Two new quinoline alkaloid with neuroprotective activities from Xylaria longipes.

Two new quinoline alkaloids with an α, ß-unsaturated amide side chain, xylarinines A and B (1 and 2), were isolated from the ethyl acetate extracts of Xylaria longipes solid fermentation. The structures of these were primarily determined though NMR and HRESIMS data analysis. The absolute configuration of compound 1 was assigned using experimental and calculated ECD data. The neuroprotective effects of compounds 1 and 2 against glutamate-induced damage in PC12 cells were evaluated in vitro bioassay. The results demonstrated that both compounds significantly improved cell viability, inhibited apoptosis, decreased malondialdehyde (MDA) levels, increased superoxide dismutase (SOD) and glutathione (GSH) levels, and reduced intracellular reactive oxygen species (ROS) accumulation. These findings suggested that these mechanisms contribute to the neuroprotective effects of the compounds.

[Characterization and identification of alkaloids in Phellodendri Chinensis Cortex and Phellodendri Amurensis Cortex based on UHPLC-IM-Q-TOF-MS].

A strategy combining collision cross section(CCS) prediction and quantitative structure-retention relationship(QSRR) model for quinoline and isoquinoline alkaloids was established based on UHPLC-IM-Q-TOF-MS and applied to Phellodendri Chinensis Cortex and Phellodendri Amurensis Cortex. The strategy included the following three steps.(1) The molecular features were extracted by the "find features" algorithm.(2) The potential quinoline and isoquinoline alkaloids were screened by filtering the original characteristic ions extracted from Phellodendri Chinensis Cortex and Phellodendri Amurensis Cortex by the established CCS vs m/z prediction interval.(3) According to the retention time of candidate compounds predicted by QSRR model, the chemical constituents were identified in combination with the characteristic fragment ions and pyrolysis law of secondary mass spectrometry. With the strategy, a total of 80 compounds were predicted, and 15 were identified accurately. The strategy is effective for the identification of small analogs of traditional Chinese medicine.

Zanthoxylum zanthoxyloides inhibits lipopolysaccharide- and synthetic hemozoin-induced neuroinflammation in BV-2 microglia: roles of NF-κB transcription factor and NLRP3 inflammasome activation.

OBJECTIVES: The effects of a root extract of Zanthoxylum zanthoxyloides on neuroinflammation in BV-2 microglia stimulated with LPS and hemozoin were investigated. METHODS: ELISA, enzyme immunoassay and Griess assay were used to evaluate levels of cytokines, PGE2 and NO in culture supernatants, respectively. Microglia-mediated neurotoxicity was evaluated using a BV-2 microglia-HT-22 neuron transwell co-culture. KEY FINDINGS: Treatment with Z. zanthoxyloides caused reduced elevated levels of TNFα, IL-6, IL-1ß, NO and PGE2, while increasing the levels of IL-10. In addition, there were reduced levels of iNOS and COX-2 proteins. This was accompanied by a prevention of microglia-mediated damage to HT-22 mouse hippocampal neurons. Z. zanthoxyloides reduced elevated levels of phospho-IκB and phospho-p65, while preventing degradation of IκB protein and DNA binding of p65. Further mechanistic studies revealed that Z. zanthoxyloides reduced the levels of pro-IL-1ß and IL-1ß in hemozoin-activated BV-2 microglia. This was accompanied by a reduction in caspase-1 activity and NLRP3 protein expression. Bioassay-guided fractionation resulted in the isolation of skimmianine as an anti-inflammatory compound in Z. zanthoxyloides. CONCLUSION: This is the first report showing the inhibition of neuroinflammation in LPS- and hemozoin-activated BV-2 microglia by the root extract of Z. zanthoxyloides by targeting the activation of both NF-κB and NLRP3 inflammasome.

Lycibarbarines A-C, Three Tetrahydroquinoline Alkaloids Possessing a Spiro-Heterocycle Moiety from the Fruits of Lycium barbarum.

Three tetrahydroquinoline alkaloids, lycibarbarines A-C (1-3), possessing a unique tetracyclic tetrahydroquinoline-oxazine-ketohexoside fused motif, were isolated from the fruits of Lycium barbarum. Their structures were determined by spectroscopic analysis and quantum-chemical calculations. Compounds 1 and 3 exhibited neuroprotective activity when evaluated for corticosterone-induced injury by reducing the apoptosis of PC12 cells through the inhibition of caspase-3 and caspase-9.

