Studies on the Alkaloids of Stephania macrantha H. S. Lo et M. Yang

Eight alkaloids had been isolated from the roots of Stephania rnacrantha H. S. Lo et M. Yang which is a novel species growing in Yang-bi district of Yunnan Province. The structures of these compounds were identified as l-tetrahydropalmatine ( Ⅰ ), isocorydine ( Ⅱ ), corydine ( Ⅲ ), corydalmine (Ⅳ), stepholidine ( Ⅴ ), palmatine ( Ⅵ ), corytuberine salt (Ⅶ) and laudanidine (Ⅷ) by means of spectral and chemical methods. Isocorydine is a main alkaloid with 1.82% yield. It is interested that laudanidine is found for the first time in the plants of Menispermaceae.     

Studies on the Alkaloids of Stephania lincangensis

Eight alkaloids have been isolated from the roots of Stephania lincangensis H. S. Lo. et M. Yang which is a novel species growing in Lincang district of Yunnan province. The structures of these compounds were identified as 1-tetrahydropalmatine (Ⅰ), capaurine (Ⅱ) isocorydine (Ⅲ), corydine (Ⅳ), roemerine (Ⅴ) and palmatine (Ⅵ) by means of spectral and chemical methods. Two others, namely lincangenine [4-hydroxy-2,3,9,10-pentamethoxyprotoberberine (Ⅶ)] and l-l,2,3,9,10-pentamethoxytetrahydroprotoberberine (Ⅷ), are new alkaloids, l-tetrahydropalmatine is the main alkaloid with 2.39% yield.     

大花地不容块根生物碱成分的研究

为研究大花地不容块根的生物碱成分,该研究采用酸提碱沉法从大花地不容块根中提取出总生物碱,通过硅胶柱色谱法和制备液相色谱技术对大花地不容块根的总生物碱提取物进行分离纯化,并利用波谱学手段对化合物进行结构鉴定。结果表明:(1)从总生物碱提取物中分离得到11个化合物,分别鉴定为青藤碱(1)、青风藤碱(2)、斯帝酚灵碱(3)、瑞枯灵(4)、异紫堇定(5)、紫堇单酚碱(6)、巴婆碱(7)、sukhodianine(8)、荷包牡丹碱(9)、7-氧代克班宁(10)和巴马汀(11)。(2)体外细胞毒性测试显示,大花地不容总生物碱和其主成分青藤碱对人类肺癌细胞A549的IC₅₀值分别为7.5×10^-4 g·mL^-1和6.59×10^-9 g·mL^-1。化合物2、3、4、7、8、9和10系首次从大花地不容中分离得到。大花地不容块根中含有吗啡烷、原阿朴啡、阿朴啡、苄基四氢异喹啉和原小檗碱5种类型的生物碱。     

Alkaloids from Toddalia aculeata

Two alkaloids N-methyl-4-hydroxy-7-methoxy-3-(2,3-epoxy-3-methylbutyl)-1H-quinolin-2-one (1) and 3-(2,3-dihydroxy-3-methylbutyl)-4,7-dimethoxy-1-methyl-1H-quinolin-2-one (2a) have been isolated from CH(2)Cl(2):methanol (1:1) and methanol extracts of leaves and stems of Toddalia aculeata. Their structures along with that of 15 other compounds, of which three are isolated for the first time from genus Toddalia, were established by their detailed spectral studies including 2D NMR viz. (1)H-(1)H COSY, (1)H-(13)C COSY, and HMBC.     

Preparative separation of isoquinoline alkaloids from Stephania yunnanensis by pH-zone-refining counter-current chromatography

In this paper, five isoquinoline alkaloids were successfully separated from a crude extract of Stephania yunnanensis using pH-zone-refining counter-current chromatography in single-step. With a two-phase solvent system composed of methyl-tert-butyl ether (MtBE)–acetonitrile–water (2:2:3, v/v) where triethylamine (10 mM) was added to the upper organic phase as a retainer and hydrochloric acid (5 mM) to the aqueous mobile phase as an eluter. From 1.4 g crude extract, 68.7 mg isocorydine, 78.2 mg corydine, 583.4 mg tetrahydropalmatine, 36.3 mg N-methylasimilobine, and 47.3 mg anonaine were separated with purities over 90%. Their structures were identified by ¹H NMR, ¹³C NMR, ESI-MS data.     

