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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 → 2)-α-D-Manp, (1 → 4)-α-D-Manp and (1 → 4)-β-D-Xylp. The main chains of SUSP-2 were (1 → 3)-α-D-Galp and (1 → 4)-α-D-Glcp, and SUSP-3 had two fragments and the main chains were (1 → 4)-α-D-GalpA and (1 → 4)-β-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-1β, 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. • Three water soluble polysaccharides were obtained from S. uncinate. • The main chain of SUSP-1 was (1 → 2)-α-D-Manp, (1 → 4)-α-D-Manp and (1 → 4)-β- D-Xylp. • The backbone structure of SUSP-2 contained (1 → 3)-α-D-Galp and (1 → 4)-α-D-Glcp. • SUSP-3 had two fragments and were composed of (1 → 4)-α-D-GalpA and (1 → 4)-β-D-Xylp. • SUSP-1, SUSP-2 and SUSP-3 improved inflammatory response in THP-1 macrophages. [ABSTRACT FROM AUTHOR]

In this study, the ethanol/salt aqueous two-phase system was firstly used to extract Selaginella doederleinii polysaccharides (SDP). Through single factor and response surface analysis, the best extraction conditions were as follows: extraction time of 40 min, ultrasonic power of 280 W, ethanol concentration of 35%, inorganic salt concentration of 0.22 g/mL, and liquid/solid ratio of 25 mL/g with optimal predicted yield of 9.85%. The preliminary structure of SDP was analyzed by HPLC, SEM, Congo red experiment, FT-IR NMR, SEM, thermogravimetric analysis and XRD. In vitro antioxidant experiments indicated that SDP exhibition a potential antioxidant activity and the scavenging rate of SDP (120 μg/mL) against DPPH +·, ABTS+· and ferrous ions were 39.35%, 43.25% and 48.63%, respectively. Also, SDP had certain antitumor activity and the IC 50 of SDP on A549 cells and HCT-116 cells were 1528 μg/mL and 2341 μg/mL, respectively. [Display omitted] • S. doederleinii polysaccharide (SDP) was extracted by aqueous two-phase system. • The optimum extraction process of SDP was gained. • The structure of SDP was characterization. • SDP has excellent antioxidant and anti-tumor activity. [ABSTRACT FROM AUTHOR]

Polygalacturonases (PGs) can modulate chemistry and mechanical properties of the plant cell wall through the degradation of pectins, one of its major constituents. PGs are largely used in food, beverage, textile, and paper industries to increase processes' performances. To improve the use of PGs, knowledge of their biochemical, structural and functional features is of prime importance. Our study aims at characterizing SmoPG1, a polygalacturonase from Selaginella moellendorffii, that belongs to the lycophytes. Transcription data showed that SmoPG1 was mainly expressed in S. moellendorffii shoots while phylogenetic analyses suggested that SmoPG1 is an exo -PG, which was confirmed by the biochemical characterization following its expression in heterologous system. Indeed, LC-MS/MS oligoprofiling using various pectic substrates identified galacturonic acid (GalA) as the main hydrolysis product. We found that SmoPG1 was most active on polygalacturonic acid (PGA) at pH 5, and that its activity could be modulated by different cations (Ca2+, Cu2+, Fe2+, Mg2+, Mn2+, Na2+, Zn2+). In addition, SmoPG1 was inhibited by green tea catechins, including (−)-epigallocatechin-3-gallate (EGCG). Docking analyses and MD simulations showed in detail amino acids responsible for the SmoPG1-EGCG interaction. Considering its expression yield and activity, SmoPG1 appears as a prime candidate for the industrial production of GalA. • SmoPG1 is most expressed in shoots where it shows importance in development. • SmoPG1 is the first produced and characterized exo-polygalacturonase in S. moellendorffii. • Docking studies and MD simulation highlight EGCG inhibition of pectinases. [ABSTRACT FROM AUTHOR]

• The ligular shape of eleven species is described for the first time. • The size of the ligule is related to the size of the supporting leaf. • Ligule rapidly reach their adult size and shape in young leaves. • Xerophytic and mesophytic species share ligular shapes and apex. The ligule is an important character in the taxonomic delimitation of Selaginella species. Here, the morphology of this organ is described in 11 American species. Four of these species are xerophytic: Selaginella convoluta, S. microphylla, S. peruviana , and S. sellowii , and seven are mesophytic: S. anceps, S. diffusa, S. flagellata, S. flexuosa, S. mollis, S. silvestris , and S. sulcata. Morphological data were obtained by traditional histological techniques. Observations were made by light and scanning electron microscopy. Variations in ligule size in vegetative leaves and sporophylls were determined using a correlation analysis with Spearman's coefficient. The ligule was found to have five body shapes: campanulate, linguiform, elliptic, fan-shaped, and rectangular. Each shape can have a lobed (bi-, tri-, or multi-lobed), rounded, or truncate apex. Size, shape, and apex are characteristic of each species and remain constant in young and mature leaves. No significant differences were observed between xerophytic and mesophytic species. The ligule of all species studied is described for the first time. Micrographs of all the species studied are presented, and the morphological results of this study have been mapped into the recent phylogeny of the genus. [ABSTRACT FROM AUTHOR]

The current understanding of photosynthesis across land plant phylogeny strongly indicates that ancient vascular plants are mainly limited by strong constitutive CO 2 diffusional constraints, particularly low stomatal and mesophyll conductance. Considering that the lycophyte Selaginella martensii can demonstrate long-term light acclimation, this study addresses the regulation extent of CO 2 assimilation in this species cultivated under contrasting light regimes of deep shade, medium shade and high light. Comparative analyses of photosynthetic traits, CO 2 conductance and leaf morpho-anatomy revealed acclimation plasticity similar to that of seed plants, though occurring in the context of an inherently low photosynthetic capacity typical of lycophytes. Specific modulations of the stomatal density and aperture, chloroplast surface exposed to mesophyll airspaces and cell wall thickness sustained a marked improvement in CO 2 diffusion from deep shade to high light. However, the maximum carboxylation rate was comparatively less effectively upregulated, leading to a greater incidence of biochemical limitations of photosynthesis. Because of a low carboxylation capacity under any light regime, a lycophyte prevents potential photodamage to the chloroplast by not only exploiting the thermal dissipation of excess absorbed energy but also diverting a large fraction of photosynthetic electrons to sinks alternative to carboxylation. • In a lycophyte the CO 2 diffusion into the leaf is strongly regulated based on growth light environment. • Changes in CO 2 diffusion depend on stomatal density and size, and on chloroplast surface facing the intercellular spaces. • Under high light, photosynthesis is more limited by biochemical than diffusional constraints. • Safety valves are thermal dissipation of excess absorbed light and electron flow to alternative sinks. • Acclimation plasticity of photosynthesis in a lycophyte is overall similar to that of seed plants. [ABSTRACT FROM AUTHOR]

Selaginella vogelii belongs to the Selaginellaceae family widely used in traditional medicine to treat hepatitis, cancer, cardiovascular, renal and inflammatory diseases. The present study was undertaken to evaluate the antihypertensive and nephroprotective effects of Selaginella vogelii aqueous extract. Reverse phase high-performance liquid chromatography (RP-HPLC) was used to analyze the chromatographic fingerprint and to identify various chemical components of the plant extract. The antihypertensive activity of the aqueous extract of Selaginella vogelii (100, 200 and 400 mg/kg of body weight) was evaluated on an L-NAME-induced hypertension model in rat. After body weight measurement, CODA non-invasive blood pressure system was used to record cardiovascular parameters as blood pressure and heart rate. Biochemical and histological analysis were performed to demonstrate the protective effect of the aqueous extract of Selaginella vogelii in gentamicin (i.p)-induced nephrotoxicity model. The phytochemical analysis indicated the presence of phenolic acids, flavonoids, and saponins. The aqueous extract of Selaginella vogelii significantly prevented (P <.01) the increase of mean blood pressure with a maximum of 47.64% at the dose of 400 mg/kg during the 4 weeks of treatment. The Selaginella vogelii aqueous extract significantly reduced ALAT (60.88%), ASAT (38.84%) and creatinine (52.81%) concentrations. In the nephroprotective assay, the plant extract (400 mg/kg) significantly decreased (P ˂ 0.01) kidney weight (39.66%). Urea and creatinine rates were reduced in both tissue and serum. Histological analysis showed that, S. vogelii extract (400 mg/kg) restored renal disorders induced by administration of gentamicin. The aqueous extract of Selaginella vogelii possesses antihypertensive and nephroprotective effects with an effective dose of 400 mg/kg. This study indicates that the aqueous extract prevented the increase of the mean blood pressure and the nephroprotective effect may be adduced to the decrease in the creatinine and urea levels in the kidneys. The findings justify the traditional use of Selaginella vogelii. • Phytochemical analysis showed that crude extract is rich in phenolic compounds. • Selaginella vogelii extract prevented blood pressure rise induced by L-NAME. • Extract improved renal function by ameliorating glomerular filtration. • Selaginella vogelii aqueous extract possessed nephroprotective effect. [ABSTRACT FROM AUTHOR]

