Evaluation of functional stability of quercetin as a raw material and in different topical formulations by its antilipoperoxidative activity.
The present study evaluates the antioxidant activity of the flavonol quercetin, and its functional stability as a raw material and when added in formulations. The iron-chelating activity was determined using the bathophenanthroline assay, and the functional stability was evaluated with the antilipoperoxidative assay. Raw material presented concentration-dependent antilipoperoxidative and iron-chelating activities. The initial antilipoperoxidative activity of the raw material, cream and gel-cream were 63%, 78%, and 69%, respectively. There was no detectable loss of activity during 182 days (6 months) of storage at all tested temperatures (4 degrees C, room temperature [RT], 37 degrees C, and 45 degrees C) for the raw material. Considering the method variability of 10%, activity loss greater than 10% for nonionic cream was detected after 126 days at 4 degrees C (20.1%), decreasing thereafter to 22.2% after 182 days. At 45 degrees C, the loss of activity started after 182 days (13.2%). For the anionic gel-cream, activity loss started after 84 days (28.4%, 45 degrees C), decreasing after 182 days to 40.3% at 45 degrees C. At 37 degrees C, activity loss was detected after 182 days (12%). In conclusion, the results suggest that the activity of quercetin depends on iron chelation, and its possible usefulness as a topical antioxidant to prevent oxidative stress-induced skin damage depends on maintaining its antilipoperoxidative activity stored at RT, which avoids special storage conditions.
Casagrande
Rúbia
R
Department of Pharmaceutical Science, Faculty of Pharmaceutical Sciences of Ribeirao Preto - University of Sao Paulo, Sao Paulo, Brazil. rubiacasa@yahoo.com.br
Georgetti
Sandra R
SR
Verri
Waldiceu A
WA
Jabor
José R
JR
Santos
Antonio C
AC
Fonseca
Maria J V
MJ
D000287:Administration, Topical; D000975:Antioxidants / Q000008:administration & dosage*; D002626:Chemistry, Pharmaceutical; D004305:Dose-Response Relationship, Drug; D004355:Drug Stability; D007502:Iron Chelating Agents / Q000494:pharmacology; D015227:Lipid Peroxidation / Q000187:drug effects*; D011794:Quercetin / Q000008:administration & dosage* / Q000737:chemistry / Q000494:pharmacology; D013696:Temperature
D000975:Antioxidants; D007502:Iron Chelating Agents; D011794:Quercetin