Increasing photostability and water-solubility of carotenoids: synthesis and characterization of β-carotene-humic acid complexes.
Carotenoids are a group of phytochemicals that are recognized as playing an important role in the prevention of several degenerative diseases due to their antioxidant activity. The low water-solubility and poor photostability of β-carotene, a potentially important dietary antioxidant, prompted us to investigate β-carotene complexes able to increase its water solubility as well as its photostability in aqueous solution. In this work we have used humic acid in order to synthesize β-carotene-humic acid complexes in different ratios. Complexes were characterized by FT-IR and DSC. β-Carotene determination were performed by HPLC and antioxidant activity of β-carotene, humic acid and the complexes were determined by the TEAC method. The formulation β-carotene-humic acid 2:1 showed the highest photostability and water solubility. The antioxidant activity of the complexes was about 20 times lower than "free" β-carotene, suggesting a decreased chemical reactivity of the carotenoid in the complex. We showed that complexation of β-carotene with humic acids was able to increase its water solubility and photostability, and to affect the antioxidant activity of β-carotene after inclusion in HAs. This work provides a useful tool to avoid antioxidants photodegradation and oxidation by radicals, thus maintaining their biological activity.
Martini
Silvia
S
Department of Pharmaceutical and Applied Chemistry, University of Siena, 53100 Siena, Italy. martinis@unisi.it
D'Addario
Claudia
C
Bonechi
Claudia
C
Leone
Gemma
G
Tognazzi
Antonio
A
Consumi
Marco
M
Magnani
Agnese
A
Rossi
Claudio
C
D000975:Antioxidants / Q000138:chemical synthesis* / Q000737:chemistry; D002152:Calorimetry, Differential Scanning; D006812:Humic Substances; D010084:Oxidation-Reduction; D010782:Photolysis; D012995:Solubility; D017550:Spectroscopy, Fourier Transform Infrared; D014867:Water / Q000737:chemistry*; D019207:beta Carotene / Q000737:chemistry*
D000975:Antioxidants; D006812:Humic Substances; D019207:beta Carotene; D014867:Water