MyMedR

A cycloartane incorporating a fused tetrahydrofuran ring and a cytotoxic lactam from Monocarpia marginalis

Lim SH, Mahmood K, Komiyama K, Kam TS

J Nat Prod, 2008 Jun;71(6):1104-6.

PMID: 18462006 DOI: 10.1021/np800123g

A new cycloartane, monocarpinine (1), incorporating a fused tetrahydrofuranyl ring, and a cytotoxic tetracyclic lactam, monomarginine (2), were isolated from a stem bark extract of the Malayan species Monocarpia marginalis. The structures of these compounds were determined using NMR and MS analysis. Monomarginine (2) showed appreciable cytotoxicity toward human KB (both drug-sensitive and drug-resistant) and Jurkat cells.

Matched MeSH terms: Nuclear Magnetic Resonance, Biomolecular

Leuconoxine, kopsinitarine, kopsijasmine, and kopsinone derivatives from Kopsia

Lim SH, Sim KM, Abdullah Z, Hiraku O, Hayashi M, Komiyama K, et al.

J Nat Prod, 2007 Aug;70(8):1380-3.

PMID: 17608533

Four new indole alkaloids were obtained from two Kopsia species, 6-oxoleuconoxine (1) from the leaf extract of K. griffithii and kopsinitarine E (2), kopsijasminine (3), and kopsonoline (4) from the stem-bark extract of K. teoi. The structures of these alkaloids were determined using NMR and MS analysis. Kopsijasminine (3) showed moderate activity in reversing multidrug resistance in vincristine-resistant KB cells.

Matched MeSH terms: Nuclear Magnetic Resonance, Biomolecular

Four tetracyclic oxindole alkaloids and a taberpsychine derivative from a Malayan Tabernaemontana

Lim KH, Sim KM, Tan GH, Kam TS

Phytochemistry, 2009 Jun;70(9):1182-1186.

PMID: 19643450 DOI: 10.1016/j.phytochem.2009.06.010

Four tetracyclic oxindole alkaloids, 7(R)- and 7(S)-geissoschizol oxindole (1 and 2), 7(R),16(R)- and 7(S),16(R)-19(E)-isositsirikine oxindole (3 and 4), in addition to a taberpsychine derivative, N(4)-demethyltaberpsychine (5), were isolated from the Malayan Tabernaemontana corymbosa and the structures were established using NMR and MS analysis.

Matched MeSH terms: Nuclear Magnetic Resonance, Biomolecular

Biologically active indole alkaloids from Kopsia arborea

Lim KH, Hiraku O, Komiyama K, Koyano T, Hayashi M, Kam TS

J Nat Prod, 2007 Aug;70(8):1302-7.

PMID: 17665953

Nine new indole alkaloids, rhazinoline (1), 19(S)-methoxytubotaiwine (2), 19(R)-methoxytubotaiwine (3), kopsamidine A (4), kopsamidine B (5), kopsinidine A (6), kopsinidine B (7), paucidactine C (8), and pericine N-oxide (9), in addition to several recently reported novel indoles and 34 other known ones, were obtained from the stem-bark extract of the Malayan Kopsia arborea. The structures were determined using NMR and MS analysis. Valparicine (12) showed pronounced cytotoxic effects against KB and Jurkat cells (IC(50) 13.0 and 0.91 microM, respectively).

Matched MeSH terms: Nuclear Magnetic Resonance, Biomolecular

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: Nuclear Magnetic Resonance, Biomolecular

Fulltext Antioxidants and α-glucosidase inhibitors from Neptunia oleracea fractions using 1H NMR-based metabolomics approach and UHPLC-MS/MS analysis

Lee SY, Mediani A, Ismail IS, Maulidiani, Abas F

BMC Complement Altern Med, 2019 Jan 07;19(1):7.

PMID: 30616569 DOI: 10.1186/s12906-018-2413-4

BACKGROUND: Neptunia oleracea is a plant cultivated as vegetable in Southeast Asia. Previous works have revealed the potential of this plant as a source of natural antioxidants and α-glucosidase inhibitors. Continuing our interest on this plant, the present work is focused in identification of the bioactive compounds from different polarity fractions of N. oleracea, namely hexane (HF), chloroform (CF), ethyl acetate (EF) and methanol (MF).

