Search Results (2,471)

Background/Objectives: Endophytic fungi represent an alternative source for resveratrol (RES) production. The present study aims to utilize mycoendophytic-derived resveratrol as a reducing agent for the synthesis of silver nanoparticles (AgNPs), in addition to further assay the cytotoxic activity of a RES-conjugated nanocarrier system toward human epidermoid carcinoma A-431 cells. Methods: Alternaria alternata AUMC 16209 was isolated from the stem of grapevine Vitis vinifera L. cultivar prime. Strain identification was achieved through morphological and molecular characterization using ITS sequencing. A. alternata AUMC 16209 exhibited RES production capability upon cultivation on PDB medium for seven days with a total of 8.25 mg/L as determined by HPLC. The crude RES was purified using flash chromatography followed by structure elucidation through ¹H and ¹³C NMR analyses. The purified RES was used for green synthesis of nanoparticles, acting as a reducing agent for silver ions. Results: Stable RES-AgNPs were fabricated at particle sizes ranging from 25 to 47 nm. RES-AgNPs observed a plasmon resonance absorption band at 415 nm with a negative zeta potential value of −38.5 mV. The crystalline structure of RES-AgNPs was addressed through X-ray diffraction analysis. FT-IR spectroscopy confirms the involvement of the functional –OH group and the aromatic C=C bond in the reduction and stabilization process. RES-AgNPs was more efficient to inhibit the cellular proliferation of human epidermoid carcinoma A-431 cells compared to RES alone. Conclusions: This report introduces for the first time an endophytic A. alternata as a sustainable source for RES production and emphasizes its potential for green synthesis of stable AgNPs with promising cytotoxic activity. Full article

Three new, previously undescribed tanzawaic acids, steckwaic acids H–J (1–3), and twenty-three known natural products (4–26) were isolated from the marine algicolous fungus Penicillium steckii SCSIO 41040. Structurally, compound 3 underwent a rare hydration reaction at the double bond of its carboxylic acid side chain. The chemical structures and stereochemistry were determined using comprehensive spectroscopic analyses, including NMR, electronic circular dichroism (ECD) calculations, and high-resolution electrospray ionization mass spectrometry (HRESIMS), and verified by literature comparison. The protective effect of tanzawaic acids on inflammatory damage to the intestinal epithelial barrier was assessed using an LPS-stimulated Caco-2/THP-1 co-culture model. Notably, immunofluorescence and Western blotting assays showed that compound 10 significantly enhanced the fluorescence signals and protein expression of ZO-1 and occludin, alleviated lipopolysaccharide (LPS)-induced intestinal barrier damage in Caco-2 cells, and contributed to the re-establishment of intestinal barrier homeostasis. Our findings demonstrate the critical role of tanzawaic acids in maintaining intestinal barrier integrity, identifying them as promising lead compounds for UC treatment. Full article

