Mapping and engineering of auxin-induced plasma membrane dissociation in BRX family proteins.

Angiosperms have evolved the phloem for the long-distance transport of metabolites. The complex process of phloem development involves genes that only occur in vascular plant lineages. For example, in Arabidopsis thaliana, the BREVIS RADIX (BRX) gene is required for continuous root protophloem differentiation, together with PROTEIN KINASE ASSOCIATED WITH BRX (PAX). BRX and its BRX-LIKE (BRXL) homologs are composed of four highly conserved domains including the signature tandem BRX domains that are separated by variable spacers. Nevertheless, BRX family proteins have functionally diverged. For instance, BRXL2 can only partially replace BRX in the root protophloem. This divergence is reflected in physiologically relevant differences in protein behavior, such as auxin-induced plasma membrane dissociation of BRX, which is not observed for BRXL2. Here we dissected the differential functions of BRX family proteins using a set of amino acid substitutions and domain swaps. Our data suggest that the plasma membrane-associated tandem BRX domains are both necessary and sufficient to convey the biological outputs of BRX function and therefore constitute an important regulatory entity. Moreover, PAX target phosphosites in the linker between the two BRX domains mediate the auxin-induced plasma membrane dissociation. Engineering these sites into BRXL2 renders this modified protein auxin-responsive and thereby increases its biological activity in the root protophloem context.

Sustainable control of Microcystis aeruginosa, a harmful cyanobacterium, using Selaginella tamariscina extracts.

Eco-friendly reagents derived from plants represent a promising strategy to mitigate the occurrence of toxic cyanobacterial blooms. The use of an amentoflavone-containing Selaginella tamariscina extract (STE) markedly decreased the number of Microcystis aeruginosa cells, thus demonstrating significant anti-cyanobacterial activity. In particular, the Microcystis-killing fraction obtained from pulverized S. tamariscina using hot-water-based extraction at temperatures of 40 °C induced cell disruption in both axenic and xenic M. aeruginosa. Liquid chromatographic analysis was also conducted to measure the concentration of amentoflavone in the STE, thus supporting the potential M. aeruginosa-specific killing effects of STE. Bacterial community analysis revealed that STE treatment led to a reduction in the relative abundance of Microcystis species while also increasing the 16S rRNA gene copy number in both xenic M. aeruginosa NIBR18 and cyanobacterial bloom samples isolated from a freshwater environment. Subsequent testing on bacteria, cyanobacteria, and algae isolated from freshwater revealed that STE was not toxic for other taxa. Furthermore, ecotoxicology assessment involving Aliivibrio fischeri, Daphnia magna, and Danio rerio found that high STE doses immobilized D. magna but did not impact the other organisms, while there was no change in the water quality. Overall, due to its effective Microcystis-killing capability and low ecotoxicity, aqueous STE represents a promising practical alternative for the management of Microcystis blooms.

A systematic review on antimicrobial activities of green synthesised Selaginella silver nanoparticles.

BACKGROUND: Metallic nanoparticles from different natural sources exhibit superior therapeutic options as compared to the conventional methods. Selaginella species have attracted special attention of researchers worldwide due to the presence of bioactive molecules such as flavonoids, biflavonoids, triterpenes, steroids, saponins, tannins and other secondary metabolites that exhibit antimicrobial, antiplasmodial, anticancer and anti-inflammatory activities. Environment friendly green synthesised silver nanoparticles from Selaginella species provide viable, safe and efficient treatment against different fungal pathogens. OBJECTIVE: This systematic review aims to summarise the literature pertaining to superior antifungal ability of green synthesised silver nanoparticles using plant extracts of Selaginella spp. in comparison to both aqueous and ethanolic raw plant extracts by electronically collecting articles from databases. METHODS: The recommendations of the Preferred Reporting Items for Systematic Reviews and Meta-Analysis were taken into consideration while preparing this review. The titles and abstracts of the collected data were stored in Endnote20 based on the inclusion and exclusion criteria. The search strategy included literature from established sources like PubMed, Google Scholar and Retrieval System Online using subject descriptors. RESULTS: The search yielded 60 articles with unique hits. After removal of duplications, 46 articles were identified, 40 were assessed and only seven articles were chosen and included in this review based on our eligibility criteria. CONCLUSION: The physicochemical and preliminary phytochemical investigations of Selaginella suggest higher drug potency of nanoparticles synthesised from plant extract against different diseases as compared to aqueous and ethanolic plant extracts. The study holds great promise as the synthesis of nanoparticles involves low energy consumption, minimal technology and least toxic effects.