New quinoline alkaloid and bisabolane-type sesquiterpenoid derivatives from the deep-sea-derived fungus Aspergillus sp. SCSIO06786.

One new quinoline alkaloid (1), two new bisabolane-type sesquiterpene derivatives (2 and 3), and a new natural product (4) along with ten known compounds (514) were isolated from the deep sea-derived fungus Aspergillus sp. SCSIO06786 which cultured on solid rice medium. Three new structures were elucidated by analysis of 1D/2D NMR data and HR-ESI-MS. The absolute configurations of 2 and 3 were established by comparison of the experimental and reported ECD values. Compounds 11-13 exhibited moderate selective inhibitory activities against the tested pathogenic bacteria with MIC values among 3.13-12.5 µg/mL.

[Mass spectrometry guided strategy based on feature fragment ions for guided-separation on quinoline alkaloids from root barks of Dictamnus dasycarpus].

The root bark of Dictamnus dasycarpus is one of common traditional Chinese medicines (TCMs). Quinoline alkaloids are one of the main active substances in this TCM and possess many biological activities including anti-titumor, anti-inflammation, anti-bacteria, anti-oxidation, and anti-platelet aggregation activities. In this study, eight quinoline alkaloids 1-8 were firstly separated from the root barks of D. dasycarpus. It was difficult to isolate more quinoline alkaloids from the remaining fraction 8 in D. dasycarpus by this conventional chemical separation, so the target analysis method combined LC-MS guided-separation of quinoline alkaloids from fraction 8 was established. MS/MS fragmentation patterns of eight quinoline alkaloids reference standard compounds 1-8 were studied by ultra-performance liquid chromatography-electrospary ionization-mass spectrometry (UPLC-ESI-MS/MS). Based on the feature fragment ion m/z 200, the parent ion scan mode was established for the target analysis of quinoline alkaloids in fraction 8. Finally, 8-methoxyflindersine (9) and N-metilatanina (10) were discovered and isolated quickly from fraction 8 guided by LC-MS, and their structures were identified by NMR and MS. Among them, compound 10 was isolated from the genus Dictamnus for the first time. These results indicated that this method is not only quick and sensitive for analyzing the quinoline alkaloids, but also to effectively guided-separate this kind of alkaloids in the root barks of D. dasycarpus.

Cytotoxic indole alkaloids from Melodinus khasianus and Melodinus tenuicaudatus.

Four new indole alkaloids, melodinusines A-D (1, 2, 6, and 7), along with 26 known indole alkaloids, were isolated from Melodinus tenuicaudatus and Melodinus khasianus (Melodinus genus). Among them, 1 and 2 are aspidospermine-aspidospermine-type bisindole alkaloids while 7 is a novel melodinus-type alkaloid. Their structures were established on the basis of comprehensive spectroscopic data analysis and the structure of 7 was further confirmed by single-crystal X-ray diffraction analysis. Their cytotoxic activities against five human cancer cell lines, HL-60, SMMC-7721, A-549, MCF-7, and SW480 were also evaluated.

Hupercumines A and B, Lycopodium Alkaloids from Huperzia cunninghamioides, Inhibiting Acetylcholinesterase.

A novel class of C38N4 Lycopodium alkaloid, hupercumine A (1), consisting of two octahydroquinolines, a decahydroquinoline, and a piperidine, and a new C27N3-type alkaloid, hupercumine B (2), were isolated from Huperzia cunninghamioides (Hayata) Holub. The structures and absolute configurations of 1 and 2 were elucidated on the basis of spectroscopic data, chemical means, and biogenetic point of view. Hupercumines A (1) and B (2) showed moderate inhibitory activity against acetylcholinesterase.

Discovery of a Novel Dibromoquinoline Compound Exhibiting Potent Antifungal and Antivirulence Activity That Targets Metal Ion Homeostasis.

