| ABSTRACT: |
|
Ellagic acid [1] is a gallic acid dimer that occurs in plants, fruits,
and nuts, either in its free form, or in a series of ellagitannins, or as
a glucoside. It has been shown to inhibit cancer induced by several types
of chemical carcinogens including polycyclic aromatic hydrocarbons,
N-nitrosamines, aflatoxin, and aromatic amines. It has been extracted from
a number of fruits, including strawberries; however, its presence in the
extracts was determined only by hplc connected with a diode array
detector. In the present report, ellagic acid was isolated as a
tetrahexanoyl derivative 2 from Fragaria ananassa and identified by 13C
and 1H nmr and ms. The 13C-nmr shifts of the aromatic carbons adjacent to
a hexanoyloxy group were assigned using two new synthetic model compounds:
3,3'-dihexanoyloxydiphenic-2,2',6,6'-dilactone [3] and
4,4'-dihexanoyloxydiphenic-2,2',6,6'-dilactone [4]. Two new derivatives of
ellagic acid [1],3,3'-di-beta-D-glucopyranosylellagic acid decaacetate [5]
and 3,3'-di-n-octyl-4,4'-dihexanoylellagic acid [7], were also
synthesized. Both derivatives were less effective as inhibitors of
benzo[a]pyrene tumorigenesis in the lungs of strain A/J mice than ellagic
acid. |