Canthin-6-one and beta-carboline alkaloids from Eurycoma harmandiana

Two alkaloids, canthin-6-one 9-O-beta-glucopyranoside and 7-hydroxy-beta-carboline 1-propionic acid, were isolated from the roots of Eurcoma harmandiana together with the five known canthin-6-one alkaloids, 9-hydroxycanthin-6-one, 9-methoxycanthin-6-one, 9,10-dimethoxycanthin-6-one, canthin-6-one and canthin-6-one N-oxide, and the two known beta-carboline alkaloids, beta-carboline 1-propionic acid and 7-methoxy-beta-carboline 1-propionic acid. Their structures were based on analyses of spectroscopic data.     

Studies on Ailanthus altissima cell suspension cultures

The uptake of L-[methylene ¹⁴C]-tryptophan from culture medium and the subsequent incorporation of the radiolabel into canthin-6-one, 1-hydroxycanthin-6-one and 1-methoxycanthin-6-one has been demonstrated in cell suspension cultures of Ailanthus altissima. Efficient incorporation has been shown to depend significantly on the time of feeding. Furthermore, feeding of L-tryptophan, at levels of 500 mg/l resulted in improved alkaloid yields, particularly when fed during the lag phase of the growth cycle.     

Phytochemical and antiulcerogenic properties of rhizomes from Simaba ferruginea St. Hill. (Simaroubaceae)

Simaba ferruginea (Simaroubaceae) is a Brazilian medicinal plant used in traditional medicine to treat several ailments, including gastric ulcers, fever, diarrhea, and dolorous and inflammatory processes. This study examines the chemical composition and antiulcerogenic effects of rhizomes from this plant. Bioassay-guided fractionation led to the isolation of two bioactive indole alkaloids called canthin-6-one (1) and 4-methoxycanthin-6-one (2). The alkaloid fraction and both alkaloids demonstrated potent antiulcerogenic effects when evaluated in gastric lesion-induced animals, as well as significant antinociceptive activity in mice. These results confirm and justify the popular use of S. ferruginea against gastric ulcers and dolorous processes.     

Studies on Ailanthus altissima cell suspension cultures. Uptake of L-[methyl-14C]methionine and incorporation of label into 1-methoxycanthin-6-one

Time-course studies of the uptake of L-[methyl ¹⁴C]-methionine have shown rapid uptake by Ailanthus altissima cells when fed at weekly stages throughout the growth cycle. The radio-label from [¹⁴C]-methionine was shown to be incorporated into 1-methoxycanthin-6-one with the highest level of incorporation being achieved with cells fed late in the growth phase.     

Methyltransferase activity in Allanthm altissima cell suspension cultures

Enzymes for the methylation of 1hydroxycanthin-6-one and a series of coumarins have been isolated from Ailanthus altissima cell suspension cultures. The coumarin methyltransferases methylate aesculetin to scopoletin and isoscopoletin, but not scopoletin, to scoparone. Fraxetin was methylated to isofraxidine but not to fraxidine and only fraxidine was methylated to 6,7,8-trimethoxycoumarin. These enzymes were studied throughout the culture growth cycle with two cell lines: 1, which produced 1-methoxycanthin-6-one as the major alkaloid and 2, in which canthin-6-one was the major alkaloid.Abbreviations UV ultraviolet - DEAE diethylaminoethyl - dw dry weight - MS mass spectrometry - NMR nuclear magnetic resonance - TLC thin layer chromatography     

Canthinones from Simaba cuspidata

Two new alkaloids, 8-methoxycanthin-6-one and 3-methoxycanthin-2,6-dione, were isolated from the EtOH extract of the bark of Simaba cuspidata Spruce ex Engl. Elucidation of the structure of the latter compound included ¹³C NMR spectral comparison with 2-methoxypyridine-N-oxide and N-methoxy-2-pyridone.     

Evidence for involvement of ketoglutarate in the biosynthesis of Canthin-6-one from cell cultures of Ailanthus altissima

¹³C enrichments at C-3, C-4, C-5 and C-6 of canthin-6-one from cell cultures of Ailanthus altissima supplemented with [1-¹³C], [2-¹³C] and [1,2-¹³C] acetate, give evidence of the involvement of ketoglutarate as an intact precursor in the biosynthetic pathway.     

Chloroform-soluble alkaloids of the root bark of Fagara viridis

Three alkaloids have been isolated from the root bark of Fagara viridis A. Cheval. (Rutaceae). One of these, canthin-6-one, is reported for the first time from an African species of Fagara while the others are the quaternary benzophenanthridine alkaloids chelerythrine and nitidine.     

