Indole alkaloids from the leaves of Philippine Alstonia scholaris

The first seco-uleine alkaloids, manilamine (1) (18-hydroxy-19,20-dehydro-7,21-seco-uleine) and N4-methyl angustilobine B (2), were isolated from the (pH 5) alkaloid extract of Philippine Alstonia scholaris leaves together with the known indole alkaloids 19,20-(E)-vallesamine (3), angustilobine B N4-oxide (4), 20(S)-tubotaiwine (5), and 6,7-seco-angustilobine B (6). The structure of the alkaloids was established from MS and NMR experiments.     

单面针的生物碱研究

自芸香科(Rutaceae)花椒属植物单面针(Zanthoxylum nitidum var. fastuosum How ex Huang)的根皮中分得五种已知生物碱:乙氧基白屈菜红碱(ethoxychelerythrine)(Ⅰ);氯化光花椒碱(nitidine chloride)(Ⅱ);去甲基白屈菜红碱(des-N-methychelerythrine)(Ⅲ);α—别隐品碱(α-allocryptopine)(Ⅳ);鹅掌揪宁(liriodenine)(Ⅴ).     

Determination of Aconitum alkaloids in blood and urine samples. I. High-performance liquid chromatographic separation, solid-phase extraction and mass spectrometric confirmation

Determination of four toxic Aconitum alkaloids, aconitine, mesaconitine, hypaconitine and jesaconitine, in blood and urine samples has been established using high-performance liquid chromatography (HPLC) combined with ultraviolet absorbance detection, solid-phase extraction and mass spectrometry (MS). These alkaloids were hydrolyzed rapidly in alkaline solution (half lives (t_1/2)<one day), were stable in solutions of acetonitrile, tetrahydrofuran and diluted hydrochloric acid (t_1/2>five months) and were unstable in solutions of methanol and ethanol (t_1/2<one month). These alkaloids were separated on an octadecylsilica column with isocratic elution using a solvent mixture of tetrahydrofuran and 0.2% trifluoroacetic acid (14:86, v/v), which was found to be the optimal solvent of the elution systems examined. Calibration curves with UV detection were linear on injection of amounts ranging from 2.5 to 500 ng, and the limit of detection was 1 ng (S/N = 3). These four alkaloids in aqueous solution were recovered almost totally by solid-phase extraction using the styrene polymer resin, Sep-Pak Plus PS-1, and were eluted using a mixture of acetonitrile and hydrochloric acid. These Aconitum alkaloids were confirmed by HPLC coupled with fast atom bombardment MS, giving their protonated molecular ions as base peaks. These alkaloids were detected by HPLC with UV detection from blood samples spiked with more than 50 ng ml⁻¹ of alkaloids, but were not detectable from urine samples spiked with 5 μg ml⁻¹ of alkaloids because of severe sample interference.     

New class of steroidal alkaloids from Fritillaria imperialis

Two members of a new class of C-nor-D-homo steroidal alkaloids, impranine (1). and dihydroimpranine (2). along with a new pyridyl-pregnane-type steroidal alkaloid, fetisinine (3). and a known base, korsevine (4). were isolated from the bulbs of Fritillaria imperialis. The structures of the compounds were established on the basis of spectroscopic techniques and some chemical transformations. Compounds 1 and 2 form a new class of steroidal alkaloids, named as "impranane."     

Alkaloidal variation in the genus Pearsonia

Several quinolizidine alkaloids, including various angelate esters, are known from the genus Pearsonia. In a detailed variation study which included 98 samples from nine of the 11 species, large qualitative and quantitative differences were recorded. The observed variation is ascribed to the following: 1, species (the alkaloids of some species and subspecies are diagnostically different); 2, provenance (various populations of the same species may have unique combinations of alkaloids); 3, developmental stage (in P. cajanifolia there is a marked decreased in esterification towards the end of the growing season); 4, plant parts extracted (seeds, for example, have high concentrations of hydroxylated lupanine-type alkaloids and only small amounts of esters). These results highlight some of the problems associated with the use of alkaloids as taxonomic characters.     

