The Optimization of Antioxidant Properties of Herbal Bathing Salts

The antioxidant properties 4 herbal infusions (of lavender flower, melissa leaf, verbena herb, and birch leaf), 2 salts (Dead Sea and Bochnia Mine salts) and 8 herbal salts (combination of herbal extract and salt) have been evaluated by 2,2-diphenyl-1-picrylhydrazyl-ESR (DPPH-ESR) test, ferric reducing antioxidant power and spin trap ESR using the Fenton reaction. The influence of herbal extracts and herbal salts on lipid membrane permeability has been studied with the spin probe ESR in the range of 293-323 K. The highest antioxidant activity was determined for melissa leaf preparations followed by birch leaf preparations in DPPH and ferric reducing antioxidant power assays whereas in the Fenton reaction the highest radical scavenging was observed for verbena herb and melissa leaf preparations. The lowest membrane permeability was observed in the presence of infusions of melissa and birch leaves, followed by corresponding herbal salts based on Bochnia Mine salt, and it was lower than in the reference system. On the other hand, lavender infusion increased the permeability of the model membrane, whereas the lavender salts decreased it. Therefore, the antioxidant activity of herbal infusions and salts towards skin could be inhibited by a lowered permeability. Thus, the combination of permeability studies with antioxidant studies in the presence of model lipids could be potentially used for optimization of other types of herbal bath salts.