Study on the anti-HBV activity of matrine alkaloids from Oxytropis ochrocephala by MTT, 3d-QSAR, molecular docking and molecular dynamics simulation.

To elucidate the structure-activity relationship of 17 matrine alkaloids from Oxytropis ochrocephala Bunge, their effect on hepatitis B surface antigen (HBsAg) secretion was studied using the MTT assay. A 3D-QSAR analysis showed a strong correlation between chemical structures and biological activities (q2 = 0.625, r2 = 0.859). Molecular docking and molecular dynamics simulations revealed that hydrogen bonding and hydrophobic interactions with hepatitis B core protein (PDB:5T2P) are key to inhibiting HBsAg secretion, suggesting potential for developing natural anti-hepatitis B drugs.

The locoweed endophyte Alternaria oxytropis affects root development in Arabidopsis in vitro through auxin signaling and polar transport.

Locoweeds are leguminous forbs known for their toxicity to livestock caused by the endophytic fungi Alternaria sect. Undifilum. Unlike the defensive mutualisms reported in many toxin-producing endophytes and their plant hosts, the benefits that A. sect. Undifilum can confer to it host plants remains unclear. Here, we conducted physiological and genetic analyses to show that A. (sect. Undifilum) oxytropis influences growth, especially root development, in its locoweed host Oxytropis ochrocephala and Arabidopsis. The presence of A. oxytropis significantly decreased primary root length while increasing the numbers of lateral roots and root hairs, and increasing plant leaf area and fresh weight. The fungus also increased the concentrations of plant endogenous auxin, and the expression of key genes for auxin biosynthesis, signaling, and transport. These effects on root development were abolished in mutants deficient in auxin signaling and polar transport. Alternaria oxytropis down-regulated expression of PIN1 but increased expression of PIN2, PIN7, and AUX1, which might reflect alterations in the spatial accumulation of auxin responsible for the changes in root architecture. Plant growth was insensitive to A. oxytropis when naphthylphthalamic acid was applied. Our findings indicate a function of A. oxytropis in promoting the growth and development of Arabidopsis via the regulation of auxin, which in turn suggests a possible role in benefiting its locoweed hosts via a process independent of its toxin production.

The plastome of Arctic Oxytropis arctobia (Fabaceae) is significantly different from that of O. splendens and other related species.

Anatomical and physiological specializations for plant adaptation to harsh climates result from molecular mechanisms that can be encoded in the nucleus or organelle. In this study, the complete plastomes of an arctic species, Oxytropis arctobia Bunge (Fabaceae), and a closely related temperate species, O. splendens Douglas ex Hook., were assembled, annotated, and analyzed to identify differences that might help explain their adaptation to different environments. This is consistent with the previously sequenced O. bicolor DC. and O. glabra plastomes, O. arctobia and O. splendens plastomes both have the common features of the inverted repeat-lacking clade (IRLC), as well as atpF intron loss, which is unique to the genus. However, significant differences were observed between the plastomes of O. arctobia and O. splendens and other closely related species (Oxytropis spp. and Astragalus spp.), including a 3 kb inversion, two large insertions (>1 kb), significant modifications of the accD gene, and an overall larger size.

UPLC-Q-TOF-MS/MS analysis of the guaiane sesquiterpenoids oxytropiols A-J and detection of undescribed analogues from the locoweed endophytic fungus Alternaria oxytropis (Pleosporaceae).

INTRODUCTION: In addition to the mycotoxin swainsonine, the locoweed endophytic fungus Alternaria oxytropis (Pleosporaceae) also produces a series of rarely reported, highly oxygenated bicyclic guaiane sesquiterpenoids. Few investigations on the electrospray tandem mass fragmentation pattern of this sesquiterpenoid have been reported. OBJECTIVES: We aimed to analyze and detect new guaiane sesquiterpenoid analogues from crude extracts of the locoweed endophytic fungus A. oxytropis by UPLC-Q-TOF-MS/MS experiments. MATERIALS AND METHODS: Oxytropiols A-J (1-10) and the extract of the locoweed endophytic fungus A. oxytropis were analyzed by UPLC-Q-TOF-MS/MS in positive mode. RESULTS: Typical neutral losses, McLafferty rearrangement, 1,2-rearrangement, and 1,3-rearrangement were considered to be the main fragmentation patterns for the [M + H]+ /[M + Na]+ ions of 1-10 by UPLC-Q-TOF-MS/MS experiments, and possible fragmentation pathways of 1-10 were suggested. A unique and undescribed analogue named oxytropiol K (11) was found in the extract based on UPLC-Q-TOF-MS/MS analysis. Compound 11 was isolated and elucidated by NMR spectrometry, and its UPLC-Q-TOF-MS/MS analysis was consistent with the fragmentation pathways of 1-10. CONCLUSION: The results further support that UPLC-Q-TOF-MS/MS is a powerful and sensitive tool for the characterization of known compounds (dereplication) and the detection of new analogues from crude extracts and imply that the locoweed endophytic fungus A. oxytropis, with few chemical investigations, is an important resource for undescribed metabolites.

