## 1 Introduction  
An imbalance in the generation of free radicals could induce oxidative stress in different mediums [1]. An elevated concentration of free radicals is responsible for the degradation of biomolecules which could lead to different pathophysiological conditions in the human body, or accelerated deterioration of different products and reduction of shelf life. Plant-based products, like extracts and essential oils, are being thoroughly investigated as natural agents with antioxidant activity for use as substitutes for potentially toxic conventional synthetic antioxidants such as propyl galle, butylatedhydroxytoluene, and butylatedhydroxyanisole [2]. Besides essential oils, some fatty oils obtained from plant seeds or berries have excellent antioxidant, anti-inflammatory, antimicrobial effects, among other effects [3]. Pomegranate and its extracts from all fruit parts were used through history from ancient times, as it was well known to have good activity [4; 5]. Nowadays it is the subject of many studies examining its chemical composition and mechanisms of activity. Pomegranate seed oil and fermented pomegranate juice extract are the most valuable products of pomegranate plants [6]. Together with them, sea-buckthorn oil is becoming an important component of cosmetic products in recent days, because of its specific combination of active ingredients [7]. Because of the high content of saturated and unsaturated fatty acids and many other valuable ingredients, they express antioxidant, anti-inflammatory, and regenerative effects to the skin [8]. They are often used in products for mature skin, and for treatment of wounds and scars. The only disadvantage of these oils is their high sensitivity to oxidation, which decreases their shelf life and limits the way of application. It is often suggested that the oils should be encapsulated in some polymer, which will maintain its activity for a more extended time [9]. Conventional techniques like extrusion, injection molding, or compression are not suitable for the production of cosmetic products containing natural compounds. Within all these techniques high temperature and/or pressure is applied, which has harmful effect on thermosensitive natural ingredients. Besides this, samples prepared this way are usually thick and lack flexibility, with low porosity and \"plastic\" feel on the skin. To ensure the activity of those materials, it is important to have a surface rich in active compounds, because the diffusion through the volume is very slow, and, in the short exposure time, often insufficient for getting an effect [10]. Also, the loading of the polymeric matrix with natural compounds needs to be very high, for successful surface activity, which increases the price of the final products. To avoid losses of valuable active compounds, encapsulation can be done by employing electrospinning technique. Electrospinning is a fiber-forming technique, where the process is running at room temperature and ambient pressure, and fiber production goes from highly viscous polymer-based solution influenced by the high voltage. On the way from the needle to the collector, two processes happened: elongation of the polymer solution and evaporation of the solvent, so at the collector nonwoven dry fibers are formed. Depending on the process parameters, it is possible to obtain different structures and morphologies of nanofibers and tailor materials' properties according to application requirements. Sensitive components like essential oils and plant extracts are now often encapsulated in nanofibers [11; 12; 13; 14; 15; 16; 17; 18; 19; 20; 21]. The main aim of this work was the examination of the antioxidant activity of functional materials containing pomegranate seed oil, sea-buckthorn oil, and extract of fermented pomegranate juice encapsulated into two different polymers: polylactide (PLA-based fibers) and poly(vinyl-pyrrolidone) (PVP-based fibers) using electrospinning technique.