Astragalus Plants Research Articles

Diversity and Anti-Infectious Components of Cultivable Rhizosphere Fungi Derived from Three Species of Astragalus Plants in Northwestern Yunnan, China

Diversity and Anti-Infectious Components of Cultivable Rhizosphere Fungi Derived from Three Species of Astragalus Plants in Northwestern Yunnan, China

Progress on metabolites of Astragalus medicinal plants and a new factor affecting their formation: Biotransformation of endophytic fungi.

It is generally believed that the main influencing factors of plant metabolism are genetic and environmental factors. However, the transformation and catalysis of metabolic intermediates by endophytic fungi have become a new factor and resource attracting attention in recent years. There are over 2000 precious plant species in the Astragalus genus. In the past decade, at least 303 high-value metabolites have been isolated from the Astragalus medicinal plants, including 124 saponins, 150 flavonoids, two alkaloids, six sterols, and over 20 other types of compounds. These medicinal plants contain abundant endophytic fungi with unique functions, and nearly 600 endophytic fungi with known identity have been detected, but only about 35 strains belonging to 13 genera have been isolated. Among them, at least four strains affiliated to Penicillium roseopurpureum, Alternaria eureka, Neosartorya hiratsukae, and Camarosporium laburnicola have demonstrated the ability to biotransform four saponin compounds from the Astragalus genus, resulting in the production of 66 new compounds, which have significantly enhanced our understanding of the formation of metabolites in plants of the Astragalus genus. They provide a scientific basis for improving the cultivation quality of Astragalus plants through the modification of dominant fungal endophytes or reshaping the endophytic fungal community. Additionally, they open up new avenues for the discovery of specialized, green, efficient, and sustainable biotransformation pathways for complex pharmaceutical intermediates.

Analysis of Microbial Diversity and Community Structure of Rhizosphere Soil of Three Astragalus Species Grown in Special High-Cold Environment of Northwestern Yunnan, China.

Astragalus is a medicinal plant with obvious rhizosphere effects. At present, there are many Astragalus plants with high application value but low recognition and resource reserves in the northwestern area of Yunnan province, China. In this study, metagenomics was used to analyze the microbial diversity and community structure of rhizosphere soil of A. forrestii, A. acaulis, and A. ernestii plants grown in a special high-cold environment of northwestern Yunnan, China, at different altitudes ranging from 3225 to 4353 m. These microbes were taxonomically annotated to obtain 24 phyla and 501 genera for A. forrestii, 30 phyla and 504 genera for A. acaulis, as well as 39 phyla and 533 genera for A. ernestii. Overall, the dominant bacterial phyla included Proteobacteria, Actinobacteria, and Acidobacteria, while the dominant fungal ones were Ascomycota and Basidiomycota. At the genus level, Bradyrhizobium, Afipia, and Paraburkholderia were the most prevalent bacteria, and Hyaloscypha, Pseudogymnoascus, and Russula were the dominant fungal genera. Some of them are considered biocontrol microbes that could sustain the growth and health of host Astragalus plants. Redundancy analysis revealed that pH, TN, and SOM had a significant impact on the microbial community structures (p < 0.05). Finally, triterpene, flavonoid, polysaccharide, and amino acid metabolisms accounted for a high proportion of the enriched KEGG pathways, which possibly contributed to the synthesis of bioactive constituents in the Astragalus plants.