Globally, invasive fungal infections pose a significant challenge to modern human medicine due to the limited number of antifungal drugs and the rise in resistance to current antifungal agents. A vast majority of invasive fungal infections are caused by species of Candida, Cryptococcus, and Aspergillus. Novel antifungal molecules consisting of unexploited chemical scaffolds with a unique mechanism are a pressing need. The present study identifies a dibromoquinoline compound (4b) with broad-spectrum antifungal activity that inhibits the growth of pertinent species of Candida (chiefly C. albicans), Cryptococcus, and Aspergillus at a concentration of as low as 0.5 µg/mL. Furthermore, 4b, at a subinhibitory concentration, interfered with the expression of two key virulence factors (hyphae and biofilm formation) involved in C. albicans pathogenesis. Three yeast deletion strains ( cox17Δ, ssa1Δ, and aft2Δ) related to metal ion homeostasis were found to be highly sensitive to 4b in growth assays, indicating that the compound exerts its antifungal effect through a unique, previously unexploited mechanism. Supplementing the media with either copper or iron ions reversed the strain sensitivity to 4b, further corroborating that the compound targets metal ion homeostasis. 4b's potent antifungal activity was validated in vivo, as the compound enhanced the survival of Caenorhabditis elegans infected with fluconazole-resistant C. albicans. The present study indicates that 4b warrants further investigation as a novel antifungal agent.

Antimicrobial Furoquinoline Alkaloids from Vepris lecomteana (Pierre) Cheek & T. Heller (Rutaceae).

Three new prenylated furoquinoline alkaloids named lecomtequinoline A (1), B (2), and C (3), together with the known compounds anhydroevoxine (4), evoxine (5), dictamnine (6), N-methylflindersine (7), evoxanthine (8), hesperidin, lupeol, ß-sitosterol, stigmasterol, ß-sitosterol-3-O-ß-d-glucopyranoside, stearic acid, and myristyl alcohol, were isolated by bioassay-guided fractionation of the methanolic extracts of leaves and stem of Vepris lecomteana. The structures of compounds were determined by spectroscopic methods (NMR, MS, UV, and IR) and by comparison with previously reported data. Crude extracts of leaves and stem displayed high antimicrobial activity, with Minimum Inhibitory Concentration (MIC) (values of 10.1-16.5 and 10.2-20.5 µg/mL, respectively, against Escherichia coli, Bacillus subtilis, Pseudomonas agarici, Micrococcus luteus, and Staphylococcus warneri, while compounds 1-6 showed values ranging from 11.1 to 18.7 µg/mL or were inactive, suggesting synergistic effect. The extracts may find application in crude drug preparations in Western Africa where Vepris lecomteana is endemic, subject to negative toxicity results in vivo.

In vitro anti-malarial interaction and gametocytocidal activity of cryptolepine.

BACKGROUND: Discovery of novel gametocytocidal molecules is a major pharmacological strategy in the elimination and eradication of malaria. The high patronage of the aqueous root extract of the popular West African anti-malarial plant Cryptolepis sanguinolenta (Periplocaceae) in traditional and hospital settings in Ghana has directed this study investigating the gametocytocidal activity of the plant and its major alkaloid, cryptolepine. This study also investigates the anti-malarial interaction of cryptolepine with standard anti-malarials, as the search for new anti-malarial combinations continues. METHODS: The resazurin-based assay was employed in evaluating the gametocytocidal properties of C. sanguinolenta and cryptolepine against the late stage (IV/V) gametocytes of Plasmodium falciparum (NF54). A fixed ratio method based on the SYBR Green I fluorescence-based assay was used to build isobolograms from a combination of cryptolepine with four standard anti-malarial drugs in vitro using the chloroquine sensitive strain 3D7. RESULTS: Cryptolepis sanguinolenta (IC50 = 49.65 nM) and its major alkaloid, cryptolepine (IC50 = 1965 nM), showed high inhibitory activity against the late stage gametocytes of P. falciparum (NF54). In the interaction assays in asexual stage, cryptolepine showed an additive effect with both lumefantrine and chloroquine with mean ΣFIC50s of 1.017 ± 0.06 and 1.465 ± 0.17, respectively. Cryptolepine combination with amodiaquine at therapeutically relevant concentration ratios showed a synergistic effect (mean ΣFIC50 = 0.287 ± 0.10) whereas an antagonistic activity (mean ΣFIC50 = 4.182 ± 0.99) was seen with mefloquine. CONCLUSIONS: The findings of this study shed light on the high gametocytocidal properties of C. sanguinolenta and cryptolepine attributing their potent anti-malarial activity mainly to their effect on both the sexual and asexual stages of the parasite. Amodiaquine is a potential drug partner for cryptolepine in the development of novel fixed dose combinations.

