Solar radiation or sunlight, emitted by the sun electromagnetic radiation, has a positive and a negative effect on the human organism. The undesirable effects include skin aging, generation of free radicals and the process of carcinogenesis. To avoid these negative effects, the protection is used in the form of a wide range of cosmetic products with UV radiation protection properties. New formulas, recipes, or forms of products and new sunscreen ingredients have been widely examined [1,2] In accordance with the growing needs of consumers and environmental aspects, natural plant sources of ingredients with UV radiation protection properties are essential to be studied and applied commercially. Solar radiation includes three types of light: infrared, visible and ultraviolet. The last one occurs in the smallest quantity, accounts for only 5% of all sunlight and can be divided into three ranges: UVA, UVB and UVC [1]. For UVA range the wavelength is from 320 to 400 nm and can be divided into UVA2 (wavelength 320–340 nm) and UVA1 (wavelength 340–400 nm). Among ultraviolet radiation, UVA makes up 95% of all UV range and can penetrate deeper layers of the skin, but its intensity depends only in small extent on different conditions like weather or season [3]. UVA radiation influences the skin properties and structure of nucleic acids and proteins like elastin or collagen [4]. UVB radiation is characterized by a wavelength ranging from 290 to 320 nm and makes up only 5% of all UV radiation range [3]. UVB radiation affects the epidermis layer of the skin and may cause erythema, which can turn to sunburn, but it also takes part in a reaction related to the formation of vitamin D in the skin [5]. UVC radiation concerns the range of wavelength from 200 to 290 nm and is almost completely absorbed by the ozone layer. The human organism can be protected naturally against UV radiation. The skin has ability to protect itself after exposition to sunlight; unfortunately, the protection does not last for a long period of time [6]. One form of natural skin protection against UV radiation is the production of melanin. This pigment can also be applied to the cosmetic formulation as naturally obtained from octopus or cuttlefish or by chemical synthesis [7]. Other skin protection mechanisms are the production of urocanic acid, which protects against UVB radiation [5], or an increase in the thickness of the stratum corneum by a process of keratinization, which becomes a barrier for harmful radiation. Natural organism protection against radiation is a mechanism related to either disrupting the reactions that cause the formation of free radicals or directly destroying free radicals by compounds like carotenoids, vitamin C, coenzyme Q, tocopherols and lipoic acid [5]. In addition, anti-radical enzyme systems, which are based on such enzymes as catalase or superoxide dismutase, are also included in the above action [5,8]. To enhance the natural protection level, the topical application of cosmetic products onto the skin is advisable. Two types of sunscreen filters can be used: physical and chemical ones. Physical, mineral filters are very common in cosmetic applications by virtue of their stability and resistance to UV radiation, but their disadvantage is that they affect the decomposition of active substances. Among physical filters, we can distinguish titanium dioxide, zinc oxide, iron oxides, calcium carbonate, talc and kaolin. The above-mentioned substances can also act as pigments in cosmetic products [3,6,7]. Titanium dioxide and zinc oxide are also used as nanoparticles, with particle size smaller than 100 nm, which can penetrate deeper skin layers in contrast to pigments. Physical filters can be coated with hydrophobic compounds that reduce their negative impact on other substances in the formulation and allow to use them in an oil phase of cosmetics [7]. Another group of filters contains synthetic chemical compounds, which include chromophore groups [3]. These groups include unsaturated bonds as well as thiocarbonyl, indole, carbonyl, nitrate groups and nitrite [4,9,10] These filters penetrate into the surface layers of the epidermis. Their mechanism of action is based on the absorption of sunlight, in which the compound goes into an excited state. Then the molecule returning to its initial state gives off excess energy in the form of heat. Chemical filters absorb radiation in different wavelength ranges. For this reason, they have been divided into three main groups. UVB filters have the ability to absorb radiation in the wavelength range of 290–320 nm. They include, among others, terpene compounds, cinnamic, p-aminobenzoic and salicylic acid derivatives, as well as imidazole, quinoline and benzimidazole derivatives. UVA filters absorb light in the wavelength range of 320–400 nm. This group includes dibenzoylmethane derivatives, benzylidenecamphors and phenylbenzimidazole. The third group is UVB + UVA filters with a wide absorption range from 290 to 380 nm. These include single substances that are distinguished by their photoprotective ability in a wide spectrum, e.g., benzophenones, phenylbenzotriazoles and triazine [11,12,13]. Usually, sunscreen products are a mixture of physical and chemical filters in order to reduce the concentration of particular filters and provide maximum protection in a wide range of UV radiation [3,14,15] However, they are not the only substances that can protect human organisms against harmful radiation. Natural, isolated-from-plants chemical compounds also have such properties [3,9]. Moreover, due to their origin, they are safer for the human body, can protect from oxidative stress, absorb radiation in a wider spectrum of wavelength and may support the removal of negative effects of sun exposition, for example skin aging [8]. Natural filters can be the extracts