Asian J Beauty Cosmetol. 2014; 12(2): 203-210.
Comparison of Antioxidant Activity of Kenaf Extract and its Flavonoids
ABSTRACT
In this work, the antioxidant activities of kaempferitrin, afzelin, rhamnoisorobin and kaemferol, which are the main flavonols of Hibiscus cannabinus L were studied. Kaempferol, aglycone of kaempferitrin, was found to be the most effective antioxidant and the antioxidant activity was decreased in the order of rhamnoisorobin, afzelin and kaempferitrin. The difference of DPPH radical scavenging activity between kaempferol and kaempferitrin was as high as 26.6 times. Although they have the same main structure except that they have two rhamnose (kaempferitrin) or one rhamnose (rhamnoisorobin, afzelin) or no rhamnose (kaemperol), the antioxidant activities of them were very different. The cause of this difference is not yet clear, but it seems that the rhamnose in the flavonol plays a critical role to determine the antioxidant activity of flavonols. From this result, we could conclude that the flavonoids with glycoside extracted from many kinds of plants should be converted into aglycones before they are employed as the antioxidant ingredient of cosmetics.
Keywords :
Kaempferol, Kaempferitrin, Kenaf, Flavonoids, Antioxdant activity
