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A Hexacyclic, Iboga-Derived Monoterpenoid Indole with a Contracted Tetrahydroazepine C-Ring and Incorporation of an Isoxazolidine Moiety, a Seco-Corynanthean, an Aspidosperma-Aspidosperma Bisindole with Anticancer Properties, and the Absolute Configuration of the Pyridopyrimidine Indole Alkaloid, Vernavosine

Nge CE, Sim KS, Lim SH, Thomas NF, Low YY, Kam TS

J Nat Prod, 2016 10 28;79(10):2709-2717.

PMID: 27759387

Examination of the EtOH extract of the Malayan Tabernaemontana corymbosa resulted in the isolation of three new alkaloids, viz., cononuridine (1), an unusual hexacyclic, iboga-derived, monoterpenoid indole characterized by contraction of the tetrahydroazepine C-ring and incorporation of an additional isoxazolidine ring, taberisidine (2), a seco-corynanthean alkaloid, and conofolidine (3), an Aspidosperma-Aspidosperma bisindole that showed pronounced in vitro growth inhibitory activity against an array of human cancer cell lines, including KB, vincristine-resistant KB, PC-3, LNCaP, MCF7, MDA-MB-231, HT-29, and HCT 116 cells. The structures and absolute configurations of 1 and 3 and the absolute configuration of the novel pyridopyrimidine indole alkaloid vernavosine (4) were confirmed by X-ray diffraction analysis. A reasonable biosynthesis route to cononuridine starting from an iboga precursor is presented.

Matched MeSH terms: KB Cells

Zinc oxide nanoparticles functionalized with cinnamic acid for targeting dental pathogens receptor and modulating apoptotic genes in human oral epidermal carcinoma KB cells

Ravikumar OV, Marunganathan V, Kumar MSK, Mohan M, Shaik MR, Shaik B, et al.

Mol Biol Rep, 2024 Feb 24;51(1):352.

PMID: 38400866 DOI: 10.1007/s11033-024-09289-9

BACKGROUND: Oral diseases are often attributed to dental pathogens such as S. aureus, S. mutans, E. faecalis, and C. albicans. In this research work, a novel approach was employed to combat these pathogens by preparing zinc oxide nanoparticles (ZnO NPs) capped with cinnamic acid (CA) plant compounds.

METHODS: The synthesized ZnO-CA NPs were characterized using SEM, FTIR, and XRD to validate their composition and structural features. The antioxidant activity of ZnO-CA NPs was confirmed using DPPH and ABTS free radical scavenging assays. The antimicrobial effects of ZnO-CA NPs were validated using a zone of inhibition assay against dental pathogens. Autodock tool was used to identify the interaction of cinnamic acid with dental pathogen receptors.

RESULTS: ZnO-CA NPs exhibited potent antioxidant activity in both DPPH and ABTS assays, suggesting their potential as powerful antioxidants. The minimal inhibitory concentration of ZnO-CA NPs against dental pathogens was found 25 µg/mL, indicating their effective antimicrobial properties. Further, ZnO-CA NPs showed better binding affinity and amino acid interaction with dental pathogen receptors. Also, the ZnO-CA NPs exhibited dose-dependent (5 µg/mL, 15 µg/mL, 25 µg/mL, and 50 µg/mL) anticancer activity against Human Oral Epidermal Carcinoma KB cells. The mechanism of action of apoptotic activity of ZnO-CA NPs on the KB cells was identified through the upregulation of BCL-2, BAX, and P53 genes.

CONCLUSIONS: This research establishes the potential utility of ZnO-CA NPs as a promising candidate for dental applications. The potent antioxidant, anticancer, and effective antimicrobial properties of ZnO-CA NPs make them a valuable option for combating dental pathogens.

Matched MeSH terms: KB Cells

Structure-activity relationship of polyisoprenyl benzophenones from Garcinia pyrifera on the tubulin/microtubule system

Roux D, Hadi HA, Thoret S, Guénard D, Thoison O, Païs M, et al.

J Nat Prod, 2000 Aug;63(8):1070-6.

PMID: 10978200

Microtubule disassembly inhibitory properties have been established for the known polyisoprenylated benzophenones xanthochymol (1a) and guttiferone E (1b). The compounds were isolated from the fruits of Garcinia pyrifera collected in Malaysia. A structure-activity relationship study, including natural and semisynthetic derivatives, delineated some structural features necessary for the interaction with tubulin within this compound class.

Matched MeSH terms: KB Cells/drug effects

Biologically active aspidofractinine alkaloids from Kopsia singapurensis

Subramaniam G, Hiraku O, Hayashi M, Koyano T, Komiyama K, Kam TS

J Nat Prod, 2008 Jan;71(1):53-7.