Selective adsorption of plant products

The results from this study demonstrate that neutral resins can selectively concentrate specific indole alkaloids from dilute aqueous mixtures. Adsorption was observed to provide a one to two order of magnitude improvement in concentrating these alkaloids, as compared to an equivalent single-staged extraction. Since the sorption correlates with the concentration of the neutral form of the dissolved alkaloid, the adsorption is dependent on both the pH of the medium and the pKa of the alkaloids. Also, adsorption is dependent on specific sorbent-sorbate characteristics. In this study, by exploiting differences in the acid-base properties and the sorption characteristics of specific indole alkaloids, separation factors of 20-30 were observed. Although this behavior is valuable for analytical separations, the present study considers the application to the primary recovery of alkaloids from plant cell processes. Throughout this study it was also observed that the polycarboxylic ester resin (XAD-7) behaved quite differently from the styrene divinylbenzene resin (XAD-4). Despite a lower capacity, the XAD-7 resin was considerably more selective in adsorbing indole alkaloids than the XAD-4 resin. These alkaloids could also be desorbed from the XAD-7 resin by acidifying the liquid, while organic solvents were required to desorb these compounds from the XAD-4 resin.     

小白撑根部二萜生物碱研究

从小白撑(Aconitum nagarum var.heterotrichum)根部分离出5个二萜生物碱,其结构通过光谱分析和化学方法鉴定为光翠雀碱(1),宋果灵(2),乌头碱(3),去氧乌头碱(4),和滇乌碱(5)。     

The effect of varying alkaloid concentrations on the feeding behavior of gypsy moth larvae, Lymantria dispar (L.) (Lepidoptera: Lymantriidae)

Nine alkaloids (acridine, aristolochic acid, atropine, berberine, caffeine, nicotine, scopolamine, sparteine, and strychnine) were evaluated as feeding deterrents for gypsy moth larvae (Lymantria dispar (L.); Lepidoptera: Lymantriidae). Our aim was to determine and compare the taste threshold concentrations, as well as the ED₅₀ values, of the nine alkaloids to determine their potency as feeding deterrents. The alkaloids were applied to disks cut from red oak leaves (Quercus rubra) (L.), a plant species highly favored by larvae of this polyphagous insect species. We used two-choice feeding bioassays to test a broad range of biologically relevant alkaloid concentrations spanning five logarithmic steps. We observed increasing feeding deterrent responses for all the alkaloids tested and found that the alkaloids tested exhibited different deterrency threshold concentrations ranging from 0.1 to 10 mM. In conclusion, it appears that this generalist insect species bears a relatively high sensitivity to these alkaloids, which confirms behavioral observations that it avoids foliage containing alkaloids. Berberine and aristolochic acid were found to have the lowest ED₅₀ values and were the most potent antifeedants. Handling Editor: Joseph Dickens.     

Determination of Aconitum alkaloids in blood and urine samples: II. Capillary liquid chromatographic–frit fast atom bombardment mass spectrometric analysis

Determination of fourteen alkaloids, toxic Aconitum alkaloids, aconitine, mesaconitine, jesaconitine, hypaconitine and deoxyaconitine, and their hydrolysis products, benzoylaconines and aconines, have been established using capillary liquid chromatography (LC) fast atom bombardment mass spectrometry (FAB-MS) with a frit interface. Protonated molecular ions were observed as base peaks in the FAB-MS for these fourteen alkaloids. All the alkaloids were simultaneously quantified with linear gradient LC elution by solvent mixture of acetonitrile and 0.3% trifluoroacetic acid using selected ion monitoring of the protonated molecular ions. The calibration curves of these alkaloids were linear in injection amounts ranging from 5 to 500 pg, and their detection limits were 1 pg per injection (S/N=3). Solid-phase extraction using Sep-Pak Plus PS-1 was also investigated to clean-up and concentrate alkaloids in blood and urine samples, and showed satisfactory recoveries. This capillary LC–frit-FAB-MS method enables determination of low levels of Aconitum alkaloids in blood and urine samples, coupled with solid-phase extraction.     

