香茶菜素,根据该结晶的元素分析,ＭＳ、ＮＭＲ、ＣＯＳＹ和ＮＯＥＳＹ等光谱数据,其结构应订正为（２）。表１表明：毛叶香茶菜素（２）的分子式由元素分析和高分辨质谱确定为Ｃ２４Ｈ３６Ｏ９,毛叶香茶菜素（１）的分子式由元素分析也应确定为Ｃ２４Ｈ３６Ｏ９。由于赵治清等误将质谱中Ｍ＋－Ｈ２Ｏ碎片离子峰ｍ／ｚ４５０当作分子离子峰（毛叶香茶菜…     

贵州紫云产黄花香茶菜的化学成分研究

采用甲醇回流提取和硅胶柱层析方法,从紫云产黄花香茶菜中分离得到6个化合物,结合1H-NMR、13C-NMR数据及文献资料鉴定为黄花香茶菜乙素(Ⅰ)、黄花香茶菜丁素(Ⅱ)、大萼变型香茶菜甲素(Ⅲ)、3β-Hydroxy-18α,19α-urs-20-en-28-oic acid(Ⅳ)、齐墩果酸(Ⅴ)和熊果酸(Ⅵ)。其中化合物Ⅳ为首次从该属植物中分离得到。     

基于3种香茶菜属药用植物高效液相色谱的主成分分析

对香茶菜(Isodon amethystoides)、显脉香茶菜(I.nervosa)和大萼香茶菜(I.macrocalyx)不同产地和器官(根、茎、叶)共21个样品进行高效液相色谱分析,以出峰时间-峰面积为指标,以样品为对象进行主成分分析,比较不同样品间的差异程度。结果发现,(1)香茶菜、大萼香茶菜、显脉香茶菜在高效液相色谱上虽然有一定的差异,但这种差异并不明显;(2)基于HPLC显示的香茶菜不同种群间差异比三个种间的差异更为明显,说明不同产地对香茶菜属植物样品的植化组成有很大的影响,不同种在植化上的相似性使它们在一定程度上可以作为替代药材;(3)研究反映出基于高效液相色谱的PCA在反映不同样品植物化学组成差异程度上具有应用价值。     

香茶菜属3种植物花粉形态的扫描电镜观察

应用扫描电子显微镜对香茶菜(Isodon amethystoides)、大萼香茶菜(I. macrocalyx)、显脉香茶菜(I. nervosa)8个居群的花粉进行了形态观察.结果表明,不同居群的香茶菜的花粉在形态上具有一定共同特性 ,但在外壁纹饰、大小、穴的形状上存在差异.香茶菜属不同种在花粉形态、大小、外壁纹饰、穴分布情况存在较明显的差异.这些花粉表面微观形态的差异可为品种鉴定提供依据.     

细锥香茶菜化学成分的研究

从细锥香茶菜（Ｒａｂｄｏｓｉａｃｏｅｔｓａ（Ｂｕｃｈ．Ｈａｍ．ｅｘＤ．Ｄｏｎ）Ｈａｒａ）的叶中分离到９个化合物,通过波谱分析阐明其结构,其中１个为新的二萜酸———７α,１２α,１４β三羟基１５酮对映贝壳杉１８羧酸,命名为细锥香茶菜酸（ｃｏｅｔｓａｎｏｉｃａｃｉｄ）。另外８个化合物分别为二氢昆明香茶菜丙素、昆明香茶菜丙素、白柔毛香茶菜甲素、大萼香茶菜丙素、４羟基Δ８,９（Ｚ）鞘氨醇２′羟基正二十（二十一二十六）碳酸酰胺、乌苏酸、２α,３β二羟基乌苏酸和胡萝卜甙。神经酰胺类化合物系首次从该属植物中分离得到。     

白叶香茶菜的化学成分

从白叶香茶菜(Rabdosia leucophylla(Dunn)Hara)地上部分的乙醇提取物中分离出5个化合物,根据其波谱分析并结合化学方法分别鉴定为:白叶香茶菜戊素(1)、白叶香茶菜己素(2)、信阳冬凌草甲素(3)、maslinic acid(4)和胡萝卜甙(5)。其中1和2为新化合物,2的结构还通过X-单晶衍射得到证实。     

Sugar-to-base correlation in nucleic acids with a 5D APSY-HCNCH or two 3D APSY-HCN experiments

A five-dimensional (5D) APSY (automated projection spectroscopy) HCNCH experiment is presented, which allows unambiguous correlation of sugar to base nuclei in nucleic acids. The pulse sequence uses multiple quantum (MQ) evolution which enables long constant-time evolution periods in all dimensions, an improvement that can also benefit non-APSY applications. Applied with an RNA with 23 nucleotides the 5D APSY-HCNCH experiment produced a complete and highly precise 5D chemical shift list within 1.5 h. Alternatively, and for molecules where the out-and-stay 5D experiment sensitivity is not sufficient, a set of out-and-back 3D APSY-HCN experiments is proposed: an intra-base (3D APSY-b-HCN) experiment in an MQ or in a TROSY version, and an MQ sugar-to-base (3D APSY-s-HCN) experiment. The two 3D peak lists require subsequent matching via the N1/9 chemical shift values to one 5D peak list. Optimization of the 3D APSY experiments for maximal precision in the N1/9 dimension allowed matching of all ¹⁵N chemical shift values contained in both 3D peak lists. The precise 5D chemical shift correlation lists resulting from the 5D experiment or a pair of 3D experiments also provide a valuable basis for subsequent connection to chemical shifts derived with other experiments.     

