Cytotoxic pentacyclic and tetracyclic aromatic sesquiterpenes from Phomopsis archeri

Research Progress on Sesquiterpene Compounds from Artabotrys Plants of Annonaceae

Artabotrys, a pivotal genus within the Annonaceae family, is renowned for its extensive biological significance and medicinal potential. The genus's sesquiterpene compounds have attracted considerable interest from the scientific community due to their structural complexity and diverse biological activities. These compounds exhibit a range of biological activities, including antimalarial, antibacterial, anti-inflammatory analgesic, and anti-tumor properties, positioning them as promising candidates for medical applications. This review aims to summarize the current knowledge on the variety, species, and structural characteristics of sesquiterpene compounds isolated from Artabotrys plants. Furthermore, it delves into their pharmacological activities and underlying mechanisms, offering a comprehensive foundation for future research.

Cholangiocarcinoma: Recent Advances in Molecular Pathobiology and Therapeutic Approaches

Cholangiocarcinomas (CCA) pose a complex challenge in oncology due to diverse etiologies, necessitating tailored therapeutic approaches. This review discusses the risk factors, molecular pathology, and current therapeutic options for CCA and explores the emerging strategies encompassing targeted therapies, immunotherapy, novel compounds from natural sources, and modulation of gut microbiota. CCA are driven by an intricate landscape of genetic mutations, epigenetic dysregulation, and post-transcriptional modification, which differs based on geography (e.g., for liver fluke versus non-liver fluke-driven CCA) and exposure to environmental carcinogens (e.g., exposure to aristolochic acid). Liquid biopsy, including circulating cell-free DNA, is a potential diagnostic tool for CCA, which warrants further investigations. Currently, surgical resection is the primary curative treatment for CCA despite the technical challenges. Adjuvant chemotherapy, including cisplatin and gemcitabine, is standard for advanced, unresectable, or recurrent CCA. Second-line therapy options, such as FOLFOX (oxaliplatin and 5-FU), and the significance of radiation therapy in adjuvant, neoadjuvant, and palliative settings are also discussed. This review underscores the need for personalized therapies and demonstrates the shift towards precision medicine in CCA treatment. The development of targeted therapies, including FDA-approved drugs inhibiting FGFR2 gene fusions and IDH1 mutations, is of major research focus. Investigations into immune checkpoint inhibitors have also revealed potential clinical benefits, although improvements in survival remain elusive, especially across patient demographics. Novel compounds from natural sources exhibit anti-CCA activity, while microbiota dysbiosis emerges as a potential contributor to CCA progression, necessitating further exploration of their direct impact and mechanisms through in-depth research and clinical studies. In the future, extensive translational research efforts are imperative to bridge existing gaps and optimize therapeutic strategies to improve therapeutic outcomes for this complex malignancy.

Comparative Analysis of Secondary Metabolites Produced by Ascochyta fabae under In Vitro Conditions and Their Phytotoxicity on the Primary Host, Vicia faba, and Related Legume Crops

Ascochyta blight, caused by Ascochyta fabae, poses a significant threat to faba bean and other legumes worldwide. Necrotic lesions on stems, leaves, and pods characterize the disease. Given the economic impact of this pathogen and the potential involvement of secondary metabolites in symptom development, a study was conducted to investigate the fungus's ability to produce bioactive metabolites that might contribute to its pathogenicity. For this investigation, the fungus was cultured in three substrates (Czapek-Dox, PDB, and rice). The produced metabolites were analyzed by NMR and LC-HRMS methods, resulting in the dereplication of seven metabolites, which varied with the cultural substrates. Ascochlorin, ascofuranol, and (R)-mevalonolactone were isolated from the Czapek-Dox extract; ascosalipyrone, benzoic acid, and tyrosol from the PDB extract; and ascosalitoxin and ascosalipyrone from the rice extract. The phytotoxicity of the pure metabolites was assessed at different concentrations on their primary hosts and related legumes. The fungal exudates displayed varying degrees of phytotoxicity, with the Czapek-Dox medium's exudate exhibiting the highest activity across almost all legumes tested. The species belonging to the genus Vicia spp. were the most susceptible, with faba bean being susceptible to all metabolites, at least at the highest concentration tested, as expected. In particular, ascosalitoxin and benzoic acid were the most phytotoxic in the tested condition and, as a consequence, expected to play an important role on necrosis's appearance.