FEATURES OF IN VITRO CULTIVATION OF ASTRAGALUS DASYANTHUS PALL PLANTS

The research is devoted to the study of the peculiarities of in vitro cultivation of the medicinal plant Astragalus dasyanthus Pall, which is listed in the Red Book of Ukraine and has the status of an endangered species. The cultivation of woolly-flowered astragalus in Ukraine is currently difficult due to the inaccessibility of the raw material base in the temporarily occupied southern part of Ukraine, as well as due to the low seed productivity of the crop. The use of in vitro plant tissue cultivation methods to restore natural communities of A. dasyanthus and expand possible sources of raw materials for the synthesis of medicinal substances is promising. In this work, we investigated the conditions for obtaining aseptic Astragalus dasyanthus plants from seeds and evaluated the effect of preliminary mechanical scarification on its germination energy, taking into account the percentage of sterile seedlings obtained. In addition, the efficiency of microclonal propagation of A. dasyanthus was determined depending on the composition of the culture medium, in particular the concentration of macronutrients and the presence and concentration of growth regulators. It has been shown that aseptic plants of Astragalus dasyanthus can be obtained by surface sterilization of seeds that have been previously subjected to mechanical scarification or by germination on Murashige and Skoog nutrient medium with the addition of 0.1 mg/l benzylaminopurine. It was determined that the type and concentration of cytokinin affects the efficiency of microclonal propagation of A. dasyanthus plants, while halving the content of macronutrients in the nutrient medium does not significantly affect this item. It was found that the addition of benzylaminopurine to the culture medium stimulates the formation of more additional shoots of A. dasyanthus in vitro compared to the culture medium containing kinetin. Thus, Murashige and Skoog medium with the addition of 0.5 mg/l of benzylaminopurine is optimal for in vitro cultivation of woolly-flowered Astragalus plants.

Coleopteran Pests Infesting Astragalus Plants on Karacadağ Mountain with a New Species for the Turkish Fauna

Coleopteran Pests Infesting Astragalus Plants on Karacadağ Mountain with a New Species for the Turkish Fauna

Functional characterization of a cycloartenol synthase and four glycosyltransferases in the biosynthesis of cycloastragenol-type astragalosides from Astragalus membranaceus.

Astragalosides are the main active constituents of traditional Chinese medicine Huang-Qi, of which cycloastragenol-type glycosides are the most typical and major bioactive compounds. This kind of compounds exhibit various biological functions including cardiovascular protective, neuroprotective, etc. Owing to the limitations of natural sources and the difficulties encountered in chemical synthesis, re-engineering of biosynthetic machinery will offer an alternative and promising approach to producing astragalosides. However, the biosynthetic pathway for astragalosides remains elusive due to their complex structures and numerous reaction types and steps. Herein, guided by transcriptome and phylogenetic analyses, a cycloartenol synthase and four glycosyltransferases catalyzing the committed steps in the biosynthesis of such bioactive astragalosides were functionally characterized from Astragalus membranaceus. AmCAS1, the first reported cycloartenol synthase from Astragalus genus, is capable of catalyzing the formation of cycloartenol; AmUGT15, AmUGT14, AmUGT13, and AmUGT7 are four glycosyltransferases biochemically characterized to catalyze 3-O-xylosylation, 3-O-glucosylation, 25-O-glucosylation/O-xylosylation and 2'-O-glucosylation of cycloastragenol glycosides, respectively. These findings not only clarified the crucial enzymes for the biosynthesis and the molecular basis for the structural diversity of astragalosides in Astragalus plants, also paved the way for further completely deciphering the biosynthetic pathway and constructing an artificial pathway for their efficient production.

The effect of temperature regimes on laboratory germination rates and germination energy of &lt;i&gt;Astragalus&lt;/i&gt; L.

Background. The temperature regime has a significant effect on the enzymatic activity of seeds. Optimum temperatures trigger physical and chemical reactions in the seed and initiate its germination. The optimum temperature depends on the environmental and geographical conditions in the area of a taxon’s origin and is determined experimentally.Materials and methods. The target material of the study were seeds of three Astragalus L. species (A. cicer L., A. onobrychis L., and A. sulcatus L.) collected from young generative plants introduced in the dry-steppe zone of Kulunda. The effect of temperature conditions (+4…+8°C, +10…+20°C, +20…+32°C) and species-specific attribution of Astragalus plants on laboratory seed germination percentage and energy was studied using the two-factor analysis of variance. The assessment of laboratory seed germination was carried out according to the guidelines by M. M. Ishmuratova and K. G. Tkachenko.Results. The analysis of variance showed a significant effect of the temperature regime (51–54%) and species specificity (23–24%) on the germination percentage rate and germination energy of Astragalus seeds. The seeds of A. onobrychis germinated under a wide range of positive temperatures (from +4…+8°C to +20…+32°C). The temperature range of +10…+20°C was optimal for A. onobrychis and A. sulcatus, with 100% germination. The optimum temperature that determined the maximum laboratory germination of A. cicer seeds was in the range of +20…+32°C. Low positive temperatures (+4…+8°C) were not effective for germination of A. cicer seeds.Conclusion. The optimum temperature conditions for germination of Astragalus seeds were identified: +10…+20°C for A. onobrychis and A. sulcatus, and +20…+32°C for A. cicer.

