[Isoquinoline alkaloids from two species of Thalictrum genus plants].

The chemical constituents from the roots of Thalictrum cultratum and T. baicalense were investigated. By various isolation methods, such as silica gel, aluminium oxide, ODS, and Sephadex LH-20 column chromatographies, and semi-preparative HPLC, 11 simple isoquinoline alkaloids were isolated from the ethanol extract of the roots of these two plants, including a new compound, named dehydrothalflavine(1), and ten known ones(2-11): N-methylcorydaline(2), N-methylthalidaldine(3), thaliflavine(4), oxyhydrastinine(5), noroxyhydrastinine(6), dimethoxyisoquinolone(7), thalactamine(8), dehydronoroxyhydrastinine(9), 6,7-dimethoxy-2-methyl-1,2,3,4-tetrahydroisoquinoline(10), and isopicnarrhine(11). Their structures were elucidated on the basis of HR-ESI-MS and 1 D and 2 D NMR techniques. Compound 1 was a new isoquinoline alkaloid. Compound 11 was obtained from Tha-lictrum plant for the first time. All compounds did not show cytotoxic activities against HL-60, U937, HCT116, Caco-2, and HepG2 cancer cell lines.

Anti-tumor alkaloids from Peganum harmala.

Six alkaloids peharmalines F-K, along with 14 known ones, were isolated from the aerial part of Peganum harmala L.. The structures of the isolated compounds were determined based on their HR-ESI-MS data, extensive NMR spectroscopic analyses, and ECD calculations. 3-(4-Hydroxyphenyl)quinoline exhibited potent antiproliferative activity against the HepG-2 cell lines with an IC50 value of 3.05 µM. Norharmane displayed a moderate inhibition against A549 and HepG-2 cells with IC50 values of 16.45 µM and 17.27 µM, respectively.

New tirucallane-type triterpenoids from the resin of Boswellia carteriiand their NO inhibitory activities.

Six new tirucallane-type triterpenoids (1-6), along with ten known triterpenoids, were isolated from methylene chloride extract of the resin of Boswellia carterii Birdw. By the application of the comprehensive spectroscopic data, the structures of the compounds were clarified. The experimental electronic circular dichroism spectra were compared with those calculated, which allowed to assign the absolute configurations. Compounds 5 and 6 possesed a 2, 3-seco tirucallane-type triterpenoid skeleton, which were first reported. Their inhibitory activity against NO formation in LPS-activated BV-2 cells were evaluated. Compound 9 showed appreciable inhibitory effect, with an IC50 value of 7.58 ± 0.87 µmol·L-1.

New lignanamides and alkaloids from Chelidonium majus and their anti-inflammation activity.

Two new lignanamides, majusamides A and B (1 and 2), and two new alkaloids, chelidoniumine (3) and tetrahydrocoptisine N-oxide (4), together with six known hydroxycinnamic acid amides (HCCA) were isolated from the 75% ethanol extract of Chelidonium majus through the silica gel, Sephadex LH-20, MCI, ODS column chromatography, and semi-HPLC. Their structures were determined on the basis of spectroscopic data and physico-chemical methods. The absolute configurations of 1-3 were determined by electronic circular dichroism (ECD) calculations. The anti-inflammatory activities of all the isolates on the NO production in lipopolysaccharide (LPS)-induced macrophages were evaluated. Compounds 7 and 9 exhibited moderate inhibitory activity with IC50 values of 25.3 ±â€¯0.5 and 23.5 ±â€¯1.7 µM, respectively.

Chiral resolution and anticancer effect of xanthones from Garcinia paucinervis.