Data mining and molecular dynamics analysis to detect HIV-1 reverse transcriptase RNase H activity inhibitor

HIV-1 is a deadly virus that affects millions of people worldwide. In this study, we aimed to inhibit viral replication by targeting one of the HIV-1 proteins and identifying a new drug candidate. We used data mining and molecular dynamics methods on HIV-1 genomes. Based on MAUVE analysis, we selected the RNase H activity of the reverse transcriptase (R.T) enzyme as a potential target due to its low mutation rate and high conservation level. We screened about 94,000 small molecule inhibitors by virtual screening. We validated the hit compounds' stability and binding free energy through molecular dynamics simulations and MM/PBSA. Phomoarcherin B, known for its anticancer properties, emerged as the best candidate and showed potential as an HIV-1 reverse transcriptase RNase H activity inhibitor. This study presents a new target and drug candidate for HIV-1 treatment. However, in vitro and in vivo tests are required. Also, the effect of RNase H activity on viral replication and the interaction of Phomoarcherin B with other HIV-1 proteins should be investigated.

New Isocoumarin and Pyrone Derivatives from the Chinese Mangrove Plant Rhizophora mangle-Associated Fungus Phomopsis sp. DHS-11

Mangrove-associated fungi are important sources for the discovery of new bioactive natural products. Three new isocoumarins (1-3) and one new pyrone derivative (4) were isolated from the ethyl acetate extract of the fermentation broth of the mangrove endophytic fungus Phomopsis sp. DHS-11. Nuclear magnetic resonance (NMR) spectroscopy (one-dimensional and two-dimensional) and mass spectrometry were used to determine the structures of these new compounds. The absolute configurations for the new isocoumarins 1-3 were determined by comparing their experimental and calculated electronic circular dichroism (ECD) spectra, while the configuration for the new pyrone-derivative 4 was tentatively solved by comparison of its ¹³C NMR data with reported data. In the biological activity test, compounds 1 and 3 showed cytotoxic activity against HeLa cells with IC₅₀ values of 11.49 ± 1.64 µM and 8.70 ± 0.94 µM, respectively. The initial structure and activity relationship (SAR) analysis revealed that the length of the side chain at C-3 for isocoumarin-type compounds 1-3 could affect the cytotoxicity against HeLa cells. Compound 4 exhibited cytotoxic activities against human hepatoma cells HepG2 with an IC₅₀ value of 34.10 ± 2.92 µM. All compounds have no immunosuppressive activity.

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.

Antiparasitic Meroterpenoids Isolated from Memnoniella dichroa CF-080171

Memnoniella is a fungal genus from which a wide range of diverse biologically active compounds have been isolated. A Memnoniella dichroa CF-080171 extract was identified to exhibit potent activity against Plasmodium falciparum 3D7 and Trypanosoma cruzi Tulahuen whole parasites in a high-throughput screening (HTS) campaign of microbial extracts from the Fundación MEDINA's collection. Bioassay-guided isolation of the active metabolites from this extract afforded eight new meroterpenoids of varying potencies, namely, memnobotrins C-E (1-3), a glycosylated isobenzofuranone (4), a tricyclic isobenzofuranone (5), a tetracyclic benzopyrane (6), a tetracyclic isobenzofuranone (7), and a pentacyclic isobenzofuranone (8). The structures of the isolated compounds were established by (+)-ESI-TOF high-resolution mass spectrometry and nuclear magnetic resonance spectroscopy. Compounds 1, 2, and 4 exhibited potent antiparasitic activity against P. falciparum 3D7 (EC₅₀ 0.04-0.243 μM) and T. cruzi Tulahuen (EC₅₀ 0.266-1.37 μM) parasites, as well as cytotoxic activity against HepG2 tumoral liver cells (EC₅₀ 1.20-4.84 μM). The remaining compounds (3, 5-8) showed moderate or no activity against the above-mentioned parasites and cells.