obtained from plants due to the presence of numerous active compounds, as many of them have the ability to absorb radiation of wavelengths belonging to the UV range [11]. Based on the presence of compounds capable of absorbing UV radiation, almost one hundred water-alcohol and water-glycolic plant macerates and tinctures had been divided into six groups: salicylates (present in willow and meadowsweet), p-aminobenzoic acid derivatives (found in extracts of chamomile, witch hazel, sage or arnica), anthracene derivatives (present in aloe, walnut, arnica or chamomile), coumarin derivatives (present in marigold, horse chestnut, fig-tree), benzophenone derivatives (present in arnica, chamomile, liquorice and rosemary) and cinnamic acid derivatives (found in rosemary, arnica, mint, dandelion and lemon balm) [11,16,17]. Different types of natural compounds with UV protective properties are vegetable fats like argan oil or macadamia oil, shea or cocoa butter and others containing unsaturated fatty acids which, just like plant extracts, do not indicate a very high level of protection, but a range of absorption of UV radiation is also broad. Furthermore, vegetable fats contain polyphenols which can exhibit the antioxidant properties. Another important group of chemical compounds with protective properties are carotenoids, such as β-carotene and lycopene which, applied in fatty medium, can support chemical filters, and when applied internally, cause an increase of skin resistance to the influence of sunlight. The research is conducted to search for and examine natural, plant-derived compounds with UV radiation protection properties and develop phyto sunscreens with satisfying effectiveness, whaich is confirmed by several examples. The photo-protective requirements may be met by numerous plant extracts containing either antioxidant, antiradical compounds or photoprotective substances. For example, extracts obtained from Brazilian plants were studied in terms of comparing their UVB radiation adsorption with total phenolic and flavonoid content and antioxidant activity. Flavonoids, phenolic compounds and esters of hydroxycinnamic acid present in plants protect their tissues from UV radiation [16,17]. The values for sun protection factor for plant extracts obtained from Lippia microphylla and Dimorphandra gardneriana were about 20, where results above 15 mean skin protection against UV radiation. In the case of these extracts, the protection was due to the presence of quercetin glycosides and sakuranetin flavonoids [10,11]. Secondary metabolites which are characterized by antioxidant properties could have the ability to indicate high absorption of UV radiation. For example, extracts of Hibiscus furcatus, Leucas zeylanica or Ophiorrhiza mungos displayed values for sun protection factor bigger than 25, which was higher in comparison to commercially available photoprotective cosmetic used as a reference. Furthermore, Leucas zeylanica or Ophiorrhiza mungos extracts have the potential for use in sunscreen of broad spectrum due to their high UV absorbance of wavelengths in a range from 260 to 350 nm. Extract of Ophiorrhiza mungos was also characterized by photostability after exposure to direct UV radiation for three weeks without significant reduction in its sun protection factor [17]. In other studies, four extracts of different species of Lippia plant were examined to develop sunscreen formulation with a single, natural UV filter. The results obtained in the experiment suggested that, among them, sunscreen with Lippia sericea indicated potential in a commercial application. Moreover, the total polyphenolic content of the plant was related to its photoprotective properties unlike its antioxidant capacity or flavonoid content [18]. Subsequent studies were also performed to develop an antioxidant phytocosmetic sunscreen product containing a mixture of plant extracts rich in flavonoids. Extracts of selected plants were used: Vitis vinifera, Ginkgo biloba, Ruta graveolens and Dimorphandra mollis. The results obtained for topical application showed sun protection properties and antioxidant activity of the created phytocosmetic formula [19]. Extracts obtained from Moringa oleifera leaves were examined as natural, herbal UV phytosunscreen ingredients [20]. All these examples of conducted research on UV radiation protection properties showed that numerous plant extracts had the potential to protect human skin from harmful radiation. In this study, four plants were selected to examine their total phenolic content, antioxidant capacity, UV radiation protection properties and spectrophotometric sun protection factor (SPF). One of them was marigold, which contains coumarin derivatives: esculetin and scopoletin; flavonoids and their glycosides for example rutin and quercetin; carotenoids like lycopene and carotenes; and polyphenols [4,21,22,23]. The second selected plant was hop characterized by a content of flavonoids: kaemferol, xanthohumulone or phytoestrogenic compounds and tannins like caffeic or gallic acid and resins like humulon and lupulone [24]. Other plants rich in carotenoids responsible for their antiradiation and antioxidant properties, were carrot and tomato. Carotenoids can absorb radiation of wavelength from 400 to 700 nm, among them lycopene, which shows the best antioxidant properties [25]. Due to the presence of all listed chemical compounds, those four selected plants show potential for use as a natural and ecological sunscreen filter; consequently, their properties were examined.

The main purpose of the study was to determine the content of phenolic compounds, antioxidant activity of water, water-glycol and oil extracts from pot marigold, hops, carrot and tomato and to determine their radiation protection properties using methods based on spectrophotometric measurements.