[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.

Cyclopentenone-Containing Tetrahydroquinoline and Geldanamycin Alkaloids from Streptomyces malaysiensis as Potential Anti-Androgens against Prostate Cancer Cells.

Malaymycin (1), a new cyclopentenone-containing tetrahydroquinoline alkaloid, and mccrearamycin E (2), a geldanamycin analogue bearing a rare ring-contracted cyclopentenone moiety, and a C2-symmetric macrodiolide (7) were isolated from Streptomyces malaysiensis SCSIO41397. Their structures including absolute configurations were determined by detailed analyses of NMR and HRMS data and ECD calculations. The occurrence of mccrearamycin E (2) bearing a ring-contracted cyclopentenone is rare in the geldanamycin class. All isolated compounds were evaluated for their cytotoxicities against five cancer cell lines. As a result, compounds 1, 4, 5, and 7 showed cytotoxicity against some or all of the five cancer cell lines with IC50 values ranging from 0.067 to 7.2 µM. In particular, compound 1 inhibited the growth of C42B and H446 cell lines with IC50 values of 67 and 70 nM, respectively. Malaymycin (1) significantly induced cell cycle arrest at the G0/G1 phase in C42B cell lines and caused cell shrinkage and inhibited the expression of the androgen receptor (AR) at both the mRNA and protein levels in a dose-dependent manner. Further examination by qRT-PCR analysis showed that 1 strongly suppressed the expression of AR target genes KLK2 and KLK3 in the C42B and 22RV1 cell lines, which suggested that 1 might be a promising potential lead compound for the development of a treatment for the castration-resistant prostate cancer (CRPC).

Development of Novel Quinoline-Based Sulfonamides as Selective Cancer-Associated Carbonic Anhydrase Isoform IX Inhibitors.

A new series of quinoline-based benzenesulfonamides (QBS) were developed as potential carbonic anhydrase inhibitors (CAIs). The target QBS CAIs is based on the 4-anilinoquinoline scaffold where the primary sulphonamide functionality was grafted at C4 of the anilino moiety as a zinc anchoring group (QBS 13a-c); thereafter, the sulphonamide group was switched to ortho- and meta-positions to afford regioisomers 9a-d and 11a-g. Moreover, a linker elongation approach was adopted where the amino linker was replaced by a hydrazide one to afford QBS 16. All the described QBS have been synthesized and investigated for their CA inhibitory action against hCA I, II, IX and XII. In general, para-sulphonamide derivatives 13a-c displayed the best inhibitory activity against both cancer-related isoforms hCA IX (KIs = 25.8, 5.5 and 18.6 nM, respectively) and hCA XII (KIs = 9.8, 13.2 and 8.7 nM, respectively), beside the excellent hCA IX inhibitory activity exerted by meta-sulphonamide derivative 11c (KI = 8.4 nM). The most promising QBS were further evaluated for their anticancer and pro-apoptotic activities on two cancer cell lines (MDA-MB-231 and MCF-7). In addition, molecular docking simulation studies were applied to justify the acquired CA inhibitory action of the target QBS.

Large-scale separation of acetylcholinesterase inhibitors from Zanthoxylum nitidum by pH-zone-refining counter-current chromatography target-guided by ultrafiltration high-performance liquid chromatography with ultraviolet and mass spectrometry screening.

A new strategy by converging ultrafiltration high-performance liquid chromatography with ultraviolet and mass spectrometry and pH-zone-refining counter-current chromatography was developed for the rapid screening and separation of potential acetylcholinesterase inhibitors from the crude alkaloidals extract of Zanthoxylum nitidum. An optimized two-phase solvent system composed of chloroform/methanol/water (4:3:3, v/v) was used in this study. And, in the optimal solvent system, 45 mM hydrochloric acid was added to the aqueous stationary phase as the retainer, while 5 mM triethylamine was added to the organic mobile phase as the eluter. As a result, with the purity of over 95%, five alkaloids including jatrorrhizine (1, 340 mg), columbamine (2, 112 mg), skimmianine (3, 154 mg), palmatine (4, 226 mg), and epiberberine (5, 132 mg) were successfully purified in one step from 3.0 g crude alkaloidals extract. And their structures were identified by ultraviolet, mass spectrometry, 1 H and 13 C NMR spectroscopy. Notably, compounds 2, 4 and 5 were firstly reported in Z. nitidum. In addition, acetylcholinesterase inhibitory activities of compounds 1-5 were evaluated, and compounds 3, 4 and 5 exhibited stronger acetylcholinesterase inhibitory activity (IC50 values at 8.52 ± 0.64, 14.82 ± 1.21 and 3.12 ± 0.32 µg/mL, respectively) than berberine (IC50 value at 32.86 ± 2.14 µg/mL, positive control). The results indicated that the proposed method is an efficient technique to rapidly screen acetylcholinesterase inhibitors from complex samples, and could be served as a large-scale preparative technique for separating ionizable active compounds.