GFT NMR Experiments for Polypeptide Backbone and 13Cβ Chemical Shift Assignment

(4,3)D, (5,3)D and (5,2)D GFT triple resonance NMR experiments are presented for polypeptide backbone and (13)C(beta) resonance assignment of (15)N/(13)C labeled proteins. The joint sampling of m = 2, 3 or 4 indirect chemical shift evolution periods of 4D and 5D NMR experiments yields the measurement of 2(m) - 1 linear combinations of shifts. To obtain sequential assignments, these are matched in corresponding experiments delineating either intra or interresidue correlations. Hence, an increased set of matches is registered when compared to conventional approaches, and the 4D or 5D information allows one to efficiently break chemical shift degeneracy. Moreover, comparison of single-quantum chemical shifts obtained after a least squares fit using either the intra or the interresidue data demonstrates that GFT NMR warrants highly accurate shift measurements. The new features of GFT NMR based resonance assignment strategies promise to be of particular value for establishing automated protocols.     

Chemical Structure of Macrocalyxin D

A new diterpenoid which exhibits cytotoxic activity, macrocalyxin D has been isolated from the e-thereal extract of the leaves of Rabdosia macrocalyx (Dunn) Hara. On the basis of chemical and spectroscopic data, the chemical structure of macrocalyxin D was established as (3).     

Chemical Structure of Macrocalyxoformin D

Macrocalyxoformin D, an new diterpenoid having a spiro secokaurene- skeleton, was isolated from the leaves of Rabdosia macrocalyx (Dunn.) Hara from (Labiatae) collected in the south of Anhui. On the basis of chemical and spectroscopic data, the chemical structure of macrocalyxoformin D was established as (Ⅲ). Macroca- lyxoformin D was shown to have inhibitory action on Hela cells, staphylococcus aureus and bacillus hay in vitro.     

Actinomycin D-deoxynucleotide complexes as models for the actinomycin D-DNA complex. The use of nuclear magnetic resonance to determine the stoichiometry and the geometry of the complexes.

The use of proton and carbon-13 magnetic resonance spectroscopy for the determination of the geometry and the stoichiometry of the actinomycin D-deoxyguanosine 5'-monophosphate complex is outlined. The dimerization of actinomycin D has been reexamined by recording the proton magnetic resonance spectrum of actinomycin D to much lower concentrations through the use of Fourier transform nuclear magnetic resonance techniques. The effect of the actinomycin D dimerization on the observed chemical shifts that results from the additon of nucleotides to an actinomycin D solution is directly demonstrated by comparing the actinomycin D-nucleotide titrations at both low (approximately 0.3 mM) and high (approximately 12 mM) concentrations of actinomycin D. In the presence of excess nucleotide the chemical shifts of the actinomycin D groups were essentially the same for both the low and high concentration titrations. The complexes of actinomycin D with pdG-dC, dG-dC, deoxyguanosine 3'-monophosphate, G-C, C-G, dIMP(5'), 2, 6-diaminopurine deoxyribose, and other nucleotides were also investigated by proton magnetic resonance and visible spectral titrations. These data were interpreted in terms of the molecular geometry of the complexes and in terms of the effect of the structure of the nucleotide base on the relative binding affinity of the nucleotides for the two nucleotide binding sites of actinomycin D. The carbon-13 chemical shifts of dGMP(5') were measured as a function of concentration over the concentration range of 0.5-0.025 M. The infinite dilution carbon-13 chemical shifts were graphically estimated from the dilution curves. These values were used to calculate the changes in the chemical shifts of the dGMP carbons that result from the formation of an actinomycin D-(dGMP)2 complex. It was not possible to interpret these carbon-13 chemical shift changes in terms of only ring current effects, which thus rules out the use of carbon-13 spectroscopy in the determination of the geometries of the actinomycin D complexes with the mono- and dinucleotides. The induced chemical shifts in the proton spectra may be used in the determination of the geometries of the complexes. A consideration of these data for the above nucleotide series shows that the predominant complex formed is one in which the guanine rings in the two nucleotide binding sites of actinomycin D are oriented in a manner very similar to that observed in the cocrystalline complex of actinomycin D with deoxyguanosine.     

