Two New Lycodine Alkaloids from Lycopodiastrum casuarinoides

Two new lycodine alkaloids, 11β‐methoxyhuperzine B ( 1 ) and 16‐oxohuperzinine ( 2 ), together with seven known ones, huperzinine N‐oxide, huperzine D, casuarinine A, huperzine B, casuarinine B, huperzinine, and N‐methyllycodine, were isolated from whole plants of Lycopodiastrum casuarinoides. Their structures were elucidated by spectroscopic methods, including NMR and MS experiments.     

Lycopodium Alkaloids from Huperzia serrata

Three new lycopodium alkaloids, huperserramines A–C ( 1 – 3 , resp.), along with 15 known ones, lycopodine‐6α,11α‐diol ( 4 ), lycoposerramine H ( 5 ), lycoposerramine I ( 6 ), lycopodine‐6α‐ol ( 7 ), lycoposerramine M ( 8 ), diphaladine A ( 9 ), lycoposerramine K ( 10 ), lycoposerramine W ( 11 ), huperzine M ( 12 ), luciduline ( 13 ), phlegmariuine N ( 14 ), huperzine A ( 15 ), huperzine B ( 16 ), lycodine ( 17 ), and lycoposerramine R ( 18 ), were isolated from the whole plant of Huperzia serrata. Their structures were established by spectroscopic methods, including 2D‐NMR and MS analyses. All the isolates were evaluated for their inhibitory effects on acetylcholinesterase (AChE) and α‐glucosidase. As a result, lycopodine‐6α,11α‐diol ( 4 ) exhibited more potent α‐glucosidase inhibitory activity (IC₅₀ 148±5.5 μM ) than the positive control acarbose (IC₅₀ 376.3±2.7 μM ).     

Two New Lycopodium Alkaloids from Lycopodium obscurum

Two new Lycopodium alkaloids, (+)‐cermizine D N‐oxide ( 1 ) and (8β)‐8‐(acetyloxy)obscurumine A ( 2 ), along with five known compounds, were isolated from the crude alkaloid portion of Lycopodium obscurum. Their structures were elucidated on the basis of spectroscopic data and chemical correlation. All of these alkaloids were tested in an assay for acetylcholine esterase (AChE) inhibitory activity.     

Lycopodium Alkaloids from Lycopodium obscurum L.

Two new Lycopodium alkaloids, named obscurumines F and G ( 1 and 2 , resp.), together with eleven known alkaloids, were isolated from the club moss Lycopodium obscurum L. Their structures were elucidated on the basis of spectroscopic analyses.     

Lycopodium Alkaloids from Huperzia serrata

Three new Lycopodium alkaloids, 2‐chlorohuperzine E ( 1 ), huperzines E′ ( 2 ), and F′ ( 3 ), along with two known compounds, huperzines E and F, were isolated from Huperzia serrata (Thunb .) Trev . Their structures were elucidated by spectroscopic methods.     

Heathcock‐Inspired Strategies for the Synthesis of Fawcettimine‐Type Lycopodium Alkaloids

The fawcettimine‐type Lycopodium alkaloids have garnered significant attention from synthetic organic chemists since the isolation of fawcettimine in 1959. Despite being targets of interest for over 50 years, most of the strategies employed in the syntheses of fawcettimine congeners have built upon Inubushi and Heathcock’s original work, realized in 1979 and 1986, respectively. This elegant strategy has been explored and expanded upon in the intervening years since the original publications, in what we now call the Heathcock‐inspired strategy. While other disconnections have been disclosed, this strategy remains one of the most efficient. In this Concept article, we focus on exploring a number of recent Heathcock‐inspired syntheses of fawcettimine‐type Lycopodium alkaloids. We also briefly discuss alternative, novel disconnections.     

Two New Nitrone Alkaloids from Huperzia serrata

Two new nitrone alkaloids were isolated from the whole plant of Huperzia serrata (Thunb .) Trev . They are both phlegmarine‐type lycopodium alkaloids with a nitrone moiety. Their structures were elucidated on the basis of spectral evidences, and their configurations were established on the basis of optical rotation, CD, and NOESY‐NMR data.     

Three New Lycopodium Alkaloids from Phlegmariurus fargesii

Three new Lycopodium alkaloids, fargesiines A – C ( 1  –  3 , resp.), along with a known compound ( 4 ), were isolated from the whole plants of Phlegmariurus fargesii. Their structures were elucidated on the basis of spectroscopic data and chemical correlations. Compounds 1  –  4 were tested in an assay for acetylcholinesterase (AChE) inhibitory activity.     

