Syntheses of Linear Biosynthetic C25-Precursors of Leucosceptroids.

An efficient synthetic approach was developed and applied to the syntheses of four linear biosynthetic C25-precursors of leucosceptroids. The synthesis features a Julia-Kocienski olefination and a late-stage bioinspired photo-oxidation as key steps. The immunosuppressive effects of all synthetic compounds on mouse T cells and macrophage RAW264.7 were determined.

Unusual immunosuppressive pyridine-containing bisnor- (c23), tetranor- (c21) and pentanor- (c20) sesterterpenoids from Tibetan Leucosceptrum canum.

An unusual pyridine-containing sesterterpenoid, leucosceptrodine (1), and five new nor-leucosceptrane sesterterpenoids, including bisnor- (C23, 2), tetranor- (C21, 3) and pentanor- (C20, 4-6) skeletons, were isolated from the leaves of Tibetan Leucosceptrum canum. Their structures including their absolute configurations were determined by extensive spectroscopic analyses and quantum chemical calculations. A single crystal of one epimer (5) was crystallized from a pair of inseparable epimers, and its structure including its absolute configuration was determined by X-ray crystallographic analysis. The immunosuppressive activities of compounds 1-4 with different potencies were evaluated by inhibiting the secretion of cytokines TNF-α and IL-6 in LPS-induced RAW264.7 macrophages.

Structurally Diverse Alkaloids with Anti-Renal-Fibrosis Activity from the Centipede Scolopendra subspinipes mutilans.

Twelve new alkaloids, scolopenolines A-L (1-7, 9-11, 13, 14), along with six known analogues, were isolated from Scolopendra subspinipes mutilans, identified by analysis of spectroscopic data and quantum chemical and computational methods. Scolopenoline A (1), a unique guanidyl-containing C14 quinoline alkaloid, features a 6/6/5 ring backbone. Scolopenoline B (2) is a novel sulfonyl-containing heterodimer comprising quinoline and tyramine moieties. Scolopenoline G (7) presents a rare C12 quinoline skeleton with a 6/6/5 ring system. Alkaloids 1, 8, 10, and 15-18 display anti-inflammatory activity, while 10 and 16-18 also exhibit anti-renal-fibrosis activity. Drug affinity responsive target stability and RNA-interference assays show that Lamp2 might be a potentially important target protein of 16 for anti-renal-fibrosis activity.

Targeting attack activity-driven networks.

Real-world complex systems demonstrated temporal features, i.e., the network topology varies with time and should be described as temporal networks since the traditional static networks cannot accurately characterize. To describe the deliberate attack events in the temporal networks, we propose an activity-based targeted attack on the activity-driven network to investigate temporal networks' temporal percolation properties and resilience. Based on the node activity and network mapping framework, the giant component and temporal percolation threshold are solved according to percolation theory and generating function. The theoretical results coincide with the simulation results near the thresholds. We find that targeted attacks can affect the temporal network, while random attacks cannot. As the probability of a highly active node being deleted increases, the temporal percolation threshold increases, and the giant component increases, thus enhancing robustness. When the network's activity distribution is extremely heterogeneous, network robustness decreases consequently. These findings help us to analyze and understand real-world temporal networks.

Exploration of the profiles of steroidal saponins from Rhizoma Paridis and their metabolites in rats by UPLC-Q-TOF-MS/MS.

INTRODUCTION: Steroidal saponins characterised by intricate chemical structures are the main active components of a well-known traditional Chinese medicine (TCM) Rhizoma Paridis. The metabolic profiles of steroidal saponins in vivo remain largely unexplored, despite their renowned antitumor, immunostimulating, and haemostatic activity. OBJECTIVE: To perform a comprehensive analysis of the chemical constituents of Rhizoma Paridis total saponins (RPTS) and their metabolites in rats after oral administration. METHOD: The chemical constituents of RPTS and their metabolites were analysed using ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS/MS). RESULTS: A reliable UPLC-Q-TOF-MS/MS method was established, and a total of 142 compounds were identified in RPTS. Specifically, diosgenin-type saponins showed the diagnostic ions at m/z 415.32, 397.31, 283.25, 271.21, and 253.20, whereas pennogenin-type saponins exhibited the diagnostic ions at m/z 413.31, 395.30, and 251.20. Based on the characteristic fragments and standard substances, 15 specific metabolites were further identified in the faeces, urine, plasma, and bile of rats. The metabolic pathways of RPTS, including phase I reactions (de-glycosylation and oxidation) and phase II reactions (glucuronidation), were explored and summarised, and the enrichment of metabolites was characterised by multivariate statistical analysis. CONCLUSION: The intricate RPTS could be transformed into relatively simple metabolites in rats through de-glycosylation, which provides a reference for further metabolic studies and screening of active ingredients for TCM.