Billaea adelpha (Loew, 1873) (Diptera: Tachinidae), a New Parasitoid of Xylotrechus sieversi baiocchii Rapuzzi Sama, 2018 (Coleoptera: Cerambycidae) from Turkey

A new dipteran larval parasitoid of longhorn beetles (Coleoptera: Cerambycidae), Billaea adelpha (Loew) (Diptera: Tachinidae) was reared from Xylotrechus sieversi baiocchii Rapuzzi &amp; Sama, 2018 on Astragalus plants in Karacağ Mountain of Diyarbakč±r, Turkey. X. sieversi baiocchii was recorded for the first time as host of this parasitoid. Some information on the host-parasitoid couple is given.

Biosystematic Study on Some Egyptian Species of Astragalus L. (Fabaceae)

Astragalus L. is one of the largest angiosperm complex genera that belongs to the family Fabaceae, subfamily Papilionoideae or Faboideae under the subtribe Astragalinae of the tribe Galegeae. The current study includes the whole plant morphology, DNA barcode (ITS2), and molecular marker (SCoT). Ten taxa representing four species of Astragalus were collected from different localities in Egypt during the period from February 2018 to May 2019. Morphologically, identification and classification of collected Astragalus plants occurred by utilizing the light microscope, regarding the taxonomic revisions of the reference collected Astragalus specimens in other Egyptian Herbaria. For molecular validation, ten SCoT primers were used in this study, producing a unique banding pattern to differentiate between ten samples of Astragalus taxa which generated 212 DNA fragments with an average of 12.2 bands per 10 Astragalus samples, with 8 to 37 fragments per primer. The 212 fragments amplified were distributed as 2 monomorphic bands, 27 polymorphic without unique bands, 183 unique bands (210 Polymorphic with unique bands), and ITS2 gene sequence was showed as the optimal barcode for identifying Astragalus L. using BLAST searched on NCBI database, and afterward, analyzing the chromatogram for ITS region, 10 samples have been identified as two samples representing A. hauarensis, four samples representing A. sieberi, three samples representing A. spinosus and one sample representing A. vogelii. Based on the ITS barcode, A. hauarensis RMG1, A. hauarensis RMG2, A. sieberi RMG1, A. sieberi RMG2, A. sieberi RMG3, A. sieberi RMG4, A. spinosus RMG1, A. spinosus RMG2, A. spinosus RMG3, A. vogelii RMG were deposited into GenBank with accession # MT367587.1, MT367591.1, MT367593.1, MT367585.1, MT367586.1, MT367588.1, MT160347.1, MT367590.1, MT367589.1, MT367592.1, respectively. These results indicated the efficiency of SCoT markers and ITS2 region in identifying and determining genetic relationships between Astragalus species.

Phylogenetic diversity of bacterial strains from root nodules of legumes grown wild in Egypt

Abstract A total of 38 bacterial strains were isolated from root nodules of Lotus, Vicia, Trifolium, Lathyrus, Astragalus, and Hippocrepis plants grown-wild at different geographical locations in Egypt. Analysis of the almost complete sequence of the 16S rRNA gene from the bacterial strains showed that seventeen of them isolated from all the six plant species were members of the genus Rhizobium, six from Lotus, Vicia and Hippocrepis were Ensifer, and the remaining six strains from Lotus and Vicia were Neorhizobium. Sequencing of the symbiotic nodC gene from eight selected rhizobial strains confirmed their affiliation with rhizobial species. These results suggest the existence of high rhizobial diversity in wild-grown Egyptian legumes. Nodules from Lotus, Trifolium, and Astragalus also contained bacterial species of the genera Achromobacter, Ancylobacter, Bacillus, Cronobacter, Curtobacterium, Flavobacterium, Paenibacillus and Pseudomonas. These results provide information about the diversity of rhizobia associated with wild-grown legumes in Egypt, and enlarged the rhizobial spectrum of Lotus, Vicia, Trifolium, Lathyrus, Hippocrepis and Astragalus, which supported to the idea that rhizobial promiscuity could be an adaption strategy to diverse environments.

