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319. Endophytes Are Hidden Producers of Maytansine in Putterlickia Roots

Author

Kusari, Souvik, Lamshöft, Marc, Kusari, Parijat, Gottfried, Sebastian, Zühlke, Sebastian, Louven, Kathrin, Hentschel, Ute, Kayser, Oliver, Spiteller, Michael, Kusari, Souvik, Lamshöft, Marc, Kusari, Parijat, Gottfried, Sebastian, Zühlke, Sebastian, Louven, Kathrin, Hentschel, Ute, Kayser, Oliver, and Spiteller, Michael

Abstract

Several recent studies have lent evidence to the fact that certain so-called plant metabolites are actually biosynthesized by associated microorganisms. In this work, we show that the original source organism(s) responsible for the biosynthesis of the important anticancer and cytotoxic compound maytansine is the endophytic bacterial community harbored specifically within the roots of Putterlickia verrucosa and P. retrospinosa plants. Evaluation of the root endophytic community by chemical characterization of their fermentation products using HPLC-HRMSn, along with a selective microbiological assay using the maytansine-sensitive type strain Hamigera avellanea revealed the endophytic production of maytansine. This was further confirmed by the presence of AHBA synthase genes in the root endophytic communities. Finally, MALDI-imaging-HRMS was used to demonstrate that maytansine produced by the endophytes is typically accumulated mainly in the root cortex of both plants. Our study, thus, reveals that maytansine is actually a biosynthetic product of root-associated endophytic microorganisms. The knowledge gained from this study provides fundamental insights on the biosynthesis of so-called plant metabolites by endophytes residing in distinct ecological niches.

Published
2014
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323. Phytochemical Analysis of a Cytotoxic Fraction of Quassia silvestris using LC-HR-ESI-MS n.

Author

Tala, Michel Feussi, Talontsi, Ferdinand Mouafo, Zeng, Guang‐Zhi, Wabo, Hippolyte Kamdem, Spiteller, Michael, Tan, Ning‐Hua, and Tane, Pierre

Abstract

Introduction The genus Quassia is a promising source of secondary metabolites with biological potential including antimalarial and cytotoxic activities. Limited data are available on the phytochemistry and pharmacology of Quassia silvestris Cheek & Jongkind, a Cameroonian medicinal plant used to treat various ailments. Objectives To carry out the bioassay-guided fractionation and LC-HR-ESI-MS analyses of the leaves extract from Q. silvestris; to purify the active fractions and isolate the major compounds using different chromatographic and spectroscopic methods. The obtained compounds will be evaluated for their biological activity. Material and methods Following the cytotoxic screening and LC-HR-ESI-MS profiling of fractions obtained from partition of the methanolic extract of Q. silvestris leaves, the CH2Cl2-soluble fraction which exhibited the highest cytotoxicity was retained for further investigations. Results Sixteen squalene-derived metabolites were identified with oxasqualenoid derivatives being the most predominant. Among the isolates, structure elucidation of two new oxasqualenoids quassiols E (1) and F (2), were achieved by NMR (one-dimensional (1D) and two-dimensional (2D)) and MS methods. The newly characterised compounds 1 and 2, together with the known tetraol (3) and 3-oxo-oleanoic acid (16) displayed moderate cytotoxicity. Conclusion The identification and structural characterisation of highly oxidised squalene derived metabolites from this plant may provide important insight data for further pharmacological investigations. The LC-HR-ESI-MS n method reported here could be developed as a rapid and efficient tool for the analyses of structurally related compounds in the genera Quassia, Simarouba, and Eurycoma of the subfamily Simarouboideae. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Published
2017
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324. Collision-induced thermochemistry of reactions of dissociation of glycyl-homopeptides-An experimental and theoretical analysis.

Author

Ivanova, Bojidarka, Spiteller, Michael, and Case, David

Abstract

The research draws on experimental and theoretical data about energetics and kinetics of mass spectrometric (MS) reactions of glycyl homopenta- ( G5) and glycyl homohexapeptides ( G6). It shows the great applicability of the methods of quantum chemistry to predict MS profile of peptides using energetics of collision induced dissociation (CID) fragment species. Mass spectrometry is among irreplaceable methods, providing unambiguous qualitative, quantitative and structural information about analytes, applicable to many scientific areas like environmental chemistry; food chemistry; medicinal chemistry; and more. Our study could be considered of substantial interdisciplinary significance, where MS proteomics is widely used. The experimental design involves electrospray ionization (ESI) and CID MS/MS. Theoretical design is based on ab initio and density functional theory (DFT) methods. Experimental MS and theoretical free Gibbs energies as well as rate constants of fragment reactions are compared. The thermodynamic encompasses gas-phase and polar continuum analysis, including polar protic and aprotic solvents within temperature T = 10-500 K; dielectric constant ε = 0-78, pH, and ionic strengths μ = 0.001-1.0 mol dm−1. There are computed and discussed 39 protonated forms of peptides at amide N- and -(NHC)= O centers; corresponding fragment ions studying their thermodynamic stability depending on experimental conditions. A correlation analysis between molecular conformations of parent ions and fragment species; their proton accepting ability and internal energy distribution is carried out. Data about ionization potentials (IPs) and electron affinities (EAs) are discussed, as well. [ABSTRACT FROM AUTHOR]

Published
2017
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327. Tramadol—A True Natural Product?

