Melodinus Suaveolens Research Articles

Suadimins D—J, Monoterpenoid Indole‐Quinoline and Bisindole Alkaloids from Melodinus suaveolens

Comprehensive SummaryCompounds 1—12, including seven complex monoterpenoid indole‐quinoline and bisindole alkaloids, suadimins D—J (1—7) with previously unreported carbon‐carbon linkages, were isolated and identified from the twigs and leaves of Melodinus suaveolens. Their structures were elucidated by a combination of diverse methods, especially the extensive spectroscopic data analysis and electric circular dichroism (ECD) calculations. The cytotoxicity of these compounds against three cancer cell lines was evaluated, some of which showed moderate activities with IC50 values ranging from 2.4 to 8.0 μM.

Cytotoxic aspidosperma-type alkaloids from Melodinus suaveolens

Four new aspidosperma-type alkaloids, melosuavines J-M (1–4) were isolated from the leaves of Melodinus suaveolens. Their structures with absolute configurations were elucidated by extensive HRESIMS and NMR spectroscopic analysis, as well as ECD calculations and Mosher's method. Their cytotoxic activities against four human cancer cell lines were also evaluated.

Suadimins A-C, Unprecedented Dimeric Quinoline Alkaloids with Antimycobacterial Activity from Melodinus suaveolens.

The suadimins A-C (1-3) from Melodinus suaveolens are the first example of monoterpenoid quinoline alkaloid dimers featuring an unprecedented carbon skeleton. Their structures and absolute configurations were established on the basis of extensive spectroscopic analyses, electric circular dichroism (ECD), and X-ray crystallography. Suadimin A showed significant antimycobacterial activity in vitro with an MIC90 of 6.76 μM against the H37Rv strain of M. tuberculosis.

New monoterpenoid indole alkaloids from Melodinus suaveolens

Three new monoterpenoid indole alkaloids (1–3), along with five known alkaloids (4–8), were isolated from the leaves of Melodinus suaveolens. Their structures were determined by extensive spectroscopic method and quantum chemical ECD calculation. All the new compounds were evaluated for their inhibitory effects on LPS-induced nitric oxide (NO) production in RAW 264.7 macrophages.

Melosuavine I, an apoptosis-inducing bisindole alkaloid from Melodinus suaveolens

A new bisindole alkaloid, melosuavine I (1) possessing an aspidosperma-aspidosperma dimeric skeleton, was isolated from the leaves of Melodinus suaveolens. The structure with absolute configuration of 1 was elucidated by a combination of MS, NMR and computational methods. MTT assays indicated that 1 exhibited significant cytotoxicity on human breast cancer BT549 cells with an IC50 value of 0.89 μM. Further study showed that 1 inhibited BT549 cell proliferation by inducing apoptosis through activation of caspase 3 and p53, and down-regulation of Bcl-2.

Anti-inflammatory lignans from Melodinus suaveolens

Three new lignans, melodinins A–C (1–3), together with four known analogues (4–7), were isolated from the stems of Melodinus suaveolens. Their structures including relative configurations were determined by spectroscopic methods, including 1D and 2D NMR, and HRESIMS. Their absolute configurations were unambiguously assigned by electronic circular dichroism (ECD) experiments, especially the application of ECD exciton chirality method. Anti-inflammatory evaluation revealed that compounds 1, 2, 4, and 5 exhibited moderate inhibitory effects on β-glucuronidase release in rat polymorphonuclear leukocytes (PMNs) induced by platelet-activating factor, with IC50 values ranging from 1.68 to 9.56 μM.

Antifungal activities and active ingredients of Melodinus suaveolens Champ. ex Benth.

Four Melodinus species with antifungal activity were found in survey of the floral resources, in Shiwan Mountain Natural Reserve, Guangxi Province, China. Crude methanolic extracts of the twigs and leaves of Melodinus suaveolens exhibited potent antifungal activities against the plant pathogenic fungi Colletotrichum musae, Colletotrichum graminicola, Colletotrichum gloeosporioides and Alternaria musae, and the ethyl acetate fraction inhibited these pathogens at rates of 85.37, 91.47, 72.77 and 89.87%, respectively (5 mg/mL). A new compound, (2R, 3S, 5S, 6R)-1-O-methyl- chiro-inositol was isolated from the ethyl acetate fraction, along with 15 known compounds. The antifungal activities of compounds (1–16) were evaluated for the first time. Compound (4) had potent antifungal activity against C. gloeosporioides, C. graminicola and A. musae.

Cytotoxic Indole Alkaloid 3α-Acetonyltabersonine Induces Glioblastoma Apoptosis via Inhibition of DNA Damage Repair.

Cytotoxic indole alkaloids from Melodinus suaveolens, which belongs to the toxic plant family Apocynaceae, demonstrated impressive antitumor activities in many tumor types, but less application in glioblastoma, which is the lethal brain tumor. In the present study, we reported the anti-glioblastoma activity of an indole alkaloid, 3α-acetonyltabersonine, which was isolated from Melodinus suaveolens. 3α-acetonyltabersonine was cytotoxic to glioblastoma cell lines (U87 and T98G) and stem cells at low concentrations. We verified 3α-acetonyltabersonine could suppress tumor cell proliferation and cause apoptosis in glioblastoma stem cells (GSCs). Moreover, detailed investigation of transcriptome study and Western blotting analysis indicated the mitogen activated protein kinase (MAPK) pathway was activated by phosphorylation upon 3α-acetonyltabersonine treatment. Additionally, we found 3α-acetonyltabersonine inhibited DNA damage repair procedures, the accumulated DNA damage stimulated activation of MAPK pathway and, finally, induced apoptosis. Further evidence was consistently obtained from vivo experiments on glioblastoma mouse model: treatment of 3α-acetonyltabersonine could exert pro-apoptotic function and prolong the life span of tumor-bearing mice. These results in vitro and in vivo suggested that 3α-acetonyltabersonine could be a potential candidate antitumor agent.