Alkaloids and phenylpropanoids from Peganum nigellastrum

Two canthin-6-one alkaloids, luotonins C and D, and two phenylpropanoids, dihydrosinapyl ferulate and dihydroconiferyl ferulate, were isolated from the aerial parts of Peganum nigellastrum along with four known alkaloids, harmine, 3-phenylquinoline, 3-(4-hydroxyphenyl)quinoline and 3-(1H-indol-3-yl)quinoline. Their structures were elucidated by spectroscopic techniques. The structures of luotonins C and D were also confirmed by chemical synthesis.     

臭椿生物碱canthin-6-one对小鼠镇静催眠作用的研究

摘要 目的：研究臭椿生物碱canthin-6-one对小鼠的镇静催眠作用。方法：选昆明小鼠随机分为空白组、地西泮阳性药物组、canthin-6-one低、中、高给药组（5、10、20 mg?kg^-1），采用阈上剂量和阈下剂量戊巴比妥钠诱导小鼠睡眠，记录入睡小鼠比例、睡眠潜伏期和睡眠持续时间。此外，酶联免疫法测定小鼠脑组织中5-HT、NE、DA和GABA含量。结果：中、高剂量canthin-6-one可使小鼠的站立次数和自主活动次数均明显减少（P＜0.05），可使阈上剂量戊巴比妥钠诱导的小鼠的睡眠潜伏期缩短（P＜0.05）；各剂量组可使阈下剂量戊巴比妥钠诱导的小鼠入睡率提高（P＜0.05）。此外，中、高剂量canthin-6-one也可降低小鼠脑组织中5-HT和NE含量，增加GABA含量（P＜0.05），对DA的含量有影响，但无统计学意义（P＞0.05）。结论：Canthin-6-one有明显的协同戊巴比妥钠改善睡眠作用，其作用与相关神经递质（5-HT、NE、GABA）具有密切关系。     

LC-MS/MS-based metabolites of Eurycoma longifolia (Tongkat Ali) in Malaysia (Perak and Pahang)

A number of three LC-MS/MS hybrid systems (QTof, TripleTof and QTrap) has been used to profile small metabolites (m/z 100-1000) and to detect the targeted metabolites such as quassinoids, alkaloids, triterpene and biphenylneolignans from the aqueous extracts of Eurycoma longifolia. The metabolite profiles of small molecules showed four significant clusters in the principle component analysis for the aqueous extracts of E. longifolia, which had been collected from different geographical terrains (Perak and Pahang) and processed at different extraction temperatures (35°C and 100°C). A small peptide of leucine (m/z 679) and a new hydroxyl methyl β-carboline propionic acid have been identified to differentiate E. longifolia extracts that prepared at 35°C and 100°C, respectively. From the targeted metabolites identification, it was found that 3,4?-dihydroeurycomanone (quassinoids) and eurylene (squalene-type triterpene) could only be detected in the Pahang extract, whereas canthin-6-one-3N-oxide could only be detected in the Perak extract. Overall, quassinoids were present in the highest concentration, particularly eurycomanone and its derivatives compared to the other groups of metabolites. However, the concentration of canthin-6-one and β-carboline alkaloids was significantly increased when the roots of the plant samples were extracted at 100°C.     

Triggered efflux of protoberberine alkaloids from cell suspension cultures ofThalictrum rugosum

Cell cultures ofThalictrum rugosum released their protoberberine alkaloids into the medium, when cells were transferred to fresh medium lacking phosphate. The nutritional factors required and the impact of the cells' physiological state for the alkaloid excretion were analyzed. Cell cultures, having released their alkaloids into the medium, continued to grow when the alkaloid containing medium was replaced by fresh growth medium.     

Alkaloids,coumarins, triterpenes and a flavanone from the root of Zanthoxylum dipetalum

The root bark of Zanthoxylum dipetalum contained the alkaloids canthin-6-one, chelerythrine, nitidine and tembetarine, the pyranocoumarins avicennol and xanthoxyletin, the triterpene lupeol and the flavanoid hesperidin. The MS fragmentation pattern for avicennol is discussed and a tentative structure is proposed for a third coumarin, designated ZD/1. The root wood of the type species and the stem bark of the γ variety contained most of the above compounds plus sitosterol and, in the root wood only, magnoflorine. The chemotaxonomic implications of these findings are briefly discussed.     

