Vakhtang Barbakadze
Tbilisi State Medical University, Georgia
Title: Natural Plant Polymer – a Prospective Therapeutic Agent
Biography
Biography: Vakhtang Barbakadze
Abstract
Within the field of pharmacologically active biopolymers the area of stable polyethers seems rather new and attractive. The high-molecular water-soluble fractions from different species (Symphytum asperum, S.caucasicum, S.officinale, S.grandiflorum and Anchusa italica) of Boraginaceae family were isolated. According to IR, 13C and 1H NMR, 2D heteronuclear 1H/13C HSQC spectral data, and 1D NOE and 2D DOSY experiments the main structural element of these preparations was found to be a regularly substituted by 3,4-dihydroxyphenyl and carboxyl groups polyoxyethylene backbone, namely poly[3-(3,4-dihydroxyphenyl)glyceric acid] (PDPGA) or poly[oxy-1-carboxy-2-(3,4-dihydroxyphenyl)ethylene]. The racemic monomer 2,3-dihydroxy-3-(3,4-dihydroxyphenyl)propionic acid (DDPPA) and its enantioselective synthesis of virtually pure enantiomers, (+)-(2R,3S)-2,3-dihydroxy-3-(3,4-dihydroxyphenyl)-propionic acid and (–)-(2S,3R)-2,3-dihydroxy-3-(3,4-dihydroxyphenyl)-propionic acid were carried out for the first time via Sharpless asymmetric dihydroxylation of trans-caffeic acid derivatives using the enantiocomplementary catalysts (DHQ)2-PHAL and (DHQD)2-PHAL. The determination of enantiomeric purity of the novel chiral glyceric acid derivatives was performed by high-performance liquid chromatographic techniques on the stage of their alkylated precursors. PDPGA has wide spectrum of biological activity: anticomplementary, antioxidant, antiinflammatory properties, burn and wound healing effect. PDPGA and DDPPA exerted anti-cancer efficacy in vitro and in vivo against androgen-dependent and –independent human prostate cancer (PCA) cells via targeting androgen receptor, cell cycle arrest and apoptosis without any toxicity, together with a strong decrease in prostate specific antigen level in plasma. However, our results showed that anticancer efficacy of PDPGA is more effective compared to its synthetic monomer. Overall, this study identifies PDPGA as a potent agent against PCA without any toxicity, and supports its clinical application.