engleski

Antioxidant activities of several Croatian honeys studied by electrons spin resonance

Honey as a bee product has been consumed for its high nutritive value and its contribution in health. Since honey is a complex system containing a variety of organic compounds its antioxidant activity greatly depend on the floral source. In this study the antioxidant properties of four honey samples from different floral sources and various Croatian regions: acacia honey (Robinia pseudoacacia), amorfa honey (Amorpha fruticosa), chestnut honey (Castanea sativa) and meadow honey. The experiments were performed using freshly prepared honey solutions in distilled water (w = 5 %). DPPH (1, 1-diphenyl-2-picrylhydrazyl) has been used as a source of free radicals. The capacity of honey solutions to quench the semi-stable free radicals has been monitored by electron spin resonance (ESR) spectroscopy (Bruker BioSpin GmbH, Rheinstetten, Germany) working in the X-band. Reference experiments were performed with artificial honey. The results obtained in this study show that meadow honey has the highest capability to quench DPPH radicals. The spin trapping agent, 5, 5-dimethyl-1-pyrroline N-oxide (DMPO) has been used for investigation hydroxyl radical production. Hydroxyl radical formation was studied by ESR and spin trapping, and it was found in all honeys tested proving their antimicrobial activity. Furthermore, the correlation between the colour of honeys and their antioxidant properties has been found in this study. This correlation may be useful for consumers, when looking for products with the highest antioxidant activity.

ESR; honey; antioxidans

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