Alkaloids in the venom of Messor ants

Tobacco alkaloids of the anabasine type have been found or confirmed in the venom of five species of arid-dwelling Messor ants. They are frequently accompanied by alkylpyrazines. Messor mediorubra contains four alkaloids, with anabasine the major component and also minor pyrazines. Anabasine was found alone in the venom of Messor semirufus and confirmed in Messor ebeninus. Messor rugosus from Tel Aviv contained a mixture of alkaloids and pyrazines, but those from Ein Yahav contained 3-ethyl-2,5-dimethylpyrazine, some 2-phenylethylamine, and N-ethylidene 2-phenylethylamine. Messor arenarius is confirmed as having a complex but variable mixture of alkaloids and pyrazines.     

Pyrrolo- and pyridoazepine alkaloids as chemical markers in Stemona species

Broad-based phytochemical investigations on 31 Stemona species and geographical provenances led to an overview concerning characteristic accumulation trends and the distribution of different Stemona alkaloids. Two major metabolic differences suggested a taxonomic segregation of the complex Stemona tuberosa group from the other species, and was supported by morphological characters. Whereas most of the Stemona species were characterised by protostemonine type alkaloids, the S. tuberosa group clearly deviated by accumulation trends towards tuberostemonine or croomine derived alkaloids belonging to two different skeletal types. Also of chemotaxonomic relevance was the structural divergence of protostemonine type alkaloids into pyrrolo- or pyridoazepine derivatives represented by stemofoline or oxystemokerrine, respectively, as major constituents. Their common occurrence in different provenances of S. curtisii, also deviating from the other species by various chromosome numbers, deserves special taxonomic attention. Species specific chemical markers were given by the unique accumulation of didehydrostemofoline (=asparagamine A) in S. collinsae and stemokerrine in S. kerrii. In contrast to previous reports, no bisdehydro derivatives with an aromatic pyrrole ring were detected supporting the hypothesis that these alkaloids are artifacts. A new stereoisomer of tuberostemonine was isolated and identified by spectroscopic methods.     

Ipangulines and minalobines, chemotaxonomic markers of the infrageneric Ipomoea taxon subgenus Quamoclit, section Mina

A comprehensive GC-MS analysis of 8 Ipomoea species belonging to the subgenus Quamoclit, section Mina revealed that the members of this taxon form combinations of two necine bases with rare necic acids resulting in unique pyrrolizidine alkaloids. The occurrence and diversity of these metabolites show remarkable variations: Some species, especially Ipomoea hederifolia and Ipomoea lobata, are able to synthesize a large number of alkaloids whereas others, especially Ipomoea coccinea and Ipomoea quamoclit, are poor synthesizers with only a few compounds. However, these metabolites are apparently chemotaxonomic markers of this infrageneric taxon in general. They represent either esters of (-)-platynecine (altogether 48 ipangulines and 4 further esters including results of a previous study) or esters of (-)-trachelanthamidine, an additional novel structural type called minalobines (altogether 21 alkaloids). Both types are characterized by section-specific rare necic acids, e.g., ipangulinic/isoipangulinic acid, phenylacetic acid. The alkaloids of Ipomoea cholulensis, I. coccinea, I. hederifolia, Ipomoea neei, and Ipomoea quamoclit were mono and diesters of platynecine. Minalobines turned out to be metabolites of I. lobata (Cerv.) Thell. (syn.: Mina lobata Cerv.) lacking ipangulines. The major alkaloid of this species, minalobine R, has been isolated and identified as 9-O-(threo-2-hydroxy-2-methyl-3-phenylacetoxy-butyryl)-(-)-trachelanthamidine on the basis of spectral data. Apparently only two of the species included in this study, Ipomoea cristulata and Ipomoea sloteri, are able to synthesize both, ipangulines as well as minalobines. Minalobine O could be isolated as a major alkaloid of I. cristulata, its structure has been established as 9-O-(erythro-2-hydroxy-2-methyl-3-tigloyloxy-butyryl)-(-)-trachelanthamidine on the basis of spectral data.     

