MyMedR

Feng X, Jiang G, Xia Z, Hu J, Wan X, Gao JM, et al.

Org. Lett., 2015 Sep 18;17(18):4428-31.

PMID: 26315849 DOI: 10.1021/acs.orglett.5b02046

The first enantioselective synthesis of (-)-conolutinine was achieved in 10 steps. The synthesis featured a catalytic asymmetric bromocyclization of tryptamine to forge the tricycle intermediate. Hydration of an alkene catalyzed by Co(acac)2 was also employed as a key step to diastereoselectively introduce the tertiary alcohol moiety. The absolute configuration of (-)-conolutinine was established to be (2S,5aS,8aS,13aR) based on this asymmetric total synthesis.

Matched MeSH terms: Indole Alkaloids/chemistry

Chemistry and pharmacology of analgesic indole alkaloids from the rubiaceous plant, Mitragyna speciosa

Takayama H

Chem Pharm Bull (Tokyo), 2004 Aug;52(8):916-28.

PMID: 15304982

The leaves of a tropical plant, Mitragyna speciosa KORTH (Rubiaceae), have been traditionally used as a substitute for opium. Phytochemical studies of the constituents of the plant growing in Thailand and Malaysia have led to the isolation of several 9-methoxy-Corynanthe-type monoterpenoid indole alkaloids, including new natural products. The structures of the new compounds were elucidated by spectroscopic and/or synthetic methods. The potent opioid agonistic activities of mitragynine, the major constituent of this plant, and its analogues were found in in vitro and in vivo experiments and the mechanisms underlying the analgesic activity were clarified. The essential structural features of mitragynines, which differ from those of morphine and are responsible for the analgesic activity, were elucidated by pharmacological evaluation of the natural and synthetic derivatives. Among the mitragynine derivatives, 7-hydroxymitragynine, a minor constituent of M. speciosa, was found to exhibit potent antinociceptive activity in mice.

Matched MeSH terms: Indole Alkaloids/chemistry*

Antiproliferative and Microtubule-stabilizing Activities of Two Iboga-vobasine Bisindoles Alkaloids from Tabernaemontana corymbosa in Colorectal Adenocarcinoma HT-29 Cells

Tan CH, Sim DSY, Lim SH, Mohd Mohidin TB, Mohan G, Low YY, et al.

Planta Med, 2022 Nov;88(14):1325-1340.

PMID: 35100653 DOI: 10.1055/a-1755-5605

Two iboga-vobasine bisindoles, 16'-decarbomethoxyvoacamine (1: ) and its 19,20-dihydro derivative, 16'-decarbomethoxydihydrovoacamine (2: ) from Tabernaemontana corymbosa exhibited potent cytotoxicity against the human colorectal adenocarcinoma HT-29 cells in our previous studies. Bisindoles 1: and 2: selectively inhibited the growth of HT-29 cells without significant cytotoxicity to normal human colon fibroblasts CCD-18Co. Treatment with bisindoles 1: and 2: suppressed the formation of HT-29 colonies via G0/G1 cell cycle arrest and induction of mitochondrial apoptosis. Owing to its higher antiproliferative activity, bisindole 2: was chosen for the subsequent studies. Bisindole 2: inhibited the formation of HT-29 spheroids (tumor-like cell aggregates) in 3D experiments in a dose-dependent manner, while an in vitro tubulin polymerization assay and molecular docking analysis showed that bisindole 2: is a microtubule-stabilizing agent which is predicted to bind at the β-tubulin subunit at the taxol-binding site. The binding resulted in the generation of ROS, which consequently activated the oxidative stress-related cell cycle arrest and apoptotic pathways, viz., JNK/p38, p21Cip1/Chk1, and p21Cip1/Rb/E2F, as shown by microarray profiling.

Matched MeSH terms: Indole Alkaloids/chemistry

Conodurine, conoduramine, and ervahanine derivatives from Tabernaemontana corymbosa

Kam TS, Sim KM

Phytochemistry, 2003 Jul;63(5):625-9.

PMID: 12809725

Four bisindole alkaloids, viz., 19'(S)-hydroxyconodurine, conodurinine, 19'(S)-hydroxyconoduramine, and 19'(S)-hydroxyervahanine A, in addition to conodurine and ervahanine A, were obtained from the leaf and stem-bark extracts of Tabernaemontana corymbosa. The structures of the new alkaloids were determined using NMR and MS analysis.

Matched MeSH terms: Indole Alkaloids/chemistry

Five new iboga alkaloids from Tabernaemontana corymbosa

Kam TS, Sim KM

J Nat Prod, 2002 May;65(5):669-72.

