Ultrastructural organization of the thylakoid system during the afternoon relocation of the giant chloroplast in Selaginella martensii Spring (Lycopodiophyta).

Within the ancient vascular plant lineage known as lycophytes, many Selaginella species contain only one giant chloroplast in the upper epidermal cells of the leaf. In deep-shade species, such as S. martensii, the chloroplast is cup-shaped and the thylakoid system differentiates into an upper lamellar region and a lower granal region (bizonoplast). In this report, we describe the ultrastructural changes occurring in the giant chloroplast hosted in the epidermal cells of S. martensii during the daily relocation of the organelle. The process occurs in up to ca. 40% of the microphylls without the plants being exposed to high-light flecks. The relocated chloroplast loses its cup shape: first, it flattens laterally toward the radial cell wall and then assumes a more globular shape. The loss of the conical cell shape, the side-by-side lateral positioning of vacuole and chloroplast, and the extensive rearrangement of the thylakoid system to only granal cooperate in limiting light absorption. While the cup-shaped chloroplast emphasizes the light-harvesting capacity in the morning, the relocated chloroplast is suggested to support the renewal of the thylakoid system during the afternoon, including the recovery of photosystem II (PSII) from photoinhibition. The giant chloroplast repositioning is part of a complex reversible reshaping of the whole epidermal cell.

Selaginellin derivatives from Selaginella tamariscina and evaluation for anti-breast cancer activity.

A phytochemical investigation of Selaginella tamariscina led to the isolation of 17 selaginellin derivatives. Their inhibitory activities against breast cancer cells were screened, and preliminary structure-activity relationships were also established. Among them, dimeric selaginellin 17 showed potential activity against MDA-MB-231 cells with an IC50 value of 3.2 ± 0.1 µM, corresponding to 4-fold higher potency than the reference compound 5-FU (IC50 14.8 ± 0.2 µM). Mechanistic studies indicated that 17 could cause G2/M phase arrest in MDA-MB-231 cells and induce apoptosis accompanied by increased ROS levels.

Genome and transcriptome of Selaginella kraussiana reveal evolution of root apical meristems in vascular plants.

The evolution of roots allowed vascular plants to adapt to land environments. Fossil evidence indicates that roots evolved independently in euphyllophytes (ferns and seed plants) and lycophytes, the two lineages of extant vascular plants. Based on a high-quality genome assembly, mRNA sequencing (mRNA-seq) data, and single-cell RNA-seq data for the lycophyte Selaginella kraussiana, we show that the two root origin events in lycophytes and euphyllophytes adopted partially similar molecular modules in the regulation of root apical meristem (RAM) development. In S. kraussiana, the RAM initiates from the rhizophore primordium guided by auxin and duplicates itself by dichotomous branching. The auxin signaling pathway directly upregulates euAINTEGUMENTAb (SkeuANTb), and then SkeuANTb directly promotes the expression of SkeuANTa and the WUSCHEL-RELATED HOMEOBOX13b (SkWOX13b) for RAM maintenance, partially similar to the molecular pathway involving the euANT-branch PLETHORA (AtPLT) genes and AtWOX5 in root initiation in the seed plant Arabidopsis thaliana. Other molecular modules, e.g., SHORT-ROOT and SCARECROW, also have partially similar expression patterns in the RAMs of S. kraussiana and A. thaliana. Overall, our study not only provides genome and transcriptome tools of S. kraussiana but also indicates the employment of some common molecular modules in RAMs during root origins in lycophytes and euphyllophytes.

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.

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.

Phytoconstituents of Selaginella effusa Alston and Their α-Glucosidase as well as Urease Inhibitory Activities.

Three new compounds (1-2, 14), as well as 22 known compounds (3-13, 15-25), were extracted for the first time from the Selaginella effusa Alston (S. effusa). For the unknown compounds, the planar configurations were determined via NMR and by high-resolution mass spectrometry, while their absolute configurations were determined by calculated electronic circular dichroism (ECD), and the configuration of the stereogenic center of biflavones 4-5 were established for the first time. The pure compounds (1-25) were tested in vitro to determine the inhibitory activity of the enzyme-catalyzed reactions. Compounds 1-9 inhibited α-glucosidase with IC50 values ranging from 0.30±0.02 to 4.65±0.04 µM and kinetic analysis of enzyme inhibition indicated that biflavones 1-3 were mixed-type α-glucosidase inhibitors. Compounds 12-13 showed excellent inhibitory activity against urease, with compound 12 (IC50 =4.38±0.31 µM) showing better inhibitory activity than the positive control drug AHA (IC50 13.52±0.61 µM). In addition, molecular docking techniques were used to simulate inhibitor-enzyme binding and to estimate the binding posture of the α-glucosidase and urease catalytic sites.