Isolation and Antimacrofouling Activity of Indole and Furoquinoline Alkaloids from 'Guatambú' Trees (Aspidosperma australe and Balfourodendron riedelianum).

In this work, the antifouling activity of five alkaloids, isolated from trees of the Atlantic rainforest, was studied. The tested alkaloids were olivacine (1), uleine (2) and N-methyltetrahydroellipticine (3) from Aspidosperma australe ('yellow guatambú') and the furoquinoline alkaloids kokusaginine (4) and flindersiamine (5) from Balfourodendron riedelianum ('white guatambú'). All these compounds can be isolated from their natural sources in high yields in a sustainable way. The five compounds were subjected to laboratory tests (attachment test of the mussel Mytilus edulis platensis) and field trials, by incorporation into soluble matrix paints, and 45 days of exposure of the painted panels in the sea. The results show that compound 3 is a very potent antifoulant, and that compounds 4 and 5 are also very active, while compounds 1 and 2 did not show any significant antifouling activity. These results open the way for the development of environmentally friendly antifouling agents, based on abundant and easy-to-purify compounds that can be obtained in a sustainable way.

The inhibitory effect of kokusaginine on the growth of human breast cancer cells and MDR-resistant cells is mediated by the inhibition of tubulin assembly.

The emergence of multidrug resistance (MDR) is a significant challenge in breast carcinoma chemotherapy. Kokusaginine isolated from Dictamnus dasycarpus Turcz. has been reported to show cytotoxicity in several human cancer cell lines including breast cancer cells MCF-7. In this study, kokusaginine showed the potent inhibitory effect on MCF-7 multidrug resistant subline MCF-7/ADR and MDA-MB-231 multidrug resistant subline MDA-MB-231/ADR. Kokusaginine markedly induced apoptosis in a concentration-dependent manner in MCF-7/ADR cells. Furthermore, kokusaginine reduced P-gp mRNA and protein levels, and suppressed P-gp function especially in MCF-7/ADR cells. In addition, kokusaginine showed to inhibit tubulin assembly and the binding of colchicine to tubulin by binding directly to tubulin and affects tubulin formation in vitro. Taken together, these results support the potential therapeutic value of kokusaginine as an anti-MDR agent in chemotherapy for breast carcinoma.

In Vitro Mechanistic Study of the Anti-inflammatory Activity of a Quinoline Isolated from Spondias pinnata Bark.

The search for new plant-based anti-inflammatory drugs continues in order to overcome the detrimental side effects of conventional anti-inflammatory agents, both steroidal and nonsteroidal. This study involves the quinoline SPE2, 7-hydroxy-6-methoxyquinolin-2(1 H)-one, isolated from the EtOAc fraction of Spondias pinnata bark. Structure elucidation was done using analytical spectroscopic methods including Fourier transform infrared spectroscopy, high-resolution electrospray ionization mass spectrometry, nuclear magnetic resonance spectroscopy, and single-crystal X-ray crystallography. The anti-inflammatory activity of SPE2 was evaluated in a lipopolysaccharide (LPS)-stimulated murine macrophage RAW 264.7 model. SPE2 effectively suppressed LPS-induced overproduction of pro-inflammatory mediators such as nitric oxide (NO), tumor necrosis factor (TNF)-α, interleukin (IL)-6, and IL-1ß, and reactive oxygen species. Expression levels of NO synthesizing enzyme, cyclooxygenase-2, TNF-α, IL-6 and IL-1ß were also determined to return to normal after SPE2 treatment. Localization of NF-κB was evaluated by confocal microscopy and Western blotting, which showed a dose-dependent reduction of NF-κB inside the nucleus and an increase in cytoplasmic NF-κB with SPE2 treatment. Collectively, the results suggest that SPE2 has anti-inflammatory activity via inhibition of NF-κB activation.

[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.

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.

Thiol-Based Probe for Electrophilic Natural Products Reveals That Most of the Ammosamides Are Artifacts.