Five anti-inflammatory compounds from the resins of Liquidambar orientalis.

Five undescribed compounds, including a triterpenoid (1), three phenylpropanoids [(±)-2 and 4], and an aromatic compound (3), as well as six known analogues (5-10), were isolated from the resins of Liquidambar orientalis Mill. Their structures, including absolute configurations, were determined by using spectroscopic and computational methods, and the five new compounds displayed anti-inflammatory activities in LPS-induced RAW264.7 cells.

New triterpenoids from the aerial parts of the Uygur medicine Salvia deserta.

Phytochemical investigation on the aerial parts of Salvia deserta led to the isolation of eight new pentacyclic triterpenoids including three oleanane- (1 - 3) and five ursane-type (4 - 8) triterpenoids, whose structures were elucidated based on extensive spectroscopic analysis and quantum chemical calculation. Weak immunosuppressive potency was observed for compounds 1, 2, and 4 - 8 via inhibiting the secretion of cytokines TNF-α and IL-6 in LPS-induced macrophages RAW264.7 at 20 µM. In addition, compounds 1, 2, and 4 - 6 exhibited moderate protective activity on t-BHP-induced oxidative injury in HepG2 cells.

Defensive Specialized Metabolites from the Latex of Euphorbia jolkinii.

Plant latex is sequestered in laticiferous structures and exuded immediately from damaged plant tissues. The primary function of plant latex is related to defense responses to their natural enemies. Euphorbia jolkinii Boiss. is a perennial herbaceous plant that greatly threaten the biodiversity and ecological integrity of northwest Yunnan, China. Nine triterpenes (1-9), four non-protein amino acids (10-13) and three glycosides (14-16) including a new isopentenyl disaccharide (14), were isolated and identified from the latex of E. jolkinii. Their structures were established on the basis of comprehensive spectroscopic data analyses. Bioassay revealed that meta-tyrosine (10) showed significant phytotoxic activity, inhibiting root and shoot growth of Zea mays, Medicago sativa, Brassica campestris, and Arabidopsis thaliana, with EC50 values ranging from 4.41 ± 1.08 to 37.60 ± 3.59 µg/mL. Interestingly, meta-tyrosine inhibited the root growth of Oryza sativa, but promoted their shoot growth at the concentrations below 20 µg/mL. meta-Tyrosine was found to be the predominant constituent in polar part of the latex extract from both stems and roots of E. jolkinii, but undetectable in the rhizosphere soil. In addition, some triterpenes showed antibacterial and nematicidal effects. The results suggested that meta-tyrosine and triterpenes in the latex might function as defensive substances for E. jolkinii against other organisms.

Discovery of Unusual Sesterterpenoids from Colquhounia coccinea var. mollis and Their Metabolic Implications.

Three unusual sesterterpenoids featuring unprecedented rearranged colquhounane (C25) and tetranorcolquhounane (C21) frameworks, colquhounoids E (1) and F (3) and norcolquhounoid F (2), were isolated from a Lamiaceae medicinal plant Colquhounia coccinea var. mollis. Their structures were elucidated by spectroscopic analysis and quantum chemical calculations. A biomimetic inspired regioselective cyclopropane cleavage was achieved under acidic conditions. The immunosuppressive activities of these new sesterterpenoids were also evaluated.

Subcortical-cortical functional connectivity as a potential biomarker for identifying patients with functional dyspepsia.

The diagnosis of functional dyspepsia (FD) presently relies on the self-reported symptoms. This study aimed to determine the potential of functional brain network features as biomarkers for the identification of FD patients. Firstly, the functional brain Magnetic Resonance Imaging data were collected from 100 FD patients and 100 healthy subjects, and the functional brain network features were extracted by the independent component analysis. Then, a support vector machine classifier was established based on these functional brain network features to discriminate FD patients from healthy subjects. Features that contributed substantially to the classification were finally identified as the classifying features. The results demonstrated that the classifier performed pretty well in discriminating FD patients. Namely, the accuracy of classification was 0.84 ± 0.03 in cross-validation set and 0.80 ± 0.07 in independent test set, respectively. A total of 15 connections between the subcortical nucleus (the thalamus and caudate) and sensorimotor cortex, parahippocampus, orbitofrontal cortex were finally determined as the classifying features. Furthermore, the results of cross-brain atlas validation showed that these classifying features were quite robust in the identification of FD patients. In summary, the current findings suggested the potential of using machine learning method and functional brain network biomarkers to identify FD patients.