Total biflavonoids extraction from Selaginella chaetoloma utilizing ultrasound-assisted deep eutectic solvent: Optimization of conditions, extraction mechanism, and biological activity in vitro.

In this study, the deep eutectic solvent based ultrasound-assisted extraction (DES-UAE) was investigated for the efficient and environmentally friendly extraction of Selaginella chaetoloma total biflavonoids (SCTB). As an extractant for optimization, tetrapropylaminium bromide-1,4-butanediol (Tpr-But) was employed for the first time. 36 DESs were created, with Tpr-But producing the most effective results. Based on response surface methodology (RSM), the greatest extraction rate of SCTB was determined to be 21.68 ± 0.78 mg/g, the molar ratio of HBD to HBA was 3.70:1, the extraction temperature was 57 °C, and the water content of DES was 22 %. In accordance with Fick's second rule, a kinetic model for the extraction of SCTB by DES-UAE has been derived. With correlation coefficients 0.91, the kinetic model of the extraction process was significantly correlated with the general and exponential equations of kinetics, and some important kinetic parameters such as rate constants, energy of activation and raffinate rate were determined. In addition, molecular dynamics simulations were used to study the extraction mechanisms generated by different solvents. Comparing the effect of several extraction methods on S.chaetoloma using ultrasound-assisted extraction and conventional methods, together with SEM examination, revealed that DES-UAE not only saved time but also enhanced SCTB extraction rate by 1.5-3 folds. SCTB demonstrated superior antioxidant activity in three studies in vitro. Furthermore, the extract could suppress the growth of A549, HCT-116, HepG2, and HT-29 cancer cells. Alpha-Glucosidase (AG) inhibition experiment and molecular docking studies suggested that SCTB exhibited strong inhibitory activity against AG and potential hypoglycemic effects. The results of this study indicated that a Tpr-But-based UAE method was suitable for the efficient and environmentally friendly extraction of SCTB, and also shed light on the mechanisms responsible for the increased extraction efficiency, which could aid in the application of S.chaetoloma and provide insight into the extraction mechanism of DES.

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 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.

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.

The phytoestrogenic potential of flavonoid glycosides from Selaginella moellendorffii via ERα-dependent signaling pathway.

ETHNOPHARMACOLOGICAL RELEVANCE: Selaginella moellendorffii (SM) has been applied as an ethnic drug to treat conditions such as osteoporosis, idiopathic thrombocytopenic purpura, and chronic inflammation. It is known to be rich in flavonoids, including apigenin glycosides and unique elements of bioflavonoids. AIM OF THE STUDY: To investigate estrogen-like constituents of SM and the possible mechanism. MATERIALS AND METHODS: We identified the main components in liquid chromatography and liquid chromatography-mass spectrometry. The estrogenic effects were examined using a recombinant yeast screening assay, an E-screen cell proliferation assay, and an in vivo uterotrophic assay. RESULTS: Flavonoid glycosides extract, some flavonoid glycosides, and apigenin showed estrogen agonistic activity in the yeast screening assay. They also induced cell proliferation in estrogen receptor-positive (ER+) cells but not in estrogen receptor-negative (ER-) cells. Consistently, the protein expression of ERα, phosphorylation protein kinase B (p-AKT), phosphatidylinositol 3 kinase (PI3K), phosphorylation mammalian target of rapamycin (p-mTOR), phosphorylation 38,000-Da protein (p-P38), and phosphorylation extracellular-regulated kinase 1/2 (p-ERK1/2) elevated following treatment with flavonoid glycoside extract (P < 0.01 or P < 0.05). These effects could be blocked by ER antagonist or ERα antagonist but not be blocked by ERß antagonist. In vivo assay, flavonoid glycoside extract could significantly increase body weight, serum estradiol level, uterine wet weight, alter uterine morphology, and promote ERα protein expression (P < 0.01 or P < 0.05). CONCLUSIONS: ERα induction via mitogen-activated protein kinases (MAPK) and PI3K/Akt/mTOR pathways might be the possible mechanism underlying the phytoestrogen effect of SM, and the flavonoid glycosides might be the critical estrogenic constituents.

Assessment of Toxicity and Wound Healing Activity of Selaginella Bryopteris Extract.