Chemical Components of Oxytropis pseudoglandulosa Induce Apoptotic-Type Cell Death of Caco-2 Cells.

Oxytropis pseudoglandulosa plant is used in traditional Mongolian medicine. However, its chemical composition and biological properties are poorly explored. In this study, the total content of polyphenols and flavonoids as well as antioxidant activity were verified in plant extract. The total phenolic and flavonoid contents were determined by spectrometric (6.62 mg GAE/g and 10.32 mg QE/g) and chromatographic (17,598 mg/kg and 17,467 mg/kg) assays. The antioxidant potential was investigated by DPPH assay and yielded IC50 at 18.76 µg/mL. Twelve phenolic compounds were identified as components of O. pseudoglandulosa extract. Kaempferol-3-O-robinosyl-7-O-rhamnoside and kaempferol-3-(p-coumaroyl)-rutinosyl-7-rhamnoside made up 80% of determined components and were found to be the major polyphenolic compounds. The biological properties of O. pseudoglandulosa extracts were determined in vitro using human epithelial adenocarcinoma Caco-2 cell line. Low concentrations of extract (0-30 µg/mL) exhibited protective effects against cell damage caused by chemically induced oxidative stress. Elevated concentrations, on the other hand, resulted in apoptotic-type cell death induction. Metabolic failure, ROS elevation and membrane permeabilization observed in cells upon incubation with extract dosages above 50 µg/mL allowed us to conclude on O. pseudoglandulosa being predominantly a necrosis inducer.

Mechanism of Action of Flavonoids of Oxytropis falcata on the Alleviation of Myocardial Ischemia-Reperfusion Injury.

Oxytropis falcata Bunge is a plant used in traditional Tibetan medicine, with reported anti-inflammatory and antioxidants effects and alleviation of myocardial ischemia reperfusion injury (MIRI). However, the underlying mechanism against MIRI and the phytochemical composition of O. falcata are vague. One fraction named OFF1 with anti-MIRI activity was obtained from O. falcata, and the chemical constituents were identified by ultra-high-performance liquid chromatography coupled with tandem mass spectrometry (UHPLC-MS). The potential targets and signaling pathways involved in the action of O. falcata against MIRI were predicted by network pharmacology analysis, and its molecular mechanism on MIRI was determined by in vitro assays. The results revealed that flavonoids are the dominant constituents of OFF1. A total of 92 flavonoids reported in O. falcata targeted 213 potential MIRI-associated factors, including tumor necrosis factor (TNF), prostaglandin-endoperoxide synthase 2 (PTGS2), and the NF-κB signaling pathway. The in vitro assay on H9c2 cardiomyocytes subjected to hypoxia/reoxygenation injury confirmed that the flavonoids in OFF1 reduced myocardial marker levels, apoptotic rate, and the inflammatory response triggered by oxidative stress. Moreover, OFF1 attenuated MIRI by downregulating the ROS-mediated JNK/p38MAPK/NF-κB pathway. Collectively, these findings provide novel insights into the molecular mechanism of O. falcata in alleviating MIRI, being a potential therapeutic candidate.

Genetic diversity of Oxytropis section Xerobia (Fabaceae) in one of the centres of speciation.

