Gouregine, an α-Gem-Dimethyltetradehydrocularine Alkaloid, and Other Aporphinoid Alkaloids from the Bark of Guatteria olivacea (Annonaceae) and Their In Vitro Cytotoxic Activities.

Guatteria olivacea R.E. Fries is an Amazonian species known as 'envira-bobó' and 'envira-fofa' and is common in the states of Amazonas, Acre, and Pará. Recently, the essential oil from the leaves of this species has shown promising antitumor activity both in vitro and in vivo. The presence of isoquinoline-derived alkaloids, including aporphinoids and tetrahydroprotoberberine alkaloids, has also been previously reported. In our ongoing search for bioactive compounds from Annonaceae Amazonian plants, the bark of G. olivacea was investigated via classical chromatography techniques, which revealed nine compounds, eight isoquinoline-derived alkaloids, a rare alkaloid with a α-gem-dimethyltetradehydrocularine structure known as gouregine, seven known aporphinoid alkaloids: isopiline, O-methylisopiline, melosmine, 9-hydroxyiguattescine, dihydromelosmine, lysicamine, and guattouregidine, and one known pimaradiene diterpene: acanthoic acid. All the isolated compounds were described for the first time in the bark of G. olivacea, and their structures were elucidated by extensive analyses of their 1D and 2D NMR spectra in combination with MS data. The NMR data of the alkaloids isopiline, O-methylisopiline, melosmine, dihydromelosmine, and guattouregidine were revised due to incomplete data in the literature and some ambiguities. The in vitro cytotoxic activities of the isolated compounds were evaluated against human cancer (HepG2, KG-1a, and HCT116) and noncancerous (MRC-5) cell lines via the Alamar blue assay after 72 h of incubation. Among the compounds evaluated against human cancer cell lines, the most active was the oxoaporphine alkaloid lysicamine, which has strong activity against HCT116 cells, with an IC50 value of 6.64 µg/mL (22.79 µmol/L). Melosmine had a moderate effect on HCT116 cells, with an IC50 value of 16.77 µg/mL (49.70 µmol/L), whereas acanthoic acid had moderate effects on HepG2 and HCT116 cells, with IC50 values of 14.63 µg/mL (48.37 µmol/L) and 21.25 µg/mL (70.25 µmol/L), respectively.

Rare oxoisoaporphine alkaloids from Menispermum dauricum with potential anti-inflammatory activity.

Eleven alkaloids including four previously undescribed oxoisoaporphine alkaloids, menisoxoisoaporphines A-D (1-4), four known analogues (5-8), and three aporphine alkaloids (9-11), were isolated and identified from the rhizomes of Menispermum dauricum. Their structures were elucidated by extensive spectroscopic data and single-crystal X-ray diffraction analyses. Among them, compounds 1 and 4 were the first samples of oxoisoaporphine with C-6 isopentylamino moiety, and 2 was a rare C-4 methylation product of oxoisoaporphine alkaloid. The in vitro anti-inflammatory activity of compounds 1-11 was performed by evaluating the inhibition of NO level in LPS-induced RAW264.7 macrophages. Among them, compound 4 exhibited the most potent NO inhibition activity with an IC50 value of 1.95 ± 0.33 µM. The key structure-activity relationships of those oxoisoaporphine alkaloids for anti-inflammatory effects have been summarized.

Artapilosines A and B, Unusual Phenanthrene Derivatives Related to Aporphine Alkaloids from Artabotrys pilosus.

Two unusual phenanthrene derivatives related to aporphine alkaloids, artapilosines A (1) and B (2), as well as two biogenetically related known aporphine alkaloids, (-)-anonaine (3) and (-)-N-acetylanonaine (4), were separated and purified from Artabotrys pilosus. Artapilosine A (1) is the first compound representative of a new class of phenanthrene derivatives having an unprecedented carbon skeleton, in which the six-membered nitrogen-containing heterocyclic structure in a typical aporphine alkaloid was substituted with a unique five-membered carbocyclic ring. This is the first report of the formation of a carbon-carbon bond between C-5 and C-6a in 1 with the loss of the nitrogen atom N-6 in the classic aporphine alkaloid. Artapilosine B (2) is a novel phenanthrene derivative having a hydroxyethyl as a substituent on the phenanthrene ring. Their chemical structures as well as absolute configurations were determined based on analysis of spectroscopic data. Additionally, the potential anti-HIV activities of all isolates 1-4 were appraised. Artapilosines A (1) and B (2) showed notable anti-HIV reverse transcriptase affects, with EC50 values of 20.93 and 125.29 nM, respectively. These results suggested that the discovery of these novel phenanthrene derivatives from A. pilosus with remarkable anti-HIV effects could be essentially important for the researching and developing of new anti-HIV agents.