The resurrection plant Selaginella pulvinata possesses an extraordinary ability to survive longterm desiccation, with the capacity to recover to normal growth after four years in a desiccated state. To understand the phenomenon, we investigated morphology, cytology, physiology, and performed PacBio single-molecule, real-time (SMRT) sequencing and Illumina RNA-sequencing of S. pulvinata during dehydration and rehydration. The full-length transcriptome dataset of S. puvinata consisted of 78,914 isoforms, and 75,819 isoforms (96.07%) were functionally annotated. The mapping rate of RNA-seq was 86.83–93.46% when utilizing the full-length transcriptome dataset as a reference. A total of 17,934 differentially expressed genes (DEGs) were identified during dehydration and rehydration. During dehydration, swollen chloroplasts and mitochondria, as well as vacuolation occupied space in desiccated cells, which cooperated with dense cytoplasm to inhibit the collapse and folding of desiccated cells. Accumulation and up-regulated gene expressions of osmotic agent and protective proteins contributed to the formation of vacuolation and dense cytoplasm. To reduce ROS damage during dehydration, two strategies were employed in S. pulvinata , i.e., reducing ROS production and scavenging ROS. Reducing exposure area, inactive PSII and down-regulated gene expression in photosynthesis decreased ROS production caused by excessive light absorption. Increased activities and up-regulated gene expressions in antioxidant enzyme system promoted ROS scavenging. ABA signaling pathway was hypothesized to play an important regulatory role in the desiccation tolerance of S. pulvinata due to significant ABA accumulation and up-regulated expressions of related genes during dehydration. Moreover, the comparative transcriptome analysis revealed that the pathways involved in dehydration and rehydration of the resurrection species S. pulvinata , S. lepidophylla and S. sellowii were consistent, indicating the similar desiccation tolerance mechanisms existing in the different resurrection species of Selaginella. Our study preliminarily revealed the desiccation tolerance mechanisms of S. pulvinata , which holds significant potential for inspiring biotechnological strategies aimed at enhancing drought tolerance in crops. • Changes of morphology, physiology, cytology and transcriptome level were observed in S. pulvinata during dehydration and rehydration. • Desiccation tolerance of S. pulvinata was an intricate process orchestrated by many genes and metabolic pathways. • The different resurrection species of Selaginella possessed the similar desiccation tolerance mechanism. [ABSTRACT FROM AUTHOR]

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 IC 50 value of 3.2 ± 0.1 μM, corresponding to 4-fold higher potency than the reference compound 5-FU (IC 50 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. [Display omitted] • 17 selaginellin derivatives including 5 previously undescribed compounds were isolated from Selaginella tamariscina. • Dimeric selaginellin 17 showed remarkable activity against MDA-MB-231 cells. • Dimeric selaginellin 17 could cause the G2/M phase arrest of MDA-MB-231 cells. • Dimeric selaginellin 17 could markedly induce apoptosis accompanied by increased ROS production. [ABSTRACT FROM AUTHOR]

• Study on sporophyll arrangement in Selaginella species from Arunachal Pradesh. • 16 Patterns of sporophyll arrangement in strobili recorded. • Few patterns were found common among spreading and non-spreading species. • Box plot analysis representing size variations in strobili and sporophylls among different species. The study on sporangial arrangement patterns in strobili of Selaginella species from Arunachal Pradesh, India aims to provide a morphological analysis of strobili in 20 species of Selaginella. The study recorded variations in the distributional patterns of sporangia in the strobili within and among the Selaginella species. It provides a detailed description of the position and features of strobili, the number and position of microsporangia and megasporangia per strobili, the shape, size and margin of sporophylls and the number of megaspores per megasporangium which are useful in taxonomic delimitation. We provided photo plates of strobili in 20 species of the genus, 16 patterns of sporangial arrangement and a table which includes sampling details along with statistical analysis based on the size of strobili and sporophylls. [ABSTRACT FROM AUTHOR]

The recent study deals with the synthesis and characterization of silver nanoparticles bounded to Selaginella bryopteris (Sanjeevini) Plant extract (SPE) as reducing and capping agents. Selaginella bryopteris plant extract silver nanoparticles (SPE@Ag-NPs) was characterized by PXRD, UV–Vis., FESEM, TEM and EDX. The highly stable SPE@Ag-NPs was found promising as antibacterial and antifungal agents when tested against human pathogens S. aureus, E. coli, and A. niger respectively. Furthermore, SPE@Ag-NPs found to show anticoagulant property by enhancing the clotting time of citrated human PRP as well as PPP from the control 160 s to 220 s and 160 s to 284 s respectively. However, SPE@Ag-NPs exhibited mild antiplatelet activity by inhibiting specifically agonist ADP induced platelet aggregation of about 23% at the concentration of 30 μg. Fascinating, SPE@Ag-NPs did not alter the agonist epinephrine-induced platelet function even at the increased dose. Interestingly, SPE@Ag-NPs did not induce edema and hemorrhage in the experimental mice and also did not hydrolyze RBC cells suggesting its nontoxic property. In conclusion, SPE@Ag-NPs was non-toxic and found to exhibit antibacterial, antifungal, anticoagulant and antiplatelet properties. Thus, SPE@Ag-NPs would be a better candidate in the biomedical field especially to treat thrombotic disorders. Unlabelled Image • Silver nanoparticles with an average size of 5-10 nm are synthesized and stabilized by a Selaginella Plant extract (SPE). • SPE supported silver nanoparticles, SPE@Ag-NPs are characterized by UV-Vis., FT-IR, FE-SEM, TEM, EDX, and PXRD. • SPE@Ag-NPs showed antibacterial, anticoagulant and antiplatelet activity. [ABSTRACT FROM AUTHOR]

Highlights • Comparative structural characterization of leaf cell walls of desiccation-tolerant and desiccation-sensitive Selaginella species. • Leaf cell walls Selaginella species are mainly composed of hemicellulosic polysaccharides namely arabinoxylan, mannan and xyloglucan. • Desiccation induces significant structural alterations of the xyloglucan and arabinoxylan in S. involvens compared to S. kraussiana and S. moellendorffii. • Structural remodeling of these hemicellulosic polysaccharides is an important process leading to desiccation tolerance in Selaginella plants. Abstract Drought-induced dehydration of vegetative tissues in lycopods affects growth and survival. Different species of Selaginella have evolved a series of specialized mechanisms to tolerate desiccation in vegetative tissues in response to water stress. In the present study, we report on the structural characterization of the leaf cell wall of the desiccation-tolerant species S. involvens and two desiccation-sensitive species, namely S. kraussiana and S. moellendorffii. Isolated cell walls from hydrated and desiccated leaves of each species were fractionated and the resulting oligosaccharide fragments were analyzed to determine their structural features. Our results demonstrate that desiccation induces substantial modifications in the cell wall composition and structure. Altogether, these data highlight the fact that structural remodeling of cell wall hemicellulosic polysaccharides including XXXG-rich xyloglucan, arabinoxylan and acetylated galactomannan is an important process in order to mitigate desiccation stress in Selaginella. [ABSTRACT FROM AUTHOR]