Two new 8-isopentenyl isoflavane derivatives from Astragalus dolichochaete diels

Astragali Radix (Huangqi) is one of the well-known traditional Chinese medicines and has been used in China for more than two thousand years. As a close species, Astragalus dolichochaete Diels was found to possess cytotoxicity during our preliminary study of Astragalus plants from Yunnan Province, China. To better understand the chemical foundation of the cytotoxicity, the major constituents of A. dolichochaete were studied. As a result, two new 8-isopentenyl isoflavane derivatives, dolichochaeteins A and B (1 and 2), together with ten known constituents were isolated, and their structures were elucidated by means of spectroscopy, mainly 1D and 2D NMR techniques. The cytotoxic activities were evaluated for the raw extract, ethyl acetate fraction, compound 2 and glyasperin H (3) against human gastric carcinoma cell line SGC-7901, human hepatoma cell line SMMC-7721 and human leukemic cell line K562. All the samples exhibited significant cytotoxicity.

The Effect of Astragaloside IV on Isoproterenol-Induced Myocardial Infarction in Rats

Background: Astragaloside IV (AST) is a saponin from the roots of Astragalus plants which has been widely used in traditional medicine to treat cardiovascular diseases. However, the effect of AST on myocardial infarction remains unknown. Thus, we aimed to investigate the cardio protective effects of AST on isoproterenol-induced myocardial infarction in rats. Methods: AST was isolated from the roots of Astragalus caspicus. Male Wistar rats were assigned to 5 groups of control, isoproterenol, and treatment with 2.5, 5 and 10 mg/kg AST given orally immediately before MI induction. Subcutaneous injection of isoproterenol (100 mg/kg) for two consecutive days was used to induce myocardial infarction. AST was given orally once daily for 4 days. On the fifth day hemodynamic and electrocardiographic parameters were assessed, and serum and tissue samples were used to evaluate histological and biochemical changes. To more assessment of the effects of AST on myocardium, we also used three doses of 0.1, 1 and 2 µM of AST in isolated heart model. In statistical analysis with one-way-ANOVA test, any differences between groups were considered significant at p&lt;0.05. Results: Isoproterenol injection caused ECG abnormality, hemodynamic depression and myocardium damage. While AST administration increased mean arterial blood pressure and heart rate and improved the left ventricular contractility. The peripheral neutrophil count, cardiac enlargement and cardiac ischemia was significantly decreased by AST. Also, histopathological evaluations showed that AST significantly diminished post MI necrosis and fibrosis in heart tissue and inhibited the inflammatory responses. The isolated heart studies hemodynamic factors showed no significant changes. Conclusion: Results showed that AST can protect heart against myocardial infarction by improving cardiac histology and ventricular contractility. Due to the lack of protection in the isolated heart, it is likely that the positive effects are more associated with the improvement of the oxidative stress markers in the systemic circulation, and the absolute effect on the isolated heart does not play an essential role in myocardium protection.

Evaluation of Phytochemical, Antioxidant and Antibacterial Activity on Astragalus Chrysostachys Boiss. Roots.

Astragalus is a well-known genus in Leguminosae family that represented more than 800 species growing in Iran. Nevertheless, there are a few reports on Astragalus plants endemic to Iran. The roots of Astragalus plants are rich in saponins, flavonoids and polysaccharides that possess various pharmacological activities. In the present study, chemical components, antioxidant and antibacterial activity of Astragalus chrysostachys Boiss. roots were evaluated. For determination of phytochemicals in Astragalus chrysostachys Boiss. roots, total hydroalcoholic extract was fractionated with ethyl acetate and n-butanol. Ethyl acetate extract as a flavonoid rich extract was analyzed using vacuum liquid chromatography and preparative TLC and consequently a major flavonoid was isolated. The structure of the obtained compound was elucidated with 1D and 2D NMR experiments. Additionally, the essential oil of the roots was analyzed by GC-MS. Antioxidant activity of all extracts was evaluated by different assays. Moreover, antibacterial activities of the extracts were also investigated against 2 Gram-positive and 2 Gram-negative bacteria using Micro-dilution Broth method. Apigenin-6, 8-di-C-glucoside was detected in ethyl acetate extract for the first time in genus Astragalus. In addition, m-tolualdehyde, acetophenone, croweacin were found to be characteristics of the volatile oil of roots. Ethyl acetate extracts revealed notable antioxidant activity in DPPH scavenging assay with IC50 value of 14.6 µg/mL. Evaluation of antibacterial activity on the tested extracts showed mild activity against Gram-positive bacteria. Since there have been no reports on Astragalus chrysostachys Boiss. to date, the present data might be promising for application of this plant derivatives in phytotherapeutic practice.

