Deveplopment of cream including plant and microalgae investigation of their antioxidant and anti-tyrosinase enzyme activities by analytical methods

With in the scope of this thesis, an extraction method was developed for Alpinia officinarum (galangal) belonging to the Zingiberaceae family, and the phenolic substances in the extracts were quantitatively determined by HPLC-DAD (high performance liquid chromatography-diode series detector). In addition, the total phenolic substance and antioxidant capacity values in the extracts of four different polarities (80% ethanol, 80% methanol, 50% ethanol and 50% methanol) were determined. Galangin was purified from the extract with column chromatography by using 80% ethanol extract including the highest galangin content. Subsequently, after galangin was encapsulated with betacyclodextrin, the residue of galangin-betacyclodextrin was used in hydrogel making by using sodium alginate and CaCl2. For maximum galangin release, the conditions for forming galangin-alginate hydrogel were optimized by the central composite design method. According to the ANOVA analysis results, the percentage of sodium alginate was 0.69% (w/v); percentage of CaCl2 1% (w/v); time 43.55 (min); extract percentage was found to be 0.48% (w/v). The galangin release concentration obtained from the hydrogel made with these values was found to be compatible with the estimated value. Structural characterization studies of the obtained galangin-alginate hydrogel were also performed with FT-IR and SEM. As microalgae Chlorella vulgaris sample was also extracted and its antioxidant properties were determined. Subsequently, galangin-betacyclodextrin residue, C. vulgaris residue and galangin-alginate hydrogel were added to the cream samples, and the antioxidant properties and antityrosinase effects of the creams were also investigated. It was concluded that the cream samples prepared in our study could be candidate samples.