Background: Prostate cancer (PCa) is the leading male urinary malignancy globally. Our previous article demonstrated the anti-PCa activity of Euphorbia humifusa Willd water extract (EHW) and some of its compounds via downregulating AR expression, but the anti-PCa active compounds from Euphorbia humifusa Willd (EH) and their mechanisms of action are yet to be clarified. Thus, the current article studied the in vitro anti-PCa effects of 3,3′-di-O-methylellagic acid (3,3′-di-O-Me-EA) derived from EHW and the related mechanism involved. Methods: 3,3’-di-O-Me-EA was isolated from EHW applying bioassay-guided fractionation. The spectroscopic methods were used to determining the structure of 3,3′-di-O-Me-EA. The drug-likeness and ADMET properties (absorption, distribution, metabolism, excretion, and toxicity) of 3,3′-di-O-Me-EA were analyzed in silico. Molecular docking and real-time surface plasmon resonance (SPR) analysis were performed to measure the interaction of 3,3′-di-O-Me-EA and VDAC1 protein. The viability and apoptosis of 22RV-1 and DU145 PCa cells were determined using MTT and Annexin V-FITC staining assay, respectively. q-PCR and Western blot experiments were used to analyzing the gene and protein expressions of VDAC1. Results: 3,3′-di-O-Me-EA was isolated and purified from EHW with a purity of ≥90.06%, and its structure was identified by HRTOF mass, NMR, and an authentic standard. In silico ADMET analysis indicated its favorable drug-like and pharmacokinetic properties. Molecular docking and SPR results confirmed that 3,3′-di-O-Me-EA could bind with the VDAC1 protein. Moreover, 3,3′-di-O-Me-EA dose- and time-dependently inhibited 22RV-1 and DU145 PCa cell viability, and induced apoptosis in a dose-dependent manner (p < 0.05). RT-qPCR and Western blot results showed that 3,3′-di-O-Me-EA dose-dependently up-regulated VDAC1 gene and protein expression levels in 22RV-1 and DU145 cells (p < 0.05). Meanwhile, in VDAC1-depleted 22RV-1 and DU145 cells, 3,3′-di-O-Me-EA down-regulated VDAC1 gene and protein expression levels, increased cell viability, and inhibited apoptosis compared to 22RV-1 and DU145 cells (p < 0.05). Furthermore, 3,3′-di-O-Me-EA enhanced VDAC1 gene and protein expression levels, inhibited cell viability, and induced apoptosis in VDAC1-overexpressed 22RV-1 and DU145 cells compared with 22RV-1 and DU145 cells (p < 0.05). Overall, EH active compound 3,3′-di-O-Me-EA may inhibit viability and induce apoptosis of 22RV-1 and DU145 PCa cells via up-regulating VDAC1 gene and protein expression levels. Conclusion: The results indicated that the 22RV1 and DU145 PCa cell viability inhibitory effects of 3,3′-di-O-Me-EA isolated from EH may be mediated by induction of apoptosis through up-regulation of VDAC1 gene and protein expression levels. Full article

Botrytis cinerea and Plasmopara viticola, the causal agents of grey mold and downy mildew, respectively, are two major grapevine pathogens whose control largely relies on synthetic fungicides, raising environmental and health concerns. Plant-derived secondary metabolites, particularly flavonoids involved in plant defense, represent promising sustainable alternatives. Among them, sakuranetin, a flavanone aglycone known for its antifungal activity in rice, remains poorly explored for grapevine protection. In this study, sakuranetin was purified from cherry branches (48 mg) and structurally characterized using UHPLC-ESI-QTOF-MS and NMR analyses. Its antifungal activity against B. cinerea and P. viticola was evaluated through in vitro, in vivo and in planta assays. For B. cinerea, our results showed a significant in vitro inhibition of mycelium growth, with EC₅₀ values of 16.43 mg·L⁻¹, while no protection of detached berries was observed. Against P. viticola, sakuranetin has no effect on the release of zoospores, but there is a total inhibition of spore germination at 1 mg·L⁻¹ in vitro, confirmed in vivo on a foliar disc. In planta, no significant protection is observed at 25 mg·L⁻¹, even if some targeted defense genes are induced. Further studies are needed to determine the best concentration of sakuranetin to use to manage B. cinerea and P. viticola in planta. Full article

