Marchaetoglobins A-D: Four Cytochalasans with Proangiogenic Activity from the Marine-Sponge-Associated Fungus Chaetomium globosum 162105.

Four new cytochalasans, marchaetoglobins A-D (1-4), along with five known compounds (5-9), were isolated from the marine-sponge-associated fungus Chaetomium globosum 162105. Compounds 1-4 represent examples of 19,20-seco-chaetoglobosins, of which compound 1 is the first furan-containing cytochalasan. Their structures and absolute configurations were elucidated by extensive spectroscopic analyses and electronic circular dichroism calculations. Compounds 5, 8, and 9 displayed weak to moderate antibacterial activities against Bacillus thuringiensis, Edwardsiella piscicida, Vibrio alginolyticus, and Pseudomonas syringae pv. actinidiae with minimum inhibitory concentration values ranging from 5 to 25 µg/mL. In addition, compounds 2, 3, and 5 showed potent in vivo proangiogenic activity in transgenic zebrafish, comparable to the positive control.

Marcytoglobosins A and B, Cytochalasans From a Marine Sponge Associated Chaetomium globosum 162105 Fungus.

Two new cytochalasans, marcytoglobosins A (1) and B (2) were isolated from the marine sponge associated fungus Chaetomium globosum 162105, along with six known compounds (3-8). The complete structures of two new compounds were determined based on 1D/2D NMR and HR-MS spectroscopic analyses coupled with ECD calculations. All eight isolates were evaluated for their antibacterial activity. Among them, compounds 3-8 displayed antibacterial effects against Staphylococcus epidermidis, Bacillus thuringiensis, Pseudomonas syringae pv. Actinidiae, Vibrio alginolyticus, and Edwardsiella piscicida with minimum inhibitory concentration (MIC) values ranging from 10 to 25 µg/mL.

Arenarialins A-F, Anti-inflammatory Meroterpenoids with Rearranged Skeletons from the Marine Sponge Dysidea arenaria.

Six new sesquiterpene quinone/hydroquinone meroterpenoids, arenarialins A-F (1-6), were isolated from the marine sponge Dysidea arenaria collected from the South China Sea. Their chemical structures and absolute configurations were determined by HRMS and NMR data analyses coupled with DP4+ and ECD calculations. Arenarialin A (1) features an unprecedented tetracyclic 6/6/5/6 carbon skeleton, whereas arenarialins B-D (2-4) possess two rare secomeroterpene scaffolds. Arenarialins A-F showed inhibitory activity on the production of inflammatory cytokines TNF-α and IL-6 in LPS-induced RAW264.7 macrophages with arenarialin D regulating the NF-κB/MAPK signaling pathway.

Dysambiol, an Anti-inflammatory Secomeroterpenoid from a Dysidea sp. Marine Sponge.

An unusual secomeroterpenoid, dysambiol (1), was isolated from a Dysidea sp. marine sponge collected from the South China Sea. Dysambiol features an unprecedented secomeroterpene scaffold with a rare lactone bridge. The structure of 1 was determined by extensive spectroscopic analysis, Mosher's method, and electronic circular dichroism calculation. Dysambiol displayed potent anti-inflammatory activity in LPS-induced Raw 264.7 macrophages by regulating the NF-κB/MPAK signaling pathway.

Aspergetherins A-D, New Chlorinated Biphenyls with anti-MRSA Activity from the Marine Sponge Symbiotic Fungus Aspergillus terreus 164018.

Aspergetherins A-D (1-4), four new chlorinated biphenyls, were isolated from the rice fermentation of a marine sponge symbiotic fungus Aspergillus terreus 164018, along with seven known biphenyl derivatives (5-11). The structures of four new compounds were determined by a comprehensive analysis of the spectroscopic data, including HR-ESI-MS and 2D NMR data. All 11 isolates were evaluated for their anti-bacterial activity against two strains of methicillin-resistant Staphylococcus aureus (MRSA). Among them, compounds 1, 3, 8 and 10 showed anti-MRSA activity with MIC values of 1.0-128 µg/mL. Preliminary structure-activity relationship analysis unveiled that both chlorinated substitution and esterification of 2-carboxylic acid could impact the antibacterial activity of biphenyls.

Natural sesquiterpene quinone/quinols: chemistry, biological activity, and synthesis.