Optimization of Pressurized Liquid Extraction of Lycopodiaceae Alkaloids Obtained from Two Lycopodium Species

Alkaloids of the Lycopodiaceae family are of great interest to researchers due to their numerous properties and wide applications in medicine. They play a very important role mainly due to their potent antioxidant, antidepressant effects and a reversible ability to inhibit acetylcholinesterase (AChE) enzyme activity. This property is of immense importance due to the growing problem of an increasing number of patients with neurodegenerative diseases in developed countries and a lack of effective and efficient treatment for them. Numerous studies have shown that Lycopodiaceae alkaloids are a rich source of AChE inhibitors. In the obtaining of new therapeutic phytochemicals from plant material, the extraction process and its efficiency is crucial. Therefore, the aim of this work was to optimize the conditions of modern PLE to obtain bioactive alkaloids from two Lycopodium species: L. clavatum L. and L. annotinum L. Five different solvents of different polarity were used for prepared plant extracts in order to compare the alkaloid content in and thereby effectiveness of the entire extraction. PLE parameters were used based on multiple studies conducted that gave the highest alkaloids recovery. Crude extracts were purified using solid-phase extraction (SPE) on Oasis HLB cartridge and examined by HPLC/ESI-QTOF–MS of the highly abundant alkaloids. To the best of our knowledge, this is the first time such high recoveries have been obtained for known Lycopodiaceae alkaloids. The best extraction results of alkaloid-lycopodine were detected in the dichloromethane extract from L. clavatum, where the yield exceeded 45%. The high recovery of annotinine above 40% presented in L. annotinum was noticed in dichloromethane and ethyl acetate extracts. Moreover, chromatograms were obtained with all isolated alkaloids and the best separation and quality of the bands in methanolic extracts. Interestingly, no alkaloid amounts were detected in cyclohexane extracts belonging to the non-polar solvent. These results could be helpful for understanding and optimizing the best conditions for isolating potent AChE inhibitors.     

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.     

Two New C20‐Diterpenoid Alkaloids from Aconitum carmichaelii

Two new C₂₀‐diterpenoid alkaloids, named aconicarchamines A and B ( 1 and 2 , resp.), were isolated from Aconitum carmichaelii. By UV, IR, MS, and 1D‐ and 2D‐NMR analyses, their structures were elucidated as 14,17‐dihydro‐14,17‐dihydroxyajabicine and 15‐O‐acetyllassiocarpine. Compound 1 is the third C₂₀‐diterpenoid alkaloid with the lycoctine skeleton bearing an exocyclic C‐atom at C(14).     

Two New 11‐Hydroxy‐Substituted Gelsedine‐Type Indole Alkaloids from the Stems of Gelsemium elegans

Two new 11‐hydroxy‐substituted gelsedine‐type indole alkaloids, named 11,14‐dihydroxygelsenicine ( 1 ) and 11‐hydroxygelsenicine ( 2 ), together with six known alkaloids, i.e., koumine, gelsemine, 14‐hydroxygelsenicine, 11‐hydroxyhumantenine, gelsenicine, and (19Z)‐akuammidine, were isolated from the EtOH extract of the stems of Gelsemium elegans Benth. Their structures were determined mainly by means of spectroscopic analyses including HR‐ESI‐MS and 2D‐NMR (HSQC, HMBC, ¹H,¹H‐COSY). The configuration of 1 was confirmed by X‐ray‐diffraction analysis.     

A New Lycopodine-type Alkaloid from Lycopodium japonicum

A new lycopodine-type alkaloid, 12β-hydroxy-acetylfawcettiine N-oxide (1), together with seven known analogues, acetyllycoposerramine M (2), lycopodine (3), lycoclavine (4), diphaladine A (5), lycoposerramine K (6), 11β-hydroxy-12-epilycodoline (7) and fawcettiine (8), were isolated from Lycopodium japonicum. Their structures were established by mass spectrometry and 1D and 2D NMR techniques. The isolated alkaloids were assayed for their inhibition activities against acetylcholinesterase, but no inhibitory activities for the compounds were detected.     