PMID: 12027738

Five new indole alkaloids of the ibogan type (1-5), in addition to 12 other known iboga alkaloids, were obtained from the leaf and stem-bark extract of the Malayan species Tabernaemontana corymbosa, viz., 19(S)-hydroxyibogamine (1), 19-epi-isovoacristine (2), isovoacryptine (3), 3R/S-ethoxyheyneanine (4), and 3R/S-ethoxy-19-epi-heyneanine (5). The structures were determined using NMR and MS analysis and comparison with known related compounds.

Matched MeSH terms: Indole Alkaloids/chemistry

Black sea cucumber (Holothuria atra Jaeger, 1833) rescues Pseudomonas aeruginosa-infected Caenorhabditis elegans via reduction of pathogen virulence factors and enhancement of host immunity

Lee WT, Tan BK, Eng SA, Yuen GC, Chan KL, Sim YK, et al.

Food Funct, 2019 Sep 01;10(9):5759-5767.

PMID: 31453615 DOI: 10.1039/c9fo01357a

A strategy to circumvent the problem of multidrug resistant pathogens is the discovery of anti-infectives targeting bacterial virulence or host immunity. Black sea cucumber (Holothuria atra) is a tropical sea cucumber species traditionally consumed as a remedy for many ailments. There is a paucity of knowledge on the anti-infective capacity of H. atra and the underlying mechanisms involved. The objective of this study is to utilize the Caenorhabditis elegans-P. aeruginosa infection model to elucidate the anti-infective properties of H. atra. A bioactive H. atra extract and subsequently its fraction were shown to have the capability of promoting the survival of C. elegans during a customarily lethal P. aeruginosa infection. The same entities also attenuate the production of elastase, protease, pyocyanin and biofilm in P. aeruginosa. The treatment of infected transgenic lys-7::GFP worms with this H. atra fraction restores the repressed expression of the defense enzyme lys-7, indicating an improved host immunity. QTOF-LCMS analysis revealed the presence of aspidospermatidine, an indole alkaloid, and inosine in this fraction. Collectively, our findings show that H. atra possesses anti-infective properties against P. aeruginosa infection, by inhibiting pathogen virulence and, eventually, reinstating host lys-7 expression.

Matched MeSH terms: Indole Alkaloids/chemistry

New bisindole alkaloids from Tabernaemontana corymbosa

Kam TS, Sim KM, Pang HS

J Nat Prod, 2003 Jan;66(1):11-6.

PMID: 12542336

Ten new bisindole alkaloids of the vobasinyl-ibogan type, viz., conodiparines A-F (1-6), conodutarines A and B (7, 8), and cononitarines A and B (9, 10), were obtained from the leaf extract of the Malayan species Tabernaemontana corymbosa. The structures were determined using NMR and MS analysis.

Matched MeSH terms: Indole Alkaloids/chemistry

Fulltext Sustainable Syntheses of (-)-Jerantinines A & E and Structural Characterisation of the Jerantinine-Tubulin Complex at the Colchicine Binding Site

Smedley CJ, Stanley PA, Qazzaz ME, Prota AE, Olieric N, Collins H, et al.

Sci Rep, 2018 Jul 13;8(1):10617.

PMID: 30006510 DOI: 10.1038/s41598-018-28880-2

The jerantinine family of Aspidosperma indole alkaloids from Tabernaemontana corymbosa are potent microtubule-targeting agents with broad spectrum anticancer activity. The natural supply of these precious metabolites has been significantly disrupted due to the inclusion of T. corymbosa on the endangered list of threatened species by the International Union for Conservation of Nature. This report describes the asymmetric syntheses of (-)-jerantinines A and E from sustainably sourced (-)-tabersonine, using a straight-forward and robust biomimetic approach. Biological investigations of synthetic (-)-jerantinine A, along with molecular modelling and X-ray crystallography studies of the tubulin-(-)-jerantinine B acetate complex, advocate an anticancer mode of action of the jerantinines operating via microtubule disruption resulting from binding at the colchicine site. This work lays the foundation for accessing useful quantities of enantiomerically pure jerantinine alkaloids for future development.

Matched MeSH terms: Indole Alkaloids/chemistry

Eucophylline, a Tetracyclic Vinylquinoline Alkaloid from Leuconotis eugenifolius

Deguchi J, Shoji T, Nugroho AE, Hirasawa Y, Hosoya T, Shirota O, et al.

J Nat Prod, 2010 Oct 22;73(10):1727-9.