METHODS: The N. oleracea fractions were obtained using solid phase extraction (SPE). A metabolomics approach that coupled the use of proton nuclear magnetic resonance (1H NMR) with multivariate data analysis (MVDA) was applied to distinguish the metabolite variations among the N. oleracea fractions, as well as to assess the correlation between metabolite variation and the studied bioactivities (DPPH free radical scavenging and α-glucosidase inhibitory activities). The bioactive fractions were then subjected to ultra-high performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) analysis to profile and identify the potential bioactive constituents.

RESULTS: The principal component analysis (PCA) discriminated EF and MF from the other fractions with the higher distributions of phenolics. Partial least squares (PLS) analysis revealed a strong correlation between the phenolics and the studied bioactivities in the EF and the MF. The UHPLC-MS/MS profiling of EF and MF had tentatively identified the phenolics present. Together with some non-phenolic metabolites, a total of 37 metabolites were tentatively assigned.

CONCLUSIONS: The findings of this work supported that N. oleracea is a rich source of phenolics that can be potential antioxidants and α-glucosidase inhibitors for the management of diabetes. To our knowledge, this study is the first report on the metabolite-bioactivity correlation and UHPLC-MS/MS analysis of N. oleracea fractions.

Matched MeSH terms: Nuclear Magnetic Resonance, Biomolecular

Pterulamides I-VI, linear peptides from a Malaysian Pterula sp

Lang G, Mitova MI, Cole AL, Din LB, Vikineswary S, Abdullah N, et al.

J Nat Prod, 2006 Oct;69(10):1389-93.

PMID: 17067148

Six new linear peptides, pterulamides I-VI (1-6), were isolated from the fruiting bodies of a Malaysian Pterula species. The structures were elucidated by MS and 2D NMR experiments, and the absolute configurations of the constituent amino acids established using Marfey's method. The pterulamides are mainly assembled from nonpolar N-methylated amino acids and, most interestingly, have non-amino-acid N-terminal groups, among them the unusual cinnamoyl, (E)-3-methylsulfinylpropenoyl, and (E)-3-methylthiopropenoyl groups. Furthermore, pterulamides I-V are the first natural peptides with a methylamide C-terminus. Pterulamides I and IV are cytotoxic against the P388 cell line with IC50 values of 0.55 and 0.95 microg/mL (0.79 and 1.33 microM), respectively.

Matched MeSH terms: Nuclear Magnetic Resonance, Biomolecular

Bipleiophylline, an unprecedented cytotoxic bisindole alkaloid constituted from the bridging of two indole moieties by an aromatic spacer unit

Kam TS, Tan SJ, Ng SW, Komiyama K

Org. Lett., 2008 Sep 4;10(17):3749-52.

PMID: 18683934 DOI: 10.1021/ol801354s

A cytotoxic bisindole alkaloid possessing an unprecedented structure in which two indole moieties are bridged by an aromatic spacer unit has been isolated from Alstonia angustifolia. The structure was established by analysis of the spectroscopic data and confirmed by X-ray diffraction analysis. A possible biogenetic pathway from pyrocatechuic acid and pleiocarpamine is presented.

Matched MeSH terms: Nuclear Magnetic Resonance, Biomolecular

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: Nuclear Magnetic Resonance, Biomolecular

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: Nuclear Magnetic Resonance, Biomolecular

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: Nuclear Magnetic Resonance, Biomolecular

New indole alkaloids from Alstonia macrophylla

Kam TS, Choo YM

J Nat Prod, 2004 Apr;67(4):547-52.

