Acetylcholinesterase inhibition studies of alkaloid components from Crinum asiaticum var. sinicum: in vitro assessments by molecular docking and molecular dynamics simulations.

Alkaloids are among the most important and best-known secondary metabolites as sources of new drugs from medicinal plants and marine organisms. A phytochemical investigation of the whole plant of Crinum asiaticum var. sinicum resulted in the isolation of seven alkaloids (1-7), including one new dimeric compound, bis-(-)-8-demethylmaritidine (1). Their structures were elucidated using NMR and HR-ESI-MS. The absolute configuration of new compound 1 was established by circular dichroism spectroscopy. All isolated compounds were evaluated for their inhibitory effects on acetylcholinesterase (AChE) activity in vitro. Among them, compound 1 exhibited the most potent AChE inhibition. Moreover, molecular docking and molecular dynamics simulations were carried out for the most active compound to investigate their binding interactions and dynamics behavior of the AChE protein-ligand complex. Therefore, compound 1 may be a potential candidate for effectively treating Alzheimer's disease.

New naphthalene derivatives and isoquinoline alkaloids from Ancistrocladus cochinchinensis with their anti-proliferative activity on human cancer cells.

Five new compounds, named ancistronaphtosides A and B (1 and 2), anciscochine (3), anciscochine 6-O-ß-d-glucopyranoside (4), and 4'-methoxy-5-epi-ancistecrorine A1 (5), together with tortoside A (6) and 4-hydroxy-2-methoxyphenyl-6-O-syringoyl-ß-d-glucopyranoside (7) were isolated from the methanolic extract of Ancistrocladus cochinchinensis. Their chemical structures were established using HR-ESI-MS, NMR spectroscopic, and chiroptical methods. Compound 5 significantly exhibited anti-proliferation against HL-60, LU-1, and SK-MEL-2 cells with IC50 values of 5.0±1.2, 6.5±1.6, and 6.8±2.0µg/mL, respectively.

Cytotoxic and anti-inflammatory activities of secondary metabolites from Ophiorrhiza baviensis growing in Thua Thien Hue, Vietnam.

A new ursane-type triterpene, 3ß,23,24-trihydroxyurs-12-en-28-oic acid (1), together with eight known compounds (2-9) were isolated from the aerial parts of Ophiorrhiza baviensis. Among them, compounds 2-5 were found for the first time from the genus Ophiorrhiza, while compounds 6-9 were reported from O. baviensis for the first time. Their structures were elucidated by analysis of HR-ESI-MS and NMR (1H-NMR, 13C-NMR, HSQC, and HMBC) spectra, as well as comparison with those reported in the literature. Moreover, all isolated compounds were evaluated for their cytotoxic activities against MCF-7, Hela, KB, A549, and SK-LU-1 cancer cell lines and their effects on LPS-induced NO production in RAW264.7 cells. This is the first report of chemical constituents and biological activities of O. baviensis.

Transcriptome sequencing and identification of cytochrome P450 monooxygenases involved in the biosynthesis of maslinic acid and corosolic acid in Avicennia marina.

Grey mangrove (Avicennia marina) is a traditional medicine used for the treatment of various diseases, including rheumatism and ulcers; however, the compounds responsible for its curative effects remain largely unknown. Triterpenoids are a diverse group of plant-specialized metabolites derived from a common precursor, 2,3-oxidosqualene. Triterpenoids are potentially responsible for the beneficial effects of A. marina; however, the chemical profiles of triterpenoids in A. marina and their biosynthetic genes have not been identified. Cytochrome P450 monooxygenases (P450s) have key roles in the structural diversification of plant triterpenoids by catalyzing site-specific oxidation of triterpene scaffolds. Recent studies have revealed that the CYP716 family represents the most common clade of P450s involved in triterpenoid biosynthesis. In this study, we performed triterpenoid profiling and RNA sequencing of A. marina leaves. Mining of CYP716 family genes and enzymatic activity assays of encoded proteins revealed that CYP716A259 catalyzed oxidation at the C-28 position of the pentacyclic triterpene skeletons of ß-amyrin, α-amyrin, and lupeol to produce oleanolic acid, ursolic acid, and betulinic acid, respectively. The other functionally defined P450, CYP716C53, catalyzed the C-2α hydroxylation of oleanolic acid and ursolic acid to produce maslinic acid and corosolic acid, respectively. The possible involvement of CYP716A259 and CYP716C53 in the biosynthesis of these health-benefiting compounds in A. marina leaves, and the possible contribution of the resulting compounds to the reported bioactivities of A. marina leaf extract, are discussed.

Two novel iridoids from Morinda longifolia.

Six secondary metabolites, including two novel iridoids, longifolides A (1) and B (2), were isolated by various chromatographic methods from a methanol extract of branches and leaves of Morinda longifolia Craib. The structures of the compounds were determined on the basis of NMR spectroscopic (1H and 13C NMR, HSQC, HMBC, 1H-1H COSY, NOESY) and FTICR-MS data, as well as by comparison of them with literature values.