苦楝子中三萜成分的研究

目的:对苦楝子的甲醇提取物中的三萜成分进行研究.方法:利用硅胶,常压RP-C18硅胶,葡聚糖凝胶 LH-20以及制备液相色谱分离纯化,通过1D-NMR,2D-NMR以及EI-MS波谱数据鉴定化合物结构.结果:从苦楝子的甲醇提取物中共分离得到4个三萜化合物经鉴定为:Meliasenin B (Ⅰ),Meliasenin ...     

反相制备高效液相色谱法分离蒜氨酸对照品

目的 制备蒜氨酸对照品,供含量测定和比旋度测定用.方法 以离子交换柱色谱法从鲜蒜中分离出蒜氨酸粗品,用制备型高效液相色谱仪进行色谱分离纯化,再以红外吸收光谱和质谱等方法进行鉴定.结果 得到L-( )蒜氨酸,经过一次分离,纯度即可达到99%.结论 反相高效液相色谱制备分离的蒜氨酸纯度高,方法简单高效.     

通光藤皂苷B的2D—NMR研究

目的研究通光藤（Caulis Marsdeniae Tenacissimac）藤茎的化学成分。方法用色谱方法分离通光藤的乙醇提取物并用2D-NMR法鉴定一个C21甾体苷类化合物I。结果归属了该化合物的全部核磁信号。结论化合物I的结构是通光藤皂苷B。     

多种光谱综合确证孕甾双烯醇酮醋酸酯中微量杂质的结构

目的对孕甾双烯醇酮醋酸酯中含量〉0.1%的杂质进行分离和结构鉴定。方法采用柱层析和制备液相色谱对杂质进行分离,用IR、2D-NMR及MS综合确证其化学结构。结果该杂质的结构为：孕甾-4、6、16-三烯-3、20-二酮。结论该法能够精确定位1个微量杂质各个原子的归属。     

异叶梁王茶化学成分的研究

从异叶梁王茶甲醇提取物中分离出八种五环三萜皂甙单体A_4,A_7,A_9,D_1,S_2,S_3,S_5、S_6。经IR、MS、1D-NMR、2D-NMR以及化学方法确定了前六种五环三萜皂甙的结构。这六种三萜皂甙均为首次从植物界中分离出的新化合物。     

可疑翼手参中的一个新三萜皂苷

目的：寻找结构新颖的三萜皂苷类化合物。方法：采用多种色谱方法．对属于枝手目瓜参科的可疑翼手参体内成分进行了分离纯化；并采用多种光谱(IR．UV，ESI-MS，2D-NMR)和化学方法对所分离化合物的结构进行了确定。结果与结论：得到一个新的三萜皂苷类化合物，我们把该化合物命名为coloehiroside A(1)。     

钩藤叶化学成分的研究

目的 研究茜草科植物钩藤Uncaria rhynchophylla(Miq.)Jacks.叶的化学成分.方法 用多种色谱方法和重结晶法进行分离和纯化,经理化、光谱和色谱分析等方法鉴定结构.结果从钩藤叶中分离得到5个化合物,鉴定为喜果苷(vincoside lactam,Ⅰ)、异去氢钩藤碱(isocorynoxeine,Ⅱ)、异钩藤碱(isorhynchophylline,Ⅲ)、去氢钩藤碱(corynoxeine,Ⅵ)、钩藤碱(rhynchophylline,Ⅴ).结论化合物Ⅲ为首次从钩藤叶中分离得到,通过2D-NMR技术完善了化合物Ⅲ的核磁数据.     

藏药五脉绿绒蒿中的生物碱

目的研究藏药五脉绿绒蒿(Meconopsis quintuplinervia Regel)的化学成分.方法用多种色谱技术进行分离纯化,用IR, MS, 1D-和2D-NMR鉴定化合物结构.结果从95%乙醇提取物中分离出3个生物碱,分别鉴定为去甲血根碱(norsanguinarine,I)、O-甲基淡黄巴豆亭碱(O-methylflavinantine,II)和五脉绿绒蒿碱(meconoquintupline,III).结论化合物III为新化合物.     

通光藤中两个新C21甾体苷类成分通光藤中两个新C21甾体苷类成分

目的研究中药通光藤的化学成分。方法用现代色谱技术分离化合物,用化学方法及现代光谱技术(IR,UV,MS,¹HNMR,¹³CNMR和各种2D-NMR技术)对所得化合物的结构进行鉴定。结果从云南昆明产通光藤茎中分离得到2个化合物,分别鉴定为通光藤苷J(tenacissosides J,I)和通光藤苷K(tenacissosides K,II)。结论化合物I和II均为新化合物。     

百蕊草生物碱成分的分离与鉴定

目的 研究百蕊草中的生物碱成分.方法 应用多种色谱手段进行分离纯化,通过IR、MS、HR-MS、NMR、2D-NMR技术鉴定化合物结构.结果 从百蕊草总生物碱部位分离得到3个化合物,分别鉴定为N-甲基金雀花碱(1)、白金雀儿碱(2)和槐果碱(3).结论 化合物N-甲基金雀花碱、白金雀儿碱、槐果碱均为首次从该植物中分离得到.     