PMID: 20836516 DOI: 10.1021/np100458b

Eucophylline (1), a new tetracyclic vinylquinoline alkaloid, was isolated from the bark of Leuconotis eugenifolius together with leucophyllidine (2). The structure and absolute configuration of 1 were elucidated on the basis of 2D NMR correlations and simulated CD analysis. Leucophyllidine (2) showed iNOS inhibitory activity and decreased the iNOS protein expression dose-dependently.

Matched MeSH terms: Indole Alkaloids/chemistry

Bisnicalaterine A, a vobasine-vobasine bisindole alkaloid from Hunteria zeylanica

Nugroho AE, Hirasawa Y, Kawahara N, Goda Y, Awang K, Hadi AH, et al.

J Nat Prod, 2009 Aug;72(8):1502-6.

PMID: 19388660 DOI: 10.1021/np900115q

A new bisindole alkaloid, bisnicalaterine A (1), consisting of two vobasine-type skeletons, and 3-epivobasinol (2) and 3-O-methylepivobasinol (3), with vobasine-type skeletons, were isolated from the leaves of Hunteria zeylanica, and their structures were elucidated on the basis of spectroscopic data and chemical correlation. Bisnicalaterine A showed moderate cytotoxicity against various human cancer cell lines.

Matched MeSH terms: Indole Alkaloids/chemistry

Bisleuconothine A Induces Autophagosome Formation by Interfering with AKT-mTOR Signaling Pathway

Wong CP, Seki A, Horiguchi K, Shoji T, Arai T, Nugroho AE, et al.

J Nat Prod, 2015 Jul 24;78(7):1656-62.

PMID: 26176165 DOI: 10.1021/acs.jnatprod.5b00258

We have previously reported that bisleuconothine A (Bis-A), a novel bisindole alkaloid isolated from Leuconotis griffithii, showed cytostatic activity in several cell lines. In this report, the mechanism of Bis-A-induced cytostatic activity was investigated in detail using A549 cells. Bis-A did not cause apoptosis, as indicated by analysis of annexin V and propidium iodide staining. Expression of all tested apoptosis-related proteins was also unaffected by Bis-A treatment. Bis-A was found to increase LC3 lipidation in MCF7 cells as well as A549 cells, suggesting that Bis-A cytostatic activity may be due to induction of autophagy. Subsequent investigation via Western blotting and immunofluorescence staining indicated that Bis-A induced formation but prevented degradation of autophagosomes. Mechanistic studies showed that Bis-A down-regulated phosphorylation of protein kinase B (AKT) and its downstream kinase, PRAS40, which is an mTOR repressor. Moreover, phosphorylation of p70S6K, an mTOR-dependent kinase, was also down-regulated. Down-regulation of these kinases suggests that the increase in LC3 lipidation may be due to mTOR deactivation. Thus, the cytostatic activity shown by Bis-A may be attributed to its induction of autophagosome formation. The Bis-A-induced autophagosome formation was suggested to be caused by its interference with the AKT-mTOR signaling pathway.

Matched MeSH terms: Indole Alkaloids/chemistry

Bisleuconothines B-D, Modified Eburnane-Aspidosperma Bisindole Alkaloids from Leuconotis griffithii

Nugroho AE, Zhang W, Hirasawa Y, Tang Y, Wong CP, Kaneda T, et al.

J Nat Prod, 2018 11 26;81(11):2600-2604.

PMID: 30362746 DOI: 10.1021/acs.jnatprod.8b00749

Three new bisindole alkaloids, bisleuconothines B-D (1-3), were isolated from the bark of Leuconotis griffithii. Their structures were elucidated by 1D and 2D NMR spectroscopy and DFT calculations. Bisleuconothine B (1) is the first monoterpene indole alkaloid dimer featuring bridges between both C-16-C-10' and C-2-O-C-9'. All compounds were deemed noncytotoxic (IC50 > 10 μM) when tested against A549 human lung adenocarcinoma cells.

Matched MeSH terms: Indole Alkaloids/chemistry

Leucophyllinines A and B, bisindole alkaloids from Leuconotis eugeniifolia

Tang Y, Nugroho AE, Hirasawa Y, Tougan T, Horii T, Hadi AHA, et al.

J Nat Med, 2019 Jun;73(3):533-540.

PMID: 30911994 DOI: 10.1007/s11418-019-01297-5

Two new bisindole alkaloids, leucophyllinines A (1) and B (2) consisting of eburnane and quebrachamine-type skeletons were isolated from the bark of Leuconotis eugeniifolia, and their structures were elucidated on the basis of spectroscopic data. Leucophyllinines A and B showed antiplasmodial activities against Plasmodium falciparum 3D7.

