Identification of azukisapogenol triterpenoid saponins from Oxytropis hirta Bunge and their aphicidal activities against pea aphid Acyrthosiphon pisum Harris.

BACKGROUND: Acyrthosiphon pisum Harris is the most destructive pest worldwide because of its ability to feed on plants directly and transmit plant viruses as a vector. This study aims to identify triterpenoid saponins from Oxytropis hirta Bunge as biopesticides to control aphids. RESULTS: Three new azukisapogenol triterpenoid saponins (1-3), a new pinoresinol lignan glycoside (8), and four known saponins (4-7) were identified from the root of O. hirta. Compounds 4-7 displayed significant aphicidal activities against A. pisum with oral toxicities (LC50  = 51.10-147.43 µg/mL, 72 h), deterrent effects (deterrence index = 1.00, 100-200 µg/mL, 24 h), and aphid reproduction inhibitory effects (inhibition rates = 75.91-86.73%, 400 µg/mL, 24 h), respectively. The carboxyl groups at C-3 GlcA and C-30 were functional groups for their aphicidal activities. The toxic symptoms caused by the optimal 5 involved insect body-color changes from light green to dark or gray-green, and then brown until death. The intestinal cavity, apical microvilli, nuclei, mitochondria, and electron dense granules in the midgut tissues of A. pisum were the target sites showing aphicidal activity. The suppression of pepsin and α-amylase, and the activation of lipase and trypsin could be the signs of organelle damage in the midgut tissues. CONCLUSION: Azukisapogenol triterpenoid saponins from O. hirta could be used as biopesticides to control aphids for their multiple efficacies, including oral toxicity, deterrent activity, and reproduction inhibitory activity. The toxic symptoms involved insect body-color changes. Midgut tissues and their related enzymes were the targets for saponins showing aphicidal activities. © 2022 Society of Chemical Industry.

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.

Quercetin promotes cutaneous wound healing in mice through Wnt/ß-catenin signaling pathway.

ETHNOPHARMACOLOGICAL RELEVANCE: Oxytropis falcata Bunge is a legume distributed in Northwest China, which is mainly used to treat knife wounds and inflammation. Quercetin is a bioactive flavonoid in O. falcata and becomes a promising healing compound for its angiogenic and anti-inflammatory activities. However, the healing mechanism of quercetin in cutaneous wound remains elusive. AIM OF THE STUDY: The purpose of this study was to evaluate the healing effect of quercetin on cutaneous wound models in vivo and in vitro, and to reveal the Wnt/ß-catenin pathway and Telomerase reverse transcriptase (TERT) involved mechanisms. MATERIALS AND METHODS: The effects of quercetin on the proliferation and migration of 4 kinds of skin cells were determined by CCK-8 and scratch assay. The wound-healing capacity of quercetin was evaluated in cutaneous wound model of C57BL/6 mice and the wound healing degree was observed by histological staining. The expressions of inflammatory factors, growth factors and the related proteins were detected via Western blot and RT-qPCR analyses. The molecular docking was adopted to evaluate the binding ability of quercetin and TERT. RESULTS: Quercetin could promote both proliferation and migration of fibroblasts, and enhance cutaneous wound healing capacity in mice. Compared to the control group, the wound healing rates in low (1.5 mg/mL), medium (3.0 mg/mL) and high dose (6.0 mg/mL) quercetin groups reached 94.67%, 97.31% and 98.42%, respectively. Moreover, the dermal structure in quercetin treated mice restored normal and the content of collagen fiber became abundant after administration. The levels of inflammatory factors, including tumor necrosis factor-α, interleukin-1ß and interleukin-6 were significantly reduced after quercetin administration. Among which, the level of IL-1ß in cutaneous wound was 0.007 times higher than that of the control group when treated with quercetin of high dose (6.0 mg/mL). The improved level of GSH in quercetin treated cutaneous wounds also indicated its higher antioxidant ability. In addition, dose-dependent positive associations were found in the expression levels of vascular endothelial growth factor, fibroblast growth factor and alpha smooth muscle actin in quercetin treated cutaneous wounds. The significantly upregulated protein levels of Wnt and ß-catenin further indicated the important role of quercetin in promoting wound healing in mice. According to molecular docking analysis, the formed hydrogen bonds between quercetin and Ala195, Gln308, Asn369 and Lys372 residues of TERT also indicated the indispensable role of TERT in improving wound healing capacity. CONCLUSION: Quercetin effectively promoted cutaneous wound healing by enhancing the proliferation and migration of fibroblasts, as well as inhibiting inflammation and increasing the expression of growth factors in mice via Wnt/ß-catenin signaling pathway and TERT. It provides a basis for a more thorough understanding of mechanism of action of O. falcata Bunge in the treatment of knife wounds and burns.

