Phenolic Content and Antioxidant Activity in Honey of Various Floral Origin

Abstract

Background: Honey has been used since ancient times due to its sensory, nutritional, and therapeutic properties [1]. The antioxidant activity of honey is related to its chemical composition, mainly to phenolic compounds. [1,2]. Because the chemical composition and biological properties of honey is highly dependent on its botanical origin, the investigation of these characteristics are very important. Aim: to determine the total phenolic content (TPC) and the antioxidant activity in vitro of honey samples (lime, buckwheat and forest honey), collected in Lithuania. Methods: lime honey was colected in 2023 from the apiary, Kaunas district (54.9025° N, 23.8043° E), forest honey in Ignalina dictrict (55.4338° N, 26.3101° E) and buckwheat honey in Trakai district (54.6238° N, 25.1113° E).). 1 g honey was dissolved in 10 ml water or 70% ethanol. TPC was investigated by Folin-Ciocâlteu assay, antioxidant activity in vitro by ABTS and CUPRAC assays. Results: The highest total phenolic content was evaluated in buckwheat honey (2.33±0.42 mg GRE/g and 2.70±0.02 mg GAE/g), in both, water and ethanol solutions, respectively, whereas in forest honey it was 0.48±0.01 mg GAE/g and 0.68± 0.32 mg GAE/g, respectively. Lime honey contained the lower total phenolic content (0.27±0.01 mg GAE/g and 0.59±0.18 mg GAE/g, p<0.05). The highest reducing activity in vitro using CUPRAC assay was determined in both, water and ethanol solutions from buckwheat honey 1.04±0.10 µmol TE/g and 0.67±0.01 µmol TE/g, respectively, vs 0.30±0.05 µmol TE/g and 0.72±0.20 µmol TE/g in forest honey. The highest antiradical activity in vitro by using ABTS assay was also determined in buckwheat honey. Conclusion: our results showed that all investigated types of honey possess antioxidant (antiradical and reducing) activities, and its phytochemical composition, as well as antioxidant activity, varies among the honey of different sources. The highest reducing and antiradical activity in vitro and the highest total phenolic content contains buckwheat honey.