Screening for α-glucosidase inhibitors from Selaginella uncinata based on the ligand fishing combined with ultra-high-performance liquid chromatography-quadrupole time-of-flight-tandem mass spectrometry.

Biflavonoids are naturally occurring compounds consisting of two flavonoid moieties that have received substantial attention from researchers. Although many kinds of biflavonoids are typically distributed in Selaginella uncinata with hypoglycemic effect, their anti-α-glucosidase activities are not yet clear. In this study, a ligand fishing strategy for fast screening of α-glucosidase inhibitors from S. uncinata was proposed. α-Glucosidase was first immobilized on Fe3 O4 magnetic nanoparticles (MNPs) and then the α-glucosidase-functionalized MNPs were incubated with crude extracts of S. uncinata to fish out the ligands. Furthermore, considering the similarity and easy confusion of the structures of biflavonoids, the fragmentation patterns of different types of biflavonoids were studied. Based on this, 11 biflavonoids ligands with α-glucosidase inhibitory activities were accurately and quickly identified from S. uncinata with ultra-high-performance liquid chromatography-quadrupole time-of-flight-tandem mass spectrometry. Furthermore, these ligands were confirmed to be potential inhibitors through the in vitro inhibitory assay and molecular docking.

Three New Selaginellin Derivatives from Selaginella pulvinata and Their α-Glucosidase Inhibitory Activity.

Three new selaginellin derivatives, selaginpulvilins V-X (1-3), together with seven known analogs (4-10) were isolated from whole plants of Selaginella pulvinata. Their structures were determined by extensive spectroscopic methods including 1D and 2D NMR, HR-ESI-MS and chemical derivatization method. Compound 1 represents a rare example of naturally occurring selaginellin with an alkynylphenol-trimmed skeleton. Biological evaluation showed that compounds 2, 6 and 8 displayed moderate inhibition against α-glucosidase with IC50 values of 3.71, 2.04 and 4.00 µM, respectively.

Advances in the Anti-Tumor Activity of Biflavonoids in Selaginella.

Despite the many strategies employed to slow the spread of cancer, the development of new anti-tumor drugs and the minimization of side effects have been major research hotspots in the anti-tumor field. Natural drugs are a huge treasure trove of drug development, and they have been widely used in the clinic as anti-tumor drugs. Selaginella species in the family Selaginellaceae are widely distributed worldwide, and they have been well-documented in clinical practice for the prevention and treatment of cancer. Biflavonoids are the main active ingredients in Selaginella, and they have good biological and anti-tumor activities, which warrant extensive research. The promise of biflavonoids from Selaginella (SFB) in the field of cancer therapy is being realized thanks to new research that offers insights into the multi-targeting therapeutic mechanisms and key signaling pathways. The pharmacological effects of SFB against various cancers in vitro and in vivo are reviewed in this review. In addition, the types and characteristics of biflavonoid structures are described in detail; we also provide a brief summary of the efforts to develop drug delivery systems or combinations to enhance the bioavailability of SFB monomers. In conclusion, SFB species have great potential to be developed as adjuvant or even primary therapeutic agents for cancer, with promising applications.

Three New Benzophenone Derivatives from Selaginella tamariscina.

Six compounds including three new benzophenones, selagibenzophenones D-F (1-3), two known selaginellins (4-5) and one known flavonoid (6), were isolated from Selaginella tamariscina. The structures of new compounds were established by 1D-, 2D-NMR and HR-ESI-MS spectral analyses. Compound 1 represents the second example of diarylbenzophenone from natural sources. Compound 2 possesses an unusual biphenyl-bisbenzophenone structure. Their cytotoxicity against human hepatocellular carcinoma HepG2 and SMCC-7721 cells and inhibitory activities on lipopolysaccharide-induced nitric oxide (NO) production in RAW264.7 cells were evaluated. Compound 2 showed moderate inhibitory activity against HepG2 and SMCC-7721 cells, and compounds 4 and 5 showed moderate inhibitory activity to HepG2 cells. Compounds 2 and 5 also exhibited inhibitory activities on lipopolysaccharide-induced nitric oxide (NO) production.

Methyl jasmonate induces selaginellin accumulation in Selaginella convoluta.