Total flavonoids of Oxytropis falcata Bunge have a positive effect on idiopathic pulmonary fibrosis by inhibiting the TGF-ß1/Smad signaling pathway.

ETHNOPHARMACOLOGICAL RELEVANCE: Idiopathic pulmonary fibrosis (IPF) is an interstitial lung disease with unknown etiology. Oxytropis falcata Bunge (O. falcata) is a 1-35 cm high perennial clustered herb, also known as edaxia, has viscosity and a special smell, and is mainly distributed in the western areas of China. The root of O. falcata has a diameter of 6 mm, is straight and deep, dark red and its stems are shortened, woody and multibranched. O. falcata has heat-clearing, detoxification, analgesic, anti-inflammatory, antibacterial, hemostatic and antitumor activities. Furthermore, O. falcata has excellent anti-inflammatory and analgesic effects, and it is one of the three major anti-inflammatory drugs in Tibetan medicine, known as "the king of herbs". Total flavonoids of Oxytropis falcata Bunge (FOFB) were previously extracted, and their pharmacological activities are consistent with those of the whole herb. In this study, FOFB was extracted from O. falcata by ethanol extraction, and the mechanism of FOFB on IPF was verified by in vivo and in vitro experiments. AIM OF THE STUDY: In this study, we aimed to observe the effects of FOFB on idiopathic pulmonary fibrosis. MATERIALS AND METHODS: In in vivo experiments, an IPF rat model was established by bleomycin induction. The rats were treated with FOFB (100, 200, 400 mg kg-1·d-1) for 4 weeks. Masson staining and the expression of TGF-ß, p-Smad2, p-Smad3 and Smad7 in the lung tissue of rats were detected. In in vitro experiments, we perfused normal rats with FOFB (100, 200, 400 mg kg-1·d-1) and obtained the corresponding drug-containing serum. The HFL-1 cell model induced by TGF-ß1 was used to detect the corresponding indices through intervention with drug-containing serum. The best intervention time for drug-containing serum was detected by the CCK-8 method. Changes in apoptosis, cytoskeleton and rough endoplasmic reticulum structure were detected. Finally, the expression of TGF-ß, p-Smad2, p-Smad3 and Smad7 in cells was examined. RESULTS: In vivo, Masson staining indicated that the degree of pulmonary fibrosis increased significantly, the expression of TGF-ß, p-smad2 and p-Smad3 increased significantly, and the expression of Smad7 decreased in the model group. We found that the degree of pulmonary fibrosis gradually decreased and that the inhibition of the TGF-ß/Smad signaling pathway became more obvious with increasing FOFB dose. FOFB (400 mg kg-1·d-1) significantly improved the degree of pulmonary fibrosis in rats. In in vitro experiments, the CCK-8 results showed that 120 h was the best intervention time for drug-containing serum. In the model group, there was no obvious apoptosis or changes in microfilaments and microtubules, the number of rough endoplasmic reticulum increased, and the expression of TGF-ß, p-Smad2 and p-Smad3 increased significantly, while the expression of Smad7 decreased significantly. We found that with the increase in drug-containing serum concentration, the apoptosis, cytoskeleton and degree of destruction of the rough endoplasmic reticulum in the HFL-1 cell model also increased, and the inhibition of the TGF-ß/Smad signaling pathway became more pronounced; the effect of the drug-containing serum administered with FOFB (400 mg kg-1·d-1) was the most significant. CONCLUSIONS: The results suggest that FOFB can improve the occurrence and development of IPF. The effect of FOFB on IPF may be mediated by inhibition of the TGF-ß1/Smad signaling pathway.

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.

Hyaluronidase inhibitory saponins and a trypanocidal isoflavonoid from the aerial parts of Oxytropis lanata.

