Free-radical degradation of high-molar-mass hyaluronan induced by Weissberger's oxidative system: potential antioxidative effect of bucillamine.
OBJECTIVE
Hyaluronan (HA), one of the main components of extracellular matrix, is a glycosaminoglycan composed of repeating disaccharide units of N-acetyl-d-glucosamine and d-glucuronic acid linked by β-(1→4) and β-(1→3) glycoside bonds. High-molar-mass HA was used as a model for studying its oxidative degradation. In the present paper protective effects of bucillamine against the free-radical degradation of HA were investigated. The HA fragments generated were characterized as well.


METHODS
To induce free-radical-mediated degradation of high-molar-mass HA under aerobic conditions, we applied Weissberger's oxidative system, comprising biogenic compounds in relevant pathophysiological concentrations, i.e. 100 µM ascorbate plus 1 µM Cu(II). Time-dependent decreases of dynamic viscosity of the HA solutions were recorded by rotational viscometry. Electron donor behaviors of bucillamine were studied by a standard ABTS test method and a chemiluminescence (CL) assay. Ability of incorporation of generated bucillamine thiyl radicals into the biopolymer was verified by Fourier-transform infrared spectroscopy (FT-IR) and size exclusion chromatography with a multi-angle light scattering photometer (SEC-MALS).


RESULTS
Decrease of HA viscosity reflected HA degradation. The drug tested was applied in two arrangements: to prevent •OH radical generation (1) and ROO• type radicals propagation (2). Bucillamine, which acted as an efficient •H donor, is also a proper electron donor, as proved by ABTS and CL assays. FT-IR and SEC-MALS methods showed that the drug tested did not incorporate into the biopolymer chains.


CONCLUSIONS
Bucillamine significantly protected high-molar-mass HA against free-radical degradation in vitro, and supposedly this positive action of the drug may be involved in its beneficial effect observed in clinical practice.
Institute of Experimental Pharmacology and Toxicology, Slovak Academy of Sciences, Bratislava, Slovakia. maria.banasova@savba.sk
Maria
M
Banasova
Vlasta
V
Sasinkova
Raniero
R
Mendichi
Tomas
T
Perecko
Katarina
K
Valachova
Ivo
I
Juranek
Ladislav
L
Soltes
D000975:Antioxidants / Q000737:chemistry* / Q000494:pharmacology; D001205:Ascorbic Acid / Q000737:chemistry / Q000494:pharmacology; D003300:Copper / Q000737:chemistry / Q000494:pharmacology; D003545:Cysteine / Q000031:analogs & derivatives* / Q000737:chemistry / Q000494:pharmacology; D005109:Extracellular Matrix / Q000737:chemistry; D005609:Free Radicals / Q000737:chemistry*; D006801:Humans; D006820:Hyaluronic Acid / Q000737:chemistry*; D008970:Molecular Weight; D010084:Oxidation-Reduction; D017550:Spectroscopy, Fourier Transform Infrared; D014783:Viscosity / Q000187:drug effects
D000975:Antioxidants; D005609:Free Radicals; D003300:Copper; D006820:Hyaluronic Acid; D003545:Cysteine; D001205:Ascorbic Acid; C026535:bucillamine