New glycosylsphingolipids from Psychotria serpens L

Abstract

In clinical, Psychotria serpens L. was often substitute for Caulis trachelospermi to treat cancer in China. Meanwhile, EtOAc and n-BuOH fractions of MeOH extract of P. serpens L. show power activity against H460, HepG2, Hela, and PC9/GR cell lines, and no toxic effects against normal 16HBE cell lines. In our ongoing search for bioactive novel compounds from Chinese material medica, one new type of glycosylsphingolipids Psychotramide (1a–1c) were isolated from P. serpens L., and their structures were identified through spectroscopic techniques including NMR (1D and 2D) and MS (LC-MS, and GC-MS).     

A New Alkaloid from the Seeds of Sophora alopecuroides L.

Alopecurin A, an alkaloid with an unprecedented skeleton, was isolated from the seeds of Sophora alopecuroides L. The absolute configuration and structure of this compound was identified as (3S,12R)‐3‐hydroxy‐1,7‐diazatricyclo[10.4.0.1^3,7]heptadecane‐11,16,17‐trione (=(7S,15aR)‐decahydro‐7‐hydroxy‐6H‐7,11‐methano‐4H‐pyrido[1,2‐a][1,7]diazacyclododecine‐4,15,16(12H)‐trione). The structure and absolute configuration was elucidated by spectroscopic methods, mainly HR‐ESI‐TOF‐MS, IR, 1D‐NMR (¹H‐ and ¹³C‐NMR), 2D‐NMR (COSY, NOESY, HSQC, HMBC), and particularly X‐ray crystal‐diffraction and CD spectral analysis.     

A New Lycopodine Alkaloid from Phlegmariurus yunnanensis Ching

A new lycopodine alkaloid, 15α‐methyllycopodane‐5β,6β‐diol N‐oxide ( 1 ), was isolated from the whole plants of Phlegmariurus yunnanensis Ching , together with the two known alkaloids 15α‐methyllycopodane‐5β,6β‐diol ( 2 ) and lycoposerramine H ( 3 ), and four serratene‐type triterpenoids, serratenediol‐3‐acetate ( 4 ), serratenediol ( 5 ), lycocryptol ( 6 ), and serratriol ( 7 ). Their structures were elucidated on the basis of spectroscopic analyses, including HR‐ESI‐MS, ¹H‐ and ¹³C‐NMR, DEPT, ¹H,¹H‐COSY, HSQC, HMBC, and NOESY.     

A New Indole Alkaloid from Cleome droserifolia

The phytochemical investigations on Cleome droserifolia resulted in the isolation and characterization of a new indole alkaloid, 5‐hydroxy‐2‐methoxy‐1‐methyl‐1H‐indole‐3‐carbaldehyde ( 1 ). The structure elucidation was carried out on the basis of 1D‐ and 2D‐NMR techniques. In addition to 1 , two known aromatic derivatives, veratrol ( 2 ) and 2‐methoxy‐4‐methylacetophenone ( 3 ), were also obtained. All these compounds were purified by repeated column chromatography of the CH₂Cl₂ fraction obtained from MeOH extract of Cleome droserifolia. The structure of the new compound 1 was finally confirmed by the combined 1D (¹H‐ and ¹³C‐) and 2D (H? C correlations; HMBC and HSQC) NMR and IR spectroscopy, mass spectrometry (MS), and UV absorption spectroscopy techniques. The comparison of the physical and spectroscopic data with those in the literature provided evidence for the structure confirmation of known compounds. All the purified compounds were subjected to urease and α‐glucosidase enzymes inhibition. The results showed that compound 1 was more potent with an IC₅₀ value 11.97±2.067 μg/ml towards urease inhibition, while the activity of α‐glucosidase enzyme was marginal.     

A New Alkaloid from Lycopodium japonicum Thunb.

A new alkaloid, miyoshianine C ( 1 ), was isolated from the whole plants of Lycopodium japonicum Thunb. , together with the known four compounds α‐obscurine ( 2 ), lycodoline ( 3 ), miyoshianine A ( 4 ), and lucidioline ( 5 ). Their structures were elucidated on the basis of in‐depth spectroscopic analysis.     