Two new compounds from Melodinus suaveolens

Two new compounds, 19-hydroxy-melodinine K (1) and melodiside (2), and 25 known compounds were isolated from leaves and twigs of Melodinus suaveolens. Their structures were elucidated based on 1- and 2-D NMR, FTIR, UV and MS spectroscopic data. 19-hydroxy-melodinine K showed cytotoxic activity against MDA-MB-231 breast, BCG-823 gastric, SW480 colon and Hela cancer cells.

Aspidosperma-type Alkaloids from Melodinus Suaveolens

Three new aspidosperma-type alkaloids, 3-oxo-11-hydroxytabersonine (2), 1 1-hydroxytabersonine N-oxide (3) and 11-methoxytabersonine N-oxide (4), along with three known ones were isolated from the twigs and leaves of Melodinus suaveolens. The structures of the new compounds were elucidated by using spectroscopic methods, and circular dichroism experiments. The known compounds were identified by comparing their spectroscopic data with those reported in the literature.

Antibacterial constituents from MeloMelodinus suaveolens

To investigate the non-alkaloidal chemical constituents of the stems and leaves of Melodinus suaveolens and their antibacterial activities. Compounds were isolated and purified by repeated silica gel, Sephadex LH-20, RP18, and preparative HPLC. Their structures were elucidated by comparison with published spectroscopic data, as well as on the basis of extensive spectroscopic analysis. The antibacterial screening assays were performed by the dilution method. Fourteen compounds were isolated, and identified as lycopersene (1), betulinic aldehyde (2), 3β-acetoxy-22,23,24,25,26,27-hexanordammaran-20-one (3), 3a-acetyl-2, 3, 5-trimethyl-7a-hydroxy-5-(4,8,12-trimethyl-tridecanyl)-1,3a,5,6,7,7a-hexahydro-4-oxainden-1-one (4), 3β-hydroxy-28-norlup-20(29)-ene-17β-hydroperoxide (5), 3β-hydroxy-28-norlup-20(29)-ene-17α-hydroperoxide (6), β-sitosterol (7), 28-nor-urs-12-ene-3β, 17β-diol (8), α-amyrin (9), ergosta-4,6,8(14),22-tetraen-3-one (10), 3β-hydroxy-urs-11-en-28,13β-olide (11), betulin (12), obtusalin (13), and ursolic acid (14). Among the isolates, compounds 1, 2, 6, 8, 10, and 14 showed potent antibacterial activities against the four bacteria. This is the first report of the antibacterial activity of the constituents of Melodinus suaveolens.

Two New Alkaloids from Melodinus suaveolens

Two new Melodinus-type alkaloids, 15β-hydroxy-14,15-dihydroscandine (1) and 14,15-dihydroscandine (2), together with 6 known ones were isolated from Melodinus suaveolens. The structures of the new compounds were identified from spectroscopic (NMR, UV, IR, CD) and mass spectrometric data and Mosher's method. The new compounds exhibited significant, dose-dependent inhibition of the production of lipopolysaccharide (LPS)-induced NO, IL-6 and IL-8 in mice macrophages.

ChemInform Abstract: Alkaloids from Melodinus suaveolens.

Abstract2 New quinoline alkaloids (I) and (II) are isolated from the twigs and leaves of Melodinus suaveolens along with 6 known alkaloids.

Melosuavines A–H, Cytotoxic Bisindole Alkaloid Derivatives from Melodinus suaveolens

Eight new bisindole alkaloids, melosuavines A-C (1-3), having an aspidosperma-scandine linkage, melosuavines D-F (4-6), possessing an aspidosperma-aspidosperma skeleton, and melosuavines G and H (7 and 8) of the aspidosperma-venalatonine type, tenuicausine (9), and melodinine J (10) were isolated from the twigs and leaves of Melodinus suaveolens. The structures of 1-8 were elucidated by extensive spectroscopic methods, and compounds 9 and 10 were identified by comparison with data in the literature. The relative configuration 9 was determined from the ROESY spectrum, and some NMR signals were reassigned. Compounds 1, 2, 4-6, 8, and 10 exhibited low micromolar cytotoxicity against one or more of five human cancer cell lines.

Melodinines M–U, Cytotoxic Alkaloids from Melodinus suaveolens

Nine new alkaloids, melodinines M-U (1-9), and 11 known alkaloids were isolated from Melodinus suaveolens. The new structures were elucidated by extensive NMR and mass spectroscopic analyses and comparison to known compounds. All compounds were evaluated for their cytotoxicity against five human cancer cell lines. Compounds 6, 11, and 16 showed significant cytotoxicity.

Alkaloids from Melodinus suaveolens

Fourteen alkaloids were isolated from the trunk of Melodinus suaveolens. Thirteen of them were identified as Δ 14-vincine, vindolinine, 11-methoxytabersonine, vincadifformine, hazuntine, 11-hydroxytabersonine, 11-methoxyvineadifformine, cathovalinine, vincoline, 19 R-hydroxytabersonine, 11-methoxy-19 R-hydroxytabersonine, 11,19 R-dihydroxytabersonine and tabersonine. The last one is a new alkaloid, named suaveolenine; its structural elucidation was achieved by means of detailed spectral analysis.

Alkaloids of melodinus suaveolens and their excretion as a common end-product in the rat

Alkaloids extracted from Melodinus suaveolens in a preliminary, exploratory study appear to be α-methylene indolines. When the alkaloidal extract is injected into the rat, there is excreted in the urine a common end-product which appears to be an alkaloid different from any of the alkaloids of the injected extract.