INTRODUCTION: Selaginellins are specialized metabolites and chemotaxonomic markers for Selaginella species. Despite the growing interest in these compounds as a result of their bioactivities, they are accumulated at low levels in the plant. Hence, their isolation and chemical characterization are often difficult, time consuming, and limiting for biological tests. Elicitation with the phytohormone methyl jasmonate (MeJA) could be a strategy to increase the content of selaginellins addressing their low availability problem, that also impairs pharmacological investigations. MATHERIALS AND METHODS: In this study, we examined MeJA elicitation in Selaginella convoluta plants, a medicinal plant found in northeastern Brazil, by treating them with two different concentrations (MeJA: 50 and 100 µM), followed by chemical profiling after 12, 24 and 48 h after application. Samples were harvested and analyzed by liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS). RESULTS AND DISCUSSCION: MeJA treatment significantly impacted the chemical phenotype. Regarding shoots differences in the time-dependent increased accumulation of all metabolites when plants were subjected to 100 µM MeJA were observed while in roots, most metabolites had their concentrations decreased in a time-dependent fashion at the same conditions. Results support organ, MeJA concentration and time post-treatment dependence of specialized metabolite accumulation, mainly the flavonoids and selaginellins. The amount of Selaginellin G in shoots of MeJA-treated specimens increased in 5.63-fold relative to control. The molecular networking approach allowed for the putative annotation of 64 metabolites, among them, the MeJA treatment followed by targeted metabolome analysis also allowed to annotate seven unprecedented selaginellins. Additionally, the in silico bioactive potential of the annotated selaginellins highlighted targets related to neurodegenerative disorders, antiproliferative, and antiparasitic issues. Taken together, data point out MeJA exposure as a strategy to induce potentially bioactive selaginellins accumulation in S. convoluta, this approach could enable a deep investigation about the metabolic function of these metabolites in the genus as well as regarding pharmacological exploration of the undervalued potential.

Cytotoxic effects of the biflavonoids isolated from Selaginella trichoclada on MCF-7 cells and its potential mechanism.

A new biflavonoid, (2''S)-6''-methyl-2'',3''-dihydroochnaflavone (1), along with two known ochnaflavones (2, 3), four known amentoflavones (4-7) and two known robustaflavones (8, 9) were obtained from the 70% EtOH extract of Selaginella trichoclada. The chemical structures of isolated compounds were elucidated by extensive spectroscopic analyses. Overall, compounds 1-9 displayed moderate cytotoxic effects against human breast cancer MCF-7 cell lines. Among them, compounds 2 and 8 exhibited relatively strong cytotoxic effects against MCF-7 cells with an IC50 value of 7.7 and 6.9 µΜ, respectively. The results of RNA-sequencing and KEGG functional enrichment analysis showed that 8 could induce ferroptosis in MCF-7 cells by down-regulating the expression of ferroptosis-related genes including ACSL4, NOXO1, NOXA1, ACSL5, STEAP3, LPCAT3, ATG7 and TP53. Then 8 could inhibit the expression of ACSL4 proteins through molecule docking analysis, which showed a strong interaction of - 11.89 Kcal/mol binding energy. Those results indicate that 8 could be chemotherapy agents to fight drug resistance in breast cancer by down-regulating the expression level of ACSL4 proteins via ferroptosis, which needs to be further certified in vitro.

Synthesis, biological evaluation, pharmacokinetic studies and molecular docking of 4'''-acetyl-delicaflavone as antitumor agents.

Structural modification of natural products is the effective option to improve their pharmacological effects and drug properties. DLF is a lead compound of antitumor drug, which is a broad-spectrum, low toxic and high-efficient component isolated from Selaginella doederleinii Hieron by our research group. Here, we report the structural modification method of this component, and find that the acetylated product of C4'''- OH (C4'''-acetyl-delicaflavone, 4'''ADLF) has better inhibitory effect on the selected cancer cell lines, including, lung, liver, colon and cervical cancer cell lines. Since the increased water solubility of 4'''ADLF may lead to higher absorption rate and activity, we evaluate the pharmacodynamics in vitro and in vivo, and the pharmacokinetic of 4'''ADLF. It shows that 4'''ADLF inhibit the proliferation and induce cycle arrest in tumor cells, and had better anticancer activity and bioavailability than DLF.

Two New C21 Steroidal Glycosides from Selaginella Braunii Baker.

Two new C21 steroidal glycosides, brapreguanes A and B (1-2) were isolated from 75 % aqueous ethanol extract of Selaginella braunii Baker. Their structures were established by spectroscopic analyses (1D/2D NMR spectra and HR-ESI-MS). The absolute configurations of sugar were elucidated by enzymatic hydrolysis and GCMS analysis. In addition, all compounds were evaluated for the anti-proliferative activities against various human cancer cells in vitro. Compounds exhibited no inhibition to various human cancer cells.

A new cyclic peptide from Selaginella tamariscina.