Two novel aporphine-derived alkaloids from the stems of Fissistigma glaucescens.

Two novel aporphine-derived alkaloids, aporaloids A and B (1 and 2), together with eight known biogenetically related alkaloids (3-10), two known isoquinoline alkaloids (3 and 4), and six known aporphinoid alkaloids (5-10) were isolated from the stems of Fissistigma glaucescens. Their structures were elucidated using comprehensive spectroscopic methods. Compounds 1 and 2 represent the rare example of a six-membered lactone ring aporphine-derived alkaloids from natural products. The inhibitory activities of all compounds against four cancer cell lines were evaluated. Aporaloids A and B (1 and 2) showed broad spectrum cytotoxic activities.

Study on the pharmacokinetics, tissue distribution and excretion of laurolitsine from Litsea glutinosa in Sprague-Dawley rats.

CONTEXT: Laurolitsine is an aporphine alkaloid and exhibits potent antihyperglycemic and antihyperlipidemic effects in ob/ob mice. OBJECTIVE: To investigate the pharmacokinetics, tissue distribution and excretion of laurolitsine. MATERIALS AND METHODS: A LC-MS/MS method was established and validated to determine laurolitsine concentrations in the biological matrix of rats (plasma, tissue homogenate, urine and faeces). 10 Sprague-Dawley (SD) rats were used for plasma exposure study: 5 rats were injected with 2.0 mg/kg of laurolitsine via the tail vein, and the other 5 rats were administered laurolitsine (10.0 mg/kg) by gavage. 25 SD rats used for tissue distribution study and 5 SD rats for urine and faeces excretion study: rats administered laurolitsine (10.0 mg/kg) by gavage. After administered, serial blood, tissue, urine and faeces were collected. Analytical quantification was performed by a previous LC-MS/MS method. The pharmacokinetics, bioavailability, tissue distribution and excretion of laurolitsine were described. RESULTS: The pharmacokinetic parameters of oral and intravenous administration with Tmax were 0.47 and 0.083 h, t1/2 were 3.73 and 1.67 h, respectively. Oral bioavailability was as low as 18.17%. Laurolitsine was found at a high concentration in the gastrointestinal tract, liver, lungs and kidneys (26 015.33, 905.12, 442.32 and 214.99 ng/g at 0.5 h, respectively) and low excretion to parent laurolitsine in urine and faeces (0.03 and 1.20% in 36 h, respectively). CONCLUSIONS: This study established a simple, rapid and accurate LC-MS/MS method to determine laurolitsine in different rat samples and successful application in a pharmacokinetic study.

Separation and purification of magnoflorine, spinosin, and 6‴-feruloyspinosin from Ziziphi Spinosae Semen by high-speed counter-current chromatography.

In the study, high-speed counter-current chromatography was used for separation and purification of magnoflorine, spinosin, and 6‴-feruloyspinosin from Ziziphi Spinosae Semen. With n-butanol-ethyl acetate-water (2:3:5, v/v) as the optimum solvent system, about 75 mg of magnoflorine, 110 mg of spinosin, and 40 mg of 6‴-feruloyspinosin were isolated from 0.5 g of crude extract of Z. Spinosae Semen, with the purity of 95.7, 97.2, and 96.4%, respectively. The chemical structures were identified by MS and NMR spectroscopy. In addition, the antidepressant activity of the isolated components was evaluated by PC12 cells injury model and chronic unpredictable mild stress depression mouse model. The results showed that high-speed counter-current chromatography could be used to realize the one-time rapid preparation and separation of magnoflorine, spinosin, and 6‴-feruloyspinosin from Z. Spinosae Semen and compatibility of these isolated components has certain antidepressant activity.

New Tyramine- and Aporphine-Type Alkamides with NO Release Inhibitory Activities from Piper puberulum.

Three new tyramine-type alkamides (1-3), three new natural products (4-6), five new N-acylated/formylated aporphine alkamides with different ratios of rotational isomers (7-11), and 20 known alkamides (12-31) were isolated from an EtOH extract of the stems and leaves of Piper puberulum. The absolute configurations of compounds 7, 8, and 10 were determined by single-crystal X-ray diffraction analysis. In the biological activity assay, compounds 3, 5, and 10-23 displayed inhibitory effects against lipopolysaccharide-induced NO release in BV-2 microglial cells, exhibiting IC50 values of 0.93-45 µM.

