Tannins and related compounds. XLI. Isolation and characterization of novel ellagitannnins, punicacorteins A, B, C and D, and punigluconin from the bark of Punica granatum L
A chemical examination of the bark of Punica granatum L. (Punicaceae) has led to the isolation of five new ellagitannins, punicacorteins A, B, C and D, and punigluconin, together with the known ellagitannins, casuariin (6) and casuarinin (7). Based on chemical and spectroscopic evidence, the structures of punicacorteins A, B, C and D were established as novel C-glycosideic ellagitannins, the former two possessing a unique tetraphenyl (gallagyl) ester group (1 and 2), and the latter two containing a galloyl group in place of the gallagyl group (3 and 4), while punigluconin was characterized as 2,3-di-O-galloyl-4,6-(S)-hexahydroxydiphenoylgluconic acid (5).
- Chem. Pharm. Bull.
Chem. Pharm. Bull. 34, 656-663, 1986