Enzymatic Synthesis and Antimicrobial Activity of Oligomer Analogues of Medicinal Biopolymers from Comfrey and Other Species of the Boraginaceae Family

This study reports the first enzymatic synthesis leading to several oligomer analogues of poly[3-(3,4-dihydroxyphenyl)glyceric acid]. This biopolymer, extracted from plants of the Boragi-naceae family has shown a wide spectrum of pharmacological properties, including antimicrobial activity. Enzymatic ring opening polymerization of 2-methoxycarbonyl-3-(3,4-dibenzyloxyphenyl)oxirane (MDBPO) using lipase from Candida rugosa leads to formation of poly[2-methoxycarbonyl-3-(3,4-dibenzyloxyphenyl)oxirane] (PMDBPO), with a degree of polymerization up to 5. Catalytic debenzylation of PMDBPO using H2 on Pd/C yields poly[2-methoxycarbonyl-3-(3,4-dihydroxyphenyl)oxirane] (PMDHPO) without loss in molecular mass. Antibacterial assessment of natural polyethers from different species of Boraginaceae family Symhytum asperum, S. caucasicum, S. grandiflorum, Anchusa italica, Cynoglossum officinale, and synthetic polymers, poly[2-methoxycarbonyl-3-(3,4-dimethoxyphenyl)oxirane (PMDMPO) and PMDHPO, reveals that only the synthetic analogue produced in this study (PMDHPO) exhibits a promising antimicrobial activity against pathogenic strains S.aureus ATCC 25923 and E.coli ATCC 25922 the minimum inhibitory concentration (MIC) being 100 µg/mL

Synthesis and Micellization of Linear−Dendritic Copolymers and Their Solubilization Ability for Poorly Water-Soluble Drugs

A series of linear-dendritic copolymers were synthesized by conjugating BE block copolymers (B8E41 and B16E42, B=1,2-butylene oxide and E=ethylene oxide) with G1-3 PAMAM dendrimers via carbamate bonds. The critical micelle concentrations of the dendrimer conjugates were less than 0.11 mmol dm-3. Light scattering measurements indicated that “flowerlike” micelles were formed when two B chains from each conjugate entered the micelle core. Further association of the micelles was found for the conjugates containing more than two BE chains per dendrimer. Drug solubilization in micellar solutions of the conjugates was mainly by the incorporation of drug molecules in micelle cores, with marginal enhancement of solubility attributable to encapsulation in the dendritic micelle coronas. The solubility of hydrophobic drugs in 1 wt%micellar solutions was increased up to 6-fold. Solubilization of ionic drugs was unfavorable due to the limited penetration of ionized drug molecules into the micelle cores