Aporphine Alkaloids from Ocotea puberula with Anti-Trypanosoma Cruzi Potential - Activity of Dicentrine-ß-N-Oxide in the Plasma Membrane Electric Potentials.

One new aporphine, dicentrine-ß-N-oxide (1), together with five related known alkaloids dehydrodicentrine (2), predicentrine (3), N-methyllaurotetanine (4), cassythicine (5), and dicentrine (6) were isolated from the leaves of Ocotea puberula (Lauraceae). Antiprotozoal activity of the isolated compounds was evaluated in vitro against trypomastigote forms of Trypanosoma cruzi. Among the tested compounds, alkaloid 1 exhibited higher potential with EC50 value of 18.2 µM and reduced toxicity against NCTC cells (CC50 >200 µM - SI>11.0), similar to positive control benznidazole (EC50 of 17.7 µM and SI=10.7). Considering the promising results of dicentrine-ß-N-oxide (1) against trypomastigotes, the mechanism of parasite death caused by this alkaloid was investigated. As observed, this compound reached the plasma membrane electric potential directly after 2 h of incubation and triggered mitochondrial depolarization, which probably leads to trypomastigote death. Therefore, dicentrine-ß-N-oxide (1), reported for the first time in this work, can contribute to future works for the development of new trypanocidal agents.

Anti-inflammatory monoterpene esters from the stems of Illigera aromatica.

Two new monoterpene esters illigerates F and G (1 and 2) together with 5 know compounds illigerate A (3), illigerate C (4), actinodaphnine (5), N-methylactinodaphnine(6) and N-methyllaurotetanine(7) were isolated from Illigera aromatica S. Z. Huang et S. L. Mo. Their structures were identified by extensive NMR data and by comparing with the known compounds. The anti-inflammatory activity of four monoterpenes (1 - 4) was evaluated by inhibiting nitric oxide (NO) production in lipopolysaccharide-activated murine macrophage RAW 264.7 cells and four monoterpenoids exhibited inhibitory effect with IC50 values of 71.5 ± 7.3, 74.7 ± 5.6, 48.0 ± 7.4 and 65.1 ± 3.7 µM, respectively.

Antifungal activity and potential mechanism of magnoflorine against Trichophyton rubrum.

Coptis alkaloids show potent antifungal activity against Trichophyton rubrum (T. rubrum), which was a Tinea pedis fungus, but little of the literature was reported to investigate the antifungal activity of magnoflorine against it. Meanwhile, the potential mechanism of magnoflorine against T. rubrum is unknown. In the present study, we found that Coptis alkaloids, especially magnoflorine had significant antifungal activities against T. rubrum and Trichophyton mentagrophyte (T. mentagrophyte). The MIC values of magnoflorine against T. rubrum and T. mentagrophyte were both 62.5 µg ml-1, but magnoflorine exerted a better fungicidal efficiency against T. rubrum than T. mentagrophyte. Magnoflorine inhibited the conidia germination and hyphal growth, and changed the mycelial morphology such as deformation growth, surface peeling, and cytoplasmic contraction in T. rubrum. Magnoflorine had no significant effect on cell wall integrity. However, magnoflorine destroyed the fungal cell membrane of T. rubrum through increasing the nucleic acid leakage, reducing the activities of squalene epoxidase and CYP51 enzyme, and decreasing the content of ergosterol in hyphae. Our study supported the potential use of magnoflorine as an antifungal agent against T. rubrum and made contributions to the clinical application of magnoflorine against fungi.

Magnoflorine-Isolation and the Anticancer Potential against NCI-H1299 Lung, MDA-MB-468 Breast, T98G Glioma, and TE671 Rhabdomyosarcoma Cancer Cells.