Fawcettimine‐Type Lycopodium Alkaloids as a Driving Force for Discoveries in Organic Synthesis

Ever since the pioneering synthetic work reported by both Inubushi and Heathcock back in 1980s, the fawcettimine‐type Lycopodium alkaloids have continuously served as a driving force for discoveries in organic synthesis. In this personal account, we summarized our recent synthetic efforts towards the total synthesis of fawcettimine‐type Lycopodium alkaloids, along with a brief summary of relevant syntheses reported by others. Our discussions focus mainly on the key reactions applied during the synthesis of fawcettimine‐type Lycopodium alkaloids.     

Lycopodine‐Type Lycopodium Alkaloids from Huperzia serrata

Eleven Lycopodium alkaloids with a lycopodine‐type skeleton were isolated from the basic material of the whole plant of Huperzia serrata (Thunb .) Trev. (Huperziaceae). Among them, 12‐epilycodoline N‐oxide (=(12α,15R)‐12‐hydroxy‐15‐methyllycopodan‐5‐one N‐oxide; 1 ), 7‐hydroxylycopodine (=(15S)‐7‐hydroxy‐15‐methyllycopodan‐5‐one; 2 ), and 4,6α‐dihydroxylycopodine (=(6α,15R)‐4,6‐dihydroxy‐15‐methyllycopodan‐5‐one; 3 ) are new compounds. Their structures were identified spectroscopically, especially by means of 1D‐ and 2D‐NMR.     

Two New Alkaloids from Flueggea virosa

Two new securinega‐type alkaloids and four known ones were isolated from the twigs and leaves of Flueggea virosa. The structures of the new compounds were elucidated by means of spectroscopic methods (UV, IR, HR‐ESI‐MS, and 1D‐ and 2D‐NMR), and the absolute configurations were assigned by CD spectra. The structures of the known compounds were identified by comparison of their physical and spectroscopic data with those reported in the literature.     

Two new Lycopodium alkaloids from Phlegmariurus phlegmaria (L.) Holub

Two new Lycopodium alkaloids, 4β-hydroxynankakurine B (1) and Δ^13,N,N_α-methylphlegmarine-N_β-oxide (2), together with three known analogues, lycoposerramine E (3), nankakurine B (4) and lobscurinol (5), were isolated from Phlegmariurus phlegmaria. Their structures were established by mass spectrometry and 1D and 2D NMR techniques.     

Norditerpenoid Alkaloids from the Aerial Parts of Aconitum cochleare Woroschin

From the aerial parts of Aconitum cochleare Woroschin, two new norditerpenoid alkaloids named aconitilearine ( 1 ) and N‐deethylmethyllycaconitine ( 2 ) were isolated along with the eight known norditerpenoid alkaloids 3 – 10 . The structures for the new compounds were established on the basis of ¹H, ¹³C, DEPT, homonuclear ¹H,¹H‐COSY, NOESY, HSQC, and HMBC NMR studies.     

New Pyrrole Alkaloids with Bulky N‐Alkyl Side Chains Containing Stereogenic Centers from Lycium chinense

Four new pyrrole alkaloids, methyl 2‐[2‐formyl‐5‐(methoxymethyl)‐1H‐pyrrol‐1‐yl]propanoate ( 1 ), methyl 2‐[2‐formyl‐5‐(methoxymethyl)‐1H‐pyrrol‐1‐yl]‐3‐(4‐hydroxyphenyl)propanoate ( 2 ), dimethyl 2‐[2‐formyl‐5‐(methoxymethyl)‐1H‐pyrrol‐1‐yl]butanedioate ( 3 ), and dimethyl 2‐[2‐formyl‐5‐(methoxymethyl)‐1H‐pyrrol‐1‐yl]pentanedioate ( 4 ), were isolated from the AcOEt extract of the fruits of Lycium chinense Miller (Solanaceae). The stereogenic center C(2) in the bulky N‐alkyl side chain in each of 1 – 4 seems to hold the H‐atoms of nearby CH₂ groups, CH₂(7′) and CH₂(3) (if R≠H), leading to two different chemical shifts in the ¹H‐NMR spectrum due to their diastereotopic characteristics. In the ¹H‐NMR data of each of 2 – 4 , the enhancement of H? C(2) signal was inhibited by the R group, probably due to steric hindrance, and its chemical shift was influenced by the anisotropy effect. The structures of 1 – 4 were elucidated by analysis of various spectroscopic data, including 1D‐ and 2D‐NMR.