Identification of an aspidospermine derivative from borage extract as an anti-amyloid compound: A possible link between protein aggregation and antimalarial drugs.

A number of human diseases, including Alzheimer's and Parkinson's have been linked to amyloid formation. To search for an anti-amyloidogenic product, alkaloid enriched extract from borage leaves was examined for anti-amyloidogenic activity using Hen Egg White Lysozyme (HEWL) as a model protein. After isolation of the plant extract using rHPLC, only one fraction indicated a significant bioactivity. TEM analysis confirmed a remarkable reduction of amyloid fibrils in the presence of the bioactive fraction. To identify the effective substance in the fraction, mass spectrometry, FTIR, and NMR were performed. Our analyses determined that the bioactive compound as 1-acetyl-19,21-epoxy-15,16-dimethoxyaspidospermidine-17-ol, a derivative of aspidospermine. To investigate the mechanism of the inhibition, ANS binding, intrinsic fluorescence, and amide I content were performed in the presence of the bioactive compound. All the results confirmed the role of the compound in assisting the proper folding of the protein. In addition, molecular docking indicated the aspidospermine derivative binds the amyloidogenic region of the protein. Our results show that the alkaloid extracted from borage leaves reduces protein aggregation mediating through structural elements of the protein, promoting the correct folding of lysozyme. Since a number of aspidospermine compounds have been shown to possess potent antimalarial activities, the action of compound identified in the present study suggests a possible link between protein aggregation and aspidospermine drugs.

Gastroprotective and anti-secretory mechanisms of 2-phenylquinoline, an alkaloid isolated from Galipea longiflora.

BACKGROUND: We previously described the gastroprotective effect of 2-phenylquinoline (2-PQ), the main alkaloid isolated from the bark of Galipea longiflora (Rutaceae). However, despite the significant and promising results, the pharmacological mechanisms of the gastroprotection induced by 2-PQ have not been investigated. PURPOSE: To evaluate the mechanisms underlying the gastroprotective effects of 2-PQ. STUDY DESIGN: We used an in vivo mouse ulcer model and in vitro methodologies involving H⁺/K⁺-ATPase and L929 murine fibroblasts. METHODS: The gastroprotective activity of 2-PQ (10-100 mg/kg, orally, p.o) was assessed against gastric ulcer induced by 60% ethanol/0.03 M hydrochloric acid (HCl) in mice or that induced by indomethacin (80 mg/kg, p.o) in rats. The cytotoxicity was assessed in L929 murine fibroblasts. Ulcerated tissues were analyzed histologically, histochemically, and biochemically. The antisecretory activity of 2-PQ was evaluated in vivo and in vitro. RESULTS: 2-PQ showed no cytotoxicity, reduced the lesion area induced by ethanol/HCl (log half-maximal effective dose, ED50 = 1.507), and the histological evaluation supported these results. Furthermore, 2-PQ reduced indomethacin-induced gastric ulceration. The gastroprotection was accompanied by normalization of superoxide dismutase (SOD) and glutathione-S-transferase (GST) activity, an intense increase in reduced glutathione (GSH) levels, and reduction in lipid peroxide (LPO) and tumor necrosis factor (TNF)-α levels in the gastric mucosa. The antisecretory properties of 2-PQ were confirmed by the decreased volume and total acidity of the gastric juice, and it reduced histamine- or pentagastrin-stimulated gastric acid secretion. However, 2-PQ did not change the in vitro H⁺/K⁺-ATPase activity or the content of gastric-adhered mucous in mice. In addition, pretreatment with N-ethylmaleimide, NG-nitro-l-arginine methyl esters, yohimbine, or indomethacin reversed the gastroprotective effect of 2-PQ, suggesting nitric oxide, nonprotein sulfhydryl compounds, α-2-receptors, and prostaglandin were involved. CONCLUSION: 2-PQ provides gastroprotection by reducing oxidative damage and inhibiting acid secretion mediated by histaminergic and gastrinergic regulatory pathways.

Cytotoxic new furoquinoline alkaloid isolated from Ammi majus L. growing in Egypt.

