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Monday, 20 June 2016


 SL guaianolide (11,13-dehydrocompressanolide). 

DEPT spectrum (CDCl 3 , 75.5 MHz) of the guaianolide. 

 Mass spectra recorded in the positive MS E mode for guaianolide and parthenolide (500.0 μg mL -1 ) of the dichloromethane fraction of the

COSY spectrum (CDCl 3 , 300 MHz) of the guaianolide

HMBC correlation spectrum (CDCl 3 , 300 MHz) of the guaianolide. 

HMQC correlation spectrum (CDCl 3 , 300 MHz) of the guaianolide.

 13 C NMR spectrum (75.5 MHz, CDCl 3 ) of the guaianolide. 

1 H NMR spectrum (CDCl 3 , 300 MHz) of the guaianolide.

Journal of the Brazilian Chemical Society

Print version ISSN 0103-5053
On-line version ISSN 1678-4790

J. Braz. Chem. Soc. vol.14 no.5 São Paulo Sept./Oct. 2003


Sesquiterpene lactones and other chemical constituents of Mikania hoehnei R.

Juliana S. Chaves; Dionéia C. R. de Oliveira*
Departamento de Física e Química. Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Via do Café s/n, 14040 903, Ribeirão Preto-SP, Brazil

8b-hydroxyzaluzanin D (1). Colorless gum; C17H20O5; IR nmax/cm-1 (NaCl film): 3494 (OH alcohol), 1750 (g-lactone), 1730 (acetyl group), 1664 and 1641 (c=c double bonds); EI-MS, m/z (relative intensity in %): 262 [M+- ketene] (14), 91 (24), 43 [CH3CO]+ (100); 1H NMR (300 MHz, CDCl3), see Table 113C NMR, DEPT 1350 and HMQC (75 MHz, CDCl3): 45.0 (d, C-1), 36.5 (t, C-2), 74.5 (d, C-3), 147.7 (s, C-4), 50.4 (d, C-5), 77.6 (d, C-6), 50.1 (d, C-7), 65.7 (d, C-8), 41.8 (t, C-9), 142.8 (s, C-10), 136.0 (s, C-11), 170.8 (s, C-12), 121.6 (t, C-13), 117.4 (t, C-14), 114.2 (t, C-15), 169.4 (s, C-1'), 21.2 (q, C-2').

Results and Discussion
The chromatographic fractionation of hexane, ethyl acetate and ethanol extracts yielded stigmasterol, b-sitosterol and campesterol, lupeyl acetate,21 b-sitosteryl and stigmasteryl glucopyranosides,22 benzil 2,6-dimethoxybenzoate,23 luteolin,24 kaempferol24 and dehydrocostuslactone.13,14 The structures were established by comparison of their spectroscopic properties (mainly IR, 1H and 13C NMR) with those reported in the literature and in some cases by direct comparison with authentic samples.
Structure of the guaianolide 1 was deduced from the IR, MS, 13C and 1H NMR spectra data and the stereochemistry was defined from the coupling constants' value J and nOe difference correlations. This lactone has been previously reported as a synthetic compound obtained in the controlled acetylation of the natural guaianolide Integrifolin (8-epi-desacylcynaropicrin).12 The IR spectrum displayed bands at 1750 cm–1 (g-lactone), at 1730 cm–1 (acetyl group), at 3494 cm-1 (hydroxyl group) and weak bands at 1664, 1641 cm–1 (c=c double bonds).
Inspection of the 1H NMR spectrum of compound 1 indicated several signals very close to those observed in Zaluzanin D15. The position and the stereochemistry (b-orientation) of hydroxyl group at C-8 were determined by nOe correlation (Figure 1). nOe's were observed between the H-8 (d 4.37) and H-13a (d 5.62), H-7 (d 2.98) and H-9b (d 2.61). In the same way, correlation of the H-3 (d 5.50) with H-2b (d 2.45) and H-15a (d 5.32) in the nOe spectrum confirmed the a-orientation of H-3 which was attached to the carbon atom which is linked to the acetate group, as previously defined as Zaluzanin D (compound 2).

Just as the NMR spectrum of 2, the NMR spectrum of guaianolide 1 exhibited two characteristic doublets at d 6.42 and 5.62 (J 3.8 and 3.2 Hz respectively) corresponding to hydrogens of H - 13a and H - 13b of an exocyclic methylene group conjugated with a g-lactone. The exocyclic methylene groups attached to C-10 and C-4 were characterized by two singlets at d 4.99 (H-14a), 5.10 (H-14b) and a pair of triplets (J 2.0 Hz) at d 5.32 (H-15a) and 5.52 (H-15b), respectively.
The stereochemistry cis of the ring junction at C-1 and C-5 was established by the coupling constant (J 8.3 Hz) between H-1 and H-5. In the case of 1b, 5a-trans- guaianolide, a value of 10.0 Hz or greater is expected according to that reported in the literature.25,26 The lactone ring junction was confirmed to be trans (6b H, 7aH) by the large coupling constant (J ~ 3.0 Hz) of the H -13-a-methylene protons this is due to H-6/H-7 (J 8.9 Hz) coupling constant.16
All other signals were in agreement with the proposed structure of the guaianolide 1 (Table 1). Heteronuclear multiple quantum correlation 1H – 13C (HMQC) allowed us to assign unambiguously the signals of all carbons.
Besides the importance chemosystematic,27 sesquiterpene lactone posseses a wide spectrum of biological activity.28 Zaluzanin C, Zaluzanin D and its derivatives have shown several biological activities, such as activity against the P 388 lymphocytic leukemia in vitro,29,30 antifungal activity,31,32 inhibitory activity on nitric oxide production and nuclear fator KB,33 inhibitory activity on ethanol absorption.34











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