A New Coumarin and Carbazole Alkaloid from Clausena vestita D. D. Tao

Phytochemical investigation of the EtOH extract of Clausena vestita D. D. Tao led to the isolation of one new coumarin, clauslactone U ( 1 ), and one new carbazole alkaloid, clauszoline N ( 2 ), together with 28 known compounds. The structures of these compounds were established by using MS and 1D‐ and 2D‐NMR techniques, and by comparison with known analogues.     

New Indole Alkaloids from Kopsia. Alkaloid Variation in Kopsia singapurensis

Five new indole alkaloids, viz., kopsiloscine G ( 2 ), kopsidarine ( 4 ), kopsimaline F ( 6 ), kopsidine C N‐oxide ( 7 ), and aspidophylline B ( 9 ), in addition to 17 other known alkaloids, were obtained from the leaf and stem‐bark extract of the Malaysian Kopsia singapurensis. The structures were determined by using NMR and MS analysis. The results are compared with the alkaloidal composition of another sample of K. singapurensis, collected from the same location but at a different time of the year, as well as with other samples of K. singapurensis collected from different locations.     

Two New Alkaloids from the Roots of Aconitum sinomontanum Nakai

Two new alkaloids, ranaconidine (=20‐ethyl‐1α,14α,16β‐trimethoxyaconitane‐4,7,8,10‐tetrol; 1 ) and N‐(chloromethyl)taspine (=1‐[2‐(N‐(chloromethyl)‐N,N‐dimethylaminium)ethyl]‐3,8‐dimethoxybenzopyrano[5,4,3‐cde]benzopyran‐5,10‐dione; 2 ), together with two known compounds, i.e., benzethonium chloride ( 3 ) and ranaconine ( 4 ) were isolated from the roots of Aconitum sinomontanum Nakai . The structures of the compounds were elucidated on the basis of spectral evidences and in the comparison with previously published data.     

A Novel Alkaloid from Melodinus henryi

The isolation and structure elucidation of a novel alkaloid, namely of the 14‐O‐ethyl‐substituted (3α,14α,16α)‐2,7‐secoeburnamine derivative 1 from the leaf of Melodinus henryi is reported. Ten known alkaloids were also isolated. Their structures were determined spectroscopically. The isolates were evaluated for their cytotoxicity.     

A New Diterpenoid and a New Diterpenoid Alkaloid from Aconitum coreanum

A new diterpenoid, guan fu diterpenoid A ( 1 ), and a new diterpenoid alkaloid, guan fu base S ( 2 ), were isolated from the Chinese medicinal herb Aconitum coreanum (Lèvl. ) Rapaics , together with five known diterpenoid alkaloids guan fu base P, guan fu base R, guan fu base G, guan fu base F, and guan fu base Z. The structures of the two new compounds were elucidated as ent‐kaurane‐16,20‐diol ( 1 ) and (11β,13S)‐2,3,15,16‐tetradehydro‐16,17‐dihydrohetisan‐11,13,14‐triol 11,13‐diacetate ( 2 ) on the basis of HR‐MS and 2D‐NMR analyses. This is the first report of an ent‐kaurane diterpenoid in Aconitum coreanum.     

Five New Steroidal Alkaloid Glycosides from Solanum tuberosum

Five new steroidal alkaloid glycosides, 1 – 5 , along with the known analog 6 , have been isolated from the aerial parts of Solanum tuberosum. The structures of the new compounds were elucidated by spectroscopic methods, including 1D‐ and 2D‐NMR and HR‐ESI‐MS techniques, as well as by comparison of the spectral data with those of related compounds. Only compound 6 showed significant cytotoxicity.     

A New Diterpenoid Alkaloid from the Roots of a White‐Flowering Aconitum orientale Sample

From the roots of a white‐flowering Aconitum orientale Miller sample, collected in Artvin‐?av?at, Turkey, a new diterpenoid alkaloid named aconitorientaline ( 1 ) was isolated, along with the known diterpenoid alkaloids septentiriodine, lappaconitine, finaconitine, ranaconitine, puberanidine and delstaphinine (Fig.). The structure of 1 was established on the basis of ¹H‐ and ¹³C‐NMR, DEPT, ¹H,¹H‐COSY, NOESY, HSQC, and HMBC studies. All the known compounds were identified by comparison of their ¹H‐ and ¹³C‐NMR data and co‐TLC behavior with those of authentic samples.     