Covering: 2010 to 2021Sesquiterpene quinone/quinols (SQs) are characterized by a C15-sesquiterpenoid unit incorporating a C6-benzoquinone/quinol moiety. Numerous unprecedented carbon skeletons have been constructed with various connection patterns between the two parts. The potent anti-cancer, anti-inflammatory, anti-microbial, anti-viral, and fibrinolytic activities of SQs are associated with their diverse structures. The representative avarol has even entered the stage of clinical phase II research as an anti-HIV agent, and was developed as paramedic medicine against psoriasis. This review provides an overall summary of 558 new natural SQs discovered between 2010 and 2021, including seven groups and sixteen structure-type subgroups, which comprehensively recapitulates their chemical structures, spectral characteristics, source organisms, biological activities, synthesis, and biosynthesis, aiming to expand the application scope of this unique natural product resource.

Multi-dimensional variables and feature parameter selection for aboveground biomass estimation of potato based on UAV multispectral imagery.

Aboveground biomass (AGB) is an essential assessment of plant development and guiding agricultural production management in the field. Therefore, efficient and accurate access to crop AGB information can provide a timely and precise yield estimation, which is strong evidence for securing food supply and trade. In this study, the spectral, texture, geometric, and frequency-domain variables were extracted through multispectral imagery of drones, and each variable importance for different dimensional parameter combinations was computed by three feature parameter selection methods. The selected variables from the different combinations were used to perform potato AGB estimation. The results showed that compared with no feature parameter selection, the accuracy and robustness of the AGB prediction models were significantly improved after parameter selection. The random forest based on out-of-bag (RF-OOB) method was proved to be the most effective feature selection method, and in combination with RF regression, the coefficient of determination (R2) of the AGB validation model could reach 0.90, with root mean square error (RMSE), mean absolute error (MAE), and normalized RMSE (nRMSE) of 71.68 g/m2, 51.27 g/m2, and 11.56%, respectively. Meanwhile, the regression models of the RF-OOB method provided a good solution to the problem that high AGB values were underestimated with the variables of four dimensions. Moreover, the precision of AGB estimates was improved as the dimensionality of parameters increased. This present work can contribute to a rapid, efficient, and non-destructive means of obtaining AGB information for crops as well as provide technical support for high-throughput plant phenotypes screening.

Dysideanones F-G and dysiherbols D-E, unusual sesquiterpene quinones with rearranged skeletons from the marine sponge Dysidea avara.

Four new sesquiterpene quinone meroterpenoids, dysideanones F-G (1-2) and dysiherbols D-E (3-4), were isolated from the marine sponge Dysidea avara collected from the South China Sea. The new structures were elucidated by extensive analysis of spectroscopic data including HR-MS and 1D and 2D NMR spectra, and their absolute configurations were assigned by single-crystal X-ray diffraction and ECD calculations. Anti-inflammatory evaluation showed that dysiherbols D-E (3-4) exhibited moderate inhibitory activity on TNF-α-induced NF-κB activation in human HEK-293T cells with IC50 values of 10.2 and 8.6 µmol·L-1, respectively.

Axinellasins A-D, Immunosuppressive Cycloheptapeptide Diastereomers, Discovered via a Precursor Ion Scanning-Supercritical Fluid Chromatography Strategy from the Marine Sponge Axinella species.

The precursor ion scanning-supercritical fluid chromatography (PI-SFC) method was applied to explore new methionine sulfoxide-containing cycloheptapeptides, axinellasins A-D (1-4), from the marine sponge Axinella sp. Their structures, including absolute configurations, were elucidated by detailed spectroscopic analyses and X-ray crystallography. The total synthesis of 4 was completed via an Fmoc solid/solution-phase synthesis. Compounds 1-4 exhibited immunosuppressive effects via inhibition of T and B cell proliferation, and 1 and 4 showed better inhibitory activities than their corresponding diastereomers.

New NF-κB Inhibitory Steroids from the Marine Sponge Dysidea avara Collected from the South China Sea.