Bioassay-guided fractionation of the dichloromethane-soluble portion of the stems of Garcinia paucinervis led to the isolation of eight new xanthones, including three pairs of enantiomers, (+) and (-) paucinervins L-N (1a-3a, and 1b-3b), one optically pure compound, (-) paucinervin O (4), and one new analogue, paucinervin P (5), as well as thirteen known xanthones (6-18). Their structures were established by detailed analysis of extensive spectroscopic data. The absolute configurations of 1-4 were confirmed by ECD calculations. All the isolates 1-18 displayed antiproliferative effect against HL-60 with IC50 values ranging from 0.87 to 29.14 µM, of which compound 5 was the most active. Compounds 6, and 14 exhibited potential inhibitory activity against PC-3 cells, while compounds 5-7, 14, and 16-17 displayed cytotoxic potency against Caco-2 cells. A preliminary structure-activity relationship was also discussed.

Racemic indole alkaloids from the seeds of Peganum harmala.

Five pairs of new 2-oxoindole alkaloids, (±)-peganumalines A-E (1-5), and a new indole alkaloid, peganumaline F (6), along with two known analogues, were isolated from the seeds of Peganum harmala. Their structures and absolute configurations were elucidated through spectroscopic analyses and quantum chemistry calculations. Notably, (±)-peganumalines A (1) represent a pair of rare 2-oxoindole dimeric alkaloid enantiomer with the hitherto unknown carbon skeleton. All isolates were tested for antiproliferative and antibacterial activities.

Four new compounds from the roots of Euphorbia ebracteolata and their inhibitory effect on LPS-induced NO production.

Three new diterpenoids, ebractenoids O~Q (1-3), and a new phenolic glucoside, γ-pyrone-3-O-ß-d-(6-galloyl)-glucopyranoside (4), together with 6 known compounds, were isolated from the 95% ethanol extract of the roots of Euphorbia ebracteolata, and their structures were elucidated on the basis of spectroscopic data. The absolute configurations of 1-3 were determined by electronic circular dichroism (ECD) calculations. The inhibitory effects of all the isolates with exception of compounds 8 and 10 on the NO production in lipopolysaccharide (LPS)-induced macrophages were evaluated. All of them exhibited significant inhibitory activity.

Antiproliferative Dimeric Aporphinoid Alkaloids from the Roots of Thalictrum cultratum.

Inspired by the intriguing structures and bioactivities of dimeric alkaloids, 11 new thalifaberine-type aporphine-benzylisoquinoline alkaloids, thalicultratines A-K, a tetrahydroprotoberberine-aporphine alkaloid, thalicultratine L, and five known ones were isolated from the roots of Thalictrum cultratum. Their structures were defined on the basis of NMR and HRESIMS data. The antiproliferative activities of compounds 1-17 were evaluated against human leukemia HL-60 and prostate cancer PC-3 cells. Most alkaloids showed potent cytotoxicity against selected cancer cells. Preliminary SARs are discussed. The most active new compound (3), with an IC50 value of 1.06 µM against HL-60 cells, was selected for mechanism of action studies. The results revealed that compound 3 induced apoptosis and arrested the HL-60 cell cycle at the S phase with the loss of mitochondria membrane potential. The nuclear morphological Hoechst 33258 staining assay was also carried out, and the results confirmed apoptosis.

Bioactive terpenoids from Silybum marianum and their suppression on NO release in LPS-induced BV-2 cells and interaction with iNOS.

Three new (1-3) and one known (4) bioactive terpenoids were isolated from the seeds of Silybum marianum based on the investigation to get new NO inhibitors. Their structures were determined by extensive NMR (1D and 2D NMR) and MS spectroscopic data, and the absolute configurations were identified by experimental and calculated ECD spectra. The NO inhibitory activities in murine microglial BV-2 cells and interactions with iNOS protein by molecular docking were evaluated for all compounds. The results showed that these compounds had potent NO inhibitory effects.

New amides from seeds of Silybum marianum with potential antioxidant and antidiabetic activities.

