**Abbreviations**

*3.4.3. Iron chelating properties of esculin and polyesculin fractions*

with the E5 fraction which was 30-folds more active than esculin.

to the loss of these groups during the rutin polymerization reaction.

*versicolor*. These polymers were fractioned by diafiltration process.

analyses indicated the presence of only C-C bond.

*3.4.4. CUPRAC of esculin and polyesculin fractions*

**3.5. Structure-antioxidant activity relationship**

in rutin polymerization reaction [44-47].

µM).

128 Biotechnology

reaction.

**4. Conclusion**

Polyesculin fractions exhibited high degree of iron chelating activity, according to the sitespecific hydroxyl radical-scavenging assay (Table 3). Results showed that iron chelating capacity was high as the *Mw* ¯ increases. The best iron chelating power was observed in the

presence of the E5 fraction (IC50=180 µM), which was 37-folds better than esculin (IC50=6800

Table 3 indicated that polyesculin fractions presented higher TEAC than esculin. This activity rose as the *Mw* ¯ increased. Therefore, the best cupric reducing antioxidant capacity was seen

The structure-antioxidant activity relationship of monomeric flavonoids and coumarins was well investigated. According to many authors [43] free hydroxyl groups on C4', C3' and C7 played a major role in antiradical activity of rutin and esculin. However, few data are available about the behaviour of these activities with polymerization. In this work we observed a decrease of polyrutin antiradical activities with *Mw* ¯ increase. This decrease could be attributed

For high iron chelating power and CUPRAC, hydroxyl groups on C5, C3 and the 4 oxo (for flavonoids) and hydroxyl groups and catechol moiety (for coumarins) were essential. So, high iron chelating and cupric reducing antioxidant capacities observed with polyrutin and polyesculin fractions suggested that these groups were not implicated in the linkage occurred

For high xanthine oxidase inhibition activity, several works reported the importance of the presence of a double bond between C2 and C3 and free hydroxyl groups on C5 and C7 [26, 48-50]. High inhibition of the xanthine oxidase obtained in the presence of polyrutin and polyesculin fractions implicated that these groups are not affected during the polymerization

Polyphenolic polymers of rutin and esculin were synthesized using a laccase from *Trametes*

The analyses of rutin polymers by FTIR showed the presence of new C-C and C-O bonds and the desperation of a C-H bond on monomer. These results suggested that polyrutin were synthesized through phenylene and oxyphenylene units. For polyesculin fraction, FTIR

Free radical scavenging activity of rutin was decreased by the enzymatic polymerization while polyesculin fractions showed a high antiradical activity compared to monomeric esculin. This AAPH: 2,2′-azobis (2-amidinopropane)dihydrochloride ; ABTS: 2,2′-azino-bis(3methylbenze‐ nothiazoline-6-sulfonic acid) diammonium salt; ATR: Attenuated Total Reflectance; CuCl2: Copper (II) chloride; DMF: dimethylformamide; DMSO: and dimethyl sulfoxyde; DPPH: 2-2 diphenyl-1-picrylhydrazyl; EDTA: Ethylenediaminetetraacetic acid; FTIR: Fourier Trans‐ formed InfraRed analysis; H2O2: Hydrogen peroxide; HOMO: Highest occupied molecular orbital; HRP: Horseradish peroxidises; IM: weight average molecular mass index; LDL: Lowdensity lipoprotein; LiBr: Lithium bromide; *M*¯ *<sup>n</sup>* : Number-average molecular mass; *Mw* ¯: Weight-average molecular mass; NH4Ac: Ammonium acetate; NH4Ac: Ammonium acetate; TBA: Thiobarbitulic acid; TCA: Trichloroacetic; TEAC: Trolox equivalent antioxidant capacity; Trolox: 6-hydroxy-2,5,7,8-tetramethylchroman-2- carboxylic acid; XO: Xanthine oxidase
