Tellimagrandin II (TG-II)

Tellimagrandin II is the first of the ellagitannins formed from 1,2,3,4,6-pentagalloyl-glucose. Tellimagrandin II is an isomer of punicafolin or nupharin A, but the hexahydroxydiphenoyl group is not attached to the same hydroxyl groups in the glucose molecule. The compound shows anti-herpesvirus properties. It is formed by oxidation of pentagalloyl glucose in Tellima grandiflora by the enzyme pentagalloylglucose: O(2) oxidoreductase, a laccase-type phenol oxidase. It is further oxidized to casuarictin, a molecule formed via oxidative dehydrogenation of 2 other galloyl groups in Casuarina and Stachyurus species. A new enzyme has been isolated from leaves of the weed Tellima grandiflora (fringe cups, Saxifragaceae) that catalyzed the O(2)-dependent oxidation of 1,2,3,4,6-penta-O-galloyl-beta-D-glucopyranose to tellimagrandin II, the first intermediate in the (4)C(1)-glucose derived series of ellagitannins.