The untapped potential of plant sesterterpenoids: chemistry, biological activities and biosynthesis.

Covering: 1969 up to 2021Sesterterpenoids, biosynthetically derived from the precursor, namely geranylfarnesyl diphosphate (GFDP) are amongst the rarest of all isoprenoids with approximately 1300 compounds known. Most sesterterpenoids originate from marine organisms (especially sponges), while only about 15% of these compounds are isolated from several families of plants such as Lamiaceae, Gentianaceae, and Nartheciaceae. Many plant sesterterpenoids possess highly oxygenated and complex cyclic skeletons and exhibit remarkable biological activities involving cytotoxic, anti-inflammatory, antimicrobial, and antifeedant properties. Thus, due to their intrinsic chemical complexity and intriguing biological profiles, plant sesterterpenoids have attracted continuing interest from both chemists and biologists. However, the biosynthesis and distribution of sesterterpenoids in the plant kingdom still remain elusive, although substantial progress has been achieved in recent years. This review provides an overall coverage of sesterterpenoids originating from plant sources, followed by a classification of their chemical skeletons, which summarizes the distribution, chemistry, biological activities, biosynthesis and evolution of plant sesterterpenoids, aiming at strengthening the research efforts toward the untapped great potential of these unique natural product resources.

Enhancement of Chemiluminescence Intensity of S2* in Non-premixed Hydrogen Microjet Flame in the Photometric Detector for Sulfur Detection.

A transparent quartz rod (q) placed vertically on top of a non-premixed hydrogen microjet flame in a flame photometric detector (qFPD) was developed and evaluated for sulfur detection. The microjet flame burned around the quartz rod because of Coanda effect, forming an extended downstream flame zone with a relatively low temperature between 550 and 650 °C, which is favorable to the formation of S2*. The emission intensity of S2* and the signal-to-noise ratio (SNR) of sulfur response were enhanced 2.6- and 2.1-fold, respectively. It was found that the quartz rod of diameter 4 mm with a tip shape of semicircle placed 6 mm above the nozzle yielded the highest SNR. The limits of detection (LOD) for seven kinds of tested sulfur-containing compounds of qFPD were 0.3-0.5 pg S s-1, which is 5-7 times better than that of commercially available FPD detectors (LOD: 1.6-2.8 pg S s-1). The selectivity of sulfur over carbon was 105 on qFPD when the SNR for the mass flow rate of S and C atoms was ∼3 times. It was the first time that a quartz rod was used vertically on top of a microjet hydrogen-rich flame in FPD to enhance the chemiluminescence of S2* and improve the LOD down to 0.3-0.5 pg S s-1.

Aberrant functional brain network dynamics in patients with functional constipation.

The aberrant static functional connectivity of brain network has been widely investigated in patients with functional constipation (FCon). However, the dynamics of brain functional connectivity in FCon patients remained unknown. This study aimed to detect the brain dynamics of functional connectivity states and network topological organizations of FCon patients and investigate the correlations of the aberrant brain dynamics with symptom severity. Eighty-three FCon patients and 80 healthy subjects (HS) were included in data analysis. The spatial group independent component analysis, sliding-window approach, k-means clustering, and graph-theoretic analysis were applied to investigate the dynamic temporal properties and coupling patterns of functional connectivity states, as well as the time-variation of network topological organizations in FCon patients. Four reoccurring functional connectivity states were identified in k-means clustering analysis. Compared to HS, FCon patients manifested the lower occurrence rate and mean dwell time in the state with a complex connection between default mode network and cognitive control network, as well as the aberrant anterior insula-cortical coupling patterns in this state, which were significantly correlated with the symptom severity. The graph-theoretic analysis demonstrated that FCon patients had higher sample entropy at the nodal efficiency of anterior insula than HS. The current findings provided dynamic perspectives for understanding the brain connectome of FCon and laid the foundation for the potential treatment of FCon based on brain connectomics.

Characterization of defensive cadinenes and a novel sesquiterpene synthase responsible for their biosynthesis from the invasive Eupatorium adenophorum.

