80044-63-9Relevant academic research and scientific papers
POLYPHENOLIC COMPOUNDS FROM CROTON LECHLERI
Cai, Y.,Evans, F. J.,Roberts, M. F.,Phillipson, J. D.,Zenk, M. H.,Gleba, Y. Y.
, p. 2033 - 2040 (2007/10/02)
The blood-red sap of Croton lechleri was found to contain proanthocyanidins as major constituents which accounted for up to 90percent of the dried weight.In addition to (+)-catechin, (-)-epicatechin, (+)-gallocatechin, (-)-epigallocatechin and dimeric procyanidins B-1 and B-4, five novel dimers and trimers were isolated and characterized as catechin-(4α->8-epigallocatechin, gallocatechin-(4α->8)-epicatechin, gallocatechin-(4α->6)-epigallocatechin, catechin-(4α->8)-gallocatechin-(4α->8)-gallocatechin and gallocatechin-(4α->8)-gallocatechin-(4α->8)-epigallocatechin.Higher oligomers were also obtained.A new procedure combining chemical degradation with 1H NMR spectroscopy has been developed for determination of the composition and molecular size of oligomeric/polymeric proanthocyanidins.The oligomers of the sap were shown to have the mean degree of polymerization of 4,5-6 and 6-7, respectively, and Mr up to 2130.The heterogeneity of the oligomers was clearly indicated by the presence of a variety of flavan-3-ols as extension and terminal units.An exceptionally high content of gallocatechin and epigallocatechin in the oligomers was observed.Key Word Index: Croton lechleri; Euphorbiaceae; Sangre de Grado; Dragon's blood; polyphenol; proanthocyanidins; flavan-3-ols; procyanidins; prodelphinidins.
Tannins and Related Compounds. LXXVII. Novel Chalcan-flavan Dimers, Assamicains A, B and C, and a New Flavan-3-ol and Proanthocyanidins from the Fresh Leaves of Camellia sinensis L. var. assamica KITAMURA
Hashimoto, Fumio,Nonaka, Gen-ichiro,Nishioka, Itsuo
, p. 77 - 85 (2007/10/02)
Three novel chalcan-flavan dimers, assamicains A (1), B (2) and C (3), and a new flavan-3-ol (14) and proanthocyanidins (19,20) have been isolated, together with the known flavan-3-ols (4-13), proanthocyanidins (15-18,21), theasinensins (22-24) and hydrolyzable tannins (25,26), from the fresh leaves of Camellia sinensis var. assamica (Camelliaceae), and their structures have been established on the basis of spectroscopic evidence in conjunction with thiolytic degradation and enzymatic hydrolysis. - Keywords: Camellia sinensis var. assamica; Camelliaceae; polyphenol; assamicain; chalcan-flavan dimer; proanthocyanidin; theasinensin; flavan-3-ol; hydrolyzable tannin; black tea