A new method for determining the constant-pressure heat capacity change associated with the protein denaturation induced by guanidinium chloride (or urea)

Differential scanning calorimetry (DSC) provides authentic and accurate value of DeltaC(p)(X), the constant-pressure heat capacity change associated with the N (native state)<-->X (heat denatured state), the heat-induced denaturation equilibrium of the protein in the absence of a chemical denaturant. If X retains native-like buried hydrophobic interaction, DeltaC(p)(X) must be less than DeltaC(p)(D), the constant-pressure heat capacity change associated with the transition, N<-->D, where the state D is not only more unfolded than X but it also has its all groups exposed to water. One problem is that for most proteins D is observed only in the presence of chemical denaturants such as guanidinium chloride (GdmCl) and urea. Another problem is that DSC cannot yield authentic DeltaC(p)(D), for its measurement invokes the existence of putative specific binding sites for the chemical denaturants on N and D. We have developed a non-calorimetric method for the measurements of DeltaC(p)(D), which uses thermodynamic data obtained from the isothermal GdmCl (or urea)-induced denaturation and heat-induced denaturation in the presence of the chemical denaturant concentration at which significant concentrations of both N and D exist. We show that for each of the proteins (ribonuclease-A, lysozyme, alpha-lactalbumin and chymotrypsinogen) DeltaC(p)(D) is significantly higher than DeltaC(p)(X). DeltaC(p)(D) of the protein is also compared with that estimated using the known heat capacities of amino acid residues and their fractional area exposed on denaturation.     

The chemical chaperones tauroursodeoxycholic and 4-phenylbutyric acid accelerate thyroid hormone activation and energy expenditure

Exposure of cell lines endogenously expressing the thyroid hormone activating enzyme type 2 deiodinase (D2) to the chemical chaperones tauroursodeoxycholic acid (TUDCA) or 4-phenylbutiric acid (4-PBA) increases D2 expression, activity and T3 production. In brown adipocytes, TUDCA or 4-PBA induced T3-dependent genes and oxygen consumption (∼2-fold), an effect partially lost in D2 knockout cells. In wild type, but not in D2 knockout mice, administration of TUDCA lowered the respiratory quotient, doubled brown adipose tissue D2 activity and normalized the glucose intolerance associated with high fat feeding. Thus, D2 plays a critical role in the metabolic effects of chemical chaperones.     

Why There is a One-way Crossability Between D. melanogaster and D. simulans?

In the Drosophila melanogaster complex, females D. melanogaster mate relatively easily with males Drosophila simulans but the reciprocal cross is rare. The species sexual isolation is mainly based on chemical and acoustic signal exchanges between partners. The male side of this communication is investigated in this paper in order to understand the asymmetry. In D. melanogaster the acoustic signature is highly significant, and is synergistically reinforced by the chemical signal. In D. simulans the importance of the two signaling channels seems to be reversed. This could explain why D. simulans males produce less precise interpulse interval (IPI) mean value in the courtship song, which can readily overlap those of D. melanogaster. As the males of the two species use the same chemical key, D. simulans males could be recognized by D. melanogaster females as a conspecific.     

Vitamin D supplementation increases the attractiveness of males' scent for female Iberian rock lizards

Evolutionary theory proposes that signals used in sexual selection can only be stable if they are honest and condition dependent. However, despite the fact that chemical signals are used by many animals, empirical research has mainly focused on visual and acoustic signals. Vitamin D is an essential nutrient for lizards, but in some lizards its precursor (cholesta-5,7-dien-3-ol=provitamin D) is found in femoral gland secretions, which males use for scent marking and intraspecific communication. By allocating provitamin D to secretions, males might need to divert vitamin D from metabolism. This might be costly and condition dependent. We tested whether diet quality affected chemical signals of male Iberian rock lizards (Lacerta monticola) and its consequences for sexual selection. After experimental supplementation of dietary vitamin D, males increased the proportion of provitamin D in femoral secretions. Further experiments showed that females detected these changes in males' signals by chemosensory cues, and discriminated provitamin D, and changes in its concentration, from similar steroids (i.e. cholesterol) found in secretions. Moreover, females preferred areas scent marked by males with more provitamin D in their secretions. This mechanism would confer honesty to chemical signals of male lizards, and, thus, females may rely on it to select high-quality males. We suggest that the allocation of vitamins and other essential nutrients to either visual (e.g. carotenoids) or chemical ornaments might be the common basis of honest sexual displays in many animals.     

Four new cassane diterpenes from the seeds of Caesalpinia minax

In our survey on the chemical composition of traditional Chinese medicines to further elucidate their chemical substances for the treatment of diseases, we investigated the chemical constituents of the seeds of plants Caesalpinia minax. The investigation led to the isolation and identification of four new cassane diterpenes, caesalpines A–D (1–4). Their structures were elucidated on the basis of extensive 1D and 2D NMR (COSY, HMQC, HMBC, and NOESY) and mass (ESIMS and HR-ESIMS) spectroscopic data analyses. The phytochemical results imply that cassane diterpenes are maybe regarded as the characteristic constituents of C. minax.