Nevskia aquatilis sp. nov. and Nevskia persephonica sp. nov., isolated from a mineral water aquifer and the emended description of the genus Nevskia

Four isolates, with an optimum temperature of about 30°C and an optimum pH for growth of 6.0-6.5, were recovered from a borehole head of a mineral water aquifer in Portugal and from the stored bottles produced on site. Strains F2-63(T) and F2-178 were yellow-pigmented and formed non-motile rod-shaped cells. Strains G6M-30(T) and G6-54 were whitish-pigmented, translucent and form rod-shaped cells with a polar flagellum. The four strains were strictly aerobic, oxidase and catalase positive. The major fatty acids of strains F2-63(T) and F2-178 were C(18:1)ω7c and C(16:0), and the major fatty acids of strains G6M-30(T) and G6-54 were C(18:1)ω7c and C(16:1)ω7c. Ubiquinone 8 was the major respiratory quinone. Based on 16S rRNA gene sequence analysis, physiological and biochemical characteristics two new species of the genus Nevskia are described; Nevskia aquatilis represented by strains F2-63(T) (=LMG 26345 =CECT 7897) and F2-178 (=LMG 26344 =CECT 7898) and Nevskia persephonica represented by strains G6M-30(T) (=DSM 24987 =CECT 7975) and G6-54 (=DSM 25048 =CECT 7976).     

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).     

Large differences in amino acid sequences among ferredoxins from several species of genus Solanum

The complete amino acid sequences of [2Fe-2S] ferredoxins from four species of genus Solanum (S. nigrum, S. lyratum, S. indicum, and S. abutiloides) were determined by automated Edman degradation of the entire S-carboxymethylcysteinyl proteins and of the peptides obtained by enzymatic digestion. The amino acid sequences of these four ferredoxins differed from each other by 12-19, whereas 0-4 differences have been observed among ferredoxins from plants in the same genus and 14-40 differences were seen between different families. This suggests that these Solanum plants are distantly related to each other taxonomically.     

Extraction and physicochemical characterization of Sargassum vulgare alginate from Brazil

Alginate fractions from Sargassum vulgare brown seaweed were characterized by (1)H NMR and fluorescence spectroscopy and by rheological measurements. The alginate extraction conditions were investigated. In order to carry out the structural and physicochemical characterization, samples extracted for 1 and 5h at 60 degrees C were further purified by re-precipitation with ethanol and denoted as SVLV (S. vulgare low viscosity) and SVHV (S. vulgare high viscosity), respectively. The M/G ratio values for SVLV and SVHV were 1.56 and 1.27, respectively, higher than the ratio for most Sargassum spp. alginates (0.19-0.82). The homopolymeric blocks F(GG) and F(MM) of these fractions characterized by (1)H NMR spectroscopy were 0.43 and 0.55 for SVHV and 0.36 and 0.58 for SVLV samples, respectively, these values typically being within 0.28-0.77 and 0.07-0.41, respectively. Therefore, the alginate samples from S. vulgare are much richer in mannuronic block structures than those from other Sargassum species. Values of M(w) for alginate samples were also calculated using intrinsic viscosity data. The M(w) value for SVLV (1.94 x 10(5)g/mol) was lower than that for SVHV (3.3 x 10(5)g/mol). Newtonian behavior was observed for a solution concentration as high as 0.7% for SVLV, while for SVHV the solutions behaved as a Newtonian fluid up to 0.5%. The optimal conditions for obtaining the alginates from S. vulgare were 60 degrees C and 5h extraction. Under these conditions, a more viscous alginate in higher yield was extracted from the seaweed biomass.     

The role of chemical fingerprinting: application to Ephedra

Ephedra sinica, known as Ma Huang, is one of the oldest medicinal herbs in Traditional Chinese Medicine (TCM). Preparations, namely teas, of E. sinica have been used for over 5000 years as a stimulant and as an antiasthmatic. In the West, extracts of E. sinica, E. intermedia or E. equisetina are most commonly used in dietary supplements as a stimulant and to promote weight loss. More than 50 species of Ephedra are native to both hemispheres, but the detection of ephedrine alkaloids has been limited to species in Eurasia. Currently, methods exist to quantitate the ephedrine alkaloids in extracts of plant material or dietary supplements, but the methods are not able to verify the extract is of an Ephedra species. Reverse phase high performance liquid chromatography with photodiode array detection was applied for the chemical fingerprinting of the Ephedra species. Two regions of comparison were determined in the chromatograms at 320 nm. The series of peaks between 52 and 64 min confirms an Ephedra species is being analyzed. The aforementioned peaks also could distinguish between Ephedra species from Eurasia, North America and South America. Peaks at ca. 57 and 59 min were isolated and determined to be two new compounds, 4-(2-eicosyloxycarbonyl-vinyl)-benzoic acid and 4-(2-docosyloxycarbonyl-vinyl)-benzoic acid respectively. Authentication of ground plant material as Ephedra can be achieved by this chemical fingerprinting method.     