The central role of YB-1 in messenger ribonucleoprotein particle (mRNP) metabolism and stress-granule biology highlights the importance of defining the determinants of its self-assembly. YB-1 fibrillogenesis has been attributed primarily to the cold shock domain (CSD). Here, we show that the YB-1 fragment spanning residues 1–129 (AP–CSD) form amyloid fibrils under near-physiological ionic strength (0.12–0.15 M KCl). Fibrillization proceeds without a pronounced exponential growth phase and increases approximately linearly over 45–50 h. Far-UV circular dichroism (CD) and attenuated total reflection Fourier-transform infrared spectroscopy (ATR-FTIR) indicate no substantial change in overall secondary-structure content during aggregation. In parallel, ¹H nuclear magnetic resonance (NMR) spectroscopy reveals the depletion of soluble species, and oriented fiber X-ray diffraction displays the hallmark cross-β reflections at approximately 4.7 Å and 10 Å. The prolonged formation time implies an activation barrier that is unlikely to require global refolding. Instead, it may reflect early association events such as dimerization or other local rearrangements required for primary nucleation, followed by consolidation into stable intermolecular contacts. Aggregation that preserves a largely native-like fold while establishing cross-β order may reduce recognition by cellular quality-control systems that preferentially target globally unfolded or strongly destabilized states. This provides a plausible framework for how YB-1 derived assemblies could persist under stress and during age-associated proteostasis decline. Full article

2-methylcamalexin, a novel derivative of the phytoalexin Camalexin, was synthesized for the first time, using a convenient two-step approach. The approach realizes coupling of two aromatic heterocyclic moieties (2-methylindole and thiazole) by sequential α-amidoalkylation/oxidative re-aromatization. The target product was obtained in a cost-effective manner, with 88% yield over two steps. The structure of the synthesized product was unequivocally determined on the basis of NMR, HRMS and FTIR spectral measurments. Full article

Coalbed methane is vital for the transition toward low-carbon energy systems, yet its recovery efficiency is critically limited by inaccurate classification of movable water during drainage and depressurization due to the complex pore–fracture system. To understand the influence of the pore–fracture structure on water flow law in coal reservoirs, this study constructed the relationship based on the memory effect of multiscale complex pore–fracture structures on seepage. Nuclear magnetic resonance (NMR) measurements were performed on water-saturated coal samples both before and after centrifugation, enabling the experimental identification of absolute irreducible water, partial movable water, and absolute movable water and yielding dual cutoffs. The complexity of the pore–fracture structure of the samples was quantified by multifractal analysis of the NMR test results. A fractional derivative model was developed to determine dual cutoffs, T_2c1 and T_2c2, based on the memory effect and validated against experimental data. Compared to empirical models, the proposed fractional derivative model improves R² fitting accuracy by 4.2% for T_2c1 and 9.7% for T_2c2, demonstrating its superior capability in translating structural complexity into physically meaningful cutoff determination. This work provides a mechanism-based approach for water typing, presenting a reliable foundation for drainage and depressurization in coalbed methane reservoir. Full article

Plant viruses from the Potyviridae family have a significant impact on crop productivity worldwide. We conducted a bioinformatic analysis of the VPg sequences from several members of the Potyviridae family. All analyzed primary structures of VPg contain an invariant arginine, which, according to the model we proposed earlier, is located in the functionally important α1–α2 hairpin of the viral protein and forms a recognition contact during the formation of its complex with the eIF4E host cell. Among the amino acid mutations observed in the sequences of VPg PVY, we separately considered those associated with adaptation to the host plant. Several strain-specific mutations were identified, the functional roles of which are currently unclear. For each of the Potyviridae species considered, a consensus VPg sequence was determined. 3D-models of the corresponding proteins were constructed by de novo molecular modelling using the consensus amino acid sequences. Cross-comparative analysis of the theoretical models and the experimental VPg PVY structure obtained by NMR showed that all these proteins share a high degree of structural homology and contain the conserved arginine within the α1–α2 hairpin. However, the spatial position of this arginine may vary across models, which apparently reflects species-specific differences in the VPg recognition module. Full article

A novel derivative from carotene-type sesquiterpene, (1S,2R,3aR,6S,8aS)-1-isopropyl-3a,6-dimethyldecahydroazulene-1,2,6-triol (1), was successfully isolated from filamentous fungus Trichoderma virens NBRC 31959. The structure and molecular formula of 1 were determined by interpretation of 1D and 2D NMR and HRMS data. The absolute configuration was established unambiguously by single-crystal X-ray diffraction, with the Flack parameter supporting the assignment. This study adds to the chemical diversity of sesquiterpene-type CAF603 derivatives of Trichoderma virens. Full article