A chemical examination of an extract from the aerial part of Oxytropis lanata led to the isolation and identification of 36 compounds, including saponins, isoflavonoids, oxazoles, and glycosides. The three among them were previously unreported oleanane-type saponins. In trypanocidal screening, 5,7,4'-trihydroxyisoflavone showed inhibitory activity against Trypanosoma congolense (IC50 = 10.5 µM), the causative agent of African trypanosomosis in animals; this activity was similar to that of active compounds from the roots of this plant. O. lanata is known to be a traditional medicinal plant in Mongolia for the treatment of inflammatory diseases. The anti-hyaluronidase effect of saponins 3, 5, 8, and 9, (IC50 = 0.15-0.22 mM) was stronger than that of sodium cromoglicate, which was used as a reference drug (IC50 = 0.37 mM). The chemical structures of the new saponins were determined based on HRFABMS, 1H and 13C NMR, 1H-1H COSY, HMQC, HMBC, and ROESY spectroscopic data along with chemical procedures.

Separation of 3-Hydroxy-3-Methylglutaryl Flavonoid Glycosides from Oxytropis falcata Using 2D Preparative Chromatography.

Oxytropis falcata Bunge, known as "the King of Herbs" in Tibetan medicine, is used for treatment of hyperpyrexia, pain, wounds, inflammation and anthrax. However, it is difficult to isolate compound with high-purity from O. falcata because of its complexity. In this work, an efficient method was successfully established for the separation of 3-hydroxy-3-methylglutaryl (HMG) flavonoid glycosides from O. falcata by 2D preparative chromatography (2D-HPLC). An ODS C18 preparative column was used for the first-dimension preparation, and the XCharge C18 preparative column with different separation selectivity to the ODS C18 stationary phase was used for the second-dimension preparation. Four HMG flavonoid glycosides (oxytroflavosides A-D) and two flavonoid glycosides (oxytroflavosides F and G) were separated with purities over 98%. Their structures were elucidated by nuclear magnetic resonance spectroscopy. The 2D-HPLC method used in this study is effective for preparative separation of HMG flavonoid glycosides from O. falcata. Additionally, this method shows great potential for the separation of flavonoid glycosides from other plant extracts.

Flavonoids as key bioactive components of Oxytropis falcata bunge, a traditional anti-inflammatory and analgesic Tibetan medicine.

The traditional Tibetan medicine Oxytropis falcata Bunge, in the Leguminosae family, is widely used in the west area owing to its significant anti-inflammatory and analgesic activities. O. falcata is rich in flavonoids, which are the main secondary metabolites and key bioactive components of this plant. Up to now, 91 flavonoids have been isolated from O. falcata, including isoflavone, flavone, flavonone, flavonol, homoisoflavonoid, chalcone, dihydrochalcone, chalcone dimers, and pterocarpans. The flavonoids in O. falcata have good anti-inflammatory and analgesic activities, which are comparable to those of a positive drug control (indomethacin). Furthermore, these flavonoids exhibit antibacterial, antioxidant, antitumour, anti-cardiovascular disease, and haemostatic activities. However, to date, O. falcata has not been reviewed comprehensively. Herein, the main secondary metabolites, biosynthetic pathways, and bioactivities of O. falcata are discussed.

Ochrocephalamines B-D, Three Alkaloids from Oxytropis ochrocephala Bunge.

Ochrocephalamines B-D (1-3), composed of fused quinolizidine and octahydroquinoline rings, were isolated from Oxytropis ochrocephala Bunge. Ochrocephalamine B (1) has a unique bridged tetracyclic ring skeleton fused with a lactam ring. The structures of 1-3 were elucidated using spectroscopic and computational approaches. Ochrocephalamine C (2) and D (3) demonstrated potent anti-HBV activities and are more potent against the secretion of HBeAg than that of HBsAg.

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.

Oxyfadichalcone C inhibits melanoma A375 cell proliferation and metastasis via suppressing PI3K/Akt and MAPK/ERK pathways.