AIM: The aim of the study was to assess the toxicity profile of Selaginella bryopteris extract and evaluate its wound healing activity. METHODS: In vitro wound healing activity of S. bryopteris extract (5% and 10%) was performed using Clonogenic and Scratch assays. The toxicity profile of S. bryopteris extract ointment was evaluated on animals using acute toxicity and dermal toxicity tests. In vivo wound healing activity of S. bryopteris extract ointment (5% and 10%) was used to determine tensile strength in the incision wound healing model. RESULTS: Results exhibited that the extract was safe up to 2000 mg/kg per oral dose and non-reactive while applied topically. In vitro results showed that S. bryopteris extract closed the wound gap created by 97.13% in 48 h. The clonogenic assay revealed that the surviving factor for HaCaT cells and MEF cells was 0.78 and 0.85 after treated with 10% concentrations of S. bryopteris. The tensile strength exhibited by S. bryopteris 5% and 10% groups was 395.4 g and 558.5 g in comparison to the control group. CONCLUSION: Thus, S. bryopteris extract can be used as an alternative safe drug therapy against topical wounds.

Mitogenome-based phylogenomics provides insights into the positions of the enigmatic sinensis group and the sanguinolenta group in Selaginellaceae (Lycophyte).

Spikemoss (Selaginellaceae) is one of the basal lineages of vascular plants. This family has a single genus Selaginella which consists of about 750 extant species. The phylogeny of Selaginellaceae has been extensively studied mainly based on plastid DNA and a few nuclear sequences. However, the placement of the enigmatic sinensis group is a long-term controversy because of the long branch in the plastid DNA phylogeny. The sanguinolenta group is also a phylogenetically problematic clade owing to two alternative positions resulted from different datasets. Here, we newly sequenced 34 mitochondrial genomes (mitogenomes) of individuals representing all seven subgenera and major clades in Selaginellaceae. We assembled the draft mitogenomes and annotated the genes and performed phylogenetic analyses based on the shared 17 mitochondrial genes. Our major results include: (1) all the assembled mitogenomes have complicated structures, unparalleled high GC content and a small gene content set, and the positive correlations among GC content, substitution rates and the number of RNA editing sites hold; (2) the sinensis group was well supported as a member of subg. Stachygynandrum; (3) the sanguinolenta group was strongly resolved as sister to all other Selaginella species except for subg. Selaginella. This study demonstrates the potential of mitogenome data in providing novel insights into phylogenetically recalcitrant problems.

Delicaflavone reactivates anti-tumor immune responses by abrogating monocytic myeloid cell-mediated immunosuppression.

BACKGROUND: Myeloid cell-mediated immunosuppression is a major obstacle to checkpoint blockade immunotherapy. We previously reported that total biflavonoids extract from Selaginella doederleinii (TBESD) and a flavone monomer isolated from TBESD, named Delicaflavone, have favorable anti-tumor activity. However, whether TBESD and Delicaflavone could affect the tumor microenvironment (TME) remains unclear. PURPOSE: In this study, we focused on the TME to determine whether TBESD and Delicaflavone could restore anti-tumor immune response. METHODS: 4T1 tumor-bearing immunocompetent BALB/c mice and T cell-deficient nude mice were used to examine the effect of TBESD on T cell-mediated immunity in vivo. Multi-parameter flow cytometry was conducted to evaluate the impacts of TBESD on TME. Primary cells, including murine CD8+ T cells, tumor associated macrophages (TAMs) and myeloid-derived suppressor cells (MDSCs) were prepared to investigate the modulatory activities of TBESD on immune cells. It was further determined whether Delicaflavone or Amentoflavone, two typical functional biflavones from TBESD, mediated those effects of TBESD. Finally, the impacts of TBESD and Delicaflavone on Jak1/STAT6 signaling pathway were explored via western blot. RESULTS: We found that TBESD significantly reduced 4T1 tumor growth in immunocompetent BALB/c mice, but not in nude mice. This effect was associated with the regulation of TME, shown as an increase in functional T cells and M1 phenotype TAMs (M1-TAMs), and a decrease in M2 phenotype TAMs (M2-TAMs), monocytic-MDSCs (M-MDSCs) and regulatory T cells (Tregs) in TBESD-treated BALB/c mouse 4T1 tumors. It was found ex vivo that TBESD restrained the viability and immunosuppressive properties of M2-TAMs and M-MDSCs, especially for the loss of arginase-1 expression. Additionally, TBESD re-educated M2-TAMs to an M1 like phenotype. Further investigations determined that Delicaflavone predominantly mediated the immuno-modulatory activities of TBESD both ex vivo and in vivo. Finally, Delicaflavone and TBESD blocked Jak1/STAT6 signaling pathway in M2-TAMs and MDSCs. CONCLUSION: The present study suggests Delicaflavone as a potent natural inhibitor of M2-TAMs and MDSCs, which fills the gap in knowledge on the immuno-modulatory effects of TBESD and Delicaflavone, and could have translational implications to improve the efficacy of cancer immunotherapy.

