Tbilisi State Medical University Institute of Pharmacochemistry, Georgia

Title: Novel biologically active caffeic acid-derived biopolymer from different species of Boraginaceae family with potential therapeutic effect


He has completed his Ph.D and D.Sci. at the ages of 33 and 54 years from Zelinsky Instiute of Organic Chemistry, Moscow, Russia and Durmishidze Institute of Biochemistry and Biotechnology, Tbilisi, Georgia, respectively. 2006 up to date he is the head of laboratory of plant biopolymers at the Tbilisi State Medical University Institute of Pharmacochemistry. 1996 and 2002 he has been a visiting scientist at Utrecht University (faculty of pharmacy), The Netherlands, by University Scholarship and The Netherlands organization for scientific research (NWO) Scholarship Scientific Program, respectively. He has published more than 64 papers in reputed journals.


The high-molecular fractions from species of two genera (Symphytum and Anchusa) of Boraginaceae family Symphytum asperum, S.caucasicum, S.officinale and Anchusa italica were isolated. According to IR, 13C and 1H NMR, 2D heteronuclear 1H/13C HSQC spectral data, the main structural element of these preparations was found to be a regularly substituted polyoxyethylene, namely poly[3-(3,4-dihydroxyenyl)glyceric acid] (PDPGA) or poly[oxy-1-carboxy-2-(3,4-dihydroxyphenyl)ethylene]. Such caffeic acid-derived biopolymer to our knowledge has not been known and has been identified for the first time. This compound represents a new class of natural polyethers with a residue of 3-(3,4-dihydroxyphenyl)glyceric acid as the repeating unit. Most of the carboxylic groups of PDPGA from A. italica unlike the polymer of S.asperum, S.caucasicum and S.officinale are methylated. The 2D DOSY experiment gave the similar diffusion coefficient for the methylated and non-methylated signals of A. italica PDPGA. Both sets of signals fell in the same horizontal. This would imply a similar molecular weight for methylated and non-methylated polymers. S.caucasicum PDPGA inhibited the growth of androgen-dependent and –independent prostate cancer (PCA) cells both in vitro and in vivo. Consistent with in vitro results, in vivo study showed that PDPGA feeding of mice strongly inhibited 22Rv1 tumors growth by 88% at 5 mg/kg body weight doses for 5 weeks, without any toxicity, together with a strong decrease in androgen receptor and prostate specific antigen expression but increase in apoptosis in tumor tissues from PDPGA-fed mice. Overall, present study identifies PDPGA as a potent agent against PCA without any toxicity, and supports its clinical application.

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