Highlights • Ligule morphology of both vegetative and reproductive leaves of four species of Selaginella. • The shape of ligules is generally constant and alone could not useful in taxonomic delineation of taxa. • The size of ligules may be influence by the habitat condition of plants. • The glandular cells at tip margin possibly indicates water secreting function of ligule. • Shuttlecock-shaped ligule in S. ganguliana is reported for the first time. Abstract The article presents the results of a study of the ligule morphology of both vegetative and reproductive leaves of four species of Selaginella , i.e. S. delicatula , S. ganguliana , S. plana and S. tenera , occurring in India. Ligules of S. ganguliana , S. plana and S. tenera are described for the first time, and the occurrence of shuttlecock-like ligules is described for the first time. Ligule shape is generally constant across the species studied but some minor morphological variations are observed within species. However, in combination with other morphological characters, the ligule may be a useful tool in the taxonomic delimitation of closely related Selaginella species. In addition, we propose that ligule size may be influenced by the habitat conditions, whereas the presence of glandular cells at their tip margins possibly indicate a water secreting function. [ABSTRACT FROM AUTHOR]

In vascular plants, the thylakoid architecture is dominated by the highly structured multiple membrane layers known as grana. The structural diversity of the thylakoid system among plant species is mainly determined by the adaptation to the growth light regime, according to a paradigm stating that shade-tolerant species are featured by a high membrane extension with an enhanced number of thylakoid layers per granum. In this study, the thylakoid system was analysed in Selaginella martensii Spring, a shade-adapted rainforest species belonging to lycophytes, a diminutive plant lineage, sister clade of all other vascular plants (euphyllophytes, including ferns and seed plants). The species is characterized by giant cup-shaped chloroplasts in the upper epidermis and, quantitatively less important, disk-shaped chloroplasts in the mesophyll and lower epidermis. The study aimed at the quantitative assessment of the thylakoid appression exploiting a combination of complementary methods, including electron microscopy, selective thylakoid solubilisation, electron paramagnetic resonance, and simultaneous analysis of fast chlorophyll a fluorescence and P700 redox state. With a chlorophyll a / b ratio of 2.6 and PSI/PSII ratio of 0.31, the plant confirmed two typical hallmarks of shade-adaptation. The morphometric analysis of electron micrographs revealed a 33% fraction of non-appressed thylakoid domains. However, contrasting with the structural paradigm of thylakoid shade-adaptation in angiosperms, S. martensii privileges the increase in the granum diameter in place of the increase in the number of layers building the granum. The very wide grana diameter, 727 nm on average, largely overcame the threshold of 500 nm currently hypothesized to allow an effective diffusion of long-range electron carriers. The fraction of non-appressed membranes based on the selective solubilisation of thylakoids with digitonin was 26%, lower than the morphometric determination, indicating the presence of non-appressed domains inaccessible to the detergent, most probably because of the high three-dimensional complexity of the thylakoid system in S. martensii. Particularly, strong irregularity of grana stacks is determined by assembling thylakoid layers of variable width that tend to slide apart from each other as the number of stacked layers increases. • Selaginella martensii shows photosynthetic hallmarks of shade adaptation. • Wide grana diameter prevails over the stacking of several layers. • 500 nm is not an upper threshold to the granum diameter. • Strong irregularity of grana leads to a structurally complex thylakoid system. • Not all stroma-exposed thylakoid domains are accessible to digitonin. [ABSTRACT FROM AUTHOR]

The detection of highly toxic Pb2+ ions has propelled the exploration of green chemistry as an environmentally benign approach to synthesizing gold nanoparticles (AuNPs) for sensing applications. Herein, a simple green synthesis method is presented without utilizing optimization conditions for stable and well-disperse AuNPs for Pb2+ ions colorimetric sensing. The Selaginella bryopteris plant (SBp) extract as a reducing, capping, stabilizing, and chelating agent was employed in the volume ratio-controlled synthesis of AuNPs. The AuNPs were characterized using UV-Vis, XRD, FTIR, and TEM analysis. The results revealed polycrystalline AuNPs with SPR, particle size, and crystallite size-tunable by SBp extract. The AuNPs bound by Pb2+ ions showed immediate aggregation and excellent selectivity compared to other metal ions (Ca2+, Cd2+, Co2+, Cu2+, Fe2+, Hg2+, Mg2+, Mn2+, Ni2+, Zn2+, and Na+). A linear colorimetric response of AuNPs was observed in the 10–60 µM Pb2+ ions concentration range and the R2 obtained was 0.99654 with LoD of 0.24 µM. The best detection of Pb2+ ions was achieved in a pH range from 3 to 9. The study suggests that the SBp extract-tunable AuNPs synthesis could be used as a sustainable and simple approach for Pb2+ ions detection in the natural environment. [Display omitted] • Simple green synthesis with Selaginella bryopteris plant extract as reducing, capping, stabilizing, and chelating agent. • Very stable and different-colored gold nanoparticles are synthesized without optimizing the synthesis conditions. • Surface plasmon resonance (SPR), nanoparticle size, and crystallite size-tunable biosynthesis method were developed. • Gold nanoparticles demonstrated excellent and rapid selectivity for lead ions (Pb2 +) across a wide pH range. [ABSTRACT FROM AUTHOR]

Lycophytes are early diverging vascular plants, representing a minor group as compared to the dominating euphyllophytes, mostly angiosperms. Having maximally developed in a CO 2 -rich atmosphere, extant lycophytes are characterized by a low carbon fixing capacity, which is compensated by a marked ability to induce the non-photochemical quenching of chlorophyll fluorescence ( NPQ ). Different kinetic components contribute to NPQ , in particular the fast relaxing high-energy quenching qE, the middle relaxing qT, and the slowly relaxing qI. Unlike angiosperms, lycophytes enhance the qT component under high light, originating from an “extra-qT”. In this research, we analyze whether in Selaginella martensii the extra-qT can reflect a photosystem (PS) I-based quenching mechanism activated upon saturation of qE capacity. From comparative analyses of fluorescence quenching parameters, carbon fixation, in vivo low- and room-temperature fluorescence spectroscopy, and thylakoid protein phosphorylation, it is proposed that the extra-qT is not mechanistically separate from the ordinary qT. The results suggest a relationship between qT and photoprotective energy spillover to PSI, which is activated upon sensing the excitation energy pressure inside PSII and is possibly facilitated by phosphorylation of Lhcb6, a minor antenna protein of PSII. Energy spillover emphasizes 77 K fluorescence emission from PSI core (F714) and becomes more relevant at irradiance levels corresponding to the CO 2 -limited, potentially photoinhibiting phase of photosynthesis. At the highest irradiances, when Lhcb6 phosphorylation potential has been saturated, the major LHCII increases in turn its phosphorylation level, probably leading to the full exploitation of PSI as a safe excitation sink. It is suggested that the low photosynthetic capacity of lycophytes could allow an easier experimental access to the use of PSI as a safe excitation quencher for PSII, a debated, emerging issue about thylakoid photoprotection in angiosperms. [ABSTRACT FROM AUTHOR]

Three new compounds, pictalignans A ( 1 ), B ( 2 ), C ( 3 ), along with three known analogues, syringaresinol ( 4 ), 3,3′,5-trimethoxy-4′,7-epoxy-8,5′-neoligan-4′,9,9′-triol ( 5 ), 4,9-dihydroxy-4′,7-epoxy-8′,9′-dinor-8,5′-neolignan-7′-oic acid ( 6 ) were isolated from the 75% aqueous ethanol extract of Selaginella picta . Their structures were established by physicochemical properties and spectroscopic methods, and absolute configurations of new compounds were elucidated by experimental and calculated ECD spectra. Compounds 1 – 3 are neolignans with additional one or two C 6 -C 3 structural units attached to hydroxypropyl group, which are extremely rare in nature. All new compounds exhibited moderate protective effect against the injury of HT-22 cells induced by L-Glutamate in vitro , and compound 1 showed better protective effect than positive drug with the concentrations of 10 μM to 15 μM. [ABSTRACT FROM AUTHOR]