Chemical investigation of the marine sponge Dysidea avara, collected from the South China Sea, yielded 13 steroids, including nine new (1-9) and four known (10-13) ones. The new structures were elucidated as (3S,14R)-3,14-dihydroxycholesta-5,8-dien-7-one (1), (22E,24R)-7α-ethoxy-5α,6α-epoxyergosta-8(14),22-dien-3ß-ol (2), 3ß-hydroxy-7α-ethoxy-5α,6α-epoxy-8(14)-cholestene (3), 3ß,5α-dihydroxy-6α-ethoxychofesta-7,9(11)-diene (4), 3ß,5α-dihydroxy-6ß-ethoxycholest-7-ene (5), (22E,24R)-24-ethoxy-3ß,5α-dihydroxy-6ß-ethoxyergosta-7,22-diene (6), (22E)-3ß,5α-dihydroxy-6ß-ethoxycholesta-7,22-diene (7), 24-ethoxy-3ß,5α-dihydroxy-6ß-ethoxycholest-7-ene (8 and 9), by extensive spectroscopic analyses, such as HR-ESI-MS, 1D and 2D NMR data. The absolute configuration of 1 was assigned by comparison the experimental ECD spectra with the calculated ones. Among the 13 metabolites, compounds 1, 4, 11, 12, and 13 showed NF-κB inhibitory activities in human HER-293 cells with IC50 values of 6.4, 18.7, 8.1, 9.6, and 7.5 µM, respectively. Preliminary structure-activity relationship analysis unveiled that the conjugated ketones or unsaturated double bonds might be the functional groups for the five active steroids.

New bisabolane-type phenolic sesquiterpenoids from the marine sponge Plakortis simplex.

Six new bisabolane-type phenolic sesquiterpenoids, including plakordiols A-D (1-4), (7R, 10R)-hydroxycurcudiol (5) and (7R, 10S)-hydroxycurcudiol (6) were isolated from the marine sponge Plakortis simplex collected from the South China Sea. Their structures were determined based on extensive analysis of spectroscopic data. Their configurations were assigned by coupling constant analysis, NOESY correlations, and the modified Mosher's method. Furthermore, their cytotoxic and antibacterial activities were evaluated.

Dysiscalarones A-E, scalarane sesterterpenoids with nitric oxide production inhibitory activity from marine sponge Dysidea granulosa.

Dysiscalarones A-E (1-5), five new scalarane-type bishomoscalarane sesterterpenoids, were isolated from marine sponge Dysidea granulosa collected from the South China Sea, together with two known ones, honulactone A (6) and phyllofolactone I (7). The new structures were determined by extensive spectroscopic analysis including HR-ESI-MS and 1D and 2D NMR data, and their absolute configurations were assigned by single crystal X-ray diffraction analyses. The inhibitory activity of all the seven isolates on the production of nitric oxide (NO) stimulated by lipopolysaccharide (LPS) in mouse RAW 264.7 macrophages was evaluated. Of these metabolites, dysiscalarones A-B (1-2), honulactone A (6), and phyllofolactone I (7) showed inhibitory activities with respective IC50 values of 16.4, 18.5, 2.6, and 3.7 µM, which suggested that the γ-methylated α,ß-unsaturated γ-lactone might be the functional group. In addition, all the seven metabolites showed no significant cytotoxicity against lung cancer PC9 cell line at the concentration of 20 µM.

Dysiarenone from Marine Sponge Dysidea arenaria Attenuates ROS and Inflammation via Inhibition of 5-LOX/NF-κB/MAPKs and Upregulation of Nrf-2/OH-1 in RAW 264.7 Macrophages.

