Due to the enormous variety of phytochemicals present in plants, their extracts have been used for centuries in the treatment of innumerable diseases, being perceived as an invaluable source of medicines for humans. Furthermore, the combination of different plants was reported as inducing an improved effect (synergism) in comparison with the additive activity of the plants present in those mixtures. Nevertheless, information regarding the effects of plant infusions added with honey is still rather scarce. Accordingly, the aim of this study was to evaluate the interaction between chestnut honey, a natural product with well-reported beneficial properties, and three medicinal plants (either as a single plant or as combinations of two and three plants), with regard to their antioxidant activity and hepatotoxicity. Antioxidant activity was evaluated by comparing the results from four different assays; hepatotoxicity was assessed in two different cell lines. Results were compared by analysis of variance and linear discriminant analysis. The addition of honey to the infusions had a beneficial result in both cases, producing a synergistic effect in all samples, except β-carotene bleaching inhibition for artichoke + milk thistle + honey preparation and also preparations with lower hepatotoxicity, except in the case of artichoke + honey. Moreover, from the discriminant linear analysis output, it became obvious that the effect of honey addition overcame that resulting from using single plant or mixed plant based infusions. Also, the enhanced antioxidant activity of infusions containing honey was confirmed by lower hepatotoxicity.
The authors are grateful to Foundation for Science and Technology (FCT, Portugal) for financial support to the research centre CIMO (strategic project PEst-OE/AGR/UI0690/2011) and L. Barros researcher contract under “Programa Compromisso com Ciência – 2008”.