Structural Characterisation of Alkaloids in Leaves and Roots of Stephania kwangsiensis by LC‐QTOF‐MS

Introduction

The tuberous roots of Stephania kwangsiensis, which contain bioactive alkaloids, are used as a traditional Chinese medicine. Overexploitation of the roots has made the plant increasingly rare, and the abundant leaves of the same plant may offer a potential alternative. However, there is insufficient phytochemical information for a comparison of alkaloid compositions in the two parts.

Objective

To characterise and compare the alkaloids in the leaves and roots of S. kwangsiensis.

Methods

The alkaloids in S. kwangsiensis were characterised using high pressure liquid chromatography coupled with positive electrospray ionisation quadrupole time‐of‐flight tandem mass spectrometry (HPLC‐(+)ESI‐QTOF‐MS/MS). The alkaloid compositions in the leaves and roots were compared by visual inspection combined with principal component analysis (PCA) of the HPLC‐MS data.

Results

Seventy‐five alkaloids comprising aporphine‐, proaporphine‐, protoberberine‐, benzylisoquinoline‐, bisbenzylisoquinoline‐ and morphine‐type alkaloids were identified or tentatively identified in the roots and leaves of S. kwangsiensis. Sixty‐three of these alkaloids have not been previously reported in this species, and three have not been previously reported in the literature. The roots and leaves had similarities in alkaloid composition but differences in the peak intensities of most alkaloids. The PCA revealed that the samples were clustered into two distinct groups, which corresponded to leaves and roots.

Conclusion

This study further clarified the chemical constituents in the roots of S. kwangsiensis, and revealed that diverse alkaloids were also present in the leaves. The comparative chemical profiling of the two parts provides useful information on their potential medicinal use. Copyright © 2017 John Wiley & Sons, Ltd.     

Arcobacter molluscorum sp. nov., a new species isolated from shellfish

Nineteen bacteria isolates recovered from shellfish samples (mussels and oysters) showed a new and specific 16S rDNA-RFLP pattern with an Arcobacter identification method designed to recognize all species described up to 2008. These results suggested that they could belong to a new species. ERIC-PCR revealed that the 19 isolates belonged to 3 different strains. The sequence of the 16S rRNA gene of a representative strain (F98-3^T) showed 97.6% similarity with the closest species Arcobacter marinus followed by Arcobacter halophilus (95.6%) and Arcobacter mytili (94.7%). The phylogenetic analysis with the16S rRNA, rpoB, gyrB and hsp60 genes placed the shellfish strains within the same cluster as the three species mentioned (also isolated from saline habitats) but they formed an independent phylogenetic line. The DDH results between strain F98-3^T and A. marinus (54.8% ± 1.05), confirmed that it represents a new species. Several biochemical tests differentiated the shellfish isolates from all other Arcobacter species. Although the new species was different from A. mytili, they shared not only the same habitat (mussels) but also the characteristic of being so far the only Arcobacter species that are simultaneously negative for urea and indoxyl acetate hydrolysis. All results supported the classification of the shellfish strains as a new species, for which the name Arcobacter molluscorum sp. nov. with the type strain F98-3^T is proposed (=CECT 7696^T = LMG 25693^T).     

Fangchinoline inhibited the antinociceptive effect of morphine in mice

Fangchinoline (FAN), a non-specific calcium antagonist, is a major alkaloidal component of the creeper Stephania tetrandra S. Moore (or fenfangji). It has been shown to possess antagonistic activity on morphine-induced antinociception in mice. This study was undertaken to assess the antagonistic mechanism. The results demonstrated that FAN (IP) attenuated morphine (SC)-induced antinociception in a dose-dependent manner with significant effect at doses of 30 and 60mg/kg body wt. (IP) in the tail-flick test but not the tail-pinch tests, carried out in mice. This antagonism was abolished by pretreatment with a serotonin precursor, 5-hydroxytryptophan (5-HTP, IP), but not by pretreatment with a noradrenaline precursor, L-dihydroxyphenylalanine (L-DOPA, IP) in the tail-flick test. On the other hand, the development of morphine-induced analgesic tolerance was not prevented by FAN. These results suggest that the serotonergic pathway may be involved in the antagonism of morphine-induced antinociception by FAN and, in agreement with other reports, also indicates the possible dissociation of the morphine analgesic effect from its tolerance-development mechanism.     