Eupatorium adenophorum is a malignant invasive plant possessing extraordinary defense potency, but its chemical weaponry and formation mechanism have not yet been extensively investigated. We identified six cadinene sesquiterpenes, including two volatiles (amorpha-4,7(11)-diene and (-)-amorph-4-en-7-ol) and four nonvolatiles (9-oxo-10,11-dehydroageraphorone, muurol-4-en-3,8-dione, 9-oxo-ageraphorone and 9ß-hydroxy-ageraphorone), as the major constitutive and inducible chemicals of E. adenophorum. All cadinenes showed potent antifeedant activity against a generalist insect Spodoptera exigua, indicating that they have significant defensive roles. We cloned and functionally characterized a sesquiterpene synthase from E. adenophorum (EaTPS1), catalyzing the conversion of farnesyl diphosphate to amorpha-4,7(11)-diene and (-)-amorph-4-en-7-ol, which were purified from engineered Escherichia coli and identified by extensive nuclear magnetic resonance (NMR) spectroscopy. EaTPS1 was highly expressed in the aboveground organs, which was congruent with the dominant distribution of cadinenes, suggesting that EaTPS1 is likely involved in cadinene biosynthesis. Mechanical wounding and methyl jasmonate negatively regulated EaTPS1 expression but caused the release of amorpha-4,7(11)-diene and (-)-amorph-4-en-7-ol. Nicotiana benthamiana transiently expressing EaTPS1 also produced amorpha-4,7(11)-diene and (-)-amorph-4-en-7-ol, and showed enhanced defense function. The findings presented here uncover the role and formation of the chemical defense mechanism of E. adenophorum - which probably contributes to the invasive success of this plant - and provide a tool for manipulating the biosynthesis of biologically active cadinene natural products.

Immunosuppresive Sesterterpenoids and Norsesterterpenoids from Colquhounia coccinea var. mollis.

A pair of new C-14 epimeric sesterterpenoids, colquhounoid D (1) and 14-epi-colquhounoid D (2), and five degradation products featuring new C20 and C21 frameworks, norcolquhounoids A-E (3-7), were isolated from Colquhounia coccinea var. mollis. Their structures were elucidated by comprehensive spectroscopic analysis and single-crystal X-ray diffraction. Degradation of the C25 skeleton to the C21 skeleton was also achieved using aqueous NaIO4 and RuCl3. Compounds 1 and 2 showed significant immunosuppressive activity on the cytokine IFN-γ secretion of mouse splenocytes induced by anti-CD3/CD4 monoclonal antibodies, with IC50 of 8.38 and 5.79 µM, respectively, and compounds 5 and 6 were moderately active.

Seasonal concentration variation and potential influencing factors of organophosphorus flame retardants in a wastewater treatment plant.

Organophosphate flame retardants (OPFRs) in both of water and sludge phase of influent and effluent of the STP were investigated in Beijing of China in five seasons. Total OPFRs concentrations in water phase of influent in five seasons were between 600 and 838 ng/L, where total OPFRs concentration was the lowest in summer of 2018. In water phase of influent and effluent, two chlorinated OPFRs (TCEP and TCPP) were major. Alkyl OPFRs decreased the most in water phase from influent to effluent. In sludge phase, the OPFRs amounts in winter were the lowest. The main OPFRs in sludge phase were TEHP and EHDP, which can be explained by the two OPFRs properties (log Kow and log Koc). Higher the values of the log Kow and log Koc of OPFRs, more amounts in sludge phase. The mass flow of OPFRs in influent were analysed by Principal Component Analysis (PCA), indicating that the influent amounts of TCEP, TDCP, TCPP and DCP were main OPFRs in four seasons to influence the characteristics of influent. Compared to OPFRs reduction in some STPs in other countries, alkyl and aryl OPFRs reduction rates were higher than chlorinated OPFRs. TBEP, TEHP and TPHP can always be effectively removed in different seasons and different STPs. The analysis methods of Pearson correlation and linear correlation were processed to check the possible factors affecting OPFRs reduction in STP. OPFRs reduction was related to some STP working parameters. Significant correlation also was found between OPFRs properties and reduction.

The effects of pre-dialysis blood pressure targets on prognosis and health-related quality of life in haemodialysis patients.