滇南草乌的化学成分研究（Ⅱ）

接前文此报告推定了从滇南草乌中分到的碱9—12的结构分别为8-去乙酰黄草乌碱甲(9),talatizidine(10),condelphine(11)和滇乌碱(12)。碱9为首次报告的新化合物,命名为南乌碱乙(austroconitine B)(9)。     

Analysis of sparteines in the seeds of Ammopiptanthus mongolica

Seven alkaloids were isolated from the seeds of Ammopiptanthus mongolica by thin layer chromatography and silica gel column chromatography, and the chemical structures of five alkaloids, 17-oxosparteine,β-isospar-teine, 3a-hydroxysparteine, sparteine, and 3β-hydroxy-sparteine were identified by IH nuclear magnetic resonance (NMR) and electron ionization mass spectrum (EIMS).     

Alkaloids of Rauwolfia nitida root bark

Thirty-three indole alkaloids were isolated from the root bark of Rauwolfia nitida. Sarpagan, dihydroindole, indolenine, yohimbine, 18-hydroxy-yohimbine ester, heteroyohimbine and anhydronium base types were isolated. The principal alkaloids were reserpine (0.034%), serpentinine (0.033%), pseudoreserpine (0.013%) and reserpiline (0.012%).     

Antimycobacterial activity of bisbenzylisoquinoline alkaloids from Tiliacora triandra against multidrug-resistant isolates of Mycobacterium tuberculosis

Bisbenzylisoquinoline alkaloids, tiliacorinine (1), 2'-nortiliacorinine (2), and tiliacorine (3), isolated from the edible plant, Tiliacora triandra, as well as a synthetic derivative, 13'-bromo-tiliacorinine (4), were tested against 59 clinical isolates of multidrug-resistant Mycobacterium tuberculosis (MDR-MTB). The alkaloids 1-4 showed MIC values ranging from 0.7 to 6.2 μg/ml, but they exhibited the MIC value at 3.1 μg/ml against most MDR-MTB isolates. The present work suggests that bisbenzylisoquinoline alkaloids are potential new chemical scaffolds for antimycobacterial activity.     

E/Z-Thesinine-O-4'-alpha-rhamnoside, pyrrolizidine conjugates produced by grasses (Poaceae)

Based on direct infusion mass spectrometry we identified a novel alkaloid as a major component of perennial ryegrass (Lolium perenne). Initial mass spectral data suggested it to be a pyrrolizidine conjugate. As this class of alkaloids has not been described before from grasses, we isolated it to elucidate its structure. The isolated alkaloid proved to be a mixture of two stereoisomers. The structures of the two compounds as determined by 1D and 2D NMR spectroscopy, were E-thesinine-O-4'-alpha-rhamnoside (1) and Z-thesinine-O-4'-alpha-rhamnoside (2). These identifications were supported by the characterisation by GC-MS and optical rotation of (+)-isoretronecanol as the necine base released on alkaline hydrolysis of these alkaloids. 1 and 2 together with the aglycone and a hexoside were also detected in tall fescue (Festuca arundinacea). This is the first report of pyrrolizidine alkaloids produced by grasses (Poaceae).     

Alkaloids from Corydalis saxicola and their anti-hepatitis B virus activity

Eight protoberberine-type alkaloids and two indole alkaloids were isolated from the MeOH extracts of the herb Corydalis saxicola Bunting (Papaveraceae). Their structures were identified as dehydrocavidine (1), dehydroapocavidine (2), dehydroisoapocavidine (3), berberine (4), dehydroisocorypalmine (5), coptisine (6), tetradehydroscoulerine (7), berbinium (8), 1-formyl-5-methoxy-6-methylindoline (9), and 1-formyl-2-hydroxy-5-methoxy-6-methylindoline (10). Compounds 3, 9, and 10 are new alkaloids. All compounds were tested for anti-HBV activity against the 2.2.15 cell line in vitro. Dehydrocavidine (1), dehydroapocavidine (2), and dehydroisoapocavidine (3) exhibited inhibitory activity against HBsAg and HBeAg, but no cytotoxicity against the 2.2.15 cell line.     

