COMPARISON OF CHEMICAL COMPOSITION AND ANTIOXIDANT ACTIVITY OF GLYCOSIDICALLY BOUND AND FREE VOLATILES FROM CLOVE (EUGENIA CARYOPHYLLATA THUNB.)

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Abstract

ABSTRACT

The present article reports on the chemical composition and antioxidant activity of clove glycosidically bound volatile compounds in comparison with their essential oil. The comparison of chemical composition of volatile aglycones with the chemical composition of essential oil revealed only eugenol as identical. To measure the antioxidative activity of the clove enzymatically released aglycones and its essential oil, two different assays were performed: the 2,2′-diphenyl-1-picrylhydrazyl (DPPH) radical-scavenging method and the ferric reducing/antioxidant power (FRAP) assay. Both methods showed that the clove volatile aglycones possess lower antioxidant properties than its essential oil. The volatile aglycones radical-scavenging activity measured by DPPH method was lower than butylated hydroxytoluene (BHT) and butylated hydroxyanisole (BHA) activity. The reducing capacity measured by FRAP method for volatile aglycones was lower than BHA capacity and higher than BHT capacity. Some differences in activity obtained by two methods could be explained with different solvent polarity.

PRACTICAL APPLICATIONS

Many secondary metabolites are glycosylated and accumulate as nonvolatile glycosides. Since the glycosides are able to release their aglycones by enzymatic hydrolysis, these compounds could be considered as possible precursors of antioxidant substances in plant. They may contribute to the total antioxidant activity of plant and could be used as natural antioxidants.

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