Isolation of Ellagitannin Monomer and Macrocyclic Dimer from Castanopsis carlesii Leaves

In a phytochemical and chemotaxonomical investigation of Castanopsis species (Fagaceae), new monomeric and dimeric ellagitannins, named carlesiins A (1) and B (2), were isolated from fresh leaves of Castanopsis carlesii along with 55 known compounds. Carlesiin A was identified as 1-O-galloyl-4,6-(S)- tergalloyl-ß-D-glucose. Carlesiin B is a macrocyclic ellagitannin dimer with a symmetrical structure composed of two tergalloyl and two glucopyranose moieties. Their structures were elucidated based on spectroscopic and chemical evidence