Three new coumarins and a new coumarin glycoside from Micromelum integerrimum.

Three new coumarins, integmarins A-C (1-3), and a new coumarin glycoside, integmaside A (4) were isolated from the leaves and stems of Micromelum integerrimum. Their structures were elucidated on the basis of 1D and 2D NMR and MS data, and their absolute configurations were assigned according to the ECD data of the in situ formed transition metal complexes and comparison of experimental and calculated ECD data. Compounds 1 and 2 are two rare coumarins with butyl and propyl moieties at the C-6 position; compound 3 is a novel coumarin with a highly oxidized prenyl group, and compound 4 is a rare bisdihydrofuranocoumarin glycoside.

A new prenylated coumarin diglycoside with insulin-release promoting activity from Clausena dunniana.

A new prenylated coumarin diglycoside, 6-prenylcoumarin-7-O-ß-D-apiofuranosyl-(1→6)-ß-D-glucopyranoside (1) and five known flavonoid glycosides (2-6) were isolated from the leaves and stems of Clausena dunniana. The structures of these isolates were elucidated based on comprehensive MS, UV, IR, and NMR spectroscopic data analysis and comparison with the data reported in literature. Compounds 2-6 are obtained from the title plant for the first time. All these isolates were evaluated for their insulin-release promoting effects, and compounds 1, 2, and 4 exhibited significant activities (2.0 to 3.3-fold higher in comparison with the control, p < 0.01) at 40 µM.[Formula: see text].

Isolation and structure characterization of cytotoxic alkaloids from Micromelum integerrimum.

Ten undescribed alkaloids, named integerrines A-J, including one racemic heterodimer of carbazole and indole, two racemic, two scalemic, and one enantiomerically enriched biscarbazoles, two aldoximes, and one racemic pyrrolone, were isolated from the dried leaves and stems of Micromelum integerrimum. The racemic or scalemic compounds were resolved using chiral-phase HPLC and their configurations were determined by comparison of experimental and calculated ECD data. Four compounds exhibited moderate to weak cytotoxicities against HepG2, HTC-116, HeLa, and PANC-1 cell lines, with IC50 values of 14.1-67.5 µM.

Coumarin and spirocyclopentenone derivatives from the leaves and stems of Murraya paniculata (L.) Jack.

Seven previously undescribed compounds, including five coumarins, (+/-)-murpanitin A and murpanitins B-D, and a pair of spirocyclopentenone enantiomers, (+/-)-murrayaspiroketone, along with 14 known coumarin derivatives were isolated from the leaves and stems of Murraya paniculata (L.) Jack. Their structures were elucidated on the basis of comprehensive analysis of 1D and 2D NMR and HRMS spectroscopic data, and the absolute configurations were assigned via calculated and experimental ECD data. Three compounds showed moderate inhibitory effects on nitric oxide production stimulated by lipopolysaccharide in BV-2 microglial cells with IC50 values of 53.2 ± 8.9, 57.7 ± 5.8, and 53.2 ± 4.4 µM, respectively.

Anti-inflammatory and cytotoxic carbazole alkaloids from Murraya kwangsiensis.

Chemical investigation of the traditional Chinese medicine, Murraya kwangsiensis, led to the isolation of 16 undescribed biscarbazole alkaloids, kwangsines A-M, two undescribed natural products, (+/-)-bispyrayafoline C, and 19 known monomeric analogues. (±)-Bispyrayafoline C and (±)-kwangsines A-C are four pairs of biscarbazole atropisomers, and they were separated by chiral HPLC to obtain the optically pure compounds. The structures of the undescribed compounds were elucidated on the basis of HRESIMS and NMR data analysis. Their absolute configurations were assigned via comparison of the specific rotation, ECD exciton coupling method, as well as comparison of experimental and calculated ECD data. A compound showed significant inhibition on NO production in lipopolysaccharide-stimulated BV-2 microglial cells, and four compounds exhibited moderate cytotoxicities against HepG2 cells, with IC50 values less than 20 µM.

Alkaloids from the stems and rhizomes of Sinomenium acutum from the Qinling Mountains, China.