Two new amide compounds, mariamides A and B (1-2), were obtained together with fourteen known compounds from the seeds of milk thistle (Silybum marianum). Their structures were established on the basis of extensive 1D and 2D NMR analyses, as well as HR-ESI-MS data. Most of the compounds showed significant antioxidant activities than positive control in ABTS and FRAP assays. However, only amide compounds 1-4 showed moderate DPPH radical scavenging activity and compounds 7 and 16 showed the most potent activity against DPPH. Most of the compounds showed moderate to stronger α-glucosidase inhibitory activities. Nevertheless, only flavonoids showed strong PTP1B inhibitory activities. These results indicate a use of milk thistle seed extracts as promising antioxidant and antidiabetic agents.

Structurally Diverse Alkaloids from the Seeds of Peganum harmala.

Investigation of the alkaloids from Peganum harmala seeds yielded two pairs of unique racemic pyrroloindole alkaloids, (±)-peganines A-B (1-2); two rare thiazole derivatives, peganumals A-B (3-4); six new ß-carboline alkaloids, pegaharmines F-K (5-10); and 12 known analogues. Their structures, including stereochemistry, were elucidated through spectroscopic analyses, quantum chemistry calculations, and single-crystal X-ray diffraction. Notably, the incorporation of pyrrole and indole moieties in peganines A-B, thiazole fragments in peganumals A-B, and a C-1 α,ß-unsaturated ester motif in pegaharmine F (5) are all rare, and their presence in the genus Peganum were demonstrated for the first time. All isolates were tested for antiproliferative activities against the HL-60, PC-3, and SGC-7901 cancer cell lines, and compounds 9, 11, 12, and 13 exhibited moderate cytotoxicity against HL-60 cancer cell lines with IC50 values in the range of 4.36-9.25 µM.

New chalcone and pterocarpoid derivatives from the roots of Flemingia philippinensis with antiproliferative activity and apoptosis-inducing property.

Investigation of the roots of Flemingia philippinensis resulted in the isolation of two new chalcones, flemiphilippinones B (1) and C (2), and one new pterocarpoid, demethylwedelolactone-11-methyl ether (3), together with 12 known compounds (4-15). The antiproliferative activity against PC-3 cells was evaluated and most compounds showed cytotoxicity, among which, compound 2 exhibited GI50 value of 14.12µM. The antiproliferative activity of 2 against Bel-7402 and CaEs-17 cells was also measured, with GI50 values of 1.91 and 2.58µM, respectively. Intensive mechanism study showed that 2 caused cell-cycle arrest at S/G2 phase and induced apoptosis in Bel-7402 cells through mitochondria-related pathway.

A Series of ß-Carboline Alkaloids from the Seeds of Peganum harmala Show G-Quadruplex Interactions.

In this study, we screened 17 medicinal plants for binding activity to G-quadruplex d(TTGGGTT)4 by (1)H NMR spectroscopy and found that the crude extract of Peganum harmala L. seeds showed the most potential binding activity. Subsequently, (1)H NMR- and bioassay-guided isolation of the extract of P. harmala L. was performed to obtain four pairs of partially racemized ß-carboline alkaloids, pegaharmines A-D (1-4). Their structures and absolute configurations were determined by extensive NMR analyses, X-ray crystallography, ECD calculations, and CD exciton chirality approaches. Interestingly, pegaharmine D (4), which showed the strongest G-quadruplex interaction, exhibited significant cytotoxic activity against three cancer cell lines. This work contributed a practical strategy for the discovery of novel G-quadruplex ligands from natural products and provided potential insights for using ß-carboline alkaloids as anticancer lead compounds specifically targeting G-quadruplexes.

Lignans and triterpenoids from Vitex negundo var. heterophylla and their biological evaluation.

Three new phenylnaphthalene-type lignans, vitexnegheteroins E-G (1-3), and a new polyoxygenated ursane-type triterpene, vitexnegheteroin H (9), were isolated from the seeds of Vitex negundo var. heterophylla, together with ten known compounds. Their structures were established on the basis of extensive 1D and 2D NMR experiments, as well as their mass spectroscopic data. The absolute configurations of compounds 1 and 2 were determined by comparing their experimental ECD spectra with that calculated by the time-dependent density functional theory (TDDFT) method. The isolates were evaluated for their cytotoxicities against three human cancer cell lines, inhibitory activities on lipopolysaccharide-induced NO production in murine microglial BV-2 cells, and antioxidant activities for ABTS radical scavenging.