Two alkaloids of the furoquinoline-type were isolated from Ammi majus L.; a new one and was identified as 4-hydro-7-hydroxy-8-methoxyfuroquinoline (1), and the other was isolated for the second time from nature and was identified as 4-hydro-7-hydroxy-8-prenyloxyfuroquinoline (2). The structures of the isolated compounds were established and confirmed by 1D and 2D NMR spectroscopy including 1H, 13C NMR, COSY, HSQC and HMBC, while the exact masses were confirmed by HRESI/MS. The cytotoxic activity of the isolated compounds (1 and 2) was evaluated against HepG-2, PC-3, A-549 and MCF-7 and the obtained results suggested selective antiproliferative and cytotoxic effects, with IC50 = 230.2 and 326.5 µM against HepG-2 and MCF-7, respectively, for compound (1). While, compound (2) recorded IC50 = 234.2 µM against MCF-7.

Quinoline Alkaloids Isolated from Choisya Aztec-Pearl and Their Contribution to the Overall Antinociceptive Activity of This Plant.

Choisya 'Aztec-Pearl', a hybrid of Choisya ternata and Choisya dumosa var. arizonica, had the antinociceptive activity in the ethanol extract (EECA) of its leaves evaluated. Two quinoline alkaloids, anhydroevoxine (A) and choisyine (C), isolated from these leaves were also tested. The results obtained pointed out to a very high antinociceptive activity measured by the hot plate model for EECA (at doses of 10, 30 and 100 mg/kg) as well as for A and C (at doses of 1, 3 and 10 mg/kg). The magnitude of the activity was two-fold higher than the one observed for the morphine treated animals for the higher doses of extracts/compounds (30, 100 mg/kg and 3, 10 mg/kg respectively). The mechanism of action for this activity was also investigated and it seems that for EECA as well as A and C, the opiate system plays an important role. Results have also shown that the nitric oxide (NO) system also play a pivotal role in the case of EECA and A while for C it seems that the cholinergic system have some involvement. The acute toxicity was evaluated for EECA with results showing no important toxic effect.

Four new tetracyclic alkaloids with cis-decahydroquinoline motif from Myrioneuron effusum.

Four new Myrioneuron alkaloids, mysumamides A-D (1-4), along with three known ones were isolated from the twigs and leaves of Myrioneuron effusum. All of these alkaloids possessed the tetracyclic skeleton and contained the decahydroquinoline (cis-DHQ) moiety. Their structures and relative configurations were elucidated on the basis of spectroscopic methods, especially 2D NMR techniques. The absolute configuration of 1 was determined by single-crystal X-ray diffraction. The cytotoxic activities of these compounds were also evaluated in vitro.

Antithrombotic and antiplatelet activities of small-molecule alkaloids from Scolopendra subspinipes mutilans.

The aim of this study was to discover small-molecule anticoagulants from Scolopendra subspinipes mutilans (SSM). A new acylated polyamine (1) and a new sulfated quinoline alkaloid (2) were isolated from SSM. Treatment with the new alkaloids 1, 2, and indole acetic acid 4 prolonged the activated partial thromboplastin time and prothrombin time and inhibited the activity and production of thrombin and activated factor X. Furthermore, compounds 1, 2, and 4 inhibited thrombin-catalyzed fibrin polymerization and platelet aggregation. In accordance with these potential in vitro antiplatelet activities, compounds 1, 2, and 4 showed enhanced antithrombotic effects in an in vivo pulmonary embolism and arterial thrombosis model. Compounds 1, 2, and 4 also elicited anticoagulant effects in mice. Collectively, this study may serve as the groundwork for commercializing SSM or compounds 1, 2, and 4 as functional food components for the prevention and treatment of pathogenic conditions and serve as new scaffolds for the development of anticoagulants.

New furoquinoline alkaloid and flavanone glycoside derivatives from the leaves of Oricia suaveolens and Oricia renieri (Rutaceae).