BACKGROUND: Marine natural products harbor a variety of pharmacological activities, and the sea species have been becoming a main source of new drug candidate. In pursuit of safer and more effective anti-inflammation drug, the anti-inflammatory activities, anti-oxygenation effects and underlying molecular mechanisms of compound dysiarenone from Dysidea arenaria were investigated via LPS-induced RAW 264.7 cell model. METHODS: Firstly, RAW 264.7 cells have been stimulated with LPS and treated with dysiarenone, and the cell viability of the LPS-treated RAW 264.7 cells was examined. One-step method, DCFH-DA fluorescence probe method was used to detect reactive oxygen species (ROS). The modulation of dysiarenone on anti-inflammation was detected by enzyme-linked immunosorbent assay by measuring the release of inflammatory cytokines (TNF-α and IL-6), and inflammatory mediators (LTB4). Further, the underlying anti-inflammatory mechanism of dysiarenone was explored by determining the expression of inducible 5-LOX, MAPKs, p-Akt, and p-NF-κB p65. Oxidative stress is tightly connected with inflammation, which was also evaluated through nuclear factor erythroid 2-related factor 2 (Nrf2)/heme oxygenase-1 (OH-1) signaling pathway. RESULTS: Our study unraveled that dysiarenone between 2 and 8 µM reduces the inflammation responses via suppressing the production of inflammatory cytokines (TNF-α and IL-6) and inflammatory mediators (LTB4). Dysiarenone down-regulated the protein levels of inducible 5-LOX via the inhibition of phosphorylation of MAPKs (including p38, ERK), Akt and NF-κB p65. Additionally, dysiarenone decreases ROS accumulation by upregulating HO-1 expression via nuclear translocation of Nrf2. CONCLUSION: In conclusion, we demonstrated that dysiarenone possesses anti-inflammation and anti-oxidation activity via inhibiting 5-LOX/NF-κB/MAPK and Nrf2/HO-1 signaling pathway. Dysiarenone might be a promising lead compound for inflammatory diseases.

Nondestructive estimation of potato yield using relative variables derived from multi-period LAI and hyperspectral data based on weighted growth stage.

BACKGROUND: The accurate estimation of potato yield at regional scales is crucial for food security, precision agriculture, and agricultural sustainable development. METHODS: In this study, we developed a new method using multi-period relative vegetation indices (rVIs) and relative leaf area index (rLAI) data to improve the accuracy of potato yield estimation based on the weighted growth stage. Two experiments of field and greenhouse (water and nitrogen fertilizer experiments) in 2018 were performed to obtain the spectra and LAI data of the whole growth stage of potato. Then the weighted growth stage was determined by three weighting methods (improved analytic hierarchy process method, IAHP; entropy weight method, EW; and optimal combination weighting method, OCW) and the Slogistic model. A comparison of the estimation performance of rVI-based and rLAI-based models with a single and weighted stage was completed. RESULTS: The results showed that among the six test rVIs, the relative red edge chlorophyll index (rCIred edge) was the optimal index of the single-stage estimation models with the correlation with potato yield. The most suitable single stage for potato yield estimation was the tuber expansion stage. For weighted growth stage models, the OCW-LAI model was determined as the best one to accurately predict the potato yield with an adjusted R2 value of 0.8333, and the estimation error about 8%. CONCLUSION: This study emphasizes the importance of inconsistent contributions of multi-period or different types of data to the results when they are used together, and the weights need to be considered.

Phakefustatins A-C: Kynurenine-Bearing Cycloheptapeptides as RXRα Modulators from the Marine Sponge Phakellia fusca.

A neutral-loss scanning mass method was used to explore new kynurenine-containing cycloheptapeptides, phakefustatins A-C (1-3), from the marine sponge Phakellia fusca. Their structures were elucidated by spectroscopic analysis and the advanced Marfey's method. 1 was total synthesized via a final-stage ozonolysis strategy by the combination of solid/solution-phase synthesis. Phakefustatin A (1) was identified as a RXRα modulator to inhibit cancer cell growth, and its pharmacophores could be Kyn and guanidine groups.

Trichodermaloids A-C, Cadinane Sesquiterpenes from a Marine Sponge Symbiotic Trichoderma sp. SM16 Fungus.

Three new cadinane sesquiterpenes, trichodermaloids A (1), B (2), and C (5) were isolated from a symbiotic fungus Trichoderma sp. SM16 derived from the marine sponge Dysidea sp., together with three known ones, aspergilloid G (3), rhinomilisin E (4), and rhinomilisin G (6). The complete structures of three new compounds were determined by HR-MS and NMR spectroscopic analyses coupled with ECD calculations. The absolute configurations of two known compounds (4 and 6) were determined for the first time. The six isolates were inactive as antibacterial agents. However, trichodermaloids A and B have shown cytotoxicity on human NCIH-460 lung, NCIC-H929 myeloma, and SW620 colorectal cancer cell lines with IC50 values at the range of 6.8-12.7 µm.

Biosynthesis of depsipeptides with a 3-hydroxybenzoate moiety and selective anticancer activities involves a chorismatase.