The genetic diversity and phylogenetic relationships of Oxytropis caespitosa, O. grandiflora, O. eriocarpa, O. mixotriche, O. nitens, O. peschkovae and O. triphylla, section Xerobia subgenus Oxytropis, in one of the main speciation centres of the genus Oxytropis (Baikal Siberia and adjacent territories of Northeastern Mongolia) were studied based on sequence analysis of the psbA-trnH, trnL-trnF and trnS-trnG intergenic spacers of cpDNA, as well as the ITS nrDNA. Most populations are characterized by a high level of chloroplast genetic diversity (h varied from 0.327 to 1.000 and π from 0.0001 to 0.0090) due to the ancient origin for some species and to hybridization and polyploidy for others. 67 haplotypes were identified, of which six were shared. Phylogenetic relationships among species could not be satisfactorily resolved. Only the haplotypes of O. triphylla formed a group with rather high support. Probably, O. caespitosa, O. grandiflora, O. mixotriche and O. nitens constitute a single genetic complex. As regards the ITS nrDNA polymorphism, we detected only two ribotypes (RX1, RX2). Both were found in O. caespitosa, O. eriocarpa, O. mixotriche and O. peschkovae, while RX1 was present in O. nitens and O. triphylla, RX2 in O. grandiflora. The absence of diagnostic species-specific variants for the markers studied, together with the sharing of cpDNA haplotypes and nrDNA ribotypes between species, and the resulting polytomies on the phylogenetic trees, confirm the hypothesis on the hybrid origin of some of them. Obviously, the reproductive barriers within the sect. Xerobia are weak. However, morphological differences between the species of the sect. Xerobia are clearly pronounced, even when they grow in sympatry.

Systematical NMR analysis of swainsonine, a mycotoxin from endophytic fungus Alternaria oxytropis.

Swainsonine (SW, 1), a unique indolizine with poly-hydroxyl groups, was re-isolated from the plant endophytic fungus Alternaria oxytropis. The structure (including planar structure and relative configuration) was systematically elucidated by NMR spectra (including 1 H, 13 C, 1 H-1 H COSY, HMQC, HMBC, and NOESY spectra in DMSO-d6 and in CD3 OD); 1 H NMR spectra of the modified Mosher's products were first used to determine the absolute configuration of SW. More importantly, the complex coupled features of H-7α, H-7ß, and H-6α in the 1 H NMR spectrum of (1) were analyzed in details, which will provide aids for the planar and relative configuration determination of analogs.

Chemical and Biological Characteristics of Oxytropis pseudoglandulosa Plant of Mongolian Origin.

Oxytropis pseudoglandulosa is used in Mongolian traditional medicine due to its numerous reported health-promoting effects. To date, there are very few scientific reports that describe this species. In this article, its volatile oil composition, lipid extract composition, total phenolic and flavonoid content, antibacterial and allergenic properties are elucidated for the first time. Hexadecanoic acid, fokienol and tricosane were determined as the most notable components of the volatile oil, at 13.13, 11.46 and 5.55%, respectively. Methyl benzoate was shown to be the most abundant component of lipid extract at 40.69, followed by (E)-prop-2-enoic acid, 3-phenyl- and benzenepropanoic acid, at 18.55 and 9.97%. With a TPC of 6.620 mg GAE g-1 and TFC of 10.316 mg QE g-1, the plant extract of O. pseudoglandulosa indicated good antioxidant activity measured by IC50 at 18.761 µg mL-1. Of the 12 tested microorganisms, B. subtilis and S. cerevisiae were the shown to be most susceptible to the plant extract, with MIC at 2.081 and 0.260% (v/v), respectively. Bet v 1-a major birch pollen allergen found in plant-based foods-was determined to be at 192.02 ng g-1 with ELISA. Such a wide spectrum of biological activity indicated by O. pseudoglandulosa lends credence for its application in food industry. Its exerted antioxidant and antimicrobial effects could improve preservation of low-processed food dedicated for consumers afflicted with allergies. Hexadecanoic acid supplemented in foods with dietary plant extracts could add to the potential anti-inflammatory impact. The analysis of lipid makeup suggests O. pseudoglandulosa extract could also be considered as natural pesticide in organic farming.

Rhizobial Microsymbionts of Kamchatka Oxytropis Species Possess Genes of the Type III and VI Secretion Systems, Which Can Affect the Development of Symbiosis.

A collection of rhizobial strains isolated from root nodules of the narrowly endemic legume species Oxytropis erecta, O. anadyrensis, O. kamtschatica, and O. pumilio originating from the Kamchatka Peninsula (Russian Federation) was obtained. Analysis of the 16S ribosomal RNA gene sequence showed a significant diversity of isolates belonging to families Rhizobiaceae (genus Rhizobium), Phyllobacteriaceae (genera Mesorhizobium, Phyllobacterium), and Bradyrhizobiaceae (genera Bosea, Tardiphaga). A plant nodulation assay showed that only strains belonging to genus Mesorhizobium could form nitrogen-fixing nodules on Oxytropis plants. The strains M. loti 582 and M. huakuii 583, in addition to symbiotic clusters, possessed genes of the type III and type VI secretion systems (T3SS and T6SS, respectively), which can influence the host specificity of strains. These strains formed nodules of two types (elongated and rounded) on O. kamtschatica roots. We suggest this phenomenon may result from Nod factor-dependent and -independent nodulation strategies. The obtained strains are of interest for further study of the T3SS and T6SS gene function and their role in the development of rhizobium-legume symbiosis. The prospects of using rhizobia having both gene systems related to symbiotic and nonsymbiotic nodulation strategies to enhance the efficiency of plant-microbe interactions by expanding the host specificity and increasing nodulation efficiency are discussed.