To date, 16 members of the ammosamide family of natural products have been discovered, and except for ammosamide D each of these metabolites is characterized by an unusual chlorinated pyrrolo[4,3,2-de]quinoline skeleton. Several ammosamides have been shown to inhibit quinone reductase 2, a flavoenzyme responsible for quelling toxic oxidative species in cells or for killing cancer cells outright. Treatment of the extract from an ammosamide-producing culture (Streptomyces strain CNR-698) with a thiol-based reagent designed to label electrophilic natural products produced an ammosamide C-thiol adduct. This observation led us to hypothesize, and then demonstrate through experimentation, that all of the other ammosamides are derived from ammosamide C via nonenzymatic processes involving exposure to nucleophiles, air, and light. Like many established electrophilic natural products, reaction with the thiol probe suggests that ammosamide C is itself an electrophilic natural product. Although ammosamide C did not show substantial cytotoxicity against cancer cells, its activity against a marine Bacillus bacterial strain may reflect its ecological role.

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.

Serralongamines B-D, three new Lycopodium alkaloids from Lycopodium serratum var. longipetiolatum, and their inhibitory effects on foam cell formation in macrophages.

Three new Lycopodium alkaloids, serralongamines B-D (1-3), have been isolated from the club moss Lycopodium serratum var. longipetiolatum, and the structures were elucidated on the basis of spectroscopic data and chemical transformation. 1 and 3 significantly exhibited the inhibitory activity against foam cell formation in human macrophages, one of characteristic features of early atherosclerotic lesions.

Pelianthinarubins A and B, Red Pyrroloquinoline Alkaloids from the Fruiting Bodies of the Mushroom Mycena pelianthina.

Pelianthinarubin A (1) and pelianthinarubin B (2), two previously unknown pyrroloquinoline alkaloids, have been isolated from fruiting bodies of Mycena pelianthina. The structures of these alkaloids have been deduced from their HR-(+)-ESIMS and 2D NMR data. The absolute configurations of the pelianthinarubins A (1) and B (2) were assigned by analysis of the NOE correlations and coupling constants and by comparison of the CD spectra of 1 and 2 and of hercynine obtained by degradation of 1 with suitable compounds of known absolute configuration. The pelianthinarubins A (1) and B (2), which contain an S-hercynine moiety, differ considerably from the known pyrroloquinoline alkaloids from marine organisms and other Mycena species, such as the mycenarubins, the haematopodins, and the sanguinones.

Antifungal Quinoline Alkaloids from Waltheria indica.

Chemical investigation of a dichloromethane extract of the aerial parts of Waltheria indica led to the isolation and characterization of five polyhydroxymethoxyflavonoids, namely, oxyanin A (1), vitexicarpin (3), chrysosplenol E (4), flindulatin (5), 5-hydroxy-3,7,4'-trimethoxyflavone (6), and six quinolone alkaloids, waltheriones M-Q (2, 7, 8, 10, 11) and 5(R)-vanessine (9). Among these, compounds 2, 7, 8, 10, and 11 have not yet been described in the literature. Their chemical structures were established by means of spectroscopic data interpretation including (1)H and (13)C, HSQC, HMBC, COSY, and NOESY NMR experiments and UV, IR, and HRESIMS. The absolute configurations of the compounds were established by ECD. The isolated constituents and 10 additional quinoline alkaloids previously isolated from the roots of the plant were evaluated for their in vitro antifungal activity against the human fungal pathogen Candida albicans, and 10 compounds (7, 9, 11-16, 18, 21) showed growth inhibitory activity on both planktonic cells and biofilms (MIC ≤ 32 µg/mL). Their spectrum of activity against other pathogenic Candida species and their cytotoxicity against human HeLa cells were also determined. In addition, the cytological effect of the antifungal isolated compounds on the ultrastructure of C. albicans was evaluated by transmission electron microscopy.

Small molecule screen yields inhibitors of Pseudomonas homoserine lactone-induced host responses.

Pseudomonas aeruginosa infections are commonly associated with cystic fibrosis, pneumonias, neutropenia and burns. The P. aeruginosa quorum sensing molecule N-(3-oxo-dodecanoyl) homoserine lactone (C12) cause multiple deleterious host responses, including repression of NF-κB transcriptional activity and apoptosis. Inhibition of C12-mediated host responses is predicted to reduce P. aeruginosa virulence. We report here a novel, host-targeted approach for potential adjunctive anti-Pseudomonal therapy based on inhibition of C12-mediated host responses. A high-throughput screen was developed to identify C12 inhibitors that restore NF-κB activity in C12-treated, lipopolysaccharide (LPS)-stimulated cells. Triazolo[4,3-a]quinolines with nanomolar potency were identified as C12-inhibitors that restore NF-κB-dependent luciferase expression in LPS- and TNF-stimulated cell lines. In primary macrophages and fibroblasts, triazolo[4,3-a]quinolines inhibited C12 action to restore cytokine secretion in LPS-stimulated cells. Serendipitously, in the absence of an inflammatory stimulus, triazolo[4,3-a]quinolines prevented C12-mediated responses, including cytotoxicity, elevation of cytoplasmic calcium, and p38 MAPK phosphorylation. In vivo efficacy was demonstrated in a murine model of dermal inflammation involving intradermalC12 administration. The discovery of triazolo[4,3-a]quinolines provides a pharmacological tool to investigate C12-mediated host responses, and a potential host-targeted anti-Pseudomonal therapy.