Neoantimycins are anticancer compounds of 15-membered ring antimycin-type depsipeptides. They are biosynthesized by a hybrid multimodular protein complex of nonribosomal peptide synthetase (NRPS) and polyketide synthase (PKS), typically from the starting precursor 3-formamidosalicylate. Examining fermentation extracts of Streptomyces conglobatus, here we discovered four new neoantimycin analogs, unantimycins B-E, in which 3-formamidosalicylates are replaced by an unusual 3-hydroxybenzoate (3-HBA) moiety. Unantimycins B-E exhibited levels of anticancer activities similar to those of the chemotherapeutic drug cisplatin in human lung cancer, colorectal cancer, and melanoma cells. Notably, they mostly displayed no significant toxicity toward noncancerous cells, unlike the serious toxicities generally reported for antimycin-type natural products. Using site-directed mutagenesis and heterologous expression, we found that unantimycin productions are correlated with the activity of a chorismatase homolog, the nat-hyg5 gene, from a type I PKS gene cluster. Biochemical analysis confirmed that the catalytic activity of Nat-hyg5 generates 3-HBA from chorismate. Finally, we achieved selective production of unantimycins B and C by engineering a chassis host. On the basis of these findings, we propose that unantimycin biosynthesis is directed by the neoantimycin-producing NRPS-PKS complex and initiated with the starter unit of 3-HBA. The elucidation of the biosynthetic unantimycin pathway reported here paves the way to improve the yield of these compounds for evaluation in oncotherapeutic applications.

Flavipesides A-C, PKS-NRPS Hybrids as Pancreatic Lipase Inhibitors from a Marine Sponge Symbiotic Fungus Aspergillus flavipes 164013.

Three unusual chlorinated PKS-NRPS hybrid metabolites, flavipesides A-C (1-3), were isolated from a strain of marine sponge symbiotic fungus Aspergillus flavipes 164013. Their structures were determined by spectroscopic data analysis, and absolute configurations were assigned by single-crystal X-ray diffraction with ECD spectral analysis. Flavipesides A-C showed potent pancreatic lipase (PL) inhibitory activity with IC50 values of 0.07-0.23 µM.

Discovery of nitrogenous sesquiterpene quinone derivatives from sponge Dysidea septosa with anti-inflammatory activity in vivo zebrafish model.

Two unique nitrogenous sesquiterpene quinone meroterpenoids, dysidinoid B (1) and dysicigyhone A (2), together with eight known analogues (3-10) were isolated and characterized from the marine sponge Dysidea septosa. Their structures with absolute configurations were established by a combination of extensive spectroscopic, electron circular dichroism (ECD) and single-crystal X-ray diffraction data analysis. Structurally, dysicigyhone A (2) possessed a unique benzo[d]oxazolidine-2-one unit. Additionally, dysidinoid B (1) exhibited significant anti-inflammatory effect by inhibiting TNF-α and IL-6 generation with IC50 values of 9.15 µM and 17.62 µM, respectively. Further in vivo anti-inflammatory assay verified that the dysidinoid B (1) alleviated the CuSO4-induced robust acute inflammatory response in zebrafish model.

Trivirensols: Selectively Bacteriostatic Sesquiterpene Trimers from the Australian Termite Nest-Derived Fungus Trichoderma virens CMB-TN16.

The termite nest-derived fungus Trichoderma virens CMB-TN16 cultivated on rice-based media produced seven new first-in-class trimeric sesquiterpenes, trivirensols A-G (11-17). Structures inclusive of absolute configurations were assigned by detailed spectroscopic analysis and biosynthetic considerations. Although trivirensols exhibit no cytotoxicity to mammalian carcinoma cells, selected examples are bacteriostatic against vancomycin-resistant Enterococcus faecalis (VRE). Structure-activity relationship (SAR) investigations combined with in situ chemical stability studies documented bacteriostatic activity for trivirensols A (11) and B (12) and the co-metabolite divirensols A (4), B (5), and G (10), all of which share a common terminal butenolide. Significantly, SAR studies also revealed bacteriostatic activity for trivirensols C (13) and G (17) and the co-metabolite divirensol C (6), all of which share a common hydrated butenolide terminal. Of note, when exposed to VRE cell cultures, the hydrated butenolides 6, 13, and 17 undergo rapid in situ dehydration to corresponding butenolides, suggesting hydrated butenolides are a pro-drug form of the butenolide VRE bacteriostatic pharmacophore.