Abstract
Three compounds, namely the interesting biflavanonol GB-2 (naringenin I-3, II-8-dihydroquercetin, 1), I-4′,I-5,II-5,I-7,II-7-pentahydroxyflavanone(I-3,II-8)chromone [naringenin-(3→8) 5,7-dihydroxychromone, 2] and stigmasterol, have been isolated from the leaves of Cratoxylum neriifolium Kurz. Compounds 1 and 2 show rotameric behavior due to the presence of a single bond between the highly substituted flavanone and flavanonol part and the flavanone and chromone part, respectively. Complete NMR spectral assignments of 1 and 2 have been done at 27 °C and 90 °C for the first time followed by a study of conformational behavior at room temperature by ROESY.
Key words
Cratoxylum neriifolium
- Guttiferae - Biflavanoids - 3,8′′-bond atropisomerism - NMR spectral assignment
References
-
1 Anonymous . Prammun Sappkoniya Thai. Association of traditional medicinal school Part II. 1967: pp 123-4
-
2 Jackson B, Locksley H D, Scheinmann F, Wolstenholme W A. Isolation and structure of four novel biflavanones from the heartwood of Garcinia buchananii Baker and G. eugeniifolia Wall. J Chem Soc 1971: 3791-804
-
3
Braide V B.
Anti-inflammatory activities of kolaviron; a biflavanoid extract of Garcinia kola
.
Fitoterapia.
1993;
64
433-6
-
4
Iwu M M.
Antihepatotoxic constituents of Garcinia kola seeds.
Experientia.
1985;
41
699-700
-
5
Iwu M M.
Biflavanones of Garcinia: Pharmacological and biological activities.
Progress in Clinical and Biological Research.
1986;
213
485-8
-
6 Coterill P J, Scheinmann F, Stenhouse I A. Extractives from Guttiferae Part 34. Kolaflavanone, A new biflavanoid from the nuts of Garcinia kola Heckel. J Chem Soc Perkin Trans I 1978: 532
-
7
Sonnenbichler J, Madubunyi I.
Stereochemistry of two hydroxybiflavanonols from Garcinia kola Nuts.
Z Naturforsch.
1987;
42C
855-7
-
8
Terashima K, Aquil M, Niwa M.
Garcinianin, a novel biflavanoid from the roots of Garcinia kola
.
Heterocycles.
1995;
41
2245-50
-
9
Iwu M M, Igoboko O A, Tempesta M S.
Biflavanoid constituents of Garcinia kola roots.
Fitoterapia.
1990;
61
178-81
-
10 Ansari W H, Rahman W, Barraclough D, Maynard R, Scheinmann F. Biflavanoids and a flavanone-chromone from the leaves of Garcinia dulcis (Roxb) Kurz. J Chem Soc Perkin Trans I 1976: 1458
-
11 Locksley H D. Chemistry of biflavanoid compounds. In: Zechmeister Z (editor) Progress in chemistry of natural products. New York; Springer Verlag 1973 30: p 263
-
12
Ito C, Itoigawa M, Miyamoto Y, Rao K S, Takayasu J, Okuda Y.
A new biflavanoid from Callophyllum panciflorum with antitumor activity.
J Nat Prod.
1999;
62
1668-71
-
13 Markham K R, Chari V M. C-13 NMR spectroscopy of flavanoids. In: Harborne JB, Mabry TJ (editors) The Flavanoids, Advances in Research. Chapman and Hall 1982: p 36
-
14
Simon A, Chulia A J, Kaouadji M, Delage C.
Quercetin 3-[triacetylarabinosyl(1→6)galactosidase] and chromones from Calluna vulgaris
.
Phytochemistry.
1994;
36
1043-5
-
15 Yamaguchi K. Spectral data of organic compounds. Amsterdam; Elsevier Publishing Co 1970 1: p 203
-
16
Akintowa A, Essein A R.
Protective effect of Garcinia kola seed extract against paracetamol induced hepatotoxicity in rats.
J Ethnopharmacology.
1990;
29
207-11
-
17
Kabangu K, Galeffi C, Aonzo E, Nicoletti M, Messana I.
A new biflavanone from the bark of Garciana kola
.
Planta Medica.
1987;
53
277
-
18
Kay L E, Keifer P, Saarinen T.
Pure absorption gradient enhanced heteronuclear single quantum correlation spectroscopy with improved sensitivity.
J Am Chem Soc.
1992;
114
10 663-5
-
19
Willker W, Leibfritz D, Kerssebaum R, Bermel W.
Gradient selection in inverse heteronuclear correlation spectroscopy.
Magn Reson Chem.
1993;
31
287-92
-
20
Bax A, Summers M F.
1H and 13C assignments from sensitivity-enhanced detection of heteronuclear multiple-bond connectivity by 2D multiple quantum NMR.
J Am Chem Soc.
1986;
108
2093-4
-
21
Markham K R, Sheppard C, Geiger H.
13C NMR studies of some of naturally occurring Amentoflavone and Hinokiflavone biflavonoids.
Phytochemistry.
1987;
26
3335-7
-
22 Günther H. NMR Spectroscopy. 2nd Edition. New York; John Wiley & Sons 1995: p 335
Prof. Dr. August Wilhelm Frahm
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