Topical application of Calendula officinalis (L.): Formulation and evaluation of hydrophilic cream with antioxidant activity

The aim of the study was the formulation of suitable medicinal form for the topical application of Calendula officinalis L. Dry Calendula extract was used as an active compound. This extract was proved to be an effective scavenger of H2O2 radicals in in vitro studies with the mitochondria of rat cardiac muscles. Several compositions of the cream base were evaluated and the hydrophilic cream containing complex emulsifier was chosen as the delivery system. Subsequently, Calendula extract was incorporated, and the concentration of extract which provided significant antioxidant effect (p < 0.05), has been determined. Antioxidant activity of the cream with Calendula extract was due to the content of carotenoids, polyphenols and flavonoids. Cream with the best properties (0.9% of Calendula extract) contained 0.73 +/- 0.04 mg/100 g of total carotenoids expressed as beta-carotene. This cream was then examined microscopically, and stability studies including evaluation of organoleptic properties, microbiologic quality, and determination of variations in total carotenoid content during the storage were made. Achieved results suggest that developed cream with Calendula extract poses the good-quality emulsion system warranting the stability of carotenoids, and thus the therapeutic, namely antioxidant activity of preparation.