A new cyclic peptide selapeptin B (1), together with one known nor-lignan glycoside moellenoside C (2), was isolated from Selaginella tamariscina. The structures of 1 and 2 were elucidated on the basis of chemical and spectral analysis, including 1D, 2D NMR analyses and HRESIMS. Two compounds were evaluated for cytotoxic activities against B16F10, MDA-MB-231, and MDA-MB-468 cell lines by MTT assay. Compound 1 showed the potent activity against B16F10 melanoma cell lines.

Two new flavonol glycosides from Selaginella tamariscina.

Two new flavonol glycosides 3,5,7-trimethoxyflavone-4'-O-[5'''-O-p-coumaroyl-ß-D-apiofuranoyl-(1'''→2'')-ß-D-glucopyranoside] (1) and 3,5,7-trimethoxyflavone -4'-O-ß-D-glucopyranoside (2) were isolated from Selaginella tamariscina. The structures of 1 and 2 were elucidated on the basis of chemical and spectral analysis, including 1D, 2D NMR analyses and HRESIMS spectrometry. Two compounds were evaluated for cytotoxic activities against A-375, MCF-7, MDA-MB-231 and MDA-MB-468 cell lines by MTT assay. Unfortunately, two compounds displayed no cytotoxic activities.

Brasesquilignan A-E, Five New Furofurans Lignans from Selaginella braunii Baker.

Five new furofurans lignans, Brasesquilignan A-E (1-5), were isolated from the aqueous ethanol extract of Selaginella braunii Baker. Their structures were elucidated by extensive analysis of NMR and HRESIMS data. Their absolute configurations were determined by CD spectra, enzymatic hydrolysis, and GCMS analysis. Furthermore, all compounds were evaluated for anti-proliferative activities against various human cancer cellsin vitro. Compounds 2 and 3 exhibited weak inhibitorypotency against five human cancer cells.

[A new cyclopeptide from Selaginella tamariscina].

One new cyclopeptide was isolated from the ethyl acetate fraction of the 75% EtOH extract of Selaginella tamariscina by various column chromatography methods(HP-20, polyamide and semi-preparative HPLC). Its structure was identified as selapeptin A(1) by extensive spectroscopic analysis(HR-ESI-MS, 1 D and 2 D NMR). Compound 1 was evaluated for cytotoxic activities by MTT assay. It showed potent cytotoxic activity against B16 F10 with the inhibition rate of 51.57%±4.34% at 40 µmol·L~(-1) while had no impacts on MDA-MB-231 and MDA-MB-468 at 100 µmol·L~(-1).

Selaginellins from the genus Selaginella: isolation, structure, biological activity, and synthesis.

Covering: 2007 to 2020 Selaginellins are a small group of pigments exclusively found in the ancient genus Selaginella. Since the first report of selaginellin from S. sinensis in 2007, more than 110 selaginellins with diverse polyphenolic skeletons have been reported. This review provides extensive coverage of the selaginellins discovered from 2007 to 2020, including 61 natural ones and 52 synthetic analogues. The isolation, chemical structures, plausible biosynthetic pathways, bioactivity, and total synthesis of these selaginellins have been summarized for the first time, and this highlights the fact that the vast uninvestigated Selaginella species may serve as a potential treasure trove of chemically diverse selaginellins waiting to be discovered.

Selaginellin Derivatives from Selaginella tamariscina and Their Upregulating Effects on Low-Density Lipoprotein Receptor Expression.

Two new dimeric selaginellins, diselaginellins C and D (1 and 2), a new unusual derivative, selapiginellin A (4), a new selaginpulvilin U (5), and a known derivative, diselaginellin A (3), were isolated from Selaginella tamariscina (P. Beauv.) Spring. Among these compounds, selapiginellin A (4) is the first naturally occurring compound comprising an ether-linked dimer of a selaginellin and a selaginpulvilin. The absolute configurations of 1, 2, and 4 were elucidated by spectroscopic data analyses. Compound 5 was found to regulate mRNA expression of the low-density lipoprotein receptor (LDLR) gene and LDLR-related genes.

Identification of a new natural biflavonoids against breast cancer cells induced ferroptosis via the mitochondrial pathway.

Breast cancer is one of the major malignant tumors in females, and currently, recurrence and metastasis are the main obstacles preventing effective breast cancer treatment. Biflavonoids of secondary metabolites from plants are excellent anticancer agents to fight sensitive and resistant breast cancer cell lines. In this study, six C-3'-C-6″ biflavonoids, including one new robustaflavone A (1, RF-A) and five known robustaflavone derivatives (2-6), were isolated from Selaginella trichoclada for the first time. We aimed to evaluate the inhibitory effects of compounds 1-6 against human breast cancer MCF-7 cells. Among the six compounds, RF-A showed the strongest activity, decreasing cell viability with an IC50 value of 11.89 µΜ. Furthermore, RF-A strikingly induced MCF-7 nonapoptotic cell death through ferroptosis by enhancing the expression of VDAC2 channels and reducing the expression of Nedd4 E3 ubiquitin ligase, leading to lipid peroxidation and ROS production. The results suggested that RF-A has potential as a novel breast cancer treatment through its regulation of the mitochondrial VDAC2 and Nedd4 pathways.