Selaginella doederleinii Hieron is a widely used as folk Chinese medicine for treatment of different cancers. Our previous investigations have confirmed that the total biflavonoids in ethyl acetate extract from S. doederleinii (SDEA) have favorable anticancer potentials. However, the in vivo process of its bioactive ingredients remains unknown. In this paper, a sensitive and reliable method was developed for simultaneous quantification of main five biflavonoids, including amentoflavone, robustaflavone, 2″,3″-dihydro-3′,3″-biapigenin, 3′,3″-binaringenin and delicaflavone in the ethyl acetate extract of S. doederleinii (SDEA extract) in rat plasma by high-performance liquid chromatography with electrospray ionization-mass spectrometry (HPLC-ESI–MS/MS). Chromatographic separation was performed using an Ultimate ® XB-C18 (100 × 2.1 mm, 3.5 μm) with gradient elution of water (0.5% acetic acid) and acetonitrile at 0.2 mL/min. All analytes with internal standard (chrysin) were detected using selective reaction monitoring (SRM) in negative ionization mode. The method showed a good linearity over a wide concentration range (r 2 > 0.99). The limits of quantification for the biflavonoids were less than 10 ng/mL. The developed method was applied to the comparatively pharmacokinetic study of the five biflavonoids after oral or intravenous administration of SDEA extract in rats. In addition, in silico assessments of permeability and solubility of these biflavonoids were also performed to understand their poor bioavailability. It is the first time to report the in vivo process profiles of the biflavonoids of SDEA extract in rats. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Eight triflavonoids, selagintriflavonoids A-H, were isolated from whole herbs of Selaginella doederleinii . The structures of compounds selagintriflavonoids A-C consisted of three naringenin units, whereas those of selagintriflavonoids D-H consisted of apigenin and two naringenin moieties. The structures and absolute configurations of the compounds were determined based on NMR, HRESIMS, and experimental and calculated electronic circular dichroism (ECD) data. The ability of the compounds to inhibit β -secretase (BACE1) was also evaluated. All compounds exhibited BACE1 inhibition with IC 50 values ranging from 0.75 to 46.99 μ M. Selagintriflavonoid A exhibited the strongest inhibition (0.75 μ M) and is thus a promising compound for treating Alzheimer's disease. [ABSTRACT FROM AUTHOR]

The chemical characterization of Selaginella tamariscina leaves resulted in the isolation of five lignanoside derivatives ( 1 – 4 and 6 ) and one neolignan ( 5 ). These compounds include three new lignanosides, tamariscinosides D–F ( 1 – 3 ), and one liriodendrin ( 4 ) that were isolated for the first time from this plant, together with two known compounds, (2 R ,3 S )-dihydro-2-(3,5-dimethoxy-4-hydroxyphenyl)-7-methoxy-5-acetyl-benzofuran ( 5 ) and moellenoside B ( 6 ). The chemical structures of these isolated compounds were determined using 1D and 2D NMR, MS, and CD spectroscopic data, and the results were compared to data previously reported in the literatures. These compounds were also evaluated in terms of their inhibition of NO production in lipopolysaccharide (LPS)-stimulated activity in the macrophage cell line RAW 264.7. Among them, compounds 1 , 2 , 5 , and 6 exhibited a significant inhibition with IC 50 values ranging from 32.3 to 55.8 μM. [ABSTRACT FROM AUTHOR]

Six new flavonoids, seladoeflavones A–F ( 1 – 6 ), were isolated from the whole herbs of Selaginella doederleinii , together with one known flavonoid ( 7 ). Their structures including absolute configuration were characterized on the basis of extensive spectroscopic methods including NMR, HRMS, and electronic circular dichroism (ECD). All compounds consist of an aryl substituent at the C-3′ position of naringenin or apigenin skeletons, and compounds 1 and 6 were identified as R configurations, which are uncommonly encountered in nature. A possible biosynthetic pathway was postulated. In addition, bioassay of the isolates revealed that 5 – 7 exhibited moderate cytotoxicity against three human cancer cell lines NCI-H460, A549, and K562 in vitro with IC 50 values ranging from 8.17 to 18.66 μM. [ABSTRACT FROM AUTHOR]

[Display omitted] • Amentoflavone (AME) and robustaflavone (ROB) were firstly extracted from S. uncinata with eco-friendly DES. • 30 DESs were prepared, novel proline-lactic acid (Pro-Lac) was selected as the optimal DESs. • DES method exhibited higher extraction efficiency than the traditional methods. • 23 flavonoids were identified in S. uncinata by UPLC-Q-TOF-MS, in which 6 compounds were first discovered. • DES extract proved to have promising antioxidant and anticancer activity. • The selected DES has good recyclability and reusability. In this study, ultrasonic-assisted deep eutectic solvents (DESs-UAE) was applied for efficient and environmentally friendly extraction of amentoflavone (AME) and robustaflavone (ROB) from Selaginella uncinata. Firstly, proline-lactic acid (Pro-Lac) was screened as the optimal DES from the 30 DESs. The maximum extraction rates of AME and ROB were obtained adopting the response surface methodology (RSM). Under the optimal conditions of molar ratio of 1:4, water content of 33 %, and extraction time of 30 min, the extraction yields of AME and ROB were 709.72 ± 11.31 μg/g and 145.13 ± 9.77 μg/g, respectively. Compared with the traditional extraction methods, the DESs-UAE extraction could enhance the extraction rates and save extraction time. At the same time, 23 flavonoids were identified by UPLC-Q-TOF-MS, of which 6 components appeared for the first time in S. uncinata. In addition, three antioxidant experiments (DPPH method, ABTS method, and hydroxyl radical scavenging method) were carried out, and the results showed that the S. uncinata extracts had potential antioxidant activity. Furthermore, S. uncinata extracts exhibited obvious growth inhibitory effect on A549, HCT-116, HT-29, sw1990, HepG2 and HeLa cancer cells. In conclusion, deep eutectic solvent, as an promising solvent, is much more effective and simple extraction of bioactive constituents from S. uncinata with high safety and low toxicity. [ABSTRACT FROM AUTHOR]

Five new carboxymethyl flavonoids named 5-carboxymethyl-3′, 4′, 7-trihydroxyflavone ( 1 ), (2 S )- 5-carboxymethyl-3′, 4′, 7-trihydroxyflavonone ( 2a ), (2 R )-5-carboxymethyl-3′, 4′, 7-trihydroxyflavonone ( 2b ), (2 S )-5-carboxymethyl-4′, 7-dihydroxyflavonone ( 3 ), 5- carbomethoxymethyl-4′, 7-dihydroxyflavone ( 4 ), and a new chromone named 5-carboxymethyl-7-hydroxychromone ( 5 ), together with two known compounds 5-carboxymethyl-4′-hydroxyflavone-7- O - β - d -glucopyranoside ( 6 ), 5-carboxymethyl-4′, 7-dihydroxyflavone ( 7 ) were isolated from Selaginella moellendorffii Hieron. Their structures including absolute configuration were elucidated by extensive spectroscopic methods and experimental electronic circular dichroism (ECD) spectra. What's worth mentioning is that a carboxymethyl substituent appeared at the C-5 position of all isolated compounds, only recently discovered in genus Selaginella . Compounds 2a and 2b were identified as a pair of chiral isomers; compound 5 was discovered as the first chromone comprising a carboxymethyl side chain. Furthermore, all compounds were evaluated for their antibacterial activities against various Gram-positives and Gram-negatives, and compared to the reference drugs amoxicillin and norfloxacin. As a result, compounds 3 and 4 exhibited as potent antimicrobial agents with a broad spectrum, and compound 5 appeared as the most promising one to combat Gram-positives. [ABSTRACT FROM AUTHOR]

