RESUMEN
Bioassay-guided fractionation in association with LC-MS and NMR detection led to the isolation of six new alkaloids, sclerotiamides C-H (1-6), from the marine gorgonian-derived fungus Aspergillus sclerotiorum LZDX-33-4. Their structures were determined from extensive spectroscopic data, including ECD data and single-crystal X-ray diffraction analysis for configurational assignments. Sclerotiamides C (1) and D (2) are notoamide-type alkaloids with the incorporation of a unique 2,2-diaminopropane unit, and sclerotiamides E (3) and F (4) are unprecedented notoamide hybrids with a new coumarin unit. Sclerotiamide H (6) represents a new highly oxidized notoamide scaffold. Sclerotiamides C and F showed significant inhibition against a panel of tumor cell lines with IC50 values ranging from 1.6 to 7.9 µM. Sclerotiamide C induces apoptosis in HeLa cells by arresting the cell cycle, activating ROS production, and regulating apoptosis-related proteins in the MAPK signaling pathway. The present study extends the scaffold diversity of the notoamides and provides a potential lead for the development of a cytotoxic agent.
Asunto(s)
Alcaloides , Antineoplásicos , Alcaloides/farmacología , Antineoplásicos/farmacología , Hongos/metabolismo , Células HeLa , Humanos , Alcaloides Indólicos/química , Estructura MolecularRESUMEN
Epigenetic manipulation of a deep-sea sediment-derived Spiromastix sp. fungus using suberoylanilide hydroxamic acid (SAHA) induction resulted in the activation of a terpene-related biosynthetic gene cluster, and nine new guaiane-type sesquiterpenes, spiromaterpenes A-I (1-9), were isolated. Their structures were determined using various spectroscopic techniques, in association with the modified Mosher's method, computed electronic circular dichroism (ECD) spectra, and chemical conversion for configurational assignments. Compounds 4-6 exhibited significant effects against the NO production on lipopolysaccharide (LPS)-induced microglia cells BV2, and the preliminary SAR analyses demonstrated that a 2(R),11-diol unit is favorable. The most active 5 abolished LPS-induced NF-κB translocation from the cytosol to the nucleus in BV-2 microglial cells, accompanied by the marked reduction of the transcription levels of pro-inflammatory cytokines, including IL-1ß, IL-6, and TNF-α dose-dependently in both LPS-induced BV-2 and BV-2 cells, as well as the protein and mRNA levels of iNOS and COX-2. This study complements the gap in knowledge regarding the anti-neuroinflammatory activity of guaiane-type sesquiterpenoids at the cellular level and suggests that 5 is promising for further optimization as a multifunctional agent for antineuroinflammation.
Asunto(s)
Antiinflamatorios/metabolismo , Epigénesis Genética , Microglía/efectos de los fármacos , Onygenales/metabolismo , Sesquiterpenos de Guayano/metabolismo , Animales , Organismos Acuáticos , Línea Celular , Ratones , Estructura Molecular , Enfermedades Neuroinflamatorias , Onygenales/genéticaRESUMEN
Cryptotanshinone (1), a major bioactive constituent in the traditional Chinese medicinal herb Dan-Shen Salvia miltiorrhiza Bunge, has been reported to possess remarkable pharmacological activities. To improve its bioactivities and physicochemical properties, in the present study, cryptotanshinone (1) was biotransformed with the fungus Cunninghamella elegans AS3.2028. Three oxygenated products (2-4) at C-3 of cryptotanshinone (1) were obtained, among them 2 was a new compound. Their structures were elucidated by comprehensive spectroscopic analysis including HRESIMS, NMR and ECD data. All of the biotransformation products (2-4) were found to inhibit significantly lipopolysaccharide-induced nitric oxide production in BV2 microglia cells with the IC50 values of 0.16-1.16 µM, approximately 2-20 folds stronger than the substrate (1). These biotransformation products also displayed remarkably improved inhibitory effects on the production of inflammatory cytokines (IL-1ß, IL-6, TNF-α, COX-2 and iNOS) in BV-2 cells via targeting TLR4 compared to substrate (1). The underlying mechanism of 2 was elucidated by comparative transcriptome analysis, which suggested that it reduced neuroinflammatory mainly through mitogen-activated protein kinase (MAPK) signaling pathway. Western blotting results revealed that 2 downregulated LPS-induced phosphorylation of JNK, ERK, and p38 in MAPK signaling pathway. These findings provide a basal material for the discovery of candidates in treating Alzheimer's disease.