Matched MeSH terms: Indole Alkaloids/chemistry*

Bisnicalaterines B and C, atropisomeric bisindole alkaloids from Hunteria zeylanica, showing vasorelaxant activity

Hirasawa Y, Hara M, Nugroho AE, Sugai M, Zaima K, Kawahara N, et al.

J Org Chem, 2010 Jun 18;75(12):4218-23.

PMID: 20469917 DOI: 10.1021/jo1006762

Two new bisindole alkaloids, bisnicalaterines B and C (1 and 2) consisting of an eburnane and a corynanthe type of skeletons, were isolated from the bark of Hunteria zeylanica. Their absolute structures were determined by combination of NMR, CD, and computational methods, and each of them was shown to be in an atropisomeric relationship. Bisnicalaterines B and C (1 and 2) showed potent vasorelaxant activity on isolated rat aorta.

Matched MeSH terms: Indole Alkaloids/chemistry*

Combinations of indole based alkaloids from Mitragyna speciosa (Kratom) and cisplatin inhibit cell proliferation and migration of nasopharyngeal carcinoma cell lines

Domnic G, Jeng-Yeou Chear N, Abdul Rahman SF, Ramanathan S, Lo KW, Singh D, et al.

J Ethnopharmacol, 2021 Oct 28;279:114391.

PMID: 34224811 DOI: 10.1016/j.jep.2021.114391

ETHNOPHARMACOLOGICAL RELEVANCE: Mitragyna speciosa (Korth.) or kratom is a medicinal plant indigenous to Southeast Asia. The leaf of M. speciosa is used as a remedy in pain management including cancer related pain, in a similar way as opioids and cannabis. Despite its well-known analgesic effect, there is a scarce of information on the cancer-suppressing potential of M. speciosa and its active constituents.

AIM OF THE STUDY: To assess the potential applicability of M. speciosa alkaloids (mitragynine, speciociliatine or paynantheine) as chemosensitizers for cisplatin in Nasopharyngeal carcinoma (NPC) cell lines.

MATERIALS AND METHODS: The cytotoxic effects of the extracts, fractions and compounds were determined by conducting in vitro cytotoxicity assays. Based on the cytotoxic screening, the alkaloid extract of M. speciosa exhibited potent inhibitory effect on the NPC cell line NPC/HK1, and therefore, was chosen for further fractionation and purification. NPC cell lines NPC/HK1 and C666-1 were treated with combinations of cisplatin and M. speciosa alkaloids combinations in 2D monolayer culture. The effect of cisplatin and mitragynine as a combination on cell migration was tested using in vitro wound healing and spheroid invasion assays.

RESULTS: In our bioassay guided isolation, both methanolic and alkaloid extracts showed mild to moderate cytotoxic effect against the NPC/HK1 cell line. Both NPC cell lines (NPC/HK1 and C666-1) were insensitive to single agent and combination treatments of the M. speciosa alkaloids. However, mitragynine and speciociliatine sensitized the NPC/HK1 and C666-1 cells to cisplatin at ~4- and >5-fold, respectively in 2D monolayer culture. The combination of mitragynine and cisplatin also significantly inhibited cell migration of the NPC cell lines. Similarly, the combination also of mitragynine and cisplatin inhibited growth and invasion of NPC/HK1 spheroids in a dose-dependent manner. In addition, the spheroids did not rapidly develop resistance to the drug combinations at higher concentrations over 10 days.

CONCLUSION: Our data indicate that both mitragynine and speciociliatine could be potential chemosensitizers for cisplatin. Further elucidation focusing on the drug mechanistic studies and in vivo studies are necessary to support delineate the therapeutic applicability of M. speciosa alkaloids for NPC treatment.

Matched MeSH terms: Indole Alkaloids/chemistry*

Quinoline, Indole, and Isogranatanine Alkaloids from Malayan Leuconotis eugeniifolia

Tan YS, Ng MP, Tan CH, Tang WK, Sim KS, Yong KT, et al.

J Nat Prod, 2024 Feb 23;87(2):286-296.

PMID: 38284153 DOI: 10.1021/acs.jnatprod.3c00960

Nine new alkaloids, eugeniinalines A-H (1-8) and (+)-eburnamenine N-oxide (9), comprising one quinoline, six indole, and two isogranatanine alkaloids, were isolated from the stem-bark extract of the Malayan Leuconotis eugeniifolia. The structures and absolute configurations of these alkaloids were established based on the analysis of the spectroscopic data, GIAO NMR calculations, DP4+ probability analysis, TDDFT-ECD method, and X-ray diffraction analysis. Eugeniinaline A (1) represents a new pentacyclic quinoline alkaloid with a 6/6/5/6/7 ring system. Eugeniinaline G (7) and its seco-derivative, eugeniinaline H (8), were the first isogranatanine alkaloids isolated as natural products. The known alkaloids leucolusine (10) and melokhanine A (11) were found to be the same compound, based on comparison of the spectroscopic data of both compounds, with the absolute configuration of (7R, 20R, 21S). Eugeniinalines A and G (1 and 7) showed cytotoxic activity against the HT-29 cancer cell line with IC50 values of 7.1 and 7.2 μM, respectively.