Magnoflorine (MGN) is a quaternary aporphine alkaloid that exhibits numerous therapeutic properties, including neuropsychopharmacological, anti-anxiety, immunomodulatory, anti-inflammatory, antioxidant, or antifungal activities. The aim of the present study was an investigation of the influence of MGN on viability, proliferation, induction of apoptosis, and cell cycle arrest in NCI-H1299 lung, MDA-MB-468 breast, T98G glioma, and TE671 rhabdomyosarcoma cancer cells. MGN was isolated from the roots of Berberis cretica L. by counter-current partition chromatography (CPC). Cell viability and proliferation assessments were performed by means of MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) and 5-bromo-2'-deoxyuridine (BrDU) assays, respectively. The induction of apoptosis and cell cycle progression was measured using fluorescence-activated cell sorting analysis. MGN in high doses inhibits proliferation, induces apoptosis, and inhibits cell cycle in S/G2 phases in a dose-dependent manner. MGN seems to be a promising anti-cancer compound in therapy of some types of lung, breast, glioma, and rhabdomyosarcoma cancers, for which current standard therapies are limited or have severe strong side effects.

Aporphine and phenanthrene alkaloids with antioxidant activity from the roots of Stephania tetrandra.

Five new alkaloids (1-5), including three new aporphine alkaloids and two new phenanthrene alkaloids, together with 10 known compounds (6-15) were obtained from the roots of Stephania tetrandra. Their structures were elucidated by spectroscopic methods, single-crystal X-ray diffraction, and electronic circular dichroism analyses. Compounds 7-10, and 13 showed antioxidant activities with malondialdehyde (MDA) inhibitory rates of 62.50 ± 1.91 to 98.44 ± 0.34% at the concentration of 10 µM.

Racemic immunosuppressive seco-aporphine derivatives from Thalictrum wangii.

Thallactones A (1) and B (2), enantiomeric aporphine alkaloids with rare cleaved rings A and B, as well as thaliglucine N-oxide (3) and their biosynthetically related precursor, northalphenine (4), were isolated from the whole plant of Thalictrum wangii. Their structures with absolute configurations were elucidated by spectral techniques and electronic circular dichroism (ECD). Moreover, compounds 1, 3, and northalphenine inhibited concanavalin A (Con A)-stimulated proliferation of mice splenocyte significantly in a dose-dependent manner.

Exploring Aporphine as Anti-inflammatory and Analgesic Lead from Dactylicapnos scandens.

Dactylicapnosines A (1) and B (2), two reconstructed aporphines with unprecedent five-membered carbon ring D, were isolated from Dactylicapnos scandens, in which dactylicapnosine A showed potent anti-inflammatory bioactivity in vitro. Inspired by its biosynthetic pathway, the total synthesis of dactylicapnosine A via 10 steps has been achieved and afforded enough material to prove its significant anti-inflammatory effect in vivo.

New aporphine alkaloids with selective cytotoxicity against glioma stem cells from Thalictrum foetidum.

Seven new isoquinoline alkaloids, 9-(2'-formyl-5', 6'-dimethoxyphenoxy)-1, 2, 3, 10-tetramethoxy dehydroaporphine (1), 9-(2'-formyl-5', 6'-dimethoxyphenoxy)-1, 2, 3, 10-tetramethoxy oxoaporphine (2), 3-methoxy-2'-formyl oxohernandalin (3), (-)-9-(2'-methoxycarbonyl-5', 6'-dimethoxyphenoxy)-1, 2, 3, 10-tetramethoxy aporphine (4), (-)-2'-methoxycarbonyl thaliadin (5), (-)-9-(2'-methoxyethyl-5', 6'-dimethoxyphenoxy)-1, 2, 3, 10-tetramethoxy aporphine (6), (-)-3-methoxy hydroxyhernandalinol (7), together with six known isoquinoline alkaloids (8-13) were isolated from the roots of Thalictrum foetidum. Their structures were elucidated by extensive spectroscopic measurements. Compounds 1 and 2 showed significant selective cytotoxicity against glioma stem cells (GSC-3# and GSC-18#) with IC50 values ranging from 2.36 to 5.37 µg·mL-1.

Antiplasmodial activity and cytotoxicity, isolation of active alkaloids, and dereplication of Xylopia sericea leaves ethanol extract by UPLC-DAD-ESI-MS/MS.

