POLYPHENOLIC COMPOUNDS FROM CROTON LECHLERI

Article abstract of DOI:10.1016/0031-9422(91)85063-6

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 M_r 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.