Nonclassical P450s of CYP74 family control the secondary conversions of fatty acid hydroperoxides to bioactive oxylipins in plants. At least ten genes attributed to four novel CYP74 subfamilies have been revealed by the recent sequencing of the spikemoss Selaginella moellendorffii Hieron genome. Two of these genes CYP74M1 and CYP74M3 have been cloned in the present study. Both recombinant proteins CYP74M1 and CYP74M3 were active towards the 13( S )-hydroperoxides of α-linolenic and linoleic acids (13-HPOT and 13-HPOD, respectively) and exhibited the activity of divinyl ether synthase (DES). Products were analyzed by gas chromatography–mass spectrometry. Individual oxylipins were purified by HPLC and finally identified by their NMR data, including the 1 H NMR, 2D-COSY, HSQC and HMBC. CYP74M1 (SmDES1) specifically converted 13-HPOT to (11 Z )-etherolenic acid and 13-HPOD to (11 Z )-etheroleic acid. CYP74M3 (SmDES2) turned 13-HPOT and 13-HPOD mainly to etherolenic and etheroleic acids, respectively. CYP74M1 and CYP74M3 are the first DESs detected in non-flowering plants. The obtained results demonstrate the existence of the sophisticated oxylipin biosynthetic machinery in the oldest taxa of vascular plants. [ABSTRACT FROM AUTHOR]

Three undescribed biflavonoids (BFVs), siamenflavones A–C along with twelve BFVs were isolated from Selaginella siamensis Hieron. and Selaginella bryopteris (L.) Baker (Selaginellaceae). The chemical structures of undescribed compounds were established through comprehensive spectroscopic techniques, chemical correlations, and X-ray crystallography. The ten isolated BFVs, siamenflavones A–C, delicaflavone, chrysocauflavone, robustaflavone, robustaflavone-4-methylether, amentoflavone, tetrahydro-amentoflavone, and sciadopitysin were evaluated for the antiproliferative effects against four human cancer cell lines A549, H1975, HepG2 and T47D. Delicaflavone and robustaflavone 4′-methylether exerted strong effects on the four human cancer cell lines. Siamenflavone B, delicaflavone and robustaflavone 4′-methylether showed potent inhibitory activities against wild-type EGFR. The inhibition of the compounds was further supported by molecular docking and predictive intermolecular interactions. Molecular dynamics simulation studies of siamenflavone B and robustaflavone-4′-methylether complexed to EGFR-TK further supported inhibition of the compounds to the ATP binding site. Finally, analysis of pharmacokinetic and electronic properties using density-functional theory and known drug index calculations suggest that the compounds are pharmaceutically compatible for drug administration. Investigation of the MeOH extract of two spike mosses led to the isolation of three undescribed and twelve known biflavonoids with potent inhibitory activities against wild-type EGFR. [Display omitted] • Siamenflavones A-C were isolated from a native Thai spike moss Selaginella siamensis. • Isolated bioflavonoids showed potent inhibitory activities against wild-type EGFR. • Robustaflavone-4′-methylether showed the most potent antiproliferative effect. [ABSTRACT FROM AUTHOR]

The triterpene squalene is a key metabolic intermediate for sterols, hopanoids and various other triterpenoids. The biosynthesis of squalene is catalyzed by squalene synthase (SQS), which converts two molecules of farnesyl diphosphate to squalene. In this study, a lycophyte Selaginella moellendorffii was found to emit squalene as a volatile compound under a number of conditions that mimic biotic stresses. Searching the genome sequence of S. moellendorffii led to the identification of a putative squalene synthase gene. It was designated as SmSQS . SmSQS is homologous to known squalene synthases from other plants and animals at both the amino acid level and structural level. Recombinant SmSQS expressed in Escherichia coli catalyzed the formation of squalene using farnesyl diphosphate as substrate. The expression of SmSQS was significantly induced by the same set of stress factors that induced the emission of volatile squalene from S. moellendorffii plants. Taken together, these results support that SmSQS is responsible for the biosynthesis of volatile squalene and volatile squalene may have a role in the defense of S. moellendorffii plants against biotic stresses. [ABSTRACT FROM AUTHOR]

Six new flavonoids, involvenflavones A–F ( 1 – 6 ), were isolated from Selaginella involven . Their structures were elucidated based on UV, IR, 1D and 2D NMR as well as HR-ESI-MS techniques. All compounds belong to apigenin derivatives with 3′-aryl substituent. This is the first report of the apigenin derivatives with 3′-aryl substituent from nature resources. These compounds also exhibited a potent effect against the injury of human umbilical vein endothelial cell (HUVECs) induced by high concentrations of glucose in vitro. [ABSTRACT FROM AUTHOR]

As part of an ongoing search for new antidiabetic agents from medicinal plants, the methanol extract of the aerial parts of Selaginella tamariscina was found to possess stimulatory effect on glucose uptake in 3T3-L1 adipocyte cells. Thus, bioassay-guided isolation of this active extract yielded two new compounds ( 1 and 2 ) along with five known biflavonoids ( 3 – 7 ). Their structures were elucidated by extensive analysis of spectroscopic and physicochemical data. The absolute configuration of compound 2 was determined by specific rotation and CD data analysis. All isolates exhibited potent inhibitory effects on PTP1B enzyme with IC 50 values ranging from 4.5 ± 0.1 to 13.2 ± 0.8 μM. Furthermore, the isolates ( 1 – 7 ) showed significant stimulatory effects on 2-NBDG uptake in 3T3-L1 adipocyte cells. Of these, compounds ( 1 , 6 , and 7 ) which exhibited mixed-competitive inhibition modes against PTP1B, showed potent stimulatory effects on 2-NBDG uptake. This result indicated the potential of these biflavonoids as lead molecules for development of antidiabetic agents and the beneficial use of S. tamariscina against hyperglycemia. [ABSTRACT FROM AUTHOR]

Nine selaginellin derivatives, including a novel isoquinoline-type selaginellin named selaginisoquinoline A ( 1 ), and three ethoxy selaginellins P–R ( 2 – 4 ), were isolated from the plant of Selaginella pulvinata . Their structures were determined by extensive spectroscopic analyses, and single-crystal X-ray diffraction, as well as CD calculations. Selaginisoquinoline A ( 1 ) is a racemate due to quinone methide-phenol tautomerism; while in the case of selaginellins P–R ( 2 – 4 ), whose tautomerism was blocked by alkylation of C10–OH, the interesting racemization process is induced by axial chirality and molecular rotation, thus existing as a pair of slowly interconverting enantiomers. Compounds 3 , 5 and 9 showed moderate cytotoxicity against BGC-823 human gastric cancer cell line. All compounds, including four enantiomers, exhibited good antifungal activities against four pathogenic fungi cell lines with MIC 80 values in the range of 4–32 μg/mL. [ABSTRACT FROM AUTHOR]

Six new flavonoids, unciflavones A–F ( 1 – 6 ), have been isolated from medicinal plant Selaginella uncinata (Desv.) Spring. Their structures were established on the basis of extensive NMR analysis including 1D NMR ( 1 H, 13 C and DEPT) and 2D NMR (COSY, HSQC, HMBC) experiments as well as HRESIMS analysis. All compounds possess exceptional structural features with an aryl substituent at the C-8 position, which are uncommonly encountered in natural resources and firstly reported in genus Selaginella . [ABSTRACT FROM AUTHOR]