Fractionation of the methanol extract of the leaves of Oricia renieri and Oricia suaveolens (Rutaceae) led to the isolation of 13 compounds including the hitherto unknown furoquinoline alkaloid named 6,7-methylenedioxy-5-hydroxy-8-methoxy-dictamnine (1) and a flavanone glycoside named 5-hydroxy-4'-methoxy-7-O-[α-L-rhamnopyranosyl(1‴→5″)-ß-D-apiofuranosyl]-flavanoside (2), together with 11 known compounds (3-13). The structures of the compounds were determined by comprehensive analyses of their 1D and 2D NMR, mass spectral data and comparison. All compounds isolated were examined for their activity against human carcinoma cell lines. The alkaloids 1, 5, 12, 13 and the phenolic 2, 8, 11 tested compounds exhibited non-selective moderate cytotoxic activity with IC50 8.7-15.9 µM whereas compounds 3, 4, 6, 7, 9 and 10 showed low activity.

Developing an activity and absorption-based quality control platform for Chinese traditional medicine: Application to Zeng-Sheng-Ping(Antitumor B).

ETHNOPHARMACOLOGICAL RELEVANCE: Zeng-Sheng-Ping (ZSP), also called antitumor B, is a marketed Chinese traditional medicine used for cancer prevention. AIM OF THE STUDY: Currently, for the quality control of Chinese traditional medicines, marker compounds are not selected based on bioactivities and pharmaceutical behaviors in most of the cases. Therefore, even if the "quality" of the medicine is controlled, the pharmacological effect could still be inconsistent. The aim of this study is to establish an activity and absorption-based platform to select marker compound(s) for the quality control of Chinese traditional medicines. MATERIALS AND METHODS: We used ZSP as a reference Chinese traditional medicine to establish the platform. Activity guided fractionation approach was used to purify the major components from ZSP. NMR and MS spectra were used to elucidate the structure of the isolated compounds. MTT assay against oral carcinoma cell line (SCC2095) was performed to evaluate the activities. UPLC-MS/MS was used to quantify the pure compounds in ZSP and the active fraction. The permeabilities of the identified compounds were evaluated in the Caco-2 cell culture model. The intracellular accumulation of the isolated compounds was evaluated in the SCC2095 cells. RESULTS: The major compounds were identified from ZSP. The contents, anti-proliferation activities, permeabilities, and intracellular accumulations of these compounds were also evaluated. The structure of these purified compounds were identified by comparing the NMR and MS data with those of references as rutaevine (1), limonin (2), evodol (3), obacunone (4), fraxinellone (5), dictamnine (6), maackiain (7), trifolirhizin (8), and matrine (9). The IC50 of compounds 5, 6, and 7 against SCC2095 cells were significantly lower than that of ZSP. The uptake permeability of compounds 5, 6, and 7 were 2.58 ± 0.3 × 10(-5), 4.33 ± 0.5 × 10(-5), and 4.27 ± 0.8 × 10(-5) respectively in the Caco-2 cell culture model. The intracellular concentrations of these compounds showed that compounds 5, 6, and 7 were significantly accumulated inside the cells. CONCLUSION: Based on the activity against oral carcinoma cell line as well as the absorption permeability, compound 5, 6, and 7 are selected as quality control markers for ZSP. An activity and absorption-based platform was established and successfully used for the quality control of ZSP.

A sequential procedure for rapid and accurate identification of putative trichomonacidal agents.

In the current report, a sequential step-wise methodology based on in silico, in vitro and in vivo experimental procedures for the prompt detection of potential trichomonacidal drugs is proposed. A combinatorial of 12 QSAR (Quantitative Structure-Activity Relationship) models based on Linear Discrimination Analysis (LDA) are suggested for the rational identification of new trichomonacidal drugs from virtual screening of in house chemical libraries and drug databases. Subsequently, compounds selected as potential anti-trichomonas are screened in vitro against Trichomonas vaginalis. Finally, molecules with specific trichomonacidal activity are evaluated in vivo. Herein, different molecules were exposed to the proposed methodology. Firstly, the agents were virtually screened and two of the eight molecules (G-1 and dimetridazole) were classified as trichomonacidals by the 12 models. Subsequently both drugs were proved in vitro and in vivo following the workflow procedure. Although a remarkable in vitro activity was observed in both cases, dimetridazole achieved higher MIC100 activity than metronidazole against the resistant isolate. Furthermore, the in vivo models showed a remarkable reduction of lesions of more than 55% in both compounds. These observations support the current flowchart screening and suggest the use of dimetridazole as a promising drug-like scaffold for novel therapeutic alternatives against T. vaginalis resistant infections.