Alkaloids from Lindera Glauca

A new amide, N‐cis‐sinapoyltyramine ( 1 ), and twelve known compounds were isolated from the aerial parts of Lindera glauca. The structure of the new compound has been established by the study of extensive 2D NMR data.     

Three New Alkaloids from the Leaves of Uncaria rhynchophylla

Three new alkaloids, 2′‐O‐β‐D ‐glucopyranosyl‐11‐hydroxyvincoside lactam ( 1 ), 22‐O‐demethyl‐22‐O‐β‐D ‐glucopyranosylisocorynoxeine ( 2 ), and (4S)‐corynoxeine N‐oxide ( 3 ) were isolated from the leaves of Uncaria rhynchophylla, together with four known tetracyclic oxindole or indole alkaloids, isocorynoxeine N‐oxide ( 4 ), rhynchophylline N‐oxide ( 5 ), isorhynchophylline N‐oxide ( 6 ), and dihydrocorynantheine ( 7 ), and an indole alkaloid glycoside, strictosidine ( 8 ). The structures of 1 – 3 were elucidated by spectroscopic methods including UV, IR, ESI‐TOF‐MS, 1D‐ and 2D‐NMR, as well as CD experiments. The activity assay showed that 8 (IC₅₀=8.3 μM ) exhibited potent inhibitory activity on lipopolysaccharide(LPS)‐induced nitrogen monoxide (NO) release in N9 microglia cells. However, only weak inhibitory activities were observed for 1 – 7 (IC₅₀>100 μM for 1 – 6 or >30 μM for 7 ).     

Alkaloids of Arundo donax. XII. Structure of the New Dimeric Indole Alkaloid Arundacine

The new dimeric indole alkaloid arundacine is isolated from the polar fraction of the total alkaloids from Arundo donax L. roots. The structure 3-N,N-dimethylaminoethyl-5-hydroxy-4-(3-N-acetyl-N-methylaminoethylindol-1-yl)indole is established using spectral data (IR, UV, mass, one-dimensional ¹H and ¹³C NMR, various two-dimensional spectra).     

Citropremide and Citropridone: A New Ceramide and a New Acridone Alkaloid from the Stem Bark of Citropsis gabunensis

The structure elucidation and complete ¹H‐ and ¹³C‐NMR assignments are reported for two new compounds: the ceramide citropremide ( 1 ), and the acridone alkaloid citropridone ( 2 ). Both of these secondary metabolites were isolated from the stem bark of Citropsis gabunensis. High‐resolution mass, IR and UV spectrometry, and NMR experiments including COSY, HMQC, and HMBC were used for the determination of the structures and NMR spectral assignments.     

A Novel Alkaloid from Aspidosperma pyricollum (Apocynaceae) and Complete 1H and 13C Chemical Shift Assignments

A novel natural product indole, alkaloid, named rel‐pyricolluminol ( 1 ), was isolated from Aspidosperma pyricollum Müll .Arg . together with six known metabolites sitsirikine ( 2 ), aparicin ( 3 ), ulein ( 4 ), stemmadenine ( 5 ), lupeol ( 6 ), and (3β)‐sitoster‐3‐yl β‐D ‐glucopyranoside ( 7 ). These compounds were characterized on the basis of their spectral data, mainly 1D‐ (¹H,¹³C‐DEPTQ) and 2D‐NMR (¹H,¹H‐COSY, NOESY, HSQC, and HMBC), and mass spectra (EI‐MS and HR‐ES‐MS), involving also comparison with data from the literature.     

Three New Prenylated Diketopiperazines from Neosartorya fischeri

Three new prenylated 2,5‐diketopiperazines, namely neofipiperazines A–C ( 1 – 3 , resp.), were isolated from the culture of Neosartorya fischeri CGMCC 3.5378, together with six known ones. The structures of the new compounds were elucidated by comprehensive spectroscopic analysis, especially HR‐ESI‐MS and NMR experiments. All the prenylated diketopiperazines, except 7 , were isolated for the first time from the species.