Polysaccharides play an important role in the pharmaceutical, food, and cosmetics areas which have useful properties for skin such as moisturizing, antioxidant ability, and improvement of elasticity. Among these properties, antioxidant activity was focused in this work. The accelerated ageing process through the free radicals generated by UV radiation could make serious damages on skin. Antioxidants are able to inhibit this process through oxidizing themselves, but unfortunately they are intrinsically highly unstable. Herein, the antioxidants were stabilized via chemical coupling with polysaccharides using epichlorohydrin as a coupling agent. The derivatives were purified through repeated precipitation, followed by dialysis against water and freeze drying. 1H-NMR and FT-IR characterizations confirmed that polyphenols were covalently bonded to polysaccharide backbone. The modified polysaccharides showed the same absorbance characteristics of UV-visible spectra as the raw antioxidants. Furthermore, its 2,2-diphenyl-1-picrylhydrazyl scavenging assay confirmed the polyphenols had antioxidant activity. The 3,4-dihydroxyphenylalanine structure presented in the antioxidants was found to improve the adhesion property of neat polysaccharide in shear  and tensile direction, which is similar to the adhesive functional group of mussel adhesive proteins. The modified polysaccharides have better solubility in water and lower viscosity than the pure polysaccharides. These unique properties could make the modified polysaccharides useful for functional encapsulation in the drug delivery, cosmetic active ingredient, and other related areas.

Tailoring the properties of polysaccharides for functional encapsulation

248th National Meeting (2014)

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