Insufficient acetylcholine (ACh) can cause cognitive and memory dysfunction, clinically known as, Alzheimer's disease (AD). Acetylcholinesterase (AChE) can hydrolyze ACh into acetic acid and inactivate choline. Therefore, inhibiting the activity of AChE would help to improve the effectiveness of AD treatment. Currently, the methods for rapid screening of AChE inhibitors are limited. This study reports the application of AChE-immobilized magnetic nanoparticles as a drug screening tool to screen AChE inhibitors for natural products. First, AChE was immobilized on a surface of amino-modified magnetic nanoparticles using covalent binding and the AChE concentration, and the pH as well as time was optimized to obtain the maximum enzyme immobilization yield (61.4 μg/mg), and the kinetic model indicated that AChE-immobilized magnetic nanoparticles and the substrate had the high affinity and specificity. Then, a ligand fishing experiment was carried out using a mixed model of tacrine (an inhibitor of AChE) and caffeic acid (a non-inhibitor of AChE) to verify the specificity of the immobilized AChE, and the conditions for ligand fishing were further optimized. Finally, the optimized immobilized AChE was combined with UPLC-MS to screen for AChE inhibitors in Selaginella doederleinii Hieron extracts. Four compounds were confirmed to be potent AChE inhibitors. Among the four compounds, amentoflavone had a stronger AChE inhibitory effect than tacrine (positive control) with an IC 50 of 0.73 ± 0.009 μmol/L. The results showed that AChE-functionalized magnetic nanoparticles can be used in the discovery of target drugs from complex matrices. [Display omitted] • A screening method using magnetic nanoparticles-based acetylcholinesterase microreactor (immobilized AChE) was established. • Immobilized AChE was firstly applied for the AChE ligand fishing from Selaginella doederleinii Hieron. • The immobilized AChE based assay offers a novel anti-acetylcholinesterase drug discovery tool. • The method may be used to other enzymes to screen bioactive ligands. [ABSTRACT FROM AUTHOR]

Abstract: Amentoflavone (8-[5-(5,7-dihydroxy-4-oxo-chromen-2-yl)-2-hydroxy-phenyl]-5,7-dihydroxy-2-(4-hydroxyphenyl) chromen-4-one; AF) is a biflavonoid derived from the extracts of Selaginella tamariscina. It has been shown that AF has diverse biological effects such as antitumour, etc. It is well known that high cell proliferation, viability, angiogenesis and low apoptosis are key factors in hypertrophic scar formation. In this study, we report that AF inhibited viability and stimulated apoptosis in hypertrophic scar fibroblasts (HSFBs). Incubation of HSFBs with AF showed its inhibitory effect on cell viability and the exhibition of a series of cellular changes that were consistent with apoptosis. By Western-blot analysis, our data indicated significant increases in the amounts of cleaved caspases 3, 8, 9 and Bax, several apoptotic promoters and a significant decrease in translationally controlled tumour protein (TCTP), an apoptotic inhibitor, in HSFBs treated with AF. Furthermore, AF showed significant inhibitions on the viability, migration and tube formation of endothelial cells, which are associated with angiogenesis. In conclusion, this study suggests that AF stimulates apoptosis in HSFBs and inhibits angiogenesis of endothelial cells. Therefore, AF is a promising molecule that can be used in hypertrophic scar treatment. [Copyright &y& Elsevier]

Abstract: Selaginella lepidophylla is a desiccation tolerant plant able to survive complete vegetative tissue dehydration and revive (‘resurrect’) in water conditions. Vegetative desiccation tolerance is an adaptive feature acquired by S. lepidophylla to withstand the long dry periods in its natural habitat, the Chihuahuan desert. Understanding the molecular basis of its drought stress tolerance may be of great benefit to help in developing novel strategies for improvement of drought stress tolerance in crops. Cell biological (e.g. gene discovery, comparative EST analysis, proteomics, metabolite profiling), ultrastructural and physiological studies have brought modest but already important insights in the desiccation tolerance mechanisms adapted by S. lepidophylla. Until recently, the desiccation tolerant mechanism of S. lepidophylla was related to its high trehalose levels. However, large-scale comparative metabolic analysis between S. lepidophylla and its desiccation susceptible relative Selaginella moellendorffii, unexpectedly revealed that S. moellendorffii contains higher trehalose levels than S. lepidophylla. Interestingly, polyols, such as sorbitol and xylitol are 100× more abundant in S. lepidophylla compared to S. moellendorffii. Whether this is linked to the higher stress tolerance remains to be established. Apart from these metabolites, we will also discuss the ultrastructural features that seem to play an important role in the desiccation tolerance of S. lepidophylla. Finally we discuss desiccation tolerance mechanism in other plant species. [Copyright &y& Elsevier]

Highlights: [•] NF-Y TFs encoded by HAP gene family bind to the CCAAT-containing promoter sequences. [•] We characterize duplicated HAP genes in Selaginella moellendorffii. [•] Evolutionary relationships of LEC1-type of HAP3 genes have been studied. [•] Detect thermodynamically stable conserved RNA secondary structures. [•] Identified several conserved motifs in LEC1 proteins among all plant lineages during evolution. [Copyright &y& Elsevier]

A unique case of liverwort mimesis in lacewing larvae of Phyllochrysa huangi has been reported from the mid-Cretaceous Kachin amber, Myanmar. However, we caution to take this interpretation for granted because of the still incomplete assessment of the plant diversity preserved in the Kachin amber inclusions. Our re-examination of the plant fossils regarded as models for Phyllochrysa huangi received evidence for a new species of the lycophyte genus Selaginella , namely S. cretacea sp. nov., and two indeterminate species of Selaginella , besides four species of the leafy liverwort family Frullaniaceae, including Frullania baerlocheri , F. kachinensis , F. partita , and Protofrullania cornigera. Careful morphological comparison recovered that the flat larvae of Phyllochrysa huangi closely match the dorsiventrally complanate strobili of Selaginella subgenus Stachygynandrum (lycophytes) represented by S. cretacea sp. nov. In turn, the larval morphology did not show obvious similarities with the shoots of the leafy liverworts. In the context of the improved taxonomic survey of the plant inclusions, it is evident that the so-called liverwort mimesis in Cretaceous lacewing larvae was actually lycophyte mimesis. The larvae of Phyllochrysa huangi provided the earliest evidence of a putative extinct Phyllochrysa - Selaginella mimetic system. • A fertile lycophyte is described as Selaginella cretacea sp. nov. in Kachin amber. • Selaginella cretacea expands the palaeodiversity of spike mosses in Kachin amber. • Liverwort mimesis in a Cretaceous lacewing larva is actually lycophyte mimesis. • The larvae provide earliest fossil evidence of Phyllochrysa - Selaginella mimesis. [ABSTRACT FROM AUTHOR]

Six flavonoids, namely, three undescribed biflavonoids, one undescribed 8-aryl flavonoid, and two known compounds, were isolated from Selaginella tamariscina (P.Beauv.) Spring. The structures and absolute configurations of those undescribed compounds were established by NMR spectroscopy data, HRESIMS analyses and electronic circular dichroism (ECD) analyses. In addition, all the isolates were evaluated for their hypoglycemic activity in HepG2 cells. Involvenflavone H, I, and J significantly increased glucose consumption in both normal and insulin-resistant HepG2 cells. Interestingly, these three compounds can effectively upregulate the protein expression of glucokinase (GCK) and adenylate cyclases (ADCYs). These results suggested that involvenflavone H, I, and J (especially involvenflavone J) may have potent hypoglycemic activity, which also provided promising molecular targets for the treatment of diabetes. [Display omitted] • Four undescribed flavonoids were isolated from Selaginella tamariscina (P.Beauv.) Spring. • Involvenflavone H, I, and J significantly increased the glucose consumption in insulin-resistant HepG2 cells. • Involvenflavone J up-regulated the protein expression of glucokinase and adenylate cyclases effectively. [ABSTRACT FROM AUTHOR]