乌头须根总生物碱提取工艺的考察

目的:考察乌头须根中总生物碱的最佳提取工艺条件。方法:酸碱滴定法测定乌头须根中总生物碱含量,以总生物碱提取率为指标,采用L9(3)~4正交实验法筛选乌头须根总生物碱的最佳提取工艺。结果:乌头须根总生物碱含量为1.094%,影响提取的主次因素为:乙醇浓度>提取次数>提取时间>乙醇用量;优选得到的最佳提取工艺为A_3B_1C_3D_3,即以8倍量80%的乙醇提取3次,每次1.5小时。结论:乌头须根总生物碱含量较高,提取工艺条件稳定、经济、可行。     

Consoramides A–C,New Zwitterionic Alkaloids from the Fungus Irpex consors

In our ongoing search for new secondary metabolites from fungi, a basidiomycete fungus Irpex consors was selected for mycochemical investigation, and three new zwitterionic alkaloids (1-3) and five known compounds (4-8) were isolated from the culture broth (16 l) of I. consors. The culture filtrate was fractionated by a series of column chromatography including Diaion HP-20, silica gel, and Sephadex LH-20, Sep-Pak C₁₈ cartridge, medium pressure liquid chromatography (MPLC), and high pressure liquid chromatography (HPLC) to yield eight compounds (1-8). The structures of the isolated compounds were elucidated by the interpretation of nuclear magnetic resonance (NMR) spectra and high-resolution mass spectrometry (HR-MS). Their antioxidant and antibacterial activities were examined. The zwitterionic structures of three new sesquiterpene alkaloids (1-3) were determined together with five known compounds identified as stereumamide E (4), stereumamide G (5), stereumamide H (6), stereumamide D (7), and sterostrein H (8). This is the first report of the zwitterionic alkaloids in the culture broth of I. consors. Three new zwitterionic alkaloids were named as consoramides A–C (1-3).     

Studies on the Alkaloids of Phlegmariurus fordii (Baker) Ching

Three alkaloids were isolated from the whole plant of Phlegmariurus fordii (Baker) Ching. One of them was identified as known Iycodoline. The other two, named phlcgmariurine A, and phlegmariur!ne B, are new alkaloids. The structure of A, was determined by means of spectral analysis and X-ray diffraction. It was proved to be a new tri-cyclie alkaloid as (Ⅰ). The structure of B, was elucidated as (Ⅱ).     

Comparative analysis of the chemical profile of wild and cultivated populations of Corydalis saxicola by high-performance liquid chromatography

Studies on the simultaneous determination and chemical fingerprinting of alkaloids in Corydalis saxicola Bunting. (Yanhuanglian) were performed for authentication purposes. Ninety samples prepared from different parts of C. saxicola, including whole plants, roots, stems, leaves and flowers, from wild and cultivated populations, were submitted to quantitative determination and fingerprint analysis. Five major alkaloids, namely, tetradehydroscoulerine, dehydroapocavidine, dehydroisoapocavidine, coptisine and dehydrocavidine, were quantitatively analysed by reversed-phase HPLC with acceptable recoveries (>98.2%). Chemical fingerprinting of C. saxicola was established and involved 11 markers. The results indicated that there were no obvious differences between the chemical profiles of wild and of cultivated C. saxicola populations, and that the mean alkaloid contents of the five marker compounds in cultivated populations were significantly higher than those of the wild plants. The highest content of total alkaloids (up to 28.8 mg/g) was found in roots of C. saxicola. The total alkaloids of the leaves were approximately 50% of those of roots, suggesting that the leaves may be employed as an alternative source of alkaloids. Chemical fingerprints and quantitative HPLC analysis will have a positive impact on the conservation and cultivation of this medicinal plant.     

New steroidal alkaloids from the bulbs of Fritillaria puqiensis

Six new steroidal alkaloids, namely puqienines C-E (1-3), puqiedine (4), 3alpha-puqiedin-7-ol (5), and puqietinedione (6), along with two known steroidal alkaloids puqiedinone (7) and peimisine (8), were isolated from the bulbs of Fritillaria puqiensis G.D. Yu et G.Y. Chen (Liliaceae). Their structures were elucidated on the basis of spectroscopic analysis, including 1D and 2D NMR experiments. Among these alkaloids, 1-3 had a veratramine-type skeleton, 4, 5, 7 a cevanine-type skeleton, 6 a secosolanidine-type skeleton, and 8 a jervine-type skeleton. The existence of multiple types of steroidal skeletons, especially of relatively large amount of veratramine-type alkaloids in one species is rare in the genus Fritillaria, and the results might be of chemotaxonomic significance for this species.