Triflavones from Selaginella Doederllein Inhibited Hypoxia-induced, Pulmonary Vascular Remodeling Through PI3K/Akt.

CONTEXT: Pulmonary hypertension (PH) is a complication of numerous pulmonary conditions. Previous studies have confirmed that Selaginella doederleini has pharmacological effects against many cancers, and triflavones have been newly isolated as one of its active ingredients, with antioxidant and antitumor activities. The chronic hypoxia model is one of the models most used to study PH pathogenesis and treatment. OBJECTIVE: The present study was designed to investigate the protective effects of triflavones from selaginella doederlleini against PH and on the proliferation and apoptosis of ASMCs in a hypoxia-induced PH model in rats. METHODS: The research team performed an animal study. SETTING: The study took place at the Tongji Medical College at the Huazhong University of Science and Technology in Wuhan, Hubei, PR China. ANIMALS: The animals were 40 specific pathogen free (SPF), male SD rats weighing 200 ± 20 g each. INTERVENTION: The animals were divided into 4 groups, with 10 animals in each group: (1) the control group, (3) the hypoxia group (PH group), (3) the control + triflavones group (Tri group) and (4) the hypoxia + triflavones group (PH + Tri group). The rats in 2 hypoxia groups were exposed to 10% oxygen to induce PH, and the animals in the 2 control groups were exposed to room air, both for 3 consecutive weeks. Animals in the 2 triflavones groups were injected with 200 µL of triflavones-100 mg/mL dissolved in 0.9% normal saline-and the animals in the control and PH groups were injected with 200 µL of 0.9% normal saline. OUTCOME MEASURES: In vitro, the primary aorta smooth muscle cells (ASMCs) were isolated, and the proliferation and apoptosis of the ASMCs were assayed by CCK-8 kit and flow cytometry. The expression levels of the alpha-smooth muscle actin (α-SMA), transforming growth factor beta 1 (TGF-ß1), and phosphoinositide 3-kinases (P13K)/ protein kinase B (Akt) in the ASMCs were also assayed by Western blot. RESULTS: Triflavones effectively decreased mPAP, the ratio of RV/ (LV + S), and the thickness of the arteries of the PH + Tri group. Furthermore, triflavones reversed the increased proliferation and inhibited apoptosis induced by chronic hypoxia for that group. Hypoxia increased TGF-ß1 protein expression and the activation of P13K/Akt, as shown in the PH group, and was abrogated by the triflavones. CONCLUSION: Triflavones are promising protective agents against PH due to their inhibitory effects on vascular remodeling through P13K/Akt signaling.

Biochemical Characterization and Function of Eight Microbial Type Terpene Synthases from Lycophyte Selaginella moellendorffii.

Selaginella moellendorffii is a lycophyte, a member of an ancient vascular plant lineage. Two distinct types of terpene synthase (TPS) genes were identified from this species, including S. moellendorffii TPS genes (SmTPSs) and S. moellendorffii microbial TPS-like genes (SmMTPSLs). The goal of this study was to investigate the biochemical functions of SmMTPSLs. Here, eight full-length SmMTPSL genes (SmMTPSL5, -15, -19, -23, -33, -37, -46, and -47) were functionally characterized from S. moellendorffii. Escherichia coli-expressed recombinant SmMTPSLs were tested for monoterpenes synthase and sesquiterpenes synthase activities. These enzymatic products were typical monoterpenes and sesquiterpenes that have been previous shown to be generated by typical plant TPSs when provided with geranyl diphosphate (GPP) and farnesyl diphosphate (FPP) as the substrates. Meanwhile, SmMTPSL23, -33, and -37 were up-regulated when induced by alamethicin (ALA) and methyl jasmonate (MeJA), suggesting a role for these genes in plants response to abiotic stresses. Furthermore, this study pointed out that the terpenoids products of SmMTPSL23, -33, and -37 have an antibacterial effect on Pseudomonas syringae pv. tomato DC3000 and Staphylococcus aureus. Taken together, these results provide more information about the catalytic and biochemical function of SmMTPSLs in S. moellendorffii plants.