The Different Resistance of Two Astragalus Plants to UV-B Stress is Tightly Associated with the Organ-specific Isoflavone Metabolism.

In this work, the changes in isoflavone levels and the expression of genes involved in their biosynthesis were studied in two Astragalus by UPLC-MS and real-time PCR after 10days of UV-B treatment (λmax =313nm, 804Jm-2 ). Isoflavones were significantly induced by UV-B irradiation. The influence might be activated by the regulation of these target genes. Our results indicate that (1) the resistance of Astragalus membranaceus might not be as good as Astragalus mongholicus in the enhanced UV-B radiation environment; (2) the enhanced accumulation of calycosin and calycosin-7-glucoside with UV-B treatment in roots of A.mongholicus might be derived from formononetin which is synthesized in the leaves; (3) the glycosylation process could be stimulated and activated by the enhanced UV-B radiation in both A.mongholicus and A.membranaceus. In other words, glycosylation of isoflavones might play a crucial role for two Astragalus plants in response to UV-B stress. Overall, this study offered a feasible elicitation strategy to understand the accumulation pattern of isoflavone in A.mongholicus and A.membranaceus, and also provided a reference for the changes in isoflavone levels of Astragalus in UV-B enhanced environment in the future.

Pursue the truth, devote to education: Chen Hua-Kui, a respectable educator and pioneer of China's soil microbiology.

Pursue the truth, devote to education: Chen Hua-Kui, a respectable educator and pioneer of China's soil microbiology.

Allelochemicals from the Rhizosphere Soil of Cultivated Astragalus hoantchy.

Astragalus hoantchy, a widely cultivated medicinal plant species in traditional Chinese and Mongolian medicine, has been often hampered by replant failure during cultivation, like many other herbs of the genus Astragalus. Root aqueous extracts of Astragalus herbs were reported to exhibit allelopathic activity against other plants and autotoxic activity on their own seedlings, but the allelochemicals released by Astragalus plants have not been specified so far. Ten compounds were isolated from the rhizosphere soil extract of cultivated A. hoantchy and elucidated by spectroscopic analysis. Compounds 1-6 observably showed allelopathic activity against Lactuca sativa seedlings and autotoxic activity against A. hoantchy seedlings. The isolated compounds were further confirmed and quantified by high-performance liquid chromatography (HPLC) in the rhizosphere soil, with a total concentration of 9.78 μg/g (dry weight). These results specify and verify the allelochemicals released by cultivated A. hoantchy into the soil environment, which may provide new insights into the allelopathic mechanisms of this medicinal plant and probably assist in clarifying the replant problems of Astragalus plants.

Advances in phytochemistry, pharmacology and biotechnology of Bulgarian Astragalus species

The genus Astragalus L., Fabaceae (Leguminosae) is presented in Bulgarian flora by 31 species including local endemics, nine of them listed in the Red Data Book. The main biologically active compounds found in the Bulgarian Astragalus plants are saponins and flavonoids with a variety of effects: immunomodulatory, hepatoprotective, cytotoxic, antioxidant, antihypoxic and others. In the recent years volatiles with cytotoxic activity have also been determined. Saponins and flavonoids are still preferably produced by plants due to their complex structures. Variable quantities and qualities of the wild plant material, plants that need to grow several years before they are ready for harvesting and over-collecting of endangered Astragalus species are just a few of the problems connected with the production of these natural products. Therefore, cultured cells are possible alternative for production of high-value secondary metabolites. This review is focused on phytochemical, pharmacological and biotechnological studies of Bulgarian Astragalus plants and includes also results from our investigations.

Roles of rhizobial symbionts in selenium hyperaccumulation in Astragalus (Fabaceae).

