Biologically Active Poly[3-(3,4-Dihydroxyphenyl)Glyceric Acid] from Borago officinalis (Boraginaceae)

Abstract

A high-molecular water-soluble preparation from stems of Borago officinalis (Boraginaceae family) was isolated. According to data from UV, IR, ¹H, ¹³C NMR, gCOSY and 2D heteronuclear ¹H/¹³C gHSQCED experiments, the main chemical constituent of this water-soluble high-molecular preparation from stems of Borago officinalis (HMP-BS) was found to be a biologically active caffeic acid-derived polymer, namely poly[oxy-1-carboxy-2-(3,4-dihydroxy­phenyl)­ethylene] also referred to as poly[3-(3,4-dihydroxyphenyl)glyceric acid] (PDPGA). PDPGA was previously detected in high-molecular preparations of Symphytum asperum, S. caucasicum, S. officinale, Anchusa italica and Cynoglossum officinale. The detection of this compound in different genera of the Boraginaceae family is interesting as this unusual caffeic acid-derived polymer could be consider a chemotaxonomic marker among Boraginaceae plants. Thus, PDPGA is interesting due to the importance of its chemotaxonomic significance, the potential biomedical applications of the Boraginaceae plants and the chemical importance of PDPGA. The presence of poly[3-(3,4-dihydroxy­phenyl)­glyceric acid] in multiple Boraginaceae species expands the resources of raw materials for this biologically active polymer.