Nonclassical P450s of the CYP74 family catalyse the secondary conversions of fatty acid hydroperoxides to bioactive oxylipins in plants. The model organism, spikemoss Selaginella moellendorffii Hieron, possesses at least ten CYP74 genes of novel J, K, L, and M subfamilies. The cloning of three CYP74L genes and catalytic properties of recombinant proteins are described in the present work. The CYP74L1 possessed mainly hydroperoxide lyase (HPL) activity towards the 13(S)-hydroperoxide of α−linolenic acids (13-HPOT) and nearly equal HPL and allene oxide synthase (AOS) activities towards the 13(S)-hydroperoxide of linoleic acids (13-HPOD). The 9-hydroperoxides were poor substrates for CYP74L1 and led to the production of mainly the α−ketols (AOS products) and minorities of HPL and epoxyalcohol synthase (EAS) products. The CYP74L2 possessed the AOS activity towards all tested hydroperoxides. CYP74L3 possessed low HPL/EAS activity. Besides, the aerial parts of S. moellendorffii plants possessed complex oxylipins patterns including divinyl ethers, epoxyalcohols, and 12-oxo-phytodienoic acid. Characterization of the CYP74L enzymes and oxylipin pattern updates the knowledge on the complex oxylipin biosynthetic machinery in the surviving oldest taxa of vascular plants. [Display omitted] • The coding sequences of Selaginella moellendorffii CYP74L genes have been cloned. • The recombinant CYP74L1 possesses mainly hydroperoxide lyase activity. • The recombinant CYP74L2 exhibits allene oxide synthase activity. • CYP74Ls append the complex picture of oxylipin biosynthesis in oldest land plants. [ABSTRACT FROM AUTHOR]

Highlights: [•] STE possesses anti-inflammatory and anti-cancer activities. [•] STE inhibits migration/invasion capacities of U2OS. [•] STE inhibits MMP-2 and MMP-9 activities and expressions. [•] STE inhibits phosphorylation of p38 and Akt. [ABSTRACT FROM AUTHOR]

Abstract: Regulation of nitrate reductase (NR) by reversible phosphorylation at a conserved motif is well established in higher plants, and enables regulation of NR in response to rapid fluctuations in light intensity. This regulation is not conserved in algae NR, and we wished to test the evolutionary origin of the regulatory mechanism by physiological examination of ancient land plants. Especially a member of the lycophytes is of interest since their NR is candidate for regulation by reversible phosphorylation based on sequence analysis. We compared Selaginella kraussiana, a member of the lycophytes and earliest vascular plants, with the angiosperm Arabidopsis thaliana, and also tested the moss Physcomitrella patens. Interestingly, optimization of assay conditions revealed that S. kraussiana NR used NADH as an electron donor like A. thaliana, whereas P. patens NR activity depended on NADPH. Examination of light/darkness effects showed that S. kraussiana NR was rapidly regulated similar to A. thaliana NR when a differential (Mg2+ contra EDTA) assay was used to reveal activity state of NR. This implies that already existing NR enzyme was post-translationally activated by light in both species. Light had a positive effect also on de novo synthesis of NR in S. kraussiana, which could be shown after the plants had been exposed to a prolonged dark period (7 days). Daily variations in NR activity were mainly caused by post-translational modifications. As for angiosperms, the post-translational light activation of NR in S. kraussiana was inhibited by 3-(3,4-dichlorophenyl)-1*1-dimethylurea (DCMU), an inhibitor of photosynthesis and stomata opening. Evolutionary, a post-translational control mechanism for NR have occurred before or in parallel with development of vascular tissue in land plants, and appears to be part of a complex mechanisms for coordination of CO2 and nitrogen metabolism in these plants. [Copyright &y& Elsevier]

Abstract: A homologous sequence was amplified from resurrection plant Selaginella pulvinta by RACE technique, proved to be the full-length cDNA of trehalose-6-phosphate synthase gene by homologous alignment and yeast complementation assay, and nominated as SpTPS1 gene. The open reading frame of this gene was truncated 225bp at the 5′-end, resulting the N-terminal truncation modification of 75 amino acids for its encoding protein. The TPS1 deletion mutant strain YSH290 of the brewer''s yeast transformed by the truncated gene SpTPS1Δ and its original full-length version restored growth on the medium with glucose as a sole carbon source and displayed growth curves with no significant difference, indicating their encoding proteins functioning as TPS enzyme. The TPS activity of the mutant strain transformed by the truncated gene SpTPS1Δ was about six fold higher than that transformed by its original version, reasoning that the extra N-terminal extension of the full-length amino acid sequence acts as an inhibitory domain to trehalose synthesis. However, the trehalose accumulation of the mutant strain transformed by the truncated gene SpTPS1Δ was only 8% higher than that transformed by its original version. This result is explained by the feedback balance of trehalose content coordinated by the comparative activities between trehalose synthase and trehalase. The truncated gene SpTPS1Δ is suggested to be used in transgenic operation, together with the inhibition of trehalase activity by the application of validamycin A or genetic deficiency of the endogenous trehalase gene, for the enhancement of trehalose accumulation and improvement of abiotic tolerance in transgenic plants. [Copyright &y& Elsevier]

Abstract: Selaginella bryopteris is a spike-moss lycophyte species with resurrection capability. These plants have small sized stomata that occur in higher density than in other fern species. The diurnal gas-exchange studies under natural conditions showed a bell shaped net photosynthesis curve. The effective quantum yield of PSII (ΔF/F m′) showed an inverse relationship with light and recovered to its maximum at sunset. This suggests that there was a complete recovery of PSII efficiency during the late evening hours. S. bryopteris displayed broad temperature optima for net photosynthesis from 28°C to 37°C. The stomatal sensitivity in response to vapor pressure deficit (VPD), was maximum at 25°C temperature while at temperatures from 30 to 35°C it was low. Our study demonstrates that S. bryopteris plants show a very poor mechanism for its stomatal regulation in response to high light, high temperature, high VPD, high CO2 and to ABA treatment. At the same time they show a high stomatal conductance leading to unrestricted rates of transpiration and a lack of capacity to optimize water use efficiency (WUE). [Copyright &y& Elsevier]

Abstract: The primary objective of this investigation was to examine the neuroprotective efficacy of an aqueous extract of Selaginella delicatula (a pteridophyte) employing a rotenone (ROT) Drosophila model in vivo. Aqueous extract of S. delicatula (SDAE) exhibited multiple antioxidant activity in selected chemical systems. Initially, we examined the ability of SDAE-enriched diet to modulate the levels of endogenous oxidative markers and antioxidant defenses in Drosophila melanogaster. Further, employing a co-exposure paradigm, we investigated the propensity of SDAE to protect flies against ROT-induced lethality, locomotor dysfunction, oxidative stress, mitochondrial dysfunctions and neurotoxicity. Adult flies were fed SDAE-enriched diet (0.05, 0.1 and 0.2%) with or without ROT (500μM) for seven consecutive days. SDAE offered concentration-dependent protection against ROT-induced lethality (30–95% protection), while the survivor flies performed better in the negative geotaxis assay suggesting attenuation of ROT-induced locomotor deficits. Biochemical analysis revealed that SDAE completely restored ROT-induced elevation in the levels of ROS, protein carbonyls and hydroperoxides in both head and body regions of flies. Elevations in the activities of antioxidant enzymes (superoxide dismutase, glutathione reductase) and glutathione-S-transferase caused by ROT were also restored to normal levels by SDAE. Further, SDAE improved the activity levels of membrane bound enzymes viz., NADH–cytochrome c reductase and succinate dehydrogenase suggesting its propensity to protect mitochondrial integrity. Interestingly, SDAE normalized the activity levels of acetylcholinesterase and ROT-induced dopamine depletion. Collectively, these findings suggest the neuromodulatory potential of SDAE and our further studies are directed toward characterization of the nature of biomolecule/s and their mechanism of action employing relevant cell models. [Copyright &y& Elsevier]

Abstract: Two cationic peroxidases from Selaginella martensii Spring. (SmaPrx2 and SmaPrx3) were purified using a three-step protocol which includes ammonium sulfate precipitation, adsorption chromatography on phenyl sepharose and cationic exchange chromatography on SP sepharose. The molecular mass for SmaPrx2 and SmaPrx3 was calculated to be 36.3 kDa and 45.6 kDa, respectively, according to MALDI-TOF/TOF. The isoelectric points were estimated in 9.2 and 9.5 for SmaPrx2 and SmaPrx3, respectively, according to isoelectrofocusing. Both enzymes show a typical peroxidase UV–visible spectrum with a Soret peak at 403 nm for SmaPrx2 and 404 nm for SmaPrx3. The specific activities showed against several substrates and the kinetic parameters suggest SmaPrx2 and SmaPrx3 have specific roles in cell wall formation and especially in lignin biosynthesis. Several peptides from tryptic digestion of both peroxidases were identified through MALDI-TOF MS/MS. The presence in these peptides of structural determinants typical of syringyl peroxidases indicates these proteins show no structural restrictions to oxidize syringyl moieties. These data, along with the in vitro capacity of using sinapyl alcohol as substrate and the low Km in the μM range suggest these two peroxidases may be responsible for the oxidation of syringyl monolignols that leads to syringyl lignins biosynthesis. [Copyright &y& Elsevier]