Are there dimensions of symbiotic root interactions that are overlooked because plant mineral nutrition is the foundation and, perhaps too often, the sole explanation through which we view these relationships? In this paper we investigate how the root nodule symbiosis in selenium (Se) hyperaccumulator and nonaccumulator Astragalus species influences plant selenium (Se) accumulation. In greenhouse studies, Se was added to nodulated and nonnodulated hyperaccumulator and nonaccumulator Astragalus plants, followed by investigation of nitrogen (N)-Se relationships. Selenium speciation was also investigated, using x-ray microprobe analysis and liquid chromatography-mass spectrometry (LC-MS). Nodulation enhanced biomass production and Se to S ratio in both hyperaccumulator and nonaccumulator plants. The hyperaccumulator contained more Se when nodulated, while the nonaccumulator contained less S when nodulated. Shoot [Se] was positively correlated with shoot N in Se-hyperaccumulator species, but not in nonhyperaccumulator species. The x-ray microprobe analysis showed that hyperaccumulators contain significantly higher amounts of organic Se than nonhyperaccumulators. LC-MS of A. bisulcatus leaves revealed that nodulated plants contained more γ-glutamyl-methylselenocysteine (γ-Glu-MeSeCys) than nonnodulated plants, while MeSeCys levels were similar. Root nodule mutualism positively affects Se hyperaccumulation in Astragalus. The microbial N supply particularly appears to contribute glutamate for the formation of γ-Glu-MeSeCys. Our results provide insight into the significance of symbiotic interactions in plant adaptation to edaphic conditions. Specifically, our findings illustrate that the importance of these relationships are not limited to alleviating macronutrient deficiencies.

Prolonged dormancy interacts with senescence for two perennial herbs

Summary Senescence is characterized by a decline in survival, fecundity and reproductive value with age among adult individuals. Simple age‐dependent life cycles progress forward through developmental stages, with each successive stage being characterized by age‐specific vital rates. In contrast, size‐ or stage‐based life cycles for perennial plants are more complex and often include stasis and retrogression to previous vegetative or reproductive life stages, indicating possible slowing or even reversing the developmental progress. Many plants remain in nonemergent, below‐ground stages during the growing season (prolonged dormancy), which may affect the process of senescence. Stasis in the dormant stage implies that senescence is interrupted while plants are below‐ground. We explored the underlying assumptions of size‐ or stage‐based life cycle graphs and developed four different demographic models for how prolonged dormancy may mediate the relationship between age and vital rates. We then tested these models using more than 20 years of demographic data on 2 perennial herbs, Astragalus scaphoides and Silene spaldingii. Results from model fitting suggest that prolonged dormancy interacts with the age dependence of vital rates. The model using true biological age (time since germination) of emergent and dormant plants to estimate vital rates was never the best model for our data. For both species, the model assuming that dormancy resets plants to the same postdormant state experienced earlier in life independent of their predormant age resulted in the best fit, though not for every vital rate. Older Astragalus plants had declining annual survival probabilities and reproductive value, suggesting senescence. Silene showed the opposite pattern for reproductive value that increased with age, indicating negative senescence. Synthesis. Using long‐term demographic data from two perennial herbs, this study shows mixed evidence for senescence in perennial plants. Our results indicate that prolonged dormancy interacts with the age dependence of vital rates and may sometimes retard the process of senescence.

재배 황기의 Phenolic Compounds 함량의 변이

This study was conducted to determine the contents of phenolic compounds and astragalosides in Astragalus membranaceus. Between the phenolic compound groups, flavonoids compounds (51.13%) had higher average concentra- tions than the phenolic acids groups. Among the 30 phenolic compounds, quercetin (353.11 ㎍ g -1 ) provided the highest con- centrations. According to different cultivation year, 3-year-cultivated Astragalus (2612.57 ㎍ g -1 ) showed the highest concentrations of phenolic compounds. According to different harvest days, 6/5 harvesting Astragalus (2615.80 ㎍ g -1 ) showed the highest concentrations of phenolic acids. Comparison between the top and subterranean parts of harvested Astragalus plants cultivated for 2 years, 3 years, and 5 years showed big difference of total phenolic compounds in concen- trations. Further, the top part had higher amounts of the total phenolic compounds than the subterranean part among all Astragalus. This tendency was similar to those of the top root and lateral root. The concentration of the phenolic compounds in the top root was higher than that of the lateral root.