The Role of Herbal Medicine in Cholangiocarcinoma Control: A Systematic Review

The growing incidence of cholangiocarcinoma (bile duct cancer) and limited treatment options stimulate a pressing demand for research and the development of new chemotherapeutics against cholangiocarcinoma. This study aimed to systematically review herbs and herb-derived compounds or herbal formulations that have been investigated for their anti-cholangiocarcinoma potential. Systematic literature searches were conducted in three electronic databases: PubMed, ScienceDirect, and Scopus. One hundred and twenty-three research articles fulfilled the eligibility critera and were included in the analysis (68 herbs, isolated compounds and/or synthetic analogs, 9 herbal formulations, and 119 compounds that are commonly found in several plant species). The most investigated herbs were Atractylodes lancea (Thunb.) DC. (Compositae) and Curcuma longa L. (Zingiberaceae). Only A. lancea (Thunb.) DC. (Compositae) has undergone the full process of nonclinical and clinical development to deliver the final product for clinical use. The extracts of A. lancea (Thunb.) DC. (Compositae), Garcinia hanburyi Hook.f. (Clusiaceae), and Piper nigrum L. (Piperaceae) exhibit antiproliferative activities against human cholangiocarcinoma cells (IC₅₀ < 15 µg/mL). Cucurbitacin B and triptolide are herbal isolated compounds that exhibit the most promising activities (IC₅₀ < 1 µM). A series of experimental studies (in vitro, in vivo, and humans) confirmed the anti-cholangiocarcinoma potential and safety profile of A. lancea (Thunb.) DC. (Compositae) and its active compounds atractylodin and β-eudesmol, including the capsule pharmaceutical of the standardized A. lancea (Thunb.) DC. (Compositae) extract. Future research should be focused on the full development of the candidate herbs to deliver products that are safe and effective for cholangiocarcinoma control.

Five new secondary metabolites from an endophytic fungus Phomopsis sp. SZSJ-7B

Two previously undescribed lactones, phomolides A and B (1 and 2), and three new sesquiterpenoids, phomenes A-C (3-5), together with one known compound, colletotricholide A (6), were isolated from the endophytic fungus Phomopsis sp. SZSJ-7B. Their chemical structures, including the absolute configurations, were comprehensively established by extensive analyses of NMR, high-resolution electrospray ionization mass spectrometry, electronic circular dichroism powered by theoretical calculations, and X-ray diffractions. Moreover, the cytotoxic and antibacterial activities of compounds 1-6 were also evaluated, and the results demonstrated that compound 2 showed significant antibacterial effects towards methicillin-resistant Staphylococcus aureus and S. aureus strains with minimum inhibitory concentration as low as 6.25 μg/ml, which was comparable to that of the clinical drug vancomycin. Moreover, all compounds showed no cytotoxic activity.

A Novel Approach for Fast Screening of a Complex Cyanobacterial Extract for Immunomodulatory Properties and Antibacterial Activity

The filamentous cyanobacteria from genus Phormidium are rich natural sources of bioactive compounds that could be exploited as pharmaceuticals or nutraceuticals. In this study, we suggest a novel approach for assessing the immunomodulatory properties of the products derived from cyanobacteria. The influence of Phormidium papyraceum extract on the human leukocyte immunophenotype was evaluated by attempting to link this activity to certain putative compounds identified in the extract. By using three staining panels and flow cytometry, we found that the cyanobacterial extract affected mainly CD4+ T cells upregulating activated CD4+CD152+ T cells (15.75 ± 1.93% treated vs. 4.65 ± 1.41% control) and regulatory CD4+CD25+ T cells (5.36 ± 0.64% treated vs. 1.03 ± 0.08% control). Furthermore, P. papyraceum extract can modulate T cell subpopulations with a CD4+ effector/memory phenotype. Extract-treated cells showed increased production of IL-2 (55 ± 12 pg/mL) and IL-6 (493 ± 64 pg/mL) compared to the untreated, 21 ± 7 pg/mL and 250 ± 39 pg/mL, respectively. No significant changes were observed in the secretion of TNF-α. In addition, P. papyraceum extract displayed antibacterial activity against both Gram-negative (inhibition zone from 18.25 ± 0.50 mm to 20.28 ± 1.50 mm) and Gram-positive (inhibition zone from 10.86 ± 0.85 mm to 17.00 ± 0.82 mm) bacteria. The chemical profile of the cyanobacterial extract was determined using LC–ESI–MS/MS analysis, where at least 112 putative compounds were detected. Many of these compounds have proven different biological activities. We speculated that compounds such as betulin and the macrolide azithromycin (or their analogues) could be responsible for the immunomodulatory potential of the investigated extract. More studies are needed to determine and validate the biological activities of the determined putative compounds.