Impacts of methyl jasmonate on Selaginella martensii: volatiles, transcriptomics, phytohormones, and gas exchange.

Methyl jasmonate (MeJA) induces various defence responses in seed plants, but for early plant lineages, information on the potential of jasmonates to elicit stress signalling and trigger physiological modifications is limited. The spikemoss Selaginella martensii was exposed to a range of MeJA concentrations (0, 10, 25, and 50 mM), and biogenic volatile organic compound (BVOC) emissions, photosynthetic rate (A), and stomatal conductance (gs) were continuously measured. In addition, changes in phytohormone concentrations and gene expression were studied. Enhancement of methanol, lipoxygenase pathway volatiles and linalool emissions, and reductions in A and gs, were MeJA dose-dependent. Before MeJA treatment, the concentration of 12-oxo-phytodienoic acid (OPDA) was 7-fold higher than jasmonic acid (JA). MeJA treatment rapidly increased OPDA and JA concentrations (within 30 min), with the latter more responsive. Some genes involved in BVOC biosynthesis and OPDA-specific response were up-regulated at 30 min after MeJA spraying, whereas those in the JA signalling pathway were not affected. Although JA was synthesized in S. martensii, OPDA was prioritized as a signalling molecule upon MeJA application. MeJA inhibited primary and enhanced secondary metabolism; we propose that fast-emitted linalool could serve as a marker of elicitation of stress-induced metabolism in lycophytes.

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.

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.

Three water soluble polysaccharides with anti-inflammatory activities from Selaginella uncinata (Desv.) Spring.

Three water soluble polysaccharides named SUSP-1, SUSP-2 and SUSP-3 from Selaginella uncinata (Desv.) Spring were purified, which contained different contents of galactose, arabinose, mannose, glucose and xylose, and SUSP-3 had large amount of galacturonic acid. Structural identification showed that the backbone structure of SUSP-1 was composed of (1 â†’ 2)-α-D-Manp, (1 â†’ 4)-α-D-Manp and (1 â†’ 4)-ß-D-Xylp. The main chains of SUSP-2 were (1 â†’ 3)-α-D-Galp and (1 â†’ 4)-α-D-Glcp, and SUSP-3 had two fragments and the main chains were (1 â†’ 4)-α-D-GalpA and (1 â†’ 4)-ß-D-Xylp. Furthermore, their anti-inflammatory activities were evaluated. THP-1 monocytes were induced into macrophages by phorbol 12-myristate 13-acetat (PMA) and then stimulated by lipopolysaccharides (LPS). The data showed that compared with model groups, SUSP-1, SUSP-2 and SUSP-3 significantly inhibited ROS levels, promoted IL-10 expression, suppressed the mRNA levels of IL-6, TNF-α and IL-1ß, and effectively blocked LPS binding to CD14 receptor to reduce inflammation. This study provided new data for the development of natural polysaccharides from S. uncinata with anti-inflammatory activities.

Selaginella tamariscina Inhibits Glutamate-Induced Autophagic Cell Death by Activating the PI3K/AKT/mTOR Signaling Pathways.

Glutamate-induced neural toxicity in autophagic neuron death is partially mediated by increased oxidative stress. Therefore, reducing oxidative stress in the brain is critical for treating or preventing neurodegenerative diseases. Selaginella tamariscina is a traditional medicinal plant for treating gastrointestinal bleeding, hematuria, leucorrhea, inflammation, chronic hepatitis, gout, and hyperuricemia. We investigate the inhibitory effects of Selaginella tamariscina ethanol extract (STE) on neurotoxicity and autophagic cell death in glutamate-exposed HT22 mouse hippocampal cells. STE significantly increased cell viability and mitochondrial membrane potential and decreased the expression of reactive oxygen species, lactate dehydrogenase release, and cell apoptosis in glutamate-exposed HT22 cells. In addition, while glutamate induced the excessive activation of mitophagy, STE attenuated glutamate-induced light chain (LC) 3 II and Beclin-1 expression and increased p62 expression. Furthermore, STE strongly enhanced the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt)/mammalian target of rapamycin (mTOR) phosphorylation activation. STE strongly inhibited glutamate-induced autophagy by activating the PI3K/Akt/mTOR signaling pathway. In contrast, the addition of LY294002, a PI3K/Akt inhibitor, remarkably suppressed cell viability and p-Akt and p62 expression, while markedly increasing the expression of LC3 II and Beclin-1. Our findings indicate that autophagy inhibition by activating PI3K/Akt/mTOR phosphorylation levels could be responsible for the neuroprotective effects of STE on glutamate neuronal damage.

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.