Merck

An unprecedented neolignan skeleton from Chimarrhis turbinata.

Journal of natural products (2011-02-24)
Carmen L Cardoso, Ian Castro-Gamboa, Giovana M Bergamini, Alberto J Cavalheiro, Dulce H S Silva, Marcia N Lopes, Angela R Araújo, Maysa Furlan, Hugo Verli, Vanderlan da S Bolzani
ABSTRACT

A lignan with a new skeleton named chimarrhinin (1) was isolated from an extract of the leaves of Chimarrhis turbinata, a Rubiaceae plant species. (13)C NMR spectrometric techniques including 1D and 2D experiments and HRESIMS provided unequivocal structural confirmation of this new C(6).C(3) skeleton type. The relative configuration of 1 was established by 2D (1)H-H analysis and J couplings, while its conformation was evaluated through molecular modeling using the RM1 semiempirical method, with the aid of coupling constants obtained by NMR analysis. The antioxidant activity of the new derivative 1 and two known and previously isolated phenolic derivatives (2 and 3) was investigated. An IC(50) value of 7.50 ± 0.5 μmol L(-1) was obtained for the new derivative 1, while 2 and 3 showed IC(50) values of 18.60 ± 0.4 and 18.50 ± 0.6 μmol, respectively.

MATERIALS
Product Number
Brand
Product Description

Sigma-Aldrich
2,6-Di-tert-butyl-4-methylphenol, purum, ≥99.0% (GC)
Sigma-Aldrich
2,6-Di-tert-butyl-4-methylphenol, tested according to Ph. Eur.
Sigma-Aldrich
Chlorogenic acid, ≥95% (titration)
Chlorogenic acid, primary reference standard