Asunto(s)
Antiinflamatorios no Esteroideos/farmacología , Inhibidores de la Colinesterasa/farmacología , Cunninghamella/metabolismo , Proteínas Quinasas Activadas por Mitógenos/antagonistas & inhibidores , Fenantrenos/farmacología , Receptor Toll-Like 4/antagonistas & inhibidores , Acetilcolinesterasa/metabolismo , Animales , Antiinflamatorios no Esteroideos/química , Antiinflamatorios no Esteroideos/metabolismo , Biotransformación , Línea Celular , Supervivencia Celular/efectos de los fármacos , Inhibidores de la Colinesterasa/química , Inhibidores de la Colinesterasa/metabolismo , Cunninghamella/química , Relación Dosis-Respuesta a Droga , Electrophorus , Ratones , Proteínas Quinasas Activadas por Mitógenos/metabolismo , Estructura Molecular , Oxígeno/metabolismo , Fenantrenos/química , Fenantrenos/metabolismo , Transducción de Señal/efectos de los fármacos , Relación Estructura-Actividad , Receptor Toll-Like 4/metabolismoRESUMEN
Structural modification of natural products by biotransformation with fungi is an attractive tool to obtain novel bioactive derivatives. In the present study, cryptotanshinone (1), a quinoid abietane diterpene from traditional Chinese medicine Salvia miltiorrhiza (Danshen), was transformed by two marine-derived fungi. By using Cochliobolus lunatus TA26-46, one new oxygenated and rearranged product (2), containing a 5,6-dihydropyrano[4,3-b]chromene moiety, together with one known metabolite (10), were obtained from the converted broth of cryptotanshinone (1) with the isolated yields of 1.0% and 2.1%, respectively. While, under the action of Aspergillus terreus RA2905, seven new transformation products (3-9) as well as 10 with the fragments of 2-methylpropan-1-ol and oxygenated p-benzoquinone were produced and obtained with the isolated yields of 0.1%-1.3%. The structures of the new compounds were elucidated by comprehensive spectroscopic analysis including High Resolution Electrospray Ionization Mass Spectroscopy (HRESIMS), Nuclear Magnetic Resonance (NMR) and Electronic Circular Dichroism (ECD). The metabolic pathways of cryptotanshinone by these two fungi were presumed to be the opening and rearrangement of furan ring, and/or oxygenation of cyclohexane ring. Cryptotanshinone (1) and its metabolites displayed anti-inflammatory activities against NO production in LPS-stimulated BV-2 cells and antibacterial activities towards methicillin-resistant Staphylococcus aureus. These findings revealed the potential of marine fungi to transform the structures of natural products by biotransformation.
Asunto(s)
Antibacterianos/metabolismo , Antiinflamatorios/metabolismo , Aspergillus/metabolismo , Curvularia/metabolismo , Fenantrenos/metabolismo , Animales , Antibacterianos/farmacología , Antiinflamatorios/farmacología , Biotransformación , Línea Celular , Staphylococcus aureus Resistente a Meticilina/efectos de los fármacos , Ratones , Pruebas de Sensibilidad Microbiana , Fenantrenos/farmacologíaRESUMEN
The deposition of aggregated human islet amyloid polypeptide (hIAPP) in the pancreas, that has been associated with ß-cell dysfunction, is one of the common pathological features of patients with type 2 diabetes (T2D). Therefore, hIAPP aggregation inhibitors hold a promising therapeutic schedule for T2D. Chitosan oligosaccharides (COS) have been reported to exhibit a potential antidiabetic effect, but the function of COS on hIAPP amyloid formation remains elusive. Here, we show that COS inhibited the aggregation of hIAPP and disassembled preformed hIAPP fibrils in a dose-dependent manner by thioflavin T fluorescence assay, circular dichroism spectroscopy, and transmission electron microscope. Furthermore, COS protected mouse ß-cells from cytotoxicity of amyloidogenic hIAPP, as well as apoptosis and cycle arrest. There was no direct binding of COS and hIAPP, as revealed by surface plasmon resonance analysis. In addition, both chitin-oligosaccharide and the acetylated monosaccharide of COS and glucosamine had no inhibition effect on hIAPP amyloid formation. It is presumed that, mechanistically, COS regulate hIAPP amyloid formation relating to the positive charge and degree of polymerization. These findings highlight the potential role of COS as inhibitors of hIAPP amyloid formation and provide a new insight into the mechanism of COS against diabetes.