Author

Kusari, Souvik, primary, Tatsimo, Simplice Joel N., additional, Zühlke, Sebastian, additional, Talontsi, Ferdinand M., additional, Kouam, Simeon Fogue, additional, and Spiteller, Michael, additional

Published
2014
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349. Polycyclic aromatic compounds in wood preservatives derived from coal and petroleum

Author

Burhenne, Juergen, Spiteller, Michael, and Jovanović, Jovan

Subjects
creosates, B[a]P - ekvivalenti, konzervatori za drvo, kreozotna ulja, B[a]P-equivalents, wood preservatives, PAC
Abstract

Five commercial coal tar oils (DB, B, GX, PO, MA) and an oil sample derived from petroleum (RPO) were investigated in this work. The contents of benzo[a]pyrene (B[a]P) and 13 other polycyclic aromatic compounds (PACs) were determined. According to today's legislation RPO, DB, B, and GX containing less than 500 mg/Kg B[a]P may be used as wood preservatives for railway sleepers and wood poles. By law it is prohibited to apply PO and MA for wood treatments in EU countries at all. The B[a]P content of creosotes and other aromatic oils could be decreased through distillation, but in that case the concentration of other PACs with lower boiling points and similar or even higher relative cancerogenic potencies compared to B[a]P could remain unchanged. For instance, RPO contains more B[a]P than DB, B, and GX, but reveals the lowest value of total B[a]P equivalents compared to other coal tar oils. Therefore, determination of total B[a]P equivalents, i. e. cancerogenic PACs in a given oil sample is much safer than that of B[a]P solely, as it has been regulated by legislation so far. U ovom radu ispitivano je pet trgovačkih uzoraka ulja dobivenih iz katrana uglja (kreozotna ulja) (DB, B, GX, PO, MA) i jedan uzorak ulja dobiven iz nafte (RPO). Određeni su, pri tome, sadržaji benzo[a]pirena (B[a]P) i 13 drugih policikličnih aromatskih ugljovodonika (PACs). U skladu sa današnjim zakonima Evropske Unije uzorci RPO, DB, B i GX, koji su sadržali manje od 500 mg/Kg B[a]P smeju se koristiti kao sredstva za zaštitu drvenih željezničkih pragova i telegrafskih i električnih stubova. Zakon Evropske Unije zabranjuje upotrebu PO i MA za zaštitu drveta u svim slučajevima. Prema tome zakonu ukoliko sredstvo za zaštitu drveta sadrži manje od 50 mg/Kg B[a]P ono se srne koristiti u svim slučajevima kada se impregnisano drvo upotrebljava u industrijske svrhe van zatvorenih prostora, odnosno ne samo za pragove i stubove (B[a]P). Koncentracija B[a]P u kreozotnim i drugim aromatskim uljima može se smanjiti pomoću destilacije. U tom slučaju, međutim, koncentracija PACs koji imaju niže tačke ključanja, a slične ili čak veće relativne kancerogene potencije, mogu ostati nepromenjene. Na primer, RPO sadrži više B[a]P od DB, B i GX, ali ima najmanji zbir ukupnih B[a]P ekvivalenata. Zato današnje zakonsko ograničenje samo sadržaja B[a]P u kreozotnim i drugim aromatskim uljima može dovesti do pogrešnih procena njihove karcenogene potencije. Saglasno ovom radu mnogo je sigurnije koristiti zbir B[a]P ekvivalenata dobivenih množenjem sadržaja svakog kancerogenog PAG sa njegovom relativnom kancerogenom potencijom. Ovo tim pre, pošto posle jednom učinjene kalibracije sa smešom PACs poznatog sastava, praktično nema dodatnog eksperimentalnog rada u određivanju zbira B[a]P ekvivalenata u poređenju sa određivanjem sadržaja B[a]R Na osnovu rezultata ovoga rada RPO, tj. uzorak ulja dobiven iz nafte, može se smatrati uspešnom zamenom za ulja dobivena iz katrana uglja, tj. kreozotnih ulja.

Published
2000

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