Diterpenes show diverse chemical structures and various physiological roles. The diversity of diterpene is primarily established by diterpene cyclases that catalyze a cyclization reaction to form the carbon skeleton of cyclic diterpene. Diterpene cyclases are divided into two types, monofunctional and bifunctional cyclases. Bifunctional diterpene cyclases (BDTCs) are involved in hormone and defense compound biosyntheses in bryophytes and gymnosperms, respectively. The BDTCs catalyze the successive two-step type-B (protonation-initiated cyclization) and type-A (ionization-initiated cyclization) reactions of geranylgeranyl diphosphate (GGDP). We found that the genome of a lycophyte, Selaginella moellendorffii, contains six BDTC genes with the majority being uncharacterized. The cDNA from S. moellendorffii encoding a BDTC-like enzyme, miltiradiene synthase (SmMDS), was cloned. The recombinant SmMDS converted GGDP to a diterpene hydrocarbon product with a molecular mass of 272 Da. Mutation in the type-B active motif of SmMDS abolished the cyclase activity, whereas (+)-copalyl diphosphate, the reaction intermediate from the conversion of GGDP to the hydrocarbon product, rescued the cyclase activity of the mutant to form a diterpene hydrocarbon. Another mutant lacking type-A activity accumulated copalyl diphosphate as the reaction intermediate. When the diterpene hydrocarbon was enzymatically synthesized from [U-13C6]mevalonate, all carbons were labeled with 13C stable isotope (>99%). The fully 13C-labeled product was subjected to 13C-13C COSY NMR spectroscopic analyses. The direct carbon-carbon connectivities observed in the multidimensional NMR spectra demonstrated that the hydrocarbon product by SmMDS is miltiradiene, a putative biosynthetic precursor of tanshinone identified from the Chinese medicinal herb Salvia miltiorrhiza. Hence, SmMDS functions as a bifunctional miltiradiene synthase in S. moellendorffii. In this study, we demonstrate that one-dimensional and multidimensional 13C NMR analyses of completely 13C-labeled compound are powerful methods for biosynthetic studies. [ABSTRACT FROM AUTHOR]

Abstract: Rhizophores – leafless axial organs, which apices are the only sites for root formation – are unique to the Selaginella genus. Both rhizophores and roots are dichotomously branched, forming a multibranch rhizophore–root system. In the examined Selaginella kraussiana, the first dichotomous division of a rhizophore results in the initiation of the twin root meristems, giving rise to the root primordia. These primordia are temporarily arrested in growth, but at the same time they are elevated, hidden inside the rhizophore apex due to the activity of a meristematic zone at the rhizophore axis. This meristematic region, located basally to the root meristems, apart from the rhizophore tissues consists of the derivative cells of root primordia and may be considered as a specific intercalary meristem. The growth mode of the roots is similar to that of the rhizophore, including dichotomous branching of the meristem and a temporary developmental arrest of the subsequent root primordia. The reiteration of the developmental program also involves the formation of new intercalary zones, thus through divisional activity, the root with dichotomized apex grows for some time as a single axis and, then the young roots emerge. At each step of the rhizophore–root branch system formation, tissues of the parental axis contribute significantly to the growth and emergence of the next axes. Therefore, dichotomous branching in Selaginella appears to be exceptional in comparison with other known dichotomies of axial organs. [Copyright &y& Elsevier]

Abstract: Selaginella bryopteris is a lycophyte resurrection plant, which incurves during desiccation and recovers on availability of moisture. The aim of the study was to test and understand the various physiological and biochemical changes the fronds undergo during desiccation and rehydration, to get an insight as to how this plant adapts and survives through the dry phase. Upon desiccation, S. bryopteris fronds showed drastic inhibition in net photosynthesis (A) and maximal photochemical efficiency of PSII (F v/F m) however, chlorophyll content did not show much variation. Dark respiration (R d) continued even at 10% relative water content (RWC), and showed a burst after rehydration, which is proposed to be crucial to establish protection mechanisms. Desiccation caused an enhanced production of reactive oxygen species (ROS) and increased lipid peroxidation. Proline accumulation increased substantially by 11-fold. Sucrose and starch contents decreased upon desiccation as compared to control. The antioxidative enzymes viz. superoxide dismutase (SOD), ascorbate peroxidase (APX) and catalase (CAT) along with soluble acid invertase increased during desiccation. S. bryopteris shows mechanical as well as physiological mechanisms for tolerance to extreme levels of desiccation stress. The rapid and almost complete recovery of F v/F m after rehydration clearly indicates the absence of marked photoinhibitory or thermal injury to PSII during desiccation. This along with the homoiochlorophyllous characteristics enables S. bryopteris to recover its A. The antioxidant metabolism further plays an important role in the desiccation tolerance of S. bryopteris. [Copyright &y& Elsevier]

Three new flavones named 5-carboxymethyl-4′,7-dihydroxyflavone (1), its ethyl ester (2) and butyl ester (3) were isolated from the herb Selaginella moellendorffii Hieron., together with ten known compounds. Their structures were elucidated on the basis of spectroscopic and chemical analysis. Selected compounds were evaluated for their anti-HBV and cytotoxic activity. Among them, compounds 2 and 3 displayed inhibitory activity in vitro on hepatitis B virus (HBV) surface antigen (HBsAg) secretion of the Hep G2.2.15 cell line with IC50 values of 0.17mg/ml and 0.46mg/ml, and on HBV e antigen (HBeAg) secretion with IC50 values of 0.42mg/ml and 0.42mg/ml, respectively. Compounds 7, 8, 10 and 12 exhibited selective cytotoxicity against the three human cancer cell lines tested. [Copyright &y& Elsevier]

Abstract: Six selaginellin derivatives, including three new analogues selaginellins D–F (1–3), were isolated from the EtOAc extract of the whole plant of Selaginella pulvinata (Hook. et Grev.) Maxim. Their structures were determined on the basis of extensive physical and chemical evidence. Compounds 1 and 4 demonstrated antifungal activities against Candida albicans; compounds 4–6 exhibited significant antibacterial activity against Staphylococcus aureus. [Copyright &y& Elsevier]

An unusual macrocyclic biflavone, selacyclicbiflavone A ( 1 ), have been isolated from Selaginella uncinata . The structure was elucidated on the basis of rigorous spectroscopic analysis including 1D and 2D NMR experiments as well as HRESIMS techniques. The absolute stereochemistry of compound 1 was further confirmed by comparing experimental data with calculated electronic circular dichroism (ECD) spectra. This is the first report of the macrocyclic biflavone with an unprecedented methylene bridge. A possible biosynthetic pathway was also postulated. [ABSTRACT FROM AUTHOR]

Abstract: A new herbaceous lycopsid, compression species, Selaginella labutae, sp. nov., is described from the Libušín (former Schőller) Mine, near Kladno, Kladno–Rakovník Basin, Czech Republic. The characterization is based on macroscopic observations and the study of in situ spores. The stratigraphic position of the type material is the Radnice Member, Bolsovian, Pennsylvanian. Strobili of S. labutae are the smallest known herbaceous lycopsid cones. Two types of leaves are recognised. Therefore, the new species belongs to Selaginella subgen. Selaginella and not to the subgenus Hexaphyllum Thomas which is characterized by three different types of leaves. Poorly preserved in situ megaspores are of the Triangulatisporites-type and in situ microspores are compared to the dispersed spore species Cirratriradites saturni. [Copyright &y& Elsevier]