Thirteen undescribed alkaloids (sinotumines A-M), including five oxoisoaporphine, a benzo[h]quinoline, an aporphine, two protoberberine, two hasubanane, and two proaporphine alkaloids, and 50 known analogues were isolated from the 95% aqueous EtOH extract of the stems and rhizomes of Sinomenium acutum. The structures and absolute configurations of the isolates were elucidated on the basis of comprehensive analysis of 1D and 2D NMR, HRMS, single-crystal X-ray diffraction, and comparison of the experimental and calculated electronic circular dichroism (ECD) data. Sinotumine F, a rare benzo[h]quinoline alkaloid, was speculated as an oxidation product of the oxoisoaporphine alkaloid, and its putative biosynthetic pathway is proposed. Sinotumines L and M are the first samples of proaporphine-based heterodimers coupled with 1-heptanone and coniferol alcohol moiety, respectively. The T-cell suppression and NO inhibition effects of the isolates were evaluated.

Cytotoxic carbazole alkaloid derivatives from the leaves and stems of Murraya microphylla.

Four new carbazole alkaloid derivatives, including a pair of enantiomers of the heterodimers of carbazole and phenylpropanoid (1a/1b) and two rare polyprenylated carbazole alkaloids (2, 3), together with 19 known analogues (4-22), were isolated from the leaves and stems of Murraya microphylla. Their structures were established by UV, IR, 1D/2D NMR, and HRESIMS data analysis, and their absolute configurations were determined by comparison of experimental and calculated ECD data and the ECD exciton coupling method. All the isolates were evaluated for their cytotoxicities against HepG2, Du145, HCT-116, and HeLa tumor cell lines. Compounds 7 and 11 exhibited obvious cytotoxic effects on four cancer cell lines in a dose-dependent manner.

Bioactive carbazole and quinoline alkaloids from Clausena dunniana.

Nine undescribed carbazole and quinoline alkaloids, named dunnines A-E, and 14 known analogues were isolated from the leaves and stems of Clausena dunniana. Their structures were elucidated on the basis of comprehensive analysis of NMR and HRMS spectroscopic data, and the absolute configurations were assigned via comparison of their specific rotations and calculated and experimental ECD data. (±)-Dunnines A-C and (±)-clausenawalline A are four pairs of biscarbazole atropisomers and (±)-dunnine D is a pair of dihydropyranocarbazole enantiomers. They were separated by chiral HPLC to obtain the optically pure compounds. Three compounds showed weak inhibitory effects on nitric oxide production stimulated by lipopolysaccharide in BV-2 microglial cells (IC50 > 50 µM); five compounds could significantly promote insulin secretion in HIT-T15 cell line (1.9-3.1-fold of the control, p < 0.01) at 40 µM, and nine compounds could inhibit the apoptosis of PC12 cell induced by 6-hydroxydopamine with IC50 values in the range of 10.9-47.2 µM.

[Chemical constituents from Murraya euchrestifolia].

The open silica gel, ODS, and Sephadex LH-20 column chromatography, along with the semi-preparative HPLC was used to isolate and purify the chemical constituents from Murraya euchrestifolia. The structures of the isolates were elucidated by their physiochemical properties, NMR, and MS spectroscopic data, as well as comparison with literature data. Eighteen compounds were isolated from the CH2Cl2 fraction of the 95% aqueous EtOH extract of M. euchrestifolia, and their structures were identified as sakuranetin (1), eriodictyol-7,4'-dimethyl ether (2), isosakuranetin (3), 5-hydroxy-7,4'-dimethoxyflavanone (4), eriodictyol-7-methyl ether (5), lichexanthon (6), 5,6,7-trimethoxycoumarin (7), 5-hydroxy-6,8-dimethoxycoumarin (8), 8-hydroxy-6-methoxy-3-n-pentylisocoumarin (9), ethyl caffeate (10), 4-hydroxy-3,5- dimethoxycinnamic acid ethyl ester (11), methyl 3-(5'-hydroxyprenyl)-coumarate (12), (E)-coniferol (13), ß-hydroxypropiovanillone (14), 3-hydroxy-7,8-didehydro-ß-ionone (15), 3ß-hydroxy-5α, 6α-epoxy-7-megastigmen-9-one (16), grasshopper ketone (17), and 4-hydroxy-3,5-dimethoxybenzaldehyde (18). Compounds 1-15 and 18 were first obtained from the plants of Murraya genus, and compounds 16 and 17 were isolated from M. euchrestifolia for the first time.