Matched MeSH terms: Indole Alkaloids/chemistry

Fulltext Naucline, a new indole alkaloid from the bark of Nauclea officinalis

Liew SY, Mukhtar MR, Hadi AH, Awang K, Mustafa MR, Zaima K, et al.

Molecules, 2012 Apr 02;17(4):4028-36.

PMID: 22469596 DOI: 10.3390/molecules17044028

A new indole alkaloid, naucline (1) together with four known alkaloids, angustine (2), angustidine (3), nauclefine (4) and naucletine (5), were isolated from the bark of Nauclea officinalis. The structures of all isolated compounds were elucidated with various spectroscopic methods such as 1D- and 2D- NMR, IR, UV and LCMS-IT-TOF. In addition to that of alkaloid 1, the complete 13C-NMR data of naucletine (5) were also reported. Naucline (1) showed a moderate vasorelaxant activity (90% relaxation at 1 × 10(-5) M) whereas, angustine (2), nauclefine (4), and naucletine (5) showed potent vasorelaxant activity (more than 90% relaxation at 1 × 10(-5) M) on an isolated rat aorta.

Matched MeSH terms: Indole Alkaloids/chemistry*

Fulltext Neonaucline, a new indole alkaloid from the leaves of Ochreinauclea maingayii (Hook. f.) Ridsd. (Rubiaceae)

Muktar MR, Osman N, Awang K, Hazni H, Qureshi AK, Hadi AH, et al.

Molecules, 2011 Dec 28;17(1):267-74.

PMID: 22205092 DOI: 10.3390/molecules17010267

A new indole alkaloid; neonaucline (1), along with six known compounds-Cadamine (2), naucledine (3), harmane, benzamide, cinnamide and blumenol A-were isolated from the leaves of Ochreinauclea maingayii (Rubiaceae). In addition to that of compound 1, (13)C-NMR data of cadamine (2) and naucledine (3) were also reported. Structural elucidations of these alkaloids were performed using spectroscopic methods especially 1D- and 2D-NMR, IR, UV and LCMS-IT-TOF. The excellent vasorelaxant activity on isolated rat aorta was observed for the alkaloids 1-3 after injection of each sample at 1 × 10(-5) M.

Matched MeSH terms: Indole Alkaloids/chemistry*

Biologically active indole and bisindole alkaloids from Tabernaemontana divaricata

Kam TS, Pang HS, Lim TM

Org Biomol Chem, 2003 Apr 21;1(8):1292-7.

PMID: 12929658

The ethanol extract of the leaves of Tabernaemontana divaricata (double flower variety) provided a total of 23 alkaloids, including the new aspidosperma alkaloids, taberhanine, voafinine, N-methylvoafinine, voafinidine, voalenine and the new bisindole alkaloid, conophyllinine in addition to the previously known, biologically active bisindole, conophylline and its congener, conofoline. The structures of the new alkaloids were established by spectroscopic methods. The preparation and characterization of the corresponding quinones of the biologically active bisindoles are also described in relation to a structure-activity study of these compounds with respect to their action in stimulating insulin expression.

Matched MeSH terms: Indole Alkaloids/chemistry*

Polyneurines A-H, iboga alkaloids from Tabernaemontana polyneura

Tang SY, Tan CH, Sim KS, Yong KT, Lim KH, Low YY, et al.

Phytochemistry, 2023 Apr;208:113587.

PMID: 36646163 DOI: 10.1016/j.phytochem.2023.113587

Eight undescribed iboga alkaloids, polyneurines A-H, were isolated from the bark of Tabernaemontana polyneura. The structures of these alkaloids were established by interpretation of the MS and NMR data, while the configurations were determined using GIAO NMR calculations and DP4+ probability analysis, TDDFT-ECD method, or X-ray diffraction analysis. Polyneurine A possesses a γ-lactone unit embedded within the iboga skeleton, while polyneurines D and E incorporate a formylmethyl moiety at C-3 of the iboga skeleton. Biosynthetic pathways towards the formation of polyneurines A, C, D, and E were proposed.

Matched MeSH terms: Indole Alkaloids/chemistry

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