# Antioxidative and Photoprotective Activity of _Pinus nigra_, _Pinus strobus_ and _Pinus mugo_
## 1 Introduction  
The human body, the outermost part of which is the skin, is constantly exposed to many harmful external factors, including solar radiation, which can lead to premature aging. Skin aging is an irreversible and inevitable physiological process that is influenced by many factors including mechanical damage due to facial expression; biological factors, mainly caused by genetically determined hormonal changes; environmental factors, such as active or passive smoking and air pollution; and factors connected with lifestyle, which include, among others, diet, skincare, stress, and disease [1, 2]. Another very important factor that accelerates skin aging is UV radiation, which is responsible for as much as 80%of its occurrence [3]. Excessive exposure to ultraviolet radiation is associated with serious health risks such as UV-induced skin damage, skin photoaging (atrophy, pigmentary changes, and wrinkles), solar sunburn, skin sensitization, and malignancy [4]. Another important factor which should be taken into account is population aging. In most countries, the number of older people is increasing rapidly. Moreover, this trend seems to be accelerating [5]. For instance, according to the results of the Seventh National Census in China, the population over 60 years has reached 264 million [6]. It is expected that, between 2015 and 2050, the proportion of the world's population over 60 years will nearly double from 12% to 22% [6]. As age is an indisputable major risk factor of skin cancer and the number of skin cancer cases is expected to increase, early prevention seems to be of importance [7]. For the older population, the application of sunscreens as well as antioxidants is important. UV radiation can initiate the formation of free radicals, which may be responsible for the damage of many skin cells and components, such as fibroblasts, keratinocytes, collagen, and elastin [8]. Antioxidants are a group of compounds which can interrupt the formation of free radicals and protect people from the above-mentioned diseases [3]. Many people pay attention to their appearance to ensure better well-being and better acceptance by others; they are looking for products containing antioxidants, i.e., ingredients that have beneficial effects on appearance. Substances that delay the skin aging process have become very popular lately. Undoubtedly, this is influenced by all kinds of efforts to maintain a youthful appearance for as long as possible [4]. People attach great importance to improving their image and, to this end, are looking for products containing antioxidants, which are ingredients that provide beneficial effects. Moreover, plant-derived antioxidants are a group of compounds that exhibit protective properties against the degenerative effects of oxidative stress on skin aging [9; 10]. Their beneficial effects on the appearance and function of the skin have led to a search in recent years for new substances with antioxidant potential among plant raw materials [9]. There are many plants widely used for this purpose. Many trees, including conifers, contain components that exhibit antioxidant properties [11; 12]. Such trees include, among others, those of the Pinaceae family: _Pinus strobus_, _Pinus nigra_, and _Pinus mugo_[13; 14]. _Pinus strobus_ is a species of coniferous tree in the Pinaceae family, which mainly grows in the northern and eastern areas of North America (Canada and the USA) [15] and in the Carpathian Mountains in the Czech Republic and southern Poland [16]. _Pinus strobus_ is a tall tree that can reach up to 50 m in height. The needles of the _Pinus strobus_ are long, gathered in bundles of five needles [17], have an intense green color, and can reach up to 15 cm in length. They are flexible and soft compared to the needles of _Pinus nigra_ and _Pinus mugo_. Extracts of _Pinus strobus_ needles are rich in active ingredients such as terpen, flavonoids, phenolic acids, vitamins, and other bioactive compounds that have beneficial properties and can be used in medicine and cosmetology.