OBJECTIVES: To assess the antiplasmodial activity of the ethanol extract of Xylopia sericea leaves, Annonaceae, often associated with antimalarial use and to perform a bioguided isolation of active compounds. METHODS: Dereplication of ethanol extract by the UPLC-DAD-ESI-MS/MS technique allowed the identification of the major constituents, isolation and identification of alkaloids. The antiplasmodial and cytotoxic activity of the extract, fractions and isolated compounds was evaluated against the chloroquine-resistant W2 strain Plasmodium falciparum and HepG2 cells, respectively. KEY FINDINGS: Ethanol extract showed high reduction of parasitemia as well as moderate cytotoxicity (86.5 ± 3.0% growth inhibition at 50 µg/ml and CC50 72.1 ± 5.1 µg/ml, respectively). A total of eight flavonoids were identified, and two aporphine alkaloids, anonaine and O-methylmoschatoline, were isolated. Anonaine disclosed significant antiplasmodial effect and moderate cytotoxicity (IC50 23.2 ± 2.7 µg/ml, CC50 38.3 ± 2.3 µg/ml, SI 1.6) while O-methylmoschatoline was not active against P. falciparum and showed a low cytotoxicity (33.5 ± 1.9% growth inhibition at 50 µg/ml, CC50 274.4 ± 0.5 µg/ml). CONCLUSIONS: Characterization of Xylopia sericea leaves ethanol extract by UPLC-DAD-ESI-MS/MS as well as its antiplasmodial activity and the occurrence of anonaine and O-methylmoschatoline in this Xylopia species are reported by the first time.

New Anti-Inflammatory Aporphine and Lignan Derivatives from the Root Wood of Hernandia nymphaeifolia.

A new aporphine, 3-hydroxyhernandonine (1) and a new lignin, 4'-O-demethyl-7-O-methyldehydropodophyllotoxin (2), have been isolated from the root wood of Hernanadia nymphaeifolia, together with thirteen known compounds (3⁻15). The structures of these compounds were determined through mass spectrometry (MS) and spectroscopic analyses. The known isolate, 2-O-methyl-7-oxolaetine (3), was first isolated from natural sources. Among the isolated compounds, 3-hydroxyhernandonine (1), 4'-O-demethyl-7-O-methyldehydropodophyllotoxin (2), hernandonine (4), oxohernangerine (5), and oxohernagine (6) displayed inhibition (IC50 values ≤5.72 µg/mL) of superoxide anion production by human neutrophils in response to formyl-l-methionyl-l-leucyl-l-phenylalanine/cytochalasin B (fMLP/CB). In addition, 3-hydroxyhernandonine (1), 4'-O-demethyl-7-O-methyldehydropodophyllotoxin (2), oxohernangerine (5), and oxohernagine (6) suppressed fMLP/CB-induced elastase release with IC50 values ≤5.40 µg/mL.

Aporphine Alkaloids from Illigera aromatica from Guangxi Province, China.

Three undescribed aporphine alkaloids laurodionine B (1), illigerine A (2), and N-formyl-laurolitsine (3) were isolated from the methanolic extracts of the Chinese medicinal plant, Illigera aromatica, together with three known analogues (4-6). The chemical structures of 1-6 were identified by spectroscopic methods including 1D and 2D NMR (1H, 13C, COSY, HSQC, and HMBC) and high resolution mass spectrometry (HRESIMS). Compounds 1-3 showed moderate inhibitory activities in vitro against two cultured tumor cell lines, Hela and SMMC7721, with IC50 values of 32.42-62.90 µM. Only compound 1 had in vitro cytotoxic activity against Bcap37 cells, with the IC50 value of 90.61 µM.

Immune-inhibitive phenyl-C1 substituent aporphine alkaloids from Thalictrum cirrhosum.

Five new phenyl-C1 substituent aporphine alkaloids, 6aR-2'-methoxycarbonyl-thaliadin (1), 6aR-2'-carboxyl-thaliadin (2), 6aR-3-methoxy-hernandalinol (3), 6aS-1,3,10-trimethoxy-natalamine (4), and 3-methoxy-2'-methoxycarbonyl-oxohernandalincin (5), together with sixteen known isoquinoline alkaloids (6-21) were isolated from the whole herb of Thalictrum cirrhosum (Levl.). Their structures were elucidated by extensive spectroscopic measurements, and six isoquinoline alkaloids showed significant inhibitory activity on concanavalin A-stimulated splenocytes proliferation with IC50 values 36-44 µM by the immunosuppressive bioassay.

Antitumor aporphine alkaloids from Thalictrum wangii.

Nine new isoquinoline alkaloids, including two proaporphine (1-2), three aporphine (3-5), two oxoaporphine (6-7), and two seco-bisbenzylisoquinoline (8-9), together with three known alkaloids (10-12) were isolated from the whole plant of Thalictrum wangii. Their structures were established on the basis of spectroscopic data. The antitumor activities of the isolated compounds were evaluated in vitro against glioma stem cells. Compounds 3-8 showed the cytotoxicity with IC50 values 15-20 µg/mL.