Preparation, characterization, and pharmacodynamic study on deep second degree burns of total flavonoids composite phospholipids liposome gel of Oxytropis falcata Bunge.

Wound healing is the treatment problem after deep second degree (II°) burns. The p38 mitogen-activated protein kinase (p38 MAPK) and nuclear factor-κB/inhibitory factor-κB (NF-κB/IκB) signal pathways play significant role in angiogenesis and wound repair after burns.This study aimed to investigate the preparation, characterization and pharmacodynamics of the total flavonoids composite phospholipids liposome of Oxytropis falcata Bunge (TFOFB-CPL) on deep II° burns to research its biological activity and underlying mechanism. The TFOFB-CPL was prepared by thin-film dispersion method and the preparation process was optimized via central composite design. The TFOFB-CPL was then characterized by using particle size, polydispersity indexes (PDIs), zeta potential, encapsulation efficiency (EE) and morphology. Moerover, in vitro transdermal test and in vivo pharmacodynamic study included wound healing rate, hematoxylin-eosin (HE) staining, masson staning, western blotting and RT-PCR. The results showed that the therapeutic effects of TFOFB-CPL gel on deep II° burns, especially during wound healing were significant. TFOFB-CPL gel has a sustained-release effect during the treatment of deep II° burns with forming drug depot in the dermis layer. The wound healing rate of TFOFB-CPL gel group was near positive group and better than the other groups. TFOFB-CPL gel could promote the growth of epidermis, skin appendages, fibrovascular and collagen fibers, and had obvious anti-inflammatory effects. Moreover, TFOFB-CPL gel inhibited the activation of p38MAPK and the degradation of IκBα, and promoted the neonatal wounds during the early stage. Therefore, TFOFB-CPL gel could be considered as a novel preparation for treating deep II° burns.

The study of metabolites from fermentation culture of Alternaria oxytropis.

BACKGROUND: The indolizidine alkaloid-swainsonine is produced by an endophytic fungus Alternaria oxytropis, which was isolated from locoweeds. Swainsonine has many biological activities such as anti-tumorigenic, anti-viral and bacteriostatic. However, the full complement of metabolites produced by Alternaria oxytropis is not known. This study is a chemical analysis of Alternaria oxytropis metabolites, which not only unravels the potential compounds from the fermentation broth but also in which solvent are they extracted, facilitating industrial application. RESULTS: Alternaria oxytropis isolated from Oxytropis gansuensis was cultured in Czapek's medium for 30d to collect the fermentation broth. The fermentation broth is treated with methanol and then evaporated to dryness to obtain a concentrate of the fermentation broth. The concentrate is added with water for the subsequent fractional extraction with petroleum ether, chloroform, ethyl acetate and n-butanol. Different fractions of the extract were eluted by wet packing and dry loading. The obtained eluate was combined by TLC to detect the same fraction, and then characterized by GC-MS and LC-MS. The results of GC-MS showed that 105 different compounds existed in the petroleum ether, chloroform, and ethyl acetate phases of Alternaria oxytropis fermentation broth. Moreover, the results of LC-MS indicated that the fermentation broth of Alternaria oxytropis contained five alkaloids, 2-hydroxy-indolizidine, retronecine, lentiginosine, swainsonine and swainsonine N-oxide. CONCLUSIONS: In addition to swainsonine and swainsonine N-oxide, 2-hydroxy-indolizidine, retronecine and lentiginosine were identified as the secondary metabolites of Alternaria oxytropis. Other compounds were also detected including 5,6-dihydroergosterol, eburicol, lanosterol, and L-phenylalanyl-L-proline lactam, which have potential applications as drugs.

Host Genotype and Precipitation Influence of Fungal Endophyte Symbiosis and Mycotoxin Abundance in a Locoweed.

