Seladelicatulasine A-G, C27 steroidal glycosides with cholinesterase inhibitory activities from Selaginella delicatula

Chemistry and anticancer activity of cardiac glycosides: A review

The objective of this review is an attempt to emphasize the development in the chemistry and to display review of diverse therapeutic actions of cardiac glycosides. Anticancer activity of cardiac glycosides is the main activity as discussed in this review. The aim of the review is to gather the recent researches on cardiac glycosides. The present manuscript gives the platform for the researcher to have complete literature on the topic.

Two new nor-lignans, siamensinols A and B, from Selaginella siamensis Hieron. and their biological activities

Two new nor-lignans siamensinols A-B (1-2) and seven known compounds agatharesinol (3), syringaresinol-glucoside (4), noreugenin (5), 8-methyleugenitol (6), melachromone (7), uncinoside A (8) and daucosterol (9) were isolated from Selaginella siamensis Hieron. The structures of the new compounds were elucidated on the basis of comprehensive spectroscopic methods, including 1 D, 2 D-NMR, HR-ESI-MS and CD spectrometry. Compounds 1-2 showed moderate inhibitory effect on MOLT-3 cells while 8-methyleugenitol (6) exhibited moderate inhibitory effect on three tumor cells (HepG2, A549 and HuCCA-1). Compounds 2-3 showed the potent cancer chemoprevention in DPPH, XXO, IXO and AIA assays.

Non-Alkaloid Cholinesterase Inhibitory Compounds from Natural Sources

Alzheimer's disease (AD) is a severe neurodegenerative disorder of different brain regions accompanied by distresses and affecting more than 25 million people in the world. This progressive brain deterioration affects the central nervous system and has negative impacts on a patient's daily activities such as memory impairment. The most important challenge concerning AD is the development of new drugs for long-term treatment or prevention, with lesser side effects and greater efficiency as cholinesterases inhibitors and the ability to remove amyloid-beta(Aβ) deposits and other related AD neuropathologies. Natural sources provide promising alternatives to synthetic cholinesterase inhibitors and many have been reported for alkaloids while neglecting other classes with potential cholinesterase inhibition. This review summarizes information about the therapeutic potential of small natural molecules from medicinal herbs, belonging to terpenoids, coumarins, and phenolic compounds, and others, which have gained special attention due to their specific modes of action and their advantages of low toxicity and high efficiency in the treatment of AD. Some show superior drug-like features in comparison to synthetic cholinesterase inhibitors. We expect that the listed phytoconstituents in this review will serve as promising tools and chemical scaffolds for the discovery of new potent therapeutic leads for the amelioration and treatment of Alzheimer's disease.

Anticholinesterase Activity of Eight Medicinal Plant Species: In Vitro and In Silico Studies in the Search for Therapeutic Agents against Alzheimer's Disease

Many Bangladeshi medicinal plants have been used to treat Alzheimer's disease and other neurodegenerative diseases. In the present study, the anticholinesterase effects of eight selected Bangladeshi medicinal plant species were investigated. Species were selected based on the traditional uses against CNS-related diseases. Extracts were prepared using a gentle cold extraction method. In vitro cholinesterase inhibitory effects were measured by Ellman's method in 96-well microplates. Blumea lacera (Compositae) and Cyclea barbata (Menispermaceae) were found to have the highest acetylcholinesterase inhibitory (IC_50, 150 ± 11 and 176 ± 14 µg/mL, respectively) and butyrylcholinesterase inhibitory effect (IC₅₀, 297 ± 13 and 124 ± 2 µg/mL, respectively). Cyclea barbata demonstrated competitive inhibition, where Blumea lacera showed an uncompetitive inhibition mode for acetylcholinesterase. Smilax guianensis (Smilacaceae) and Byttneria pilosa (Malvaceae) were also found to show moderate AChE inhibition (IC_50, 205 ± 31 and 221 ± 2 µg/mL, respectively), although no significant BChE inhibitory effect was observed for extracts from these plant species. Among others, Thunbergia grandiflora (Acanthaceae) and Mikania micrantha (Compositae) were found to display noticeable AChE (IC₅₀, 252 ± 22 µg/mL) and BChE (IC₅₀, 314 ± 15 µg/mL) inhibitory effects, respectively. Molecular docking experiment suggested that compounds 5-hydroxy-3,6,7,3′,4′-pentamethoxyflavone (BL4) and kaempferol-3-O-α-L-rhamnopyranosyl-(1⟶6)-β-D-glucopyranoside (BL5) from Blumea lacera bound stably to the binding groove of the AChE and BChE by hydrogen-bond interactions, respectively. Therefore, these compounds could be candidates for cholinesterase inhibitors. The present findings demonstrated that Blumea lacera and Cyclea barbata are interesting objects for further studies aiming at future therapeutics for Alzheimer's disease.