Cytotoxic and nitric oxide inhibitory activities of triterpenoids from Lycopodium clavatum L.

Using combined chromatographic separation techniques, three new triterpenoids named lycomclavatols A-C (1-3), a new natural product, methyl lycernuate-A (4), as well as seven known compounds (5-11), were isolated from the methanol extract of the whole plants of Lycopodium clavatum. Their chemical structures were established based on 1 D/2D NMR and HR-ESI-MS spectroscopic analyses. Among the isolates, compound 1 exhibited inhibitory activity on NO production in LPS-stimulated BV2 cells (IC50 = 36.0 µM). In addition, 1 was cytotoxic against both HepG2 and A549 cancer cell lines, with IC50 values of 40.7 and 87.0 µM, respectively. Compounds 10 and 11 showed cytotoxicity on only HepG2 and A549 cells, with IC50 values of 91.2 and 57.6 µM, respectively. Our results contribute to understanding more the secondary metabolites produced by L. clavatum and provide a scientific rationale for further investigations of anti-inflammatory and anticancer effects for this valuable medicinal plant.

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.

Labdane-type diterpenoids from Vitex limonifolia and their antivirus activities.

Phytochemical investigation of the methanol extract of Vitex limonifolia leaves led to the isolation of three new labdane-type diterpenoids, vitexlimolides A-C (1-3) and eight known compounds, 5,4'-dihydroxy-3,7-dimethoxyflavone (4), vitecetin (5), 5,4'-dihydroxy-7,3'-dimethoxyflavone (6), verrucosin (7), 2α, 3α-dihydroxy-urs-12-en-28-oic acid (8), euscaphlic acid (9), 18,19-seco, 2α, 3α-dihydroxy-19-oxo-urs-11,13(18)-dien-28-oic acid (10), and maslinic acid (11). Their chemical structures were elucidated by physical and chemical methods. All compounds were evaluated for antiviral activities against CVB3, HRV1B, and EV71 viruses. As a result, compounds 4 and 6 showed potent antiviral activity against CVB3 infection with IC50 values of 0.12 ± 0.06 and 1.86 ± 0.18 (µM), respectively.

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.

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.