Five new secondary metabolites from the fungus Phomopsis asparagi

Five new compounds, including a pair of diphenylcyclopentenone enantiomers (±)-phomopsisin A (1), a sesquiterpenoid 15-hydroxylithocarin A (2), a new diketopiperazine alkaloid prenylcyclotryprostatin A (3) and 7-hydroxy-cis-L(-)-3,6-dibenzyl-2,5-dioxopiperazine (6), along with five known compounds were isolated from the fungus Phomopsis asparagi. Their structures were elucidated on the basis of spectroscopic analyses (1D and 2D NMR), theoretical electronic circular dichroism (ECD) calculation, modified Mosher's method, and X-ray crystallography. The racemates of (±)-phomopsisin A showed inhibition on α-glucosidase with IC₅₀ of 30.07 ± 0.75 μM (positive control acarbose, 121 ± 2.7 μM).

Bioactive Secondary Metabolites of the Genus Diaporthe and Anamorph Phomopsis from Terrestrial and Marine Habitats and Endophytes: 2010-2019

The genus Diaporthe and its anamorph Phomopsis are distributed worldwide in many ecosystems. They are regarded as potential sources for producing diverse bioactive metabolites. Most species are attributed to plant pathogens, non-pathogenic endophytes, or saprobes in terrestrial host plants. They colonize in the early parasitic tissue of plants, provide a variety of nutrients in the cycle of parasitism and saprophytism, and participate in the basic metabolic process of plants. In the past ten years, many studies have been focused on the discovery of new species and biological secondary metabolites from this genus. In this review, we summarize a total of 335 bioactive secondary metabolites isolated from 26 known species and various unidentified species of Diaporthe and Phomopsis during 2010-2019. Overall, there are 106 bioactive compounds derived from Diaporthe and 246 from Phomopsis, while 17 compounds are found in both of them. They are classified into polyketides, terpenoids, steroids, macrolides, ten-membered lactones, alkaloids, flavonoids, and fatty acids. Polyketides constitute the main chemical population, accounting for 64%. Meanwhile, their bioactivities mainly involve cytotoxic, antifungal, antibacterial, antiviral, antioxidant, anti-inflammatory, anti-algae, phytotoxic, and enzyme inhibitory activities. Diaporthe and Phomopsis exhibit their potent talents in the discovery of small molecules for drug candidates.

Bioactive sesquiterpene derivatives from mangrove endophytic fungus Phomopsis sp. SYSU-QYP-23: Structures and nitric oxide inhibitory activities

Eight new sesquiterpene derivatives (2, 4-6 and 10-13), along with five known analogues were isolated from the mangrove endophytic fungus Phomopsis sp. SYSU-QYP-23. Their structures of new compounds were established by spectroscopic methods, and the absolute configurations were confirmed by single-crystal X-ray diffraction analysis and comparison of the experimental ECD spectra. The absolute configuration of the side chain in 1 was first defined by modified Mosher's method. Compounds 1-7 showed potent inhibitory activities against nitric oxide (NO) production in lipopolysaccharides (LPS) induced RAW 264.7 cells with IC₅₀ values ranging from 8.6 to 14.5 μM. The molecular docking results implied that the bioactive sesquiterpenes may directly bind with targeting residues in the active cavity of iNOS protein.

