Lycodine-Type Lycopodium Alkaloids from the Whole Plants of Huperzia serrata

t Three new lycodine-type Lycopodium alkaloids,namely 1-methyllycodine(1),8a-hydroxy-15,16-dehydro-desN-methyl-a-obscurine(2),N-methyl-16-hydroxyhuperzine B(3),and one new natural lycodine-type Lycopodium alkaloid,N-methylhuperzine A(4),along with 11 known analogues(5–15),were isolated from the whole plants of club moss Huperzia serrata.The structures of 1–4 were elucidated on the basis of NMR spectroscopic and mass spectrometry data.Among them,compound 1 was the first lycodine-type alkaloid possessing a methyl group at C-1.In addition,the structure of 5 was confirmed by the single-crystal X-ray crystallography data and its^(13)C NMR was reported for the first time in current study.Compounds 1–5 were tested their BACE1 inhibitory activity.

Lycoplanines B-D,Three Lycopodium Alkaloids from Lycopodium complanatum

A novel Ci7N Lycopodium alkaloid(LA),lycoplanine B(1),containing an unusual formyl group,along with two new LAs,lycoplanines C(2)and D(3),were isolated from the whole plant of Lycopodium complanatum.Their structures were elucidated by extensive NMR techniques,including 1D-and 2D-NMR experiments,as well as comparing their spectral data with those of the known analogues.A possible biogenetic pathway for 1 was also proposed.

Lyconadins G and H,Two Rare Lyconadin-Type Lycopodium Alkaloids from Lycopodium complanatum

Two rare lyconadin-type Lycopodium alkaloids,lyconadins G(1)and H(2),together with four known ones(3–6),were isolated from Lycopodium complanatum.The structures were determined on the basis of their spectroscopic analyses,and the absolute configuration of 1 was established by an X-ray crystallographic analysis.It is the first time to establish the absolute configuration of lyconadin-type Lycopodium alkaloid by an X-ray diffraction experiment.In addition,these findings may provide more information for the biosynthesis of lyconadins.

Carinatines A and B,Lycopodium Alkaloids from Phlegmariurus carinatus

Carinatine A(1),a C16N2-type Lycopodium alkaloid possessing a 5/6/6/6 ring system formed by a new C-4/C-12 bond,and carinatine B(2),the first derivative of lycojaponicumin C,along 16 known compounds,were isolated from the whole plant of Phlegmariurus carinatus.Their structures were elucidated based on the spectroscopic data.The two new isolates were no inhibitory activity for the acetylcholinesterase(AChE).

One-step synthesis of Lycopodium alkaloid(-)-huperzine W via Suzuki-Miyaura coupling

The first total synthesis of(-)-huperzine W(1)has been achieved.Key element of the synthesis is a highly convergent assemblage for the two rings system of target molecule utilizing an efficient Suzuki-Miyaura coupling reaction between chiral iodide 2 and 2-allylpyrrolidinone 4.Evaluation of the AchE inhibition of synthetic huperzine W was also carried out.

Carbonic anhydrase-like enzymes in the formation of Lycopodium alkaloid

Plant alkaloids,renowned for their structural diversity and bioactivity,are prominent in both modern and traditional medicine[1].Unraveling the intricacies of plant alkaloid biosynthesis could pave the way for the discovery of new natural products and pathways.It may also shed light on the roles of existing pathways in host biology and provide valuable tools for metabolic engineering in plants and microbes[2].Unlike other major classes of plant natural products,such as terpenoids and polyketides,the formation of alkaloid scaffolds does not conform to a uniform chemical theme or depend on a singular enzyme class[3].A case in point is the Lycopodium alkaloids in the Lycopodiaceae family,where the enzymes responsible for their core scaffold construction remain unidentified[4].

Chemical constituents and biological activities of lycophytes and ferns

Lycophytes and ferns are unique and charismatic members of many terrestrial ecosystems and occupy the pivotal position in land plant origin and evolution.The Chinese lycophytes and ferns flora,with approximately 2000 species,contributes a substantial component to the global lycophytes and ferns diversity,with estimates of 12000 species.Among them,about 433 species are medicinally recorded and researches based on their phytochemical properties are important topics in natural medicines.This paper reviewed the research history and current status of chemical constituents and biological activities of lycophytes and ferns,which had highlighted the research progress of our group.