PMID: 15104482

Ten new indole alkaloids, alstomaline (1), 10,11-dimethoxynareline (2), alstohentine (3), alstomicine (4), 16-hydroxyalstonisine (5), 16-hydroxyalstonal (6), 16-hydroxy-N(4)-demethylalstophyllal oxindole (7), alstophyllal (8), 6-oxoalstophylline (9), and 6-oxoalstophyllal (10), in addition to 21 other known ones, were obtained from the leaf extract of the Malayan Alstonia macrophylla. The structures were determined using NMR and MS analysis.

Matched MeSH terms: Nuclear Magnetic Resonance, Biomolecular

Alkaloids from Alstonia angustifolia

Kam TS, Choo YM

Phytochemistry, 2004 Mar;65(5):603-8.

PMID: 15003424

Six new alkaloids, viz., alstolactone, affinisine oxindole, lagumicine, N(4)-demethylalstonerine, N(4)-demethylalstonerinal, and 10-methoxycathafoline N(4)-oxide, in addition to 36 other known alkaloids, were obtained from the leaf extract of Alstonia angustifolia var. latifolia. The structures of the new alkaloids were determined using NMR and MS analysis.

Matched MeSH terms: Nuclear Magnetic Resonance, Biomolecular

Molecular docking studies and in vitro cholinesterase enzyme inhibitory activities of chemical constituents of Garcinia hombroniana

Jamila N, Yeong KK, Murugaiyah V, Atlas A, Khan I, Khan N, et al.

Nat Prod Res, 2015;29(1):86-90.

PMID: 25219673 DOI: 10.1080/14786419.2014.952228

Garcinia species are reported to possess antimicrobial, anti-inflammatory, anticancer, anti-HIV and anti-Alzheimer's activities. This study aimed to investigate the in vitro cholinesterase enzyme inhibitory activities of garcihombronane C (1), garcihombronane F (2), garcihombronane I (3), garcihombronane N (4), friedelin (5), clerosterol (6), spinasterol glucoside (7) and 3β-hydroxy lup-12,20(29)-diene (8) isolated from Garcinia hombroniana, and to perform molecular docking simulation to get insight into the binding interactions of the ligands and enzymes. The cholinesterase inhibitory activities were evaluated using acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) enzymes. In this study, compound 4 displayed the highest concentration-dependent inhibition of both AChE and BChE. Docking studies exhibited that compound 4 binds through hydrogen bonds to amino acid residues of AChE and BChE. The calculated docking and binding energies also supported the in vitro inhibitory profiles of IC50. In conclusion, garcihombronanes C, F, I and N (1-4) exhibited dual and moderate inhibitory activities against AChE and BChE.

Matched MeSH terms: Nuclear Magnetic Resonance, Biomolecular

Chrotacumines A-D, chromone alkaloids from Dysoxylum acutangulum

Ismail IS, Nagakura Y, Hirasawa Y, Hosoya T, Lazim MI, Lajis NH, et al.

J Nat Prod, 2009 Oct;72(10):1879-83.

PMID: 19757855 DOI: 10.1021/np9003849

Four new chromone alkaloids, chrotacumines A-D (1-4), consisting of a 5,7-dihydroxy-2-methylchromone, an N-Me piperidine ring, and an ester side chain were isolated from Dysoxylum acutangulum, and their structures including absolute configurations were elucidated on the basis of spectroscopic data interpretation including 2D NMR, CD spectra, and X-ray analysis. The known compound rohitukine (5) showed moderate cytotoxicity against human HL-60 promyelocytic leukemia and HCT-116 colon cancer cells.

Matched MeSH terms: Nuclear Magnetic Resonance, Biomolecular

Fulltext A new 4alpha-methylated sterol from a Nephthea sp. (Nephtheidae) Bornean soft coral

Ishii T, Matsuura H, Zhaoqi Z, Vairappan CS

Molecules, 2009;14(9):3360-6.

PMID: 19783930 DOI: 10.3390/molecules14093360

A new 4alpha-methyl sterol, 4alpha-methyl-ergosta-6,8(14),22E-triene-3beta-ol (1), was isolated along with cholesterol from a Nephthea sp. Bornean soft coral The structure of compound 1 was elucidated on the basis of spectroscopic analysis and comparison of the data with those of the related compounds.