Asunto(s)
Amiloide/metabolismo , Quitosano/farmacología , Citoprotección/efectos de los fármacos , Células Secretoras de Insulina/patología , Polipéptido Amiloide de los Islotes Pancreáticos/metabolismo , Oligosacáridos/farmacología , Animales , Benzotiazoles/metabolismo , Puntos de Control del Ciclo Celular/efectos de los fármacos , Muerte Celular/efectos de los fármacos , Línea Celular Tumoral , Quitosano/síntesis química , Quitosano/química , Quitosano/aislamiento & purificación , Fluorescencia , Humanos , Células Secretoras de Insulina/efectos de los fármacos , Polipéptido Amiloide de los Islotes Pancreáticos/química , Polipéptido Amiloide de los Islotes Pancreáticos/ultraestructura , Cinética , Ratones , Oligosacáridos/síntesis química , Oligosacáridos/química , Oligosacáridos/aislamiento & purificación , Agregado de Proteínas/efectos de los fármacos , Estructura Secundaria de ProteínaRESUMEN
A chemical fingerprinting approach utilizing LC-MS/MS coupled with 2D NMR data was established to characterize the profile of sorbicilinoid-type metabolites from a deep-sea derived fungus Penicillium rubens F54. Targeted isolation of the cultured fungus resulted in the discovery of 11 undescribed sorbicilinoids namely sorbicillinolides A-K (1-11). Their structures were identified by extensive analyses of the spectroscopic data, including the calculation of electronic circular dichroism and optical rotation for configurational assignments. The cyclopentenone core of sorbicillinolides A-D is likely derived from sorbicillin/dihydrosorbicillin through a newly oxidative rearrangement. The stereoisomers of sorbicillinolides E-G incorporate a nitrogen unit, forming a unique hydroquinoline nucleus. Sorbicillinolides A and C exhibited significant anti-neuroinflammation in LPS-stimulated BV-2 macrophages, achieved by potent inhibition of NO and PGE2 production through the interruption of RNA transcription of iNOS, COX-2 and IL6 in the NF-κB signaling pathway. Further investigation identified COX-2 as a potential target of sorbicillinolide A. These findings suggest sorbicillinolide A as a potential lead for the development of a non-steroidal anti-neuroinflammatory agent.
Asunto(s)
Penicillium , Espectrometría de Masas en Tándem , Ciclooxigenasa 2/metabolismo , Cromatografía Liquida , Macrófagos/metabolismo , Hongos/química , Penicillium/químicaRESUMEN
AIMS AND OBJECTIVES: The aim of this study is to discuss the influence of endotoxin on insulin amyloid formation, to provide guidance for therapeutic insulin preparation and storage. MATERIALS AND METHODS: The ThT and ANS binding assays were applied to characterize the dynamics curve of insulin amyloid formation with the presence or absence of endotoxin. The morphological structures of intermediate and mature insulin fibrils were observed with SEM and TEM. Secondary structural changes of insulin during fibriliation were examined with CD, FTIR and Raman spectral analysis. The cytotoxic effects of oligomeric and amyloidogenic insulin aggregates were detected using a cck-8 cell viability assay kit. The influence of endotoxin on insulin efficacy was analyzed by monitoring the activation of insulin signal transduction. KEY FINDINGS: ThT analysis showed that endotoxin, regardless of species, accelerated insulin fibrils formation in a dose-dependent manner, as observed with a shorter lag phase. ANS binding assay demonstrated endotoxin provoked the exposure of insulin hydrophobic patches. The results of SEM and TEM data displayed that endotoxin drove insulin to cluster into dense and viscous form, with thicker and stronger filaments. Based on CD, FTIR and Raman spectra, endotoxin promoted the transition of α-helix to random coil and ß-strand secondary structures during insulin aggregation. Insulins in both oligomeric and amyloidogenic forms were cytotoxic to HepG2 cells, with the former being more severe. Finally, the efficacy of endotoxin treated insulin obviously decreased. SIGNIFICANCE: Our studies revealed that endotoxin disrupts the structural integrity of insulin and promotes its amyloidosis. These findings offered theoretical guidance for insulin storage and safe utilization, as well as pointing up a new direction for insulin resistance research.
Asunto(s)
Amiloidosis , Insulina , Humanos , Amiloide/química , Amiloidosis/metabolismo , Insulina/metabolismo , Estructura Secundaria de Proteína , Transducción de Señal , EndotoxinasRESUMEN
Notoamides are a family of prenylated indole alkaloids with unusual ring systems and possessing a range of significant pharmaceutical activities. Based on LC-MS/MS and genome orientations, ten undescribed notoamide-type alkaloids namely sclerotiamides I-R were isolated from a marine gorgonian-derived fungus Aspergillus sclerotiorum LZDX-33-4. Their structures were determined by extensive spectroscopic data, in association with ECD data and single-crystal X-ray diffraction for configurational assignments. Bioassays resulted in sclerotiamide J along with five analogs possessing inhibitory effects against LDH and IL-1ß expression in BV-2 cells. Further investigation revealed that sclerotiamide J signiï¬cantly inhibited NLRP3 inï¬ammasome activation and blocked NLRP3 inï¬ammasome-induced pyroptosis via amelioration of mitochondria damage. In addition, sclerotiamide L exhibited potent inhibition against pathogenic Staphylococcus aureus ATCC 29213 with MIC value of 4.0 µM and the growth of MRSA T144 and Enterococcus faecalis ATCC 29212. This study extends the chemical diversity of notoamide-type alkaloids, and provides potential anti-inï¬ammasome and antibacterial lead compounds for further structure optimization.