## 6 Kiwi Bioactives in Cosmetics Applications  
### Kiwi as a Sustainable Natural Source of Bioactives for Healthy Natural Cosmetics  
The continuous growth of the cosmetics industry is mainly due to the responsive attitude of consumers toward the trends and standards of promoting and maintaining a youthful appearance. These attitudes have been shaped and promoted by social media, resulting in the continuous development of the sector over the last 100 years. In addition, the terms well-being and prosperity include not only cosmetic products, but any goods that promote beauty, health, and protection against pollution (an aspect of cosmetics that is receiving enormous attention and is being researched continuously in the 21 st century). The first efforts to develop better products, aimed at improving both the skin all over the body and hair, were made with the use of pharmaceutical composites [90]. However, their repeated use, as expected, brought to the surface various disadvantages, which led to the interest of consumers and companies in finding naturally derived products. Thus, due to this new trend and the constant competition between industries to make available for sale new innovative products that would attract customers due to their herbal origin, research into the use of plant extracts was initiated. So-called \"green cosmetics\" or \"bio-cosmetics\" is a revolutionary idea of ecological interest, with positive effects on the health of the person using them. The applied plant extracts contain a range of bioactive ingredients, such as those present in both kiwi and its derivatives. Naturally, factors such as the methods and time of extraction vary according to the ingredients required, thus the composition of each extract varies. However, they all contain substances derived from fruits, flowers, plants, and other products of the earth that promote human health. Great attention seems to be being paid to the process of antiaging and skin tightening, i.e., the attempt to slow down the appearance of wrinkles, blotches, spots, and general scars, as well as photoproduction from solar radiation, which is directly related to the previous processes [90; 91; 92]. Exposure to ultraviolet radiation and other damage leads to skin aging and skin disorders [93]. Aging is an irreversible, continuous process of natural change that begins pretty early in life. During this process, many bodily functions begin to dysfunction and reactive oxygen species accumulate, which is the main occurrence affecting this process. Skin aging results from intrinsic and extrinsic factors, leading to reduced skin functionality and structure. UV radiation also generates reactive oxygen species (ROS) that damage lipids, proteins, and DNA. ROS-induced DNA damage and the activation of enzymes like collagenase and elastase contribute to skin photoaging, leading to collagen breakdown, elastin abnormalities, wrinkles, and the loss of elasticity. Consequently, consuming natural, nutrient-rich diets with antioxidant properties, such as fruits and vegetables and products based on them, has a significant role in the delay of the aging process. Moreover, fruits and vegetables have the capacity to transfer moisture to the skin of the consumer [94]. Kiwi fruit, and also its by-products, such as peel, branches, and leaves, can be used in the cosmetics industry. The application of the bioactives of kiwi in cosmetic products has many benefits, including antioxidant, anti-inflammatory, and antibacterial effects (Table 5). Through experiments, a kiwi extract was used in moisturizing and antiaging creams [95]. The incorporation of a kiwi extract into sunscreen was also performed, since sunlight is considered one of the most harmful environmental hazards for the skin, leading to premature skin aging, inflammation, and a higher risk of skin cancer. Kiwi's antiaging activity was studied in vivo with C. elegans as the animal model, which has plenty of homologous genes with humans.