Changes in contents of gamma-glutamyl peptides and fructan during growth of Allium sativum

Determination of gamma-glutamyl peptides, alliin, and fructan during growth of Allium sativum L. was carried out by HPLC. The contents of gamma-glutamyl peptides and alliin in garlic bulbs remarkably increased during one month before the garlic leaves withered.     

A high-throughput method for the quantitative determination of alliin

The quality of most garlic (Allium sativum L., Alliaceae) preparations made from garlic powder or garlic dry extract is determined by their content of alliin. Therefore, a comprehensive documentation of alliin concentration beginning with the crude material up to the final remedy is required. The newly developed analytical method described in this paper was designed in order to fulfill these demands. In contrast to conventional HPLC methods, neither a pre-column derivatization nor a chromatographic separation are involved in this analytical procedure allowing a high throughput of samples. The currently investigated technique is based on immobilized alliinase (EC 4.4.1.4) which was combined with a two-channel flow injection analyser (FIA) coupled to an ammonia detecting device. A high specificity for alliin could be demonstrated and a variety of garlic samples including garlic powders, dry extracts, and garlic preparations was analysed. The results were in good correlation with those obtained by conventional HPLC methods.     

Formation of allicin from dried garlic (Allium sativum): a simple HPTLC method for simultaneous determination of allicin and ajoene in dried garlic and garlic preparations.]

In garlic (Allium sativum L.) the enzyme alliin lyase catalyzes the cleavage of alliin into allicin which reacts further to furnish ajoene. A simultaneous determination of allicin and ajoene is introduced which, in contrast to the determination of alliin only, allows for the testing of the activity of alliin lyase. It can be demonstrated that at a pH value of less than 3 the enzyme produces only small amounts of allicin. For this reason preparations from garlic should be administered only as enteric-coated formulations.     

The ability of callus tissues induced from three Allium plants to accumulate health-beneficial natural products,S-alk(en)ylcysteine sulfoxides

Journal of Natural Medicines - S-Alk(en)ylcysteine sulfoxides (CSOs), such as methiin, alliin, and isoalliin, are health-beneficial natural products biosynthesized in the genus Allium....     

Stabilization and pharmaceutical use of alliinase

In recent years, numerous clinical trials were undertaken in order to elucidate the active principle of garlic (Allium sativum L., Alliaceae). The most prominent effect of garlic preparations is a contribution to the prevention of stroke and arteriosclerosis. Allicin[(2-propenyl)-2-propenethiosulfinate] and other sulfur containing compounds were suggested as active compounds. The extremely unstable allicin itself is liberated from the more stable alliin [S-(+)-2-propenyl-L-cysteine sulfoxide] by the enzyme alliinase (EC 4.4.1.4) if fresh garlic is crunched or garlic powder is moistened. Therefore, an active enzyme is required in alliin containing remedies like those prepared from garlic powder. In order to investigate enzyme stability, alliinase was isolated from garlic powder. The partially purified enzyme could be stabilized over several months by addition of sodium chloride, sucrose, and pyridoxal-5'-phosphate. Alliinase may also be freeze-dried. This allows combinations of synthetic alliin and purified alliinase as components of an acid resistant tablet or capsule. In the intestine, the pro-drug alliin would be enzymatically converted to allicin. In clinical trials, highly dosed preparations of this kind should yield a precise information about the physiological effects of allicin. In addition, alliin-homologues substances which bear a modified alkyl side chain and do not occur in nature may be tested.     

TLC analysis of Allium sativum constituents

A steadily increasing number of garlic (Allium sativum) preparations during the last years resulted in a high interest in practical analytical methods for its active principles. In the present work, TLC separation of alliin from other compounds was improved over previous methods. A modified ninhydrin detection reagent was used to optimize the differentiation between cysteine sulfoxides and other amino acid derivatives. In addition, a sensitive and specific colour reaction was developed for detection of allicin after TLC.     

In vitro inhibition of cytochrome P-450 reductases from pig liver microsomes by garlic extracts.