Using differential mobility spectrometry to measure ion solvation: an examination of the roles of solvents and ionic structures in separating quinoline-based drugs.

Understanding the mechanisms and energetics of ion solvation is critical in many scientific areas. Here, we present a methodlogy for studying ion solvation using differential mobility spectrometry (DMS) coupled to mass spectrometry. While in the DMS cell, ions experience electric fields established by a high frequency asymmetric waveform in the presence of a desired pressure of water vapor. By observing how a specific ion's behavior changes between the high- and low-field parts of the waveform, we gain knowledge about the aqueous microsolvation of that ion. In this study, we applied DMS to investigate the aqueous microsolvation of protonated quinoline-based drug candidates. Owing to their low binding energies with water, the clustering propensity of 8-substituted quinolinium ions was less than that of the 6- or 7-substituted analogues. We attribute these differences to the steric hinderance presented by subtituents in the 8-position. In addition, these experimental DMS results were complemented by extensive computational studies that determined cluster structures and relative thermodynamic stabilities.

Azaphilones from an Acid Mine Extremophile Strain of a Pleurostomophora sp.

An extremophilic fungus identified as a Pleurostomophora sp. was isolated from the Berkeley Pit, an acid mine waste lake. When grown in liquid culture, the fungus produced berkchaetoazaphilones A-C (1, 2, and 5), the red pigment berkchaetorubramine (6), and the known compound 4-(hydroxymethyl)quinoline. These compounds were evaluated as inhibitors of matrix metalloproteinase-3, caspase-1, and proinflammatory cytokine production in induced THP-1 cells. Berkchaetoazaphilone B (2) inhibited IL-1ß, TNFα, and IL-6 production in the induced inflammasome assay and was cytotoxic toward human retinoblastoma cell line Y79 (IC50 = 1.1 µM), leukemia cell lines CCRF-CEM and SR, and the melanoma cell line LOX IMVI (IC50 = 10 µM).

Carriebowlinol, an antimicrobial tetrahydroquinolinol from an assemblage of marine cyanobacteria containing a novel taxon.

A combined biodiversity- and bioassay-guided natural products discovery approach was used to explore new groups of marine cyanobacteria for novel secondary metabolites with ecologically relevant bioactivities. Phylogenetic analysis of cyanobacterial collections from Belize revealed a new taxon not previously well explored for natural products. The new alkaloid 5-hydroxy-4-(chloromethyl)-5,6,7,8-tetrahydroquinoline (1), named carriebowlinol, and the known compound lyngbic acid (2) were isolated from a nonpolar extract and identified by NMR and MS techniques. Compounds 1 and 2 inhibited the growth of pathogenic and saprophytic marine fungi, and 1 inhibited the growth of marine bacteria, suggesting an antimicrobial ecological function.

Truncated norzoanthamine exhibiting similar collagen protection activity, toward a promising anti-osteoporotic drug.

The marine alkaloid, norzoanthamine, is considered to be a promising drug for osteoporosis treatment. Due to its rarity and complicated structure, a practical supply method must be developed. Here, we designed a truncated norzoanthamine, which has two-thirds of the original structure, and found that it exhibited similar collagen protection activity.

Antitrypanosomal quinoline alkaloids from the roots of Waltheria indica.

Chemical investigation of the dichloromethane root extract of Waltheria indica led to the isolation and characterization of 10 quinoline alkaloids, namely, 8-deoxoantidesmone (1), waltheriones E-L (2-9), and antidesmone (10). Among these, compounds 2-9 have not yet been described in the literature. Their chemical structures were established by means of spectroscopic data interpretation including (1)H and (13)C NMR, HSQC, HMBC, COSY, and NOESY experiments and UV, IR, and HRESIMS. The absolute configurations of the compounds were established by comparison of experimental and TDDFT-calculated ECD spectra. In addition, the isolated constituents were evaluated for their in vitro antitrypanosomal activity. Compounds 4, 5, and 8 showed potent and selective growth inhibition toward Trypanosoma cruzi with IC50 values between 0.02 and 0.04 µM. Cytotoxicity for mouse skeletal L-6 cells was also determined for these compounds.