Alkaloid formation by habituated and tumorous cell suspension cultures of Catharanthus roseus

Habituated and tumorous Catharanthus roseus cells grown in the absence of hormones accumulated indole alkaloids. Total alkaloids and alkaloid pattern were the same when cells were cultured in medium without hormones or in alkaloid production medium with and without indole acetic acid. Treatment of cells with Pythium homogenate as elicitor did not increase total alkaloids or change the pattern of alkaloids produced. When either habituated or tumorous cells were grown in 1B5 medium after Gamborg et al (1968) containing 2,4-dichlorophenoxyacetic acid (2,4-D), their capacity to accumulate alkaloids decreased with time. The levels of tryptophan decarboxylase (TDC) and strictosidine synthase (SS) specific activities were constant throughout growth except when cells were exposed to 2,4-D in 1B5 medium, where enzyme activities declined in step with the decrease in alkaloid accumulation. Neither habituated nor tumorous cell suspension cultures accumulated vindoline, nor could they be induced to produce this alkaloid by any of the given treatments.NRCC No. 27514     

Permeabilization of Cinchona ledgeriana cells by dimethylsulphoxide. effects on alkaloid release and long-term membrane integrity

Dimethyl sulphoxide (DMSO) has been used to permeabilize cells of Cinchona ledgeriana in suspension culture and promote the release of intracellular alkaloids. 5–6% v/v is required before any release is seen, and greater than 20% DMSO is required for full release. Even at these high levels of DMSO release is slow, taking in excess of seven hours to reach completion. Conditions which produce significant release of alkaloids have a deleterious effect on cells. Many of the membranes permeabilized did not recover their ability to selectively exclude compounds such as mannitol when the DMSO was removed. It is concluded that DMSO is not a suitable material for inducing alkaloid release in any biotechnological exploitation of alkaloid production by C. ledgeriana.Abbreviations DMSO Dimethyl sulphoxide - 2,4D 2,4-Dichlorophenoxyacetic acid     

Effects of Picrasma quassioides and its active constituents on Alzheimer's disease in vitro and in vivo

Alzheimer disease (AD), a prevalent neurodegenerative disorder, is one of the leading causes of dementia. However, there is no effective drug for this disease to date. Picrasma quassioides (D.Don) Benn, a Chinese traditional medicine, was used mainly for the treatment of inflammation, fever, microbial infection and dysentery. In this paper, we reported that the EtOAc extract of Picrasma quassioides stems showed potential neuroprotective activities in l-glutamate-stimulated PC12 and Aβ_25-35-stimulated SH-SY5Y cell models, as well as improved memory and cognitive abilities in AD mice induced by amyloid-β peptide. Moreover, it was revealed that the anti-AD mechanism was related to suppressing neuroinflammatory and reducing Aβ_1-42 deposition using ELISA assay kits. To clarify the active components of the EtOAc extract of Picrasma quassioides stems, a systematic phytochemistry study led to isolate and identify six β-carboline alkaloids (1–6), seven canthin-6-one alkaloids (7–13), and five quassinoids (14–18). Among them, four β-carbolines (1–3, and 6) and six canthin-6-ones (7–11, and 13) exhibited potential neuroprotective activities in vitro. Based on these date, the structure-activity relationships of alkaloids were discussed. Furthermore, molecular docking experiments showed that compounds 2 and 3 have high affinity for both of dual-specificity tyrosine phosphorylation-regulated kinase 1A (DYPKIA) and butyrylcholinesterase (BuChE).     

Design and synthesis of C10 modified and ring-truncated canthin-6-one analogues as effective membrane-active antibacterial agents

A series of canthin-6-one analogues were designed and synthesized in order to study their antibacterial activity and structure–activity relationships. Compound 22 showed a broad spectrum of antibacterial activity and exhibited better bactericidal effect (8-fold superiority against Staphylococcus aureus and 2-fold superiority against Ralstonia solanacearum) than fosfomycin sodium and propineb with a minimum inhibitory concentration value of 2?μg/mL. Moreover, it showed low cytotoxicity, stimulation on germination rates and good “drug-like” properties. Membrane-active mechanism was further studied by fluorescent microscopy, scanning electron microscopy, cytoplasmic β-galactosidase leakage assay and evaluation of the molecular docking. The results showed that 22 may exert its bactericidal effect by damaging bacterial cell membranes and influencing the membrane formation, both of which could lead to cell death. The in vivo antibacterial assay with a protective efficacy of 68% demonstrated the potential of C ring-truncated canthin-6-one 22 as a new bactericide.     

Semi-continuous production of sanguinarine and dihydrosanguinarine by Papaver somniferum L. cell suspension cultures treated with fungal homogenate

Papaver somniferum L. (opium poppy) cells were elicited with a Botrytis sp. homogenate and cultured by a semi-continuous process. Elicitation induced synthesis of sanguinarine and dihydrosanguinarine. Significant release of both alkaloids into the culture medium occurred. Medium exchange at 2-day intervals enabled product recovery from spent medium and maintained culture viability. Culture growth was not inhibited by elicitor treatment necessitating sub-culture prior to re-elicitation. Re-elicited cultures displayed an increasing sensitivity (reduced growth rate, higher alkaloid yield) to the elicitor with each successive treatment and did not survive a fourth elicitation.Abbreviations DW dry weight - FW fresh weight - 2,4-D 2,4-dichlorophenoxyacetic acid - SGE sanguinarine - DSGE dihydrosanguinarine Publication 29143 from the National Research Council of Canada