Chemotaxonomy of the pantropical genus Merremia (Convolvulaceae) based on the distribution of tropane alkaloids

The occurrence and distribution of tropane and biogenetically related pyrrolidine alkaloids in 18 Merremia species of paleo-, neo-, and pantropical occurrence have been studied. The extensive GC-MS study included members of almost all sections of the genus and has been carried out with epigeal vegetative parts as well as with roots. It comprises altogether 74 tropanes and 13 pyrrolidines including nicotine. Along with datumetine known already from a solanaceous species, the study led to the isolation (from M. dissecta and M. guerichii, respectively) and structure elucidation (spectral data) of four novel 3alpha-acyloxytropanes, merresectines A-D: 3alpha-(4-methoxybenzoyloxy)nortropane (A), 3alpha-kurameroyloxytropane (B), 3alpha-nervogenoyloxytropane (C), 3alpha-[4-(beta-D-glucopyranosyloxy)-3-methoxy-5-(3-methyl-2-butenyl)benzoyloxy]tropane (beta-d-glucoside of D). Moreover, the novel 3alpha,6beta-di-(4-methoxybenzoyloxy)tropane (merredissine) has been isolated from M. dissecta and structurally elucidated. In addition the structures of datumetine and merresectine A could be confirmed by synthesis. Spectral data for two known 3alpha-acyloxytropanes (merresectine E beta-D-glucoside, 4'-dihydroconsabatine) and one known 3beta-acyloxytropane (concneorine) are documented for the first time. The structures of three further merresectines (F-H) have been determined by mass spectrometry. Furthermore, the linkage (2',3- and 2',4-, respectively) of two position isomer N-methylpyrrolidinylhygrines was proven by synthesis. The results of the study contribute to the solution of infrageneric taxonomic problems. Whereas all species yield pyrrolidine alkaloids without suitably differentiating results the diverging occurrence of tropane alkaloids leads to three groups of sections: (1) taxa free of tropanes, (2) taxa with simple tropanes, and (3) taxa with merresectines in addition to simple tropanes.     

Isolation and chemotaxonomic significance of tuberostemospironine-type alkaloids from Stemona tuberosa

An alkaloid named 6alpha-hydroxycroomine (1) as well as the known croomine (2), both belonging to the tuberostemospironine-alkaloid type, were isolated from Stemona tuberosa as the major components. The structure of 1 was elucidated through extensive spectroscopic analyses. Comparison of the HPLC profiles of the total alkaloids and the crude methanol extract showed that both compounds are naturally occurring. The first isolation of 1 and 2 from S. tuberosa has chemotaxonomic significance, confirming the close relationship between Stemona and Croomia. The trnL sequences of plants from the four genera of Stemonaceae cluster together as a clade, further lending support to retaining them in a single family.     

Comparative study of the alkaloids in tribe Datureae and their chemosystematic significance

Sixty-six tropane alkaloids from crude leaf and root alkaloid mixtures of 12 different species and their varieties and subspecies from tribe Datureae were determined by GC–MS. The alkaloids 3β-hydroxy-6β-acetoxytropane, 3-propionyloxy-6-hyroxytropane, 3β-hydroxy-6β-tigloyloxytropane, 3β-tigloyloxy-6β-acetoxytropane and 3-tigloyloxy-7-isobutyryloxytropane are new reported tropane alkaloids.     

Identification of two mosquitocidal Bacillus cereus strains showing different host ranges

Mosquitocidal bacteria, M413 and C32 have been isolated from sediment samples collected from woodland and ditch, respectively. Gas chromatographic analysis of fatty acids methyl esters (GC-FAME) and 16S rRNA gene sequence alignment results showed these isolates belong to Bacillus cereus. The SDS-PAGE analysis of sporulated cultures of both isolates showed two major bands very similar in size. Interestingly, however, M413 is mainly toxic to 4th instars of Ochlerotatus taeniorhynchus whereas C32 is to those of Culex quinquefasciatus.