OBJECTIVE: The aim of the study is to investigate the effects of pre-dialysis blood pressure targets on health-related quality of life and prognosis and to determine the optimal target for pre-dialysis blood pressure in haemodialysis patients. METHODS: A total of 58 haemodialysis patients undergoing dialysis for more than 3 months were enrolled in the study from 1 January 2018 to 31 December 2018. The subjects were divided into two groups according to their pre-dialysis blood pressure: a standard target group (pre-dialysis systolic blood pressure of 110-140 mm Hg) and a relaxed target group (pre-dialysis systolic blood pressure of 155-165 mm Hg). The Quality Metrics SF-36 survey instrument was used to assess health-related quality of life in the study participants. In addition, general clinical data and biochemical indicators including heart rate, respiration rate, blood pressure and ultrafiltration volume and rate during dialysis were observed and recorded. Patients were followed-up for 12 months, and prognostic data were recorded. Death was regarded as the endpoint. RESULTS: Scores on the SF-36 in the standard target group were significantly higher than those in the relaxed target group, with the exception of the role-emotional (RE) and mental health (MH) dimensions. At the end of the study, the number of mortality events in the relaxed target group was higher than in the standard target group. There were no other significant differences between the two groups. CONCLUSION: The scores from the health-related quality of life survey were higher in standard target group, but no differences in mortality risk between the two groups were observed.

Cloning and Functional Characterization of a Squalene Synthase from Paris polyphylla var. yunnanensis.

Paris polyphylla Smith var. yunnanensis (Franch.) Hand. - Mazz. is a precious traditional Chinese medicine, and steroidal saponins are its major bioactive constituents possessing extensive biological activities. Squalene synthase (SQS) catalyzes the first dedicated step converting two molecular of farnesyl diphosphate (FDP) into squalene, a key intermediate in the biosynthetic pathway of steroidal saponins. In this study, a squalene synthase gene (PpSQS1) was cloned and functionally characterized from P. polyphylla var. yunnanensis, representing the first identified SQS from the genus Paris. The open reading frame of PpSQS1 is 1239 bp, which encodes a protein of 412 amino acids showing high similarity to those of other plant SQSs. Expression of PpSQS1 in Escherichia coli resulted in production of soluble recombinant proteins. Gas chromatography-mass spectrometry analysis showed that the purified recombinant PpSQS1 protein could produce squalene using FDP as a substrate in the in vitro enzymatic assay. qRT-PCR analysis indicated that PpSQS1 was highly expressed in rhizomes, consistent with the dominant accumulation of steroidal saponins there, suggesting that PpSQS1 is likely involved in the biosynthesis of steroidal saponins in the plant. The findings lay a foundation for further investigation on the biosynthesis and regulation of steroidal saponins, and also provide an alternative gene for manipulation of steroid production using synthetic biology.

A Cryptic Plant Terpene Cyclase Producing Unconventional 18- and 14-Membered Macrocyclic C25 and C20 Terpenoids with Immunosuppressive Activity.

A versatile terpene synthase (LcTPS2) producing unconventional macrocyclic terpenoids was characterized from Leucosceptrum canum. Engineered Escherichia coli and Nicotiana benthamiana expressing LcTPS2 produced six 18-/14-membered sesterterpenoids including five new ones and two 14-membered diterpenoids. These products represent the first macrocyclic sesterterpenoids from plants and the largest sesterterpenoid ring system identified to date. Two variants F516A and F516G producing approximately 3.3- and 2.5-fold, respectively, more sesterterpenoids than the wild-type enzyme were engineered. Both 18- and 14-membered ring sesterterpenoids displayed significant inhibitory activity on the IL-2 and IFN-γ production of T cells probably via inhibition of the MAPK pathway. The findings will contribute to the development of efficient biocatalysts to create bioactive macrocyclic sesterterpenoids, and also herald a new potential in the well-trodden territory of plant terpenoid biosynthesis.

A highly simulated scar model developed by grafting human thin split-thickness skin on back of nude mouse: The remodeling process, histological characteristics of scars.

A predictive scar animal model is needed in order to study the mechanism and assess the therapies before its use in humans. However, due to the differences in wound healing patterns and regeneration ability, none of the existing models can fully simulate the characteristics of human scar. The aim of this study was to build a model that recapitulated the developing process and outcomes of human hypertrophic scar (HS). Nude mice were grafted with thin split-thickness human skins. The dynamic changes and final outcomes of the grafts were investigated. The results showed that human skin grafts survived and underwent progressive scarring remodeling in morphology and histology. Scar related markers (α-SMA, CD34, Collage I, TGF-ß1) were positive in immunohistology. Protein expressions in TGF-ß1/Smad2/3 pathway were increased in accordance with HS during the development process by western blotting. It was finally proved that scar reconstructed by this model matches a real-world human HS. This is a stable, easy to reproduce model for studying the scar formation process and its properties.