AIMS: Melanoma remains to be one of the most incurable cancers. Discovery of novel antitumor agent for melanoma therapy is expected. We recently isolated Oxyfadichalcone C from Oxytropis falcate and investigated the anti-proliferative and anti-metastatic activity on human melanoma A375 cells in vitro. MAIN METHODS: Cell viability was determined using MTT assay and soft agar cloning formation assay. The effect of Oxyfadichalcone C on cell cycle distribution and apoptosis were analyzed by flow cytometry. Cell metastasis was determined by wound healing assay, Transwell assay and Gelatin zymography assay. The effect of Oxyfadichalcone C on signal proteins of PI3K/Akt and MAPK/ERK pathways was examined by western blot analysis. Synergism assay was employed to determine whether combination of Oxyfadichalcone C with Vemurafenib would enhance the anti-proliferative effect. KEY FINDINGS: Oxyfadichalcone C potently inhibited proliferation, induced G1 phase arrest and weak apoptosis in A375 cells. Anti-migration and anti-invasion activities were also indicated. Such effects were associated with upregulation of p27, reduction of cyclin D1, p-pRb, p-Integrin ß1, as well as the proteolytic activity of metalloproteinase (MMP)-2/9. Meanwhile, key molecules of PI3K/Akt and MAPK/ERK pathways were downregulated, which might be involved in the inhibition against proliferation and metastasis of A375 cells by Oxyfadichalcone C. In addition, combination of Oxyfadichalcone C with Vemurafenib at a ratio of IC50 Oxyfadichalcone C: 5 × IC50 Vemurafenib exhibited synergistic anti-proliferative effect on A375 cells. SIGNIFICANCE: Our findings suggest that Oxyfadichalcone C has the potential to be developed as a promising drug candidate for the treatment of melanoma.

Extract of Oxytropis pseudoglandulosa inhibits vascular smooth muscle cell proliferation and migration via suppression of ERK1/2 and Akt signaling pathways1.

Excessive vascular smooth muscle cell (VSMC) proliferation and migration accelerate the development of occlusive vascular disease. Therefore, finding a means to control the aberrant proliferation and migration of VSMCs has own clinical significance. In the present study, we examined the feasibility of using extract from medicinal plant Oxytropis pseudoglandulosa (OG) to control pathologic proliferation and migration of VSMCs, which never have been tested. Our data indicate that the extract of OG significantly suppressed proliferation and migration of VSMCs without cytotoxic effect, suggesting the OG extract may be an alternative agent to effectively control the aberrant VSMC proliferation and migration without any serious adverse effect. These data suggest that the extract of OG may be a potent therapeutic agent for the treatment of occlusive vascular disease and warrant further studies to identify the major acting ingredient and to validate in vivo efficacy.

Structurally Diverse Cytotoxic Dimeric Chalcones from Oxytropis chiliophylla.

Ten isomeric cyclobutane- and cyclohexene-containing chalcone dimers, oxyfadichalcones A-G, were isolated from the aerial parts of Oxytropis chiliophylla. These included six new compounds and three pairs of enantiomers that are being reported from natural sources for the first time. The relative configurations were elucidated by spectroscopic data analysis, while the absolute configurations were determined by comparing the experimental and calculated electronic circular dichroism spectra. Quantitative LC-MS analysis of the main dimers from different parts of the plant revealed their characteristic accumulation in the viscous secretion and provided supporting evidence for the hypothesized photochemical biosynthesis. In addition, the cytotoxic activities of all isolates against the PC-3 human prostate cancer cell line are reported.

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.

Reproductive Toxicities Caused by Swainsonine from Locoweed in Mice.

Swainsonine is the primary toxin in locoweeds. It causes intention tremors, reproductive dysfunction, emaciation, and death. The objective of the present study was to evaluate the potential reproductive and developmental toxicities caused by swainsonine in mice. The treatment groups consisting of three generations of mice were given a range of concentrations of swainsonine by intraperitoneal injection (2.50 mg/kg body weight (BW), 1.20 mg/kg BW, 0.60 mg/kg BW, and 0 mg/kg BW). The 0 mg/kg BW group exhibited significantly fewer estrous cycles and an increased number of estrous ones compared to the 2.50 mg/kg BW, 1.20 mg/kg BW, and 0.60 mg/kg BW groups (P < 0.05). All three generations of mice treated with swainsonine had significantly higher spleen, liver, and kidney indices and significantly lower body weights compared to the 0 mg/kg BW group (P < 0.05). For the first and second generations of treatment group, the copulation indices and the numbers of live pups on postnatal days (PND) 0, 4, and 15 were significantly decreased compared to those of the 0 mg/kg BW group (P < 0.05). The fertility and gestation indices of the treatment group of the first generation were significantly increased compared to the 2.50 mg/kg BW, 1.20 mg/kg BW, and 0.60 mg/kg BW groups of the second generation (P < 0.05). Cumulatively, these results indicate that swainsonine may cause reproductive and developmental toxicities in mice in both parents and offspring.