Many plant endophytes produce mycotoxins, but how host genetic variation influences endophyte colonization and mycotoxin production under natural conditions is poorly understood. This interaction has not been fully considered in many previous studies which used controlled experiments with agronomic or model plant species. Here, we investigated this interaction in a naturally occurring forb (a locoweed species) Oxytropis ochrocephala, its symbiotic endophyte Alternaria oxytropis, and the mycotoxin swainsonine. Host genetic variation was characterized by microsatellite markers. Endophyte infection rate and swainsonine levels were determined by PCR and HPLC, respectively. Genetic markers defined two distinct host populations and revealed that host genetics were significantly correlated with geographical location, elevation, and precipitation. As the host diverged, symbiotic interactions were reduced or failed to produce detectable swainsonine in one host population. Host genotype and precipitation had a significant impact in shaping swainsonine production at the population level. This study highlights the effect of host genotype in influencing this interaction in locoweeds.

Oxytrodiflavanone A and Oxytrochalcoflavanones A,B: New Biflavonoids from Oxytropis chiliophylla.

Three previously undescribed biflavonoids, oxytrodiflavanone A (1), and oxytrochalcoflavanones A,B (2,3), were isolated from the aerial part of Oxytropis chiliophylla, together with their putative biosynthetic monomers, i.e., (2S)-5,7-dihydroxyflavanone (4), (2S)-7-hydroxyflavanone (5), and 2',4'-dihydroxychalcone (6). The structures of these compounds were elucidated by a combination analysis of spectroscopic data. The cytotoxic activities of all the isolated compounds against PC-3 human prostate cancer cell line are also presented.

Application of Toxigenic Alternaria oxytropis to Soybeans and its Effect on Swainsonine Detection in Different Environments.

Alternaria oxytropis is an endophytic fungus of locoweeds that synthesizes swainsonine toxin. In this work, we evaluated the effect of A. oxytropis on soybean seedlings and quantified swainsonine in different culture conditions. Soybean (Glycine max) seeds were co-cultured with A. oxytropis (at different concentrations of mycelial suspensions) in agar media and soil culture, and swainsonine was assayed using LC-MS/MS. The results showed evidence that A. oxytropis infected soybean seedlings produced detectable swainsonine in agar culture while the toxin was undetectable or below the detection limit (0.006% of swainsonine dry weight) in soil media even at higher concentrations of the fungus. These results suggest that swainsonine detection is highly dependent on culture conditions and that soybeans co-cultured with A. oxytropis in soil could potentially be used to limit toxin production.

Phyllobacterium zundukense sp. nov., a novel species of rhizobia isolated from root nodules of the legume species Oxytropis triphylla (Pall.) Pers.

Gram-negative strains Tri-36, Tri-38, Tri-48T and Tri-53 were isolated from root nodules of the relict legume Oxytropis triphylla (Pall.) Pers. originating from Zunduk Cape (Baikal Lake region, Russia). 16S rRNA gene sequencing showed that the novel isolates were phylogenetically closest to the type strains Phyllobacterium sophorae LMG 27899T, Phyllobacterium brassicacearum LMG 22836T, Phyllobacterium endophyticum LMG 26470T and Phyllobacterium bourgognense LMG 22837T while similarity levels between the isolates and the most closely related strain P. endophyticum LMG 26470T were 98.8-99.5 %. The recA and glnII genes of the isolates showed highest sequence similarities with P. sophorae LMG 27899T (95.4 and 89.5 %, respectively) and P. brassicacearum LMG 22836T (91.4 and 85.1 %, respectively). Comparative analysis of phenotypic properties between the novel isolates and the closest reference strains P. sophorae LMG 27899T, P. brassicacearum LMG 22836T and P. endophyticum LMG 26470T was performed using a microassay system. Average nucleotide identities between the whole genome sequences of the isolates Tri-38 and Tri-48T and P. sophorae LMG 27899T, P. brassicacearum LMG 22836T and P. endophyticum LMG 26470T ranged from 79.23 % for P. endophyticum LMG 26470T to 85.74 % for P. sophorae LMG 27899T. The common nodABC genes required for legume nodulation were absent from strains Tri-38 and Tri-48T, although some other symbiotic nod and fix genes were detected. On the basis of genotypic and phenotypic analysis, a novel species, Phyllobacterium zundukense sp. nov. (type strain Tri-48T=LMG 30371T=RCAM 03910T), is proposed.

Azukisapogenol Triterpene Glycosides from Oxytropis chiliophylla Royle.

