Flax and hemp fibers are known as textile raw materials with pro-health properties. This paper presents results of research aimed at investigating the antioxidant activity of the fibers in order to explain a mechanism for the favorable influence of textiles made of these fibers when in contact with human skin. The study presents a new approach in evaluation of textile fibers in terms of their inherent pro-health properties. Antioxidant properties of flax and hemp fibers were tested with the use of FRAP and DPPH methods. The content of phenolic acids: syringic, sinapinic, p-coumaric and ferulic acid was determined with the use of HPLC. The results proved that the antioxidant activity of the tested fibers depends on a type and variety of fibrous plants, a method of fiber extraction and subsequent stages of preliminary processing of the fibers. Both decorticated flax and hemp fibers showed higher antioxidant activity in comparison to the fibers obtained with other extraction methods, while decorticated flax of different varieties presented the highest value of the FRAP. Wet methods of fiber extraction and processing caused reduction of phenolic acids content and significantly lower values of the FRAP and DPPH.

This study presents the quantity and quality of flax (Linum usitatissimum L.) and hemp (Cannabis sativa L.) fibers obtained depending on the fiber extraction method. The extraction methods used in this study were osmotic degumming, dew retting, and water retting. The degummed straw was analyzed for fiber content, while the metrological, chemical, and physical properties were determined for the fibers obtained. It was shown that these properties change based on the method of fiber extraction used. The highest fiber content in the straw was obtained using the osmotic degumming method. These fibers are characterized by a light color, no unpleasant odor, low linear mass, good tenacity, lowest hygroscopicity, and reduced flammability compared to fibers obtained via the dew and water retting of straw.

The article presents the exploration of flax and hemp fibers’ surface free energy depending on the chemical composition of the fiber, which is closely related to the plant variety and the method of extracting the fiber. For this purpose, tests of the surface free energy (SFE), evaluation of the percentage content of individual fiber components and FTIR analyses were conducted. The research was carried out with the use of fibrous materials prepared in three different ways: 1. To analyze the effect of subsequent stages of flax fibers refining process on chemical composition and SFE, 2. to explore the dependence of fiber SFE on hemp variety, the water-retting hemp fibers were used, 3. To evaluate the influence of the retting method of hemp fibers BIAŁOBRZESKIE variety on SFE, the fibers extracted with the use of dew and water retting were used as the research material. The study confirmed that the content of individual components in the fiber influenced its sorption capacity and therefore determined its hydrophilic properties. The values of Pearson’s linear correlation coefficients determined in the statistical analysis proved that the surface free energy was strongly correlated with the content of individual components in the fibers. Understanding the wettability characteristics of bast fibers will allow modeling the properties of products made of these fibers and designing surface modification processes in order to obtain specific functionality of textile products, depending on their intended utilization.

Hemp fiber variety, Bialobrzeskie, contains phenolic acids in its chemical composition giving it inherent antioxidant and antibacterial activity. The use of this raw material in fabric manufacture allows the creation of functional clothing with a positive effect on human skin. The aim of the study was to develop biologically active functional clothing made of pure industrial hemp raw materials, where cannabidiol (CBD) extract applied on the fabric surface strengthened the fiber bioactivity. The design of the clothing technology was focused on keeping the hemp inherent properties on a steady level and avoiding the use of chemicals in each stage of the value chain from plant cultivation up to garment manufacture. The research covered the evaluation of phenolic acids content and The Ferric Ion Reducing Antioxidant Power FRAP antioxidant activity of the hemp fabric. The hemp fabric enriched with CBD was used for clothing preparation. The human trials covered wearing of the clothing by 15 volunteers for six weeks and evaluation of hemp garment effect on human skin. The skin parameters were tested twice, before and after six weeks of clothing wearing, according to the own methodology that included measurements of skin biophysical properties including tests of skin moisture, transepidermal water loss, and sebum. Also, the effect of the active substances present on the fabrics on the in vitro culture of human keratinocytes was evaluated. Results of the research proved, that the wearing of developed functional hemp clothing with CBD extracts applied on the fabric surface was safe and caused improvement of skin condition, which can have an influence on slowing down of skin aging. The invention covering the pure hemp functional clothing with hybrid bioactivity resulting from the joined activity of fiber and cannabidiol was applied for a patent, Patent Application No: P.438388, 2021.

The objectives of the study were to develop functional natural fiber clothing with microcapsules containing active herbal extracts with properties enhancing the treatment of dermatoses and to confirm the efficiency of the clothing's activity by testing its effect on the biophysical parameters of human skin. As a result of the work, clothing enriched with green tea and Viola tricolor extracts enclosed in ethyl cellulose microcapsules was produced. The microcapsules were applied on the inner surface of linen knitted fabric, which ensured direct contact of the active substances with the patients' affected skin. The efficiency of the clothing was tested according to our own methodology, which included wearing tests, microbiological tests of the skin and tests of skin moisture, transepidermal water loss and itching intensity. Also, the effect of the active substances present on the fabrics on the in vitro culture of human keratinocytes was evaluated. The test results confirmed that linen clothing enriched with medicinal plant extracts enclosed in microcapsules had an effect on the reduction of itching intensity, an increase in skin moisture, reduction of transepidermal water loss and a reduction of pathogenic bacterial colonies residing on the patients' skin. They confirmed that the new method of administering herbal substances to the skin of dermatological patients via the wearing of functional clothing is effective and leads to symptom relief. The studies allowed for the filing of a patent submission, number P 411869, titled “The clothing acting as a dressing supplement in the therapy of dermatological diseases.”