Two new benzylisoquinoline alkaloids from Thalictrum foliolosum and their antioxidant and in vitro antiproliferative properties.

Two novel rare chloro-containing benzylisoquinoline alkaloids, thalfoliolosumines A (1) and B (2), along with eight known isoquinoline alkaloids (3-10) were isolated from the whole plant of Thalictrum foliolosum. The structures of these compounds were elucidated by spectral analyses, including 1D and 2D NMR (COSY, HSQC, HMBC and NOESY) experiments. The antiproliferative effects of all the isolated compounds were evaluated by MTT method against MCF-7, PC-3, and U937 cells, and trypan blue method against HL-60 cells. New compounds 1 and 2 exhibited moderate in vitro antiproliferative activity against MCF-7, PC-3, and HL-60 cells, and good inhibitory effects against U937 cells with IC50 values of 7.50 and 6.97 µM, respectively. Compounds 7 and 10 showed the strongest in vitro antiproliferative with IC50 values of 0.93 and 1.69 µM against HL-60 cell line. The antioxidant properties were also measured, bisbenzyltetrahydroisoquinoline alkaloids 3-6 showed the strongest antioxidant activities in ABTS assay.

Xanthones from Garcinia paucinervis with in vitro anti-proliferative activity against HL-60 cells.

Three new xanthones, paucinervins H-J (1-3), as well as eleven known compounds (4-14), were isolated from the leaves of Garcinia paucinervis. The structures of the new compounds (1-3) were elucidated by 1D, 2D NMR spectra and HR ESIMS. In vitro antiproliferative activity against human promyelocytic leukemia HL-60 cells was tested, among which, compounds 2, 5, 6 and 7 exhibited strong growth inhibitory effects with GI50 values ranging from 1.30 to 9.08 µM, respectively. Preliminary SARs were also discussed.

Quinolone and indole alkaloids from the fruits of Euodia rutaecarpa and their cytotoxicity against two human cancer cell lines.

Four quinolone alkaloids (1-4) and three indole alkaloids (20-22), together with 30 known alkaloids (5-19, 23-37), were isolated from the fruits of Euodia rutaecarpa. Their structures were established by spectroscopic analyses. The in vitro cytotoxic activities of these alkaloids against leukaemia HL-60 and prostate cancer PC-3 cell lines were evaluated.

Antimicrobial constituents from the flowers of Trollius chinensis.

A new 1-aryl-isochroman, trolliusol A (1), was isolated from the flowers of Trollius chinensis, along with seven known phenolic compounds in an antimicrobial activity-directed phytochemical investigation. The structures of these compounds were elucidated by spectroscopic methods, and their inhibitory activities against one fungus and four bacterial strains were measured.

Anti-inflammatory diterpenoids from the roots of Euphorbia ebracteolata.

Thirteen diterpenoids (1-13), including two new norditerpene lactones (1-2) and eight new rosane diterpenoids (3-10), were isolated from the roots of Euphorbia ebracteolata. The structures were determined by 1D and 2D NMR, HRESIMS, and electronic circular dichroism (ECD). The ECD-based empirical rule for α,ß-unsaturated-γ-lactones was applied to determine the absolute configurations of 1 and 2. Compounds 7, 10, and 13 exhibited significant inhibition of nitric oxide production in RAW 264.7 lipopolysaccharide-induced macrophages, with IC50 values of 2.44, 2.76, and 1.02 µM, respectively.

Novel decaturin alkaloids from the marine-derived fungus Penicillium oxalicum.

From the mycelia of Penicillium oxalicum two new compounds, decaturins E (1) and F (2), have been isolated, along with four known analogues, decaturin A (3), decaturin C (4), decaturin D (5), and oxalicine B (6). The structures were determined by HR-ESI-MS and 1D and 2D NMR analysis.