Synthesis of phthalide derivatives and evaluation on their antiplatelet aggregation and antioxidant activities

As part of our continuing efforts to discover structurally interesting bioactive phthalide derivatives, 23 of them with a structure incorporating thiophen or halogens were designed and synthesized, 17 of which are previously unreported. In vitro antiplatelet aggregation activity screening showed that 14b could significantly inhibit platelet aggregation induced by arachidonic acid, compared with edaravone (p < 0.01). Meanwhile, oxidative damage models using SH-SY5Y and PC12 cells induced by H₂O₂ were built to evaluate the antioxidant activity of the phthalide derivatives. In SH-SY5Y cells, compared with aspirin, 1a significantly increased the relative cell survival rate (p < 0.05). Compared with edaravone, 1a (p < 0.01) and 15b (p < 0.05) significantly increased the relative cell survival rate. In PC12 cells, 1a (p < 0.01), 15b (p < 0.01), and 12a (p < 0.05) remarkably increased the cell survival rate compared with edaravone. The present study identified lead structures to develop potential anti-ischemic stroke agents.

Natural Polyketides Isolated from the Endophytic Fungus Phomopsis sp. CAM212 with a Semisynthetic Derivative Downregulating the ERK/IκBα Signaling Pathways

Three previously undescribed natural products, phomopsinin A - C (1:  - 3: ), together with three known compounds, namely, cis-hydroxymellein (4: ), phomoxanthone A (5: ) and cytochalasin L-696,474 (6: ), were isolated from the solid culture of Phomopsis sp. CAM212, an endophytic fungus obtained from Garcinia xanthochymus. Their structures were determined on the basis of spectroscopic data, including IR, NMR, and MS. The absolute configurations of 1: and 2: were assigned by comparing their experimental and calculated ECD spectra. Acetylation of compound 1: yielded 1A: , a new natural product derivative that was tested together with other isolated compounds on lipopolysaccharide-stimulated RAW 264.7 cells. Cytochalasin L-696,474 (6: ) was found to significantly inhibit nitric oxide production, but was highly cytotoxic to the treated cells, whereas compound 1: slightly inhibited nitric oxide production, which was not significantly different compared to lipopolysaccharide-treated cells. Remarkably, the acetylated derivative of 1: , compound 1A: , significantly inhibited nitric oxide production with an IC₅₀ value of 14.8 µM and no cytotoxic effect on treated cells, thereby showing the importance of the acetyl group in the anti-inflammatory activity of 1A: . The study of the mechanism of action revealed that 1A: decreases the expression of inducible nitric oxide synthase, cyclooxygenase 2, and proinflammatory cytokine IL-6 without an effect on IL-1β expression. Moreover, it was found that 1A: exerts its anti-inflammatory activity in lipopolysaccharide-stimulated RAW 264.7 macrophage cells by downregulating the activation of ERK1/2 and by preventing the translocation of nuclear factor κB. Thus, derivatives of phomopsinin A (1: ), such as compound 1A: , could provide new anti-inflammatory leads.

Secondary metabolites produced by Colletotrichum lupini, the causal agent of anthachnose of lupin (Lupinus spp.)

COLLETOTRICHUM LUPINI

is the causal agent of lupin (Lupinus albus L.) anthracnose, a destructive seed-borne disease affecting stems and pods. Despite that several biological studies have been carried out on this pathogen, the production of secondary metabolites has not yet been investigated. Thus, a strain of C. lupini, obtained from symptomatic stems of L. albus, has been grown in vitro to evaluate its ability to produce bioactive compounds. From its culture filtrates, a 3-substituted indolinone, named lupindolinone, and a 5,6-disubstituted tetrahydro-α-pyrone, named lupinlactone, were isolated together with the known (3R)-mevalonolactone and tyrosol. Lupindolinone and lupinlactone were characterized as 3-ethylindolin-2-one and 5-hydroxy-6-methyltetrahydropyran-2-one by spectroscopic methods (essentially nuclear magnetic resonance [NMR] and high-resolution electrospray ionization mass spectrometry [HR ESI-MS]). The R absolute configuration (AC) at C-5 of lupinlactone was determined by applying the modified Mosher's method. Thus, considering its relative stereochemistry assigned by NMR spectroscopy, the AC of lupinlactone could be formulated as 5R,6S. Lupindolinone was isolated as racemic mixture as shown by investigation using chiroptical methods. The metabolites were assayed in different biological tests and proved to have some activities at the used concentration.