Genome sequencing has revealed that microorganisms have the potential to produce many more natural products than previously thought; the challenge is to establish efficient ways to “wake up” those “sleeping” biosynthetic pathways or genes, which are undoubtedly expressed in nature under specific conditions that are not normally reproduced in the laboratory. To activate these cryptic natural products, co-cultivation of cross-kingdom microorganisms between Candida albicans and Streptomyces longshengensis was performed in this study. A novel peak generated through co-culture was isolated and analyzed by a high-performance liquid chromatograph (HPLC), and its chemical structure was further determined by using mass spectrum (MS) and nuclear magnetic resonance (NMR) analyses. Bioassays of antimicrobial and antitumor activities were performed, and heterologous expression in Escherichia coli was attempted. The chemical structure was identified as tryptophol, and the bioassays revealed that tryptophol showed antitumor activity with IC₅₀ values of 154.5, 144.3, 122.6, and 110.7 μg/mL against A549, MC38, HepG2, and MCF-7 cells, respectively. As a valuable compound, tryptophol was also heterologously expressed in E. coli C41 to address the drawbacks of chemical synthesis. These findings combine co-cultivation with genetic engineering for tryptophol biosynthesis, expanding its antitumor application and laying a foundation for its industrial and sustainable production. Full article

Microorganisms provide critical lead compounds for drug development, yet most biosynthetic gene clusters remain silent under standard culture conditions. The OSMAC strategy activates these clusters by adjusting cultivation parameters, thereby enabling the discovery of novel compounds from a single strain. Here, we applied OSMAC to explore the metabolic potential of the soft coral-derived fungus Aspergillus sclerotiorum SCSIO 41031. Three different culture media were employed for the large-scale fermentation process. After isolation by chromatography, the compounds were structurally characterized using NMR, MS, and X-ray single-crystal diffraction, and their absolute configurations were determined by electronic circular dichroism (ECD) calculations. In total, three new compounds, named 6,6′-diacetyl-1,1′-dihydroxy-3,3′-dimethoxydibenzyl ether (1), esterwortmannolol (17) and pestalpolyol I (20), along with 19 known compounds (2–16, 18–19 and 21–22) were obtained. This study validates the efficacy of the OSMAC strategy and underscores that A. sclerotiorum SCSIO 41031 serves as a valuable resource for producing structurally diverse natural products with potent biological activities. Full article

Fufang Yinhua Jiedu Granules (FFYHG) is usually applied to treat influenza and the common cold. However, there is no available report concerning the effects of chemical constituents in FFYHG on antiviral activity. In our study, four new terpenoid derivatives (1–4) and seventeen known compounds were isolated from FFYHG. Their structures and absolute configurations were determined by various techniques, including high-resolution mass spectrometry analysis, 1/2-dimensional (1D/2D) nuclear magnetic resonance (NMR) analysis, comparative electronic circular dichroism (ECD) studies (experiment vs. calculation), and acid hydrolysis. In addition, the inhibitory effects of twenty-one isolated compounds against influenza A viruses (H1N1) including A/California/07/2009 (CA07) and A/WSN/1933 (WSN) strains were evaluated in vitro, and compound 4 exhibited a moderate inhibitory effect on CA07 strain, with a half maximal inhibitory concentration (IC₅₀) value of 37.10 ± 1.35 μM. This study enhanced the understanding of the active ingredients in FFYHG against influenza virus, providing a foundation for further research on the material basis and quality control of FFYHG. Full article