Trypanocidal Activity of 2,5-Diphenyloxazoles Isolated from the Roots of Oxytropis lanata.

Eleven 2,5-diphenyloxazole derivatives (1-11), together with six known isoflavonoid derivatives, were isolated from the roots of Oxytropis lanata. The 2,5-diphenyloxazole (1) obtained proved to be identical to a standard sample used as a scintillator and liquid laser dye. The other oxazole derivatives isolated were found to have one to four hydroxy and/or O-methyl groups in their phenyl rings. Seven of the oxazole derivatives obtained are new (3-9). The inhibitory activity of the isolated compounds was evaluated against Trypanosoma congolense, the causative agent of African trypanosomosis in animals. Oxazoles with di- and trihydroxy groups showed trypanocidal activity, and 2-(2',3'-dihydroxyphenyl)-5-(2″-hydroxyphenyl)oxazole (4) exhibited the most potent inhibitory activity (IC50 1.0 µM).

Analysis of Swainsonine and Swainsonine N-Oxide as Trimethylsilyl Derivatives by Liquid Chromatography-Mass Spectrometry and Their Relative Occurrence in Plants Toxic to Livestock.

There are limited data concerning the occurrence of swainsonine N-oxide in plants known to contain swainsonine and its relative impact on toxicity of the plant material. A liquid chromatography-mass spectrometry method based on a solvent partitioning extraction procedure followed by trimethylsilylation and analysis using reversed phase high-pressure liquid chromatography-mass spectrometry was developed for the analysis of swainsonine and its N-oxide. The concentrations of each were measured in several swainsonine-containing taxa as well as two endophytic isolates that produce swainsonine. In vegetative samples the relative percent of N-oxide to free base ranged from 0.9 to 18%. In seed samples the N-oxide to free base ratio ranged from 0 to 10%. The measured concentrations of swainsonine N-oxide relative to swainsonine only slightly increases the actual toxicity of the various plant samples in a combined assay of both compounds.

A swainsonine survey of North American Astragalus and Oxytropis taxa implicated as locoweeds.

Swainsonine, an indolizidine alkaloid with significant physiological activity, is an α-mannosidase and mannosidase II inhibitor that causes lysosomal storage disease and alters glycoprotein processing. Swainsonine is found in a number of plant species worldwide, and causes severe toxicosis in livestock grazing these plants, leading to a chronic wasting disease characterized by weight loss, depression, altered behavior, decreased libido, infertility, and death. Swainsonine has been detected in 19 Astragalus and 2 Oxytropis species in North America by thin layer chromatography, gas chromatography-mass spectrometry, liquid chromatography-mass spectrometry and a jack bean α-mannosidase inhibition assay. In addition, 5 species in North America are presumed to contain swainsonine based upon reports from field cases. Many of these plant species have not been analyzed for swainsonine using modern instrumentation such as gas or liquid chromatography coupled with mass spectrometry. To provide clarification, 22 Astragalus species representing 93 taxa and 4 Oxytropis species representing 18 taxa were screened for swainsonine using both liquid chromatography-mass spectrometry and gas chromatography-mass spectrometry. Swainsonine was detected in 48 Astragalus taxa representing 13 species and 5 Oxytropis taxa representing 4 species. Forty of the fifty-three swainsonine-positive taxa had not been determined to contain swainsonine previously using liquid or gas chromatography coupled with mass spectrometry. The list of swainsonine-containing taxa reported here will serve as a reference for risk assessment and diagnostic purposes.

Alkaloids from Oxytropis ochrocephala and antiproliferative activity of sophoridine derivatives against cancer cell lines.

Ten alkaloids (1-10), with sophoridine (1) as the most abundant component, were obtained from the whole plants of Oxytropis ochrocephala Bunge. Furthermore, eight new sophoridine derivatives (11-16, 20, 21), with modification on the C-14 position of 1 were synthesized. All compounds (1-16, 20, 21) were evaluated for antiproliferative activity against five human tumor cell lines. Among them, the newly synthesized derivative 20 exhibited the best inhibitory activity against the tested cell lines. Its activity was increased by more than fourfold as compared with parent compound 1.