The activity of microsomal NADPH-cytochrome-P-450-reductase and NADH-cytochrome-b5-reductase are inhibited after the addition of an aqueous extract of a pharmaceutical preparation of garlic (Allium sativum, L.) to buffer-suspended microsomes. Incubation of garlic extract with isolated pig liver microsomes also decreases the activity of cytochrome P-450-dependent ethoxycoumarin deethylation. As measured by malondialdehyde release, the effects on the enzyme system are evidently not due to lipid peroxidation. No loss of cytochrome P-450 pigment is observed. Moreover, it could be shown that addition of garlic extract displays no protective effect on microsomal lipids when oxidation occurs spontaneously or is enforced by short-wave UV-irradiation. The above findings were reproduced after applying a HPLC-purified preparation of alliin to the incubation mixtures, suggesting that alliin is the active principle for the inhibitory effects observed in vitro.     

蒜氨酸精制品的纯化与结构确证

目的:制备蒜氨酸精制品并确证其结构.方法:采用反相制备液相和减压干燥技术制备高纯度的蒜氨酸精制品,用紫外光谱(UV)、红外(IR)、质谱(MS)、一维及二维核磁共振谱(1HNMR,13CNMR,1H-1HCOSY,DEPT,HSQC,HSBC)等波谱技术确证其化学结构,用旋光技术确定其立体构型.结果:蒜氨酸精制品的纯度为99.5%,所有的NMR谱信号均能得到合理的归属,质谱的裂解途径和离子特征也与蒜氨酸的分子结构相符,红外、紫外特征吸收峰均有合理的解释,比旋度测定结果与文献报道的S型蒜氨酸一致.结论:该制备方法可以得到高纯度的蒜氨酸精制品,其结构为S-烯丙基-L-半胱氨酸亚砜.     

Unusual cystine lyase activity of the enzyme alliinase: direct formation of polysulphides

Garlic ( Allium sativum L.) and related species are highly estimated as foods, spices, and herbal remedies in many parts of the world. Sulphur-containing flavour compounds like allicin (allyl 2-propenethiosulphinate) are responsible for the smell and taste of freshly crunched garlic. These substances are formed by the action of alliinase (EC 4.4.1.4) on cysteine sulphoxides, e. g., alliin [ S-(+)-allyl- L-cysteine sulphoxide]. Additionally, alliinase catalyses the C-S lysis of cystine in the manner of a cystine lyase. Ammonium, pyruvate and elementary sulphur but not cysteine could be detected as reaction products. The ratios between cystine, ammonium and pyruvate are 1 : 1.9 : 1.9 suggesting a new type of reaction mechanism. Thiocysteine and disulphine were assumed as intermediates. The pH optimum of the cystine lyase activity was found at pH 7.5 and the temperature optimum was at 44 degrees C. The KM value for the homogeneous enzyme was at 2.65 mM and Vmax was at 4.12 nkat/mg using cystine as substrate. Moreover, parallel incubation of cystine and alliin gave mainly allyl (poly)sulphides as reaction products instead of allicin. These substances had not been observed as direct enzymatic products until now. Thus, the significance of alliinase and its enzymatic products has to be newly considered in terms of ecological, pharmacological, and biochemical aspects.     

Alliin obtained from leaf extract of garlic grown under in situ conditions possess higher therapeutic potency as analyzed in alloxan-induced diabetic rats

Context: Garlic, Allium sativum L. (Liliaceae), possesses high therapeutic and pharmacological properties. Hypoglycemic activity is attributed to alliin (S-allyl cysteine sulfoxide), the main active principle localized in garlic cloves.

Objective: To compare the production and therapeutic efficiency of alliin extracted from garlic leaves of plants grown under ex situ and in situ conditions.

Materials and methods: Alliin content of leaves was quantified and aqueous leaf extracts (from ex situ and in situ grown plants) were given to normal and alloxan-induced diabetic rats for five weeks.

Results: Alliin production noted ~50% enhancement in leaves from plants grown under in situ conditions. Serum glucose, triglycerides, total lipids, total cholesterol, low-density lipoprotein (LDL)-, and very low-density lipoprotein (VLDL)-cholesterol in diabetic rats treated with alliin produced from in situ grown plants noted significant reduction of ~54%, 15%, 14%, 20%, 24%, and 15%, while 35%, 14%, 10%, 12%, 17% and 11% reduction was noted in diabetic rats treated with alliin produced from ex situ grown plants in comparison with those administered with distilled water. High-density lipoprotein (HDL)-cholesterol did not show any significant change. Leaf extract of plants lowered serum enzyme levels (alkaline phosphatase, aspartate aminotransferase, and alanine aminotransferase) toward the norm better than glibenclamide. The histopathological alteration in pancreas caused by alloxan was also reduced by leaf extract.

Discussion and conclusion: These findings demonstrate leaf extract obtained from plants grown under in situ condition possess higher therapeutic efficiency in comparison with leaf extract obtained from plants grown under ex situ condition. Studies suggest that environmental factors influence production of alliin and its therapeutic potential.