Three novel chromanones with biological activities from the endophytic fungus Phomopsis CGMCC No. 5416

Three undescribed chromanones (1-3) and two known chromanones (4 and 5) were isolated from the culture of endophytic fungus Phomopsis CGMCC No. 5416 from the stems of Achyranthes bidentata. Their structures were determined by spectroscopic analysis. Compounds 1 and 2 showed inhibitory activities against HIV-1 with IC₅₀ values of 20.4 and 32.5 μg ml^-1, respectively. Compounds 1-3 displayed moderate cytotoxicity with CC₅₀ values of 36.5-79.3 μg ml^-1 against A549, MDA-MB-231, and PANC-1 cell lines. Moreover, compound 3 can induce the early apoptosis of PANC-1 cancer cells with the apoptosis rate of 10.52%.

Antiplasmodial natural products: an update

Background

Malaria remains a significant public health challenge in regions of the world where it is endemic. An unprecedented decline in malaria incidences was recorded during the last decade due to the availability of effective control interventions, such as the deployment of artemisinin-based combination therapy and insecticide-treated nets. However, according to the World Health Organization, malaria is staging a comeback, in part due to the development of drug resistance. Therefore, there is an urgent need to discover new anti-malarial drugs. This article reviews the literature on natural products with antiplasmodial activity that was reported between 2010 and 2017.

Methods

Relevant literature was sourced by searching the major scientific databases, including Web of Science, ScienceDirect, Scopus, SciFinder, Pubmed, and Google Scholar, using appropriate keyword combinations.

Results and Discussion

A total of 1524 compounds from 397 relevant references, assayed against at least one strain of Plasmodium, were reported in the period under review. Out of these, 39% were described as new natural products, and 29% of the compounds had IC₅₀ ≤ 3.0 µM against at least one strain of Plasmodium. Several of these compounds have the potential to be developed into viable anti-malarial drugs. Also, some of these compounds could play a role in malaria eradication by targeting gametocytes. However, the research into natural products with potential for blocking the transmission of malaria is still in its infancy stage and needs to be vigorously pursued.

Phenylspirodrimane Derivatives From Cultures of the Fungus Stachybotrys chartarum YIM DT 10079

A new phenylspirodrimane derivative, stachartin F (1), and 2 known secondary metabolites stachybonoid E (2) and stachybonoid F (3) were isolated from cultures of the tin mine tailings-associated fungus Stachybotrys chartarum YIM DT 10079. Their structures were determined with the help of extensive spectroscopic analyses and absolute configuration of compound 1 was rationalized by quantum chemical calculations of the electronic circular dichroism spectra.

Protoilludane, Illudalane, and Botryane Sesquiterpenoids from the Endophytic Fungus Phomopsis sp. TJ507A

To explore the chemical diversity of metabolites from endophytic fungi, the strain Phomopsis sp. TJ507A, isolated from the medicinal plant Phyllanthus glaucus, was investigated. A 2,3- seco-protoilludane-type sesquiterpenoid (1), eight protoilludane-type sesquiterpenoids (2-9), four illudalane-type sesquiterpenoids (10a/10b, 11, and 12), and a botryane-type sesquiterpenoid (13) in addition to seven known sesquiterpenoids (14-20) were identified from the liquid culture of the fungus. Structures of the isolated compounds, including their absolute configurations, were elucidated based on extensive spectroscopic analyses, a modified Mosher analysis, electronic circular dichroism (ECD) calculations, and [Rh₂(OCOCF₃)₄]-induced ECD spectra as well as X-ray crystallographic analyses. Compound 1 represents the first example of a naturally occurring sesquiterpenoid containing the unusual 2,3- seco-protoilludane scaffold. Compounds 1 ( p < 0.001); 2-6, 15, and 18 ( p < 0.01); and 7, 9, and 20 ( p < 0.05) displayed β-site amyloid precursor protein cleaving enzyme 1 (BACE1) inhibitory activities ranging from 19.4% to 43.8% at the concentration of 40 μM. LY2811376 was used as the positive control with an inhibitory activity of 38.6% ( p < 0.01). Furthermore, none of these compounds showed obvious hepatotoxicity at concentration of 40 μM.