Matched MeSH terms: Nuclear Magnetic Resonance, Biomolecular

Three new cembranoids from the Bornean soft coral Nephthea sp

Ishii T, Kamada T, Vairappan CS

J Asian Nat Prod Res, 2016 May;18(5):415-22.

PMID: 26983053 DOI: 10.1080/10286020.2016.1145670

Three new cembranoid diterpenes, 10-hydroxy-nephthenol acetate (1), 7,8-epoxy-10-hydroxy-nephthenol acetate (2), and 6-acetoxy-7,8-epoxy-10-hydroxy-nephthenol acetate (3), along with a known compound, 6-acetoxy-7,8-epoxy-nephthenol acetate (4), were isolated from the Bornean soft coral Nephthea sp. Antibacterial and anticancer activities were exhibited by compounds 1 and 2 against Staphylococcus aureus (ATCC 6538)/Escherichia coli (ATCC 13311) and Hela/MCF-7, respectively.

Matched MeSH terms: Nuclear Magnetic Resonance, Biomolecular

Meliternatin: a feeding deterrent and larvicidal polyoxygenated flavone from Melicope subunifoliolata

Hung Ho S, Wang J, Sim KY, Ee GC, Imiyabir Z, Yap KF, et al.

Phytochemistry, 2003 Apr;62(7):1121-4.

PMID: 12591266

We screened more than 60 Malaysian plants against two species of insects and found that Melicope subunifoliolata (Stapf) T.G. Hartley (Rutaceae) showed strong feeding deterrent activity against Sitophilus zeamais Motsch. (Curculionidae) and very good larvicidal activity against Aedes aegypti L. (Diptera). One anti-insect compound, meliternatin (3,5-dimethoxy-3',4',6,7-bismethylendioxyflavone) (6) and six other minor polyoxygenated flavones were isolated from M. subunifoliolata.

Matched MeSH terms: Nuclear Magnetic Resonance, Biomolecular

Langkolide, a 32-membered macrolactone antibiotic produced by Streptomyces sp. Acta 3062

Helaly SE, Kulik A, Zinecker H, Ramachandaran K, Tan GY, Imhoff JF, et al.

J Nat Prod, 2012 Jun 22;75(6):1018-24.

PMID: 22642587 DOI: 10.1021/np200580g

A new 32-membered macrolactone antibiotic, named langkolide, was isolated from the mycelium of Streptomyces sp. Acta 3062. The langkolide structure was determined by HR-MS and 1D and 2D NMR as a 32-membered macrolactone connected from an overhanging polyketide tail to a naphthoquinone unit mediated by two carbohydrate moieties. The producing strain was isolated from a rhizosphere soil of Clitorea sp. collected at Burau Bay, Langkawi, Malaysia, and was characterized by its morphological and chemotaxonomic features in addition to its 16S rRNA gene sequence. It was identified as a member of the Streptomyces galbus clade. Langkolide exhibited various bioactivities including antimicrobial and antiproliferative activities. Furthermore, langkolide inhibited human recombinant phosphodiesterase 4 with an IC(50) value of 0.48 μM.

Matched MeSH terms: Nuclear Magnetic Resonance, Biomolecular

Two new xanthones from Artocarpus obtusus

Hashim N, Rahmani M, Sukari MA, Ali AM, Alitheen NB, Go R, et al.

J Asian Nat Prod Res, 2010 Feb;12(2):106-12.

PMID: 20390751 DOI: 10.1080/10286020903450411

Two new xanthones, pyranocycloartobiloxanthone A (1) and dihydroartoindonesianin C (2), were isolated from the stem bark of Artocarpus obtusus Jarrett by chromatographic separation. Their structures were determined by using spectroscopic methods and comparison with known related compounds. Pyranocycloartobiloxanthone A (1) showed strong free radical scavenging activity by using DPPH assay as well as cytotoxicity towards K562, HL-60, and MCF7 cell lines.

Matched MeSH terms: Nuclear Magnetic Resonance, Biomolecular

Displaying publications 41 - 60 of 92 in total