By-products of cultivated plants are one of the major environmental concerns worldwide. Due to the high concentration of bioactive chemicals, such waste may be considered hazardous due to the interference with the plant growth, deterioration of the drinking water quality or toxic effects on sensitive marine organisms. Moreover, plant-derived by-products, with proper handling, may represent a low-cost source of bioactive compounds potentially important for pharmaceutical and cosmetics industries. The aim of the study was to evaluate the phytochemical composition, antioxidant activity, the influence of tyrosinase activity, in vitro sun protecting factor and cytotoxicity of 15 extracts from peels of five cultivars of Cucurbita maxima and C. moschata. The extracts were prepared using “green solvents” (water, 50% propylene glycol, and 20% ethanol) and ultrasound-assisted extraction. The performed analysis showed that the peel extracts from various cultivars differ significantly in respect to the phytochemical content and activity. The type of solvent also had a significant impact on the extract’s composition and bioactivity. Aqueous peel extracts contained the highest amounts of flavonoids, showed the greatest antioxidant potential and the most significant in vitro SPF values. In vitro studies showed that the analyzed peel extracts are not cytotoxic for human keratinocytes up to the concentration of 1000 µg/mL and thus might be considered as non-irritant for the skin. The study confirms the potential application of peel extracts from Cucurbita spp. cultivars in cosmetic products.

Aesthetic medicine is an intensively developing field, more and more focused on stimulating and regenerating the skin, rather than on emergency treatment. There are many methods used by doctors for biostimulating therapies, but the most popular procedure in recent years is the implantation of platelet-rich plasma (PRP) used to date successfully in ophthalmology, dermatology, surgery, dentistry and even in orthopedics. The procedure uses autologous material, and its essence is a repair action on damaged cells of the patient as well as the activation of healthy cells and their stimulation for more effective work. The aim of the paper is to present current knowledge about platelet-rich plasma therapy in anti-aging treatment, the effectiveness of therapy with its use, and the mechanism and safety of PRP. The composition of the autologous preparation and its use in aesthetic medicine were also analyzed. PRP is a procedure that uses the patient’s own cells, and growth factors are of key importance in the process of skin regeneration and biostimulation. The correctly performed procedure, including the appropriate collection and administration of a buffy coat to the patient and compliance with all the rules of sterility, results in positive effects of the therapy. Numerous studies prove the effectiveness and safety of the platelet-rich plasma treatment. Highly concentrated platelets in the deposited preparation stimulate the surrounding cells to angiogenesis, differentiation, proliferation and synthesis of components essential for remodeling of the treated area. The therapy is highly effective and safe to use.