The chemical composition of natural products is complex and the investigation of bioactivities of compounds of interest demands their isolation. S. terebinthifolia Raddi is a tree belonging to the Anacardiaceae family and is used in Brazilian folk medicine; its fruit (pink peppers) are used in cooking and its bark in phytomedicine. Extracts of other parts of this plant contain a plethora of components and merit further studies. Countercurrent chromatography (CCC) is frequently employed with natural products due to the high sample recovery rate. The objective of this work was to determine the best solvent system (SS) to fraction the ethanol extracts of leaves, flowers and fruit of Schinus terebinthifolia by CCC and isolate compounds of interest and elucidate their structures through nuclear magnetic resonance (NMR) and mass spectrometry (MS). In addition, antiproliferative, potential cell regeneration and antioxidant activities of the fractions of interest were evaluated. In the present work, three compounds were isolated; two were identified as anacardic acids [(6-(8′, 11′-heptadecadienyl)-salicylic acid and 6-(8′-heptadecenyl)-salicylic acid], as well as (Z)-masticadienoic acid. These compounds showed antiproliferative and potential cell regeneration activities as well as varying degrees of antioxidant capacity. Although these compounds present potential therapeutic activity, more studies are necessary to confirm their safety. Full article

(1) Background: Gastric cancer (GC) remains a major global health challenge due to its high heterogeneity and aggressive progression. The discovery of novel bioactive molecules with anticancer properties has, therefore, become a critical research focus. In this study, we synthesized and characterized 4,4′-(5,8-dioxa-2,11-diazadodecane-1,11-diene-1,12-diyl)diphenol (DODP) and evaluated its anticancer potential using molecular docking, bioinformatics, and experimental analyses. (2) Methods: The chemical structure of DODP was confirmed through ¹H and ¹³C NMR spectroscopy. Molecular docking was conducted to examine the interaction of DODP with apoptosis and cell cycle-related proteins (TP53, MDM2, and MYC) and the immune checkpoint marker CD274 (PD-L1). Cytotoxicity against AGS GC cells was determined using the MTT assay at concentrations ranging from 0.01 to 50 µM, and gene expression alterations were analyzed by quantitative polymerase chain reaction (qPCR) and bioinformatics evaluation. (3) Results: NMR data verified the successful synthesis of DODP. The docking results indicated strong binding affinity, especially with TP53 and CD274. DODP showed notable cytotoxicity after 72 h of exposure and induced upregulation of TP53, MYC, and CD274 and downregulation of MDM2 in AGS cells. Although the patterns were consistent with cell-based and bioinformatic analyses, significant discriminatory ability in blood samples was observed only for MYC (AUC = 0.651; p = 0.044). (4) Conclusions: DODP influenced apoptosis-associated transcriptional responses in GC, offering early mechanistic evidence that should be evaluated in more comprehensive biological models. Full article

The fluorescence properties of organic molecules are largely determined by molecular architecture, π-conjugation, and electronic substituent effects. In this study, three novel pyrene-chromone Schiff base derivatives were designed and synthesized to investigate substituent-driven modulation of photophysical behavior. The compounds were obtained via condensation of 1-aminopyrene with three different chromone-based aldehydes and fully characterized by FT-IR, ¹H-NMR, and mass spectrometry. The molecular design involves a donor-π-acceptor architecture: pyrene donates electrons, while the chromene moiety accepts them, enabling charge transfer upon excitation. UV-Vis and fluorescence spectroscopy revealed intense absorption in the 430–440 nm range and tunable emission in the 540–565 nm region, corresponding to large Stokes shifts (107–125 nm). Substituent effects significantly influenced optical band gaps and emission intensities, with the nitro-substituted derivative exhibiting a reduced band gap and pronounced fluorescence quenching due to enhanced intramolecular charge transfer. Concentration-dependent absorption studies demonstrated linear Beer–Lambert behavior, indicating the absence of aggregation within the investigated range. These results establish clear structure–property relationships in pyrene-chromene Schiff bases and highlight their potential as promising candidates for optoelectronic and fluorescence-based sensing applications. Full article