PMID: 18078327

Ten new indole alkaloids of the aspidofractinine type, in addition to several recently reported indole alkaloids and 20 other known alkaloids, were obtained from the leaf and stem-bark extract of the Malayan Kopsia singapurensis, viz., kopsimalines A-E (1-5), kopsinicine (6), kopsofinone (7), and kopsiloscines H-J (8-10). The structures of these alkaloids were determined using NMR and MS analysis. Kopsimalines A (1), B (2), C (3), D (4), and E (5) and kopsiloscine J (10) were found to reverse multidrug-resistance in vincristine-resistant KB cells, with 1 showing the highest potency.

Matched MeSH terms: KB Cells

Biologically active aspidofractinine, rhazinilam, akuammiline, and vincorine alkaloids from Kopsia

Subramaniam G, Hiraku O, Hayashi M, Koyano T, Komiyama K, Kam TS

J Nat Prod, 2007 Nov;70(11):1783-9.

PMID: 17939738

Eleven new indole alkaloids, in addition to the previously reported rhazinal (1), and 14 other known alkaloids, were obtained from the Malayan Kopsia singapurensis, viz., kopsiloscines A-F (2-7), 16-epikopsinine (8), kopsilongine- N-oxide (9), 16-epiakuammiline (10), aspidophylline A (11), and vincophylline (12). The structures of these alkaloids were determined using NMR and MS analyses. Rhazinal (1), rhazinilam (17), and rhazinicine (18) showed appreciable cytotoxicity toward drug-sensitive as well as vincristine-resistant KB cells, while kopsiloscines A (2), B (3), and D (5) and aspidophylline A (11) were found to reverse drug-resistance in drug-resistant KB cells.

Matched MeSH terms: KB Cells

Strychnan and secoangustilobine A type alkaloids from Alstonia spatulata. Revision of the C-20 configuration of scholaricine

Tan SJ, Low YY, Choo YM, Abdullah Z, Etoh T, Hayashi M, et al.

J Nat Prod, 2010 Nov 29;73(11):1891-7.

PMID: 21043460 DOI: 10.1021/np100552b

A total of 25 alkaloids were isolated from the leaf and stem-bark extracts of Alstonia spatulata, of which five are new alkaloids of the strychnan type (alstolucines A-E, 1-5) and the other, a new alkaloid of the secoangustilobine A type (alstolobine A, 6). The structures of these alkaloids were established using NMR and MS analysis and, in the case of alstolucine B (2), also confirmed by X-ray diffraction analysis. A reinvestigation of the stereochemical assignment of scholaricine (13) by NMR and X-ray analyses indicated that the configuration at C-20 required revision. Alkaloids 1, 2, 6, 7, 9, 10, and 13 reversed multidrug resistance in vincristine-resistant KB cells.

Matched MeSH terms: KB Cells

Aspidofractinine and Eburnane Alkaloids from a North Borneo Kopsia. Ring-Contracted, Additional Ring-Fused, and Paucidactine-Type Aspidofractinine Alkaloids from K. pauciflora

Yap WS, Gan CY, Sim KS, Lim SH, Low YY, Kam TS

J Nat Prod, 2016 Jan 22;79(1):230-9.

PMID: 26717050 DOI: 10.1021/acs.jnatprod.5b00992

Eleven new indole alkaloids (1-11) comprising seven aspidofractinine and four eburnane alkaloids, were isolated from the stem-bark extract of Kopsia pauciflora occurring in Malaysian Borneo. The aspidofractinine alkaloids include a ring-contracted, an additional ring-fused, a paucidactine regioisomer, two paucidactine, and one kopsine alkaloid. The structures of several of these alkaloids were also confirmed by X-ray diffraction analyses. The bisindole alkaloids isolated, norpleiomutine and kopsoffinol, showed in vitro growth inhibitory activity against human PC-3, HCT-116, MCF-7, and A549 cells and moderate effects in reversing multidrug-resistance in vincristine-resistant human KB cells.

Matched MeSH terms: KB Cells

Grandilodines A-C, biologically active indole alkaloids from Kopsia grandifolia

Yap WS, Gan CY, Low YY, Choo YM, Etoh T, Hayashi M, et al.

J Nat Prod, 2011 May 27;74(5):1309-12.

PMID: 21428274 DOI: 10.1021/np200008g

Three new indole alkaloids (1-3), named grandilodines A-C, and five known ones were obtained from the Malayan Kopsia grandifolia. The structures were established using NMR and MS analyses and, in the case of 1 and 2, were confirmed by X-ray diffraction analyses. Alkaloids 1, 3, and lapidilectine B (8) were found to reverse multidrug resistance in vincristine-resistant KB cells.

Matched MeSH terms: KB Cells

Displaying publications 21 - 28 of 28 in total