Three xanthone dimers from the Thai mangrove endophytic fungus Phomopsis sp. xy21

Three new xanthone dimers, named phomoxanthones C-E (1-3), were obtained from the Thai mangrove fungus Phomopsis sp. xy21, together with four known ones. The structures of these compounds were elucidated by the analysis of HRESIMS and extensive NMR spectroscopic data. The absolute configuration of 1 was established by the analysis of single-crystal X-ray diffraction with Cu Kα radiation. Phomoxanthones C (1) and D (2) possess a highly oxidized hexahydroxanthone skeleton.

Lithocarpins A–D: four tenellone-macrolide conjugated [4 + 2] hetero-adducts from the deep-sea derived fungus Phomopsis lithocarpus FS508

Lithocarpins A–D, four novel tenellone-macrolide conjugated dimers containing a fascinating 9,14-epoxynaphtho[2,3-e]oxecin-3(2H)-one skeleton.

Genome of Diaporthe sp. provides insights into the potential inter-phylum transfer of a fungal sesquiterpenoid biosynthetic pathway

Fungi have highly active secondary metabolic pathways which enable them to produce a wealth of sesquiterpenoids that are bioactive. One example is Δ6-protoilludene, the precursor to the cytotoxic illudins, which are pharmaceutically relevant as anticancer therapeutics. To date, this valuable sesquiterpene has only been identified in members of the fungal division Basidiomycota. To explore the untapped potential of fungi belonging to the division Ascomycota in producing Δ6-protoilludene, we isolated a fungal endophyte Diaporthe sp. BR109 and show that it produces a diversity of terpenoids including Δ6-protoilludene. Using a genome sequencing and mining approach 17 putative novel sesquiterpene synthases were identified in Diaporthe sp. BR109. A phylogenetic approach was used to predict which gene encodes Δ6-protoilludene synthase, which was then confirmed experimentally. These analyses reveal that the sesquiterpene synthase and its putative sesquiterpene scaffold modifying cytochrome P450(s) may have been acquired by inter-phylum horizontal gene transfer from Basidiomycota to Ascomycota. Bioinformatic analyses indicate that inter-phylum transfer of these minimal sequiterpenoid secondary metabolic pathways may have occurred in other fungi. This work provides insights into the evolution of fungal sesquiterpenoid secondary metabolic pathways in the production of pharmaceutically relevant bioactive natural products.

Natural products containing 'decalin' motif in microorganisms

Microorganisms are well-known producers of a wide variety of bioactive compounds that are utilized not only for their primary metabolism but also for other purposes such as defense, detoxification, or communication with other micro- and macro-organisms. Natural products containing a 'decalin ring' occur often in microorganisms. They exhibit diverse and remarkable biological activities, including antifungal, antibacterial, anticancer and immunosuppressive activities, to name a few. This review surveys the natural decalin-type compounds that have been isolated from microorganisms, with emphasis on both chemical and biological implications. Total syntheses of some important decalin moiety-containing natural products are also highlighted.

Chemical Assessment and Antimicrobial and Antioxidant Activities of Endophytic Fungi Extracts Isolated from Costus spiralis (Jacq.) Roscoe (Costaceae)

Costus spiralis (Costaceae) is a species native to the Amazon region and is used in traditional medicine. The endophytic fungi used in this study were obtained from leaves of this plant. 13 strains were selected to obtain hydroethanolic extracts and were submitted to hydroalcoholic extraction and evaluated for antioxidant activity by DPPH (2,2-difenil-1-picrilhidrazil) and FRAP (ferric reducing antioxidant power), and all of the fungi had positive results. The antimicrobial action of crude extracts had a good range of activities. All extracts had inhibitory activities against the yeasts of Candida albicans and C. parapsilosis, with 125 to 500 μg/mL MIC. Eight extracts had antimicrobial activities against Bacillus subtilis (MIC from 62.4 to 125 μg/mL), 5 against Pseudomonas aeruginosa (MIC from 125 to 500 μg/mL), 2 against Salmonella enterica (MIC from 125 to 62.5 μg/mL), and 2 against Enterococcus faecalis (MIC from 500 to 125 μg/mL). The presence of secondary metabolites, including coumarins, was observed during chemical evaluation by thin layer chromatography. Total phenol content was estimated, and a strong positive correlation to antioxidant activity was observed, according to its Pearson coefficient. This is the first report of the bioactive potential of endophytic fungi isolated from the Costaceae family in Brazilian ecosystems.