Eight azukisapogenol triterpene glycosides, including five new compounds, oxychiliotriterpenosides A⁻E (1⁻5), two new methyl glucuronide derivatives that proved to be artifacts, oxychiliotriterpenoside E-glucuronic acid methyl ester (6) and myrioside B-glucuronic acid methyl ester (7), and a known one, myrioside B (8), was isolated from the aerial part of Oxytropis chiliophylla Royle. Their structures were elucidated based on extensive spectroscopic analyses and chemical methods. Triterpene glycosides were first obtained from O. chiliophylla, and those containing a galactose unit (1, 2, 5 and 6) and diglucosidic or triglucosidic linkage at C-29 (1⁻4), were reported from Oxytropis species for the first time, which might be recognized as a chemotaxonomic feature of O. chiliophylla. All isolated compounds were evaluated for their anti-inflammatory activities against NO production using lipopolysaccharide (LPS)-induced RAW 264.7 cells, but no compounds showed potent inhibition on NO production.

Phylogenetic study of the endemic species Oxytropis almaatensis (Fabaceae) based on nuclear ribosomal DNA ITS sequences.

BACKGROUND: Oxytropis almaatensis Bajt. is a rare, narrow endemic species of the Trans-Ili Alatau mountains in Kazakhstan. Up to now, no studies regarding the taxonomy and variation of key morphological traits of O. almaatensis were undertaken. The purpose of this analysis was to evaluate phenotypic variation of O. almaatensis and assess the position of the species within the genus based on nucleotide sequences of the nuclear ribosomal DNA internal transcribed spacer (ITS) region. RESULTS: Two populations of O. almaatensis were collected in neighboring gorges of the Trans-Ili Alatau Mountains. The ITS sequences from the samples of two populations of O. almaatensis were identical. The phylogenetic analysis indicated that O. almaatensis is within Oxytropis genetically close to O. glabra as these species formed a separate subclade. The phenotypic variation of populations was assessed using nine morphological traits and compared to descriptions of O. glabra. The range of variation for the traits between two populations was established. A clear morphological difference of O. almaatensis and O. glabra was found in peduncle length to leaf length ratio. This was in O. almaatensis 1.56, while in O. glabra, it was 1.0. CONCLUSIONS: The study provides the first phenotypic description and phylogenetic placement of the rare endemic species O. almaatensis. The morphological traits in two O. almaatensis populations showed a high level of phenotypic variability. Although clearly different from O. glabra, the ITS phylogeny grouped these species in a subclade within the genus.

Efficient separation of high-purity compounds from Oxytropis falcata using two-dimensional preparative chromatography.

The separation of high-purity compounds from traditional Tibetan medicines plays an important role in investigating their bioactivity. Nevertheless, it is often quite difficult to isolate compounds with high purity because of the complexity of traditional Tibetan medicines. In this work, an offline two-dimensional reversed-phase preparative method was successfully developed for the separation of high-purity compounds from Oxytropis falcata. Based on the analysis results, an ODS C18 prep column was used for first-dimensional preparation, and 14.8 g of the crude sample was separated into five fractions with a recovery of 74.6%. Then, an XAqua C18 prep column was used to isolate high-purity compounds in the second-dimensional preparation because its separation selectivity is different with the ODS C18 stationary phase. As a result, eight compounds in the crude sample were isolated in more than 98% purity. This is the first report of trans-cinnamic acid (1) and trifolirhizin (2) from Oxytropis falcata. This method has the potential to be an efficient separation method of high-purity compounds from Oxytropis falcata and it shows great promise for the separation of high-purity compounds from complex samples.

A Screen for Swainsonine in Select North American Astragalus Species.

Swainsonine is found in several plant species worldwide, and causes severe toxicosis in livestock grazing these plants, leading to a chronic condition characterized by weight loss, altered behavior, depression, decreased libido, infertility, and death. Swainsonine has been detected in 13 North American Astragalus species of which eight belong to taxa in four taxonomic sections, the Densifolii, Diphysi, Inflati, and Trichopodi. These sections belong to two larger groups representing several morphologically related species, the Pacific Piptolobi and the small-flowered Piptolobi. The objective of this study was to screen the other 31 species for swainsonine in sections Densifolii, Diphysi, Inflati, and Trichopodi previously not known to contain swainsonine. Furthermore, to broaden the scope further, 21 species within the 8 sections of the Pacific Piptolobi and the small flowered Piptolobi were screened for swainsonine. Swainsonine was detected for the first time in 36 Astragalus taxa representing 29 species using liquid and gas chromatography coupled with mass spectrometry. Several taxonomic sections were highly enriched in species that contain swainsonine while others were not. A systematic examination for swainsonine in these species will provide important information on the toxic risk of these species and may be a valuable reference for diagnosticians and land managers.