# Plant-Origin Additives from _Boswellia_ Species in Emulgel Formulation for Radiotherapy Skin Care
## 4 Discussion  
### Composition and Characterization of Formulations  
The clinical success in the antioxidants studied in radiodermatitis achieved with topical superoxide dismutase has stimulated interest in exploring naturally occurring and more-affordable antioxidant substances, especially those rich in polyphenols [10; 26]. One of the plants that possesses therapeutic components is _Boswellia_. There are four main species of _Boswellia_, which include _Boswellia carterii_, _B. freruna_, _B. sacra_, and _B. serrata_[27]. This work is the first study indicating the possibility of using raw materials from _Boswellia_ spp. as an antioxidant in topical preparations, i.e., emulgels and emulsions intended to care for the skin and limit unwanted skin reactions during radiotherapy. Apart from being used in medicine, _Boswellia_ is also an important cosmetic ingredient. There are 25 cosmetic ingredients in the CosIng database that can be obtained from the _Boswellia_ species. These are resin extract, resin water, bark powder, gums, gum water, oils, and gum ferment extract. Our research used select CO\({}_{2}\) extracts obtained via the extraction of supercritical carbon dioxide, which works as a solvent for naturally occurring plant ingredients. The CO\({}_{2}\) select extracts contain mainly volatile components typical for essential oils (with molecules ranging from C5 to C25). They have intensive, perceptible odors; heavier waxes, resins and color compounds are generally not present in this raw material, as reflected in the visual assessment and sensory analysis of samples. The CO\({}_{2}\) extract used, according to the manufacturer's data (INCI name: Boswellia Serrata Resin Extract, alpha-Pinene, Limonene, beta-Pinene, alpha-Terpinene, Terphinolene, Linalool, Limonene), contains approx. 70-90% essential oil, sesquiterpenes, diterpene alcohols (serratol, incensol), and boswellic acid. The allowable concentration of the extract for use in cosmetics ranges from 0.1 to 1% and from 0.4 to 0.75% in facial cosmetics. Another ingredient was an essential oil obtained via the steam distillation of oleoresin _Boswellia carterii_. According to the manufacturer, the raw material came from India. It is a dark yellow liquid with an intense odor. It contains, among other ingredients, \(\alpha\)-pinene, limonene, \(\alpha\)-thujene, linalool, and cithrol. An extract rich in carbohydrates, tannins, glycosides, terpenes, flavonoids, and alkaloids can be obtained via Soxhelt extraction [28; 29]. According to the literature data, they exhibit skin care effects, including anti-aging (reducing lines and wrinkles), anti-ace (anti-bacterial, anti-fungal properties), hair care (preventing hair loss), and nail care effects; they smooth, tonify, and protect skin, as well as providing fragrance. Due to their antioxidant properties, they prevent the formation of post-sun discoloration and reduce redness [30]. On the European Union market, there are no products dedicated to post-radiotherapy skin containing plant-origin additives from _Boswellia_ species. However, all products available on the market containing this plant raw material are intended for very dry, damaged skin that requires regeneration, hydration, and soothing. Moreover, the market offers products in various physicochemical forms, such as bar soap, shower gel, serum, cream or sheet mask; however, there are no emulgel formulations. Emulgels belong to the polymeric gels group: semi-solid formulations obtained by immobilizing the external phase of the emulsion (o/w or w/o type) using suitable gelators [31]. Therefore, they exhibit the properties of gels, which are characterized by a faster and better release of the active ingredient compared to an ointment or cream base. Due to their physicochemical form, they are characterized by higher stability than emulsions. In these systems, the risk of phase separation and the cream phenomenon that occurs in emulsions is reduced. In addition, they are simple and economical to produce.