# Plant-Origin Additives from _Boswellia_ Species in Emulgel Formulation for Radiotherapy Skin Care
## Results
### Antioxidant Properties and Polyphenols Content of Formulations  
Table 4 lists the types of the most important vibrations and the corresponding wavenumber for the tested plant materials of the _Boswellia_ spp. The FTIR spectra of extracts from _Boswellia_ spp. showed characteristic peaks at 3357 cm\({}^{-1}\) and 3578 cm\({}^{-1}\) (OH stretching); 2969 cm\({}^{-1}\) and 2957 cm\({}^{-1}\) (C-H stretching); 1712 cm\({}^{-1}\) and 1642 cm\({}^{-1}\) (C=O stretching); 1453 cm\({}^{-1}\) and1381 cm\({}^{-1}\) and at 879 cm\({}^{-1}\) and 778 cm\({}^{-1}\) (OH deformation), respectively, for Soxhlet and the select CO\({}_{2}\) extract. For essential oil from _B. carterii_, characteristic peaks were at 3446 cm\({}^{-1}\) (OH stretching), 2957 cm\({}^{-1}\) (C-H stretching), 1738 cm\({}^{-1}\) (C=O stretching), 1447 cm\({}^{-1}\), and 778 cm\({}^{-1}\) (OH deformation). Because the intensity of the bands depended on the type of extraction method used, the _Boswellia_ spp. raw materials used in this research were characterized by different concentrations of biologically active compounds, which translates in their different antioxidant activity and polyphenol contents (Figure 4). The select CO\({}_{2}\) extract and essential oil (OE) had the highest % inhibition of the DPPH radical, amounting to 54.8%, and 49.9% respectively, while the essential oil had the highest polyphenol content of 57.3 mg/dm\({}^{3}\), expressed as gallic acid. \(\alpha\)-pinene, \(\alpha\)-thujene, \(\beta\)-pinene, and limonene may be responsible for such a high content of polyphenols, as well as the high % inhibition of the DPPH radical, while the high % inhibition in the case of the CO\({}_{2}\) extract may be due to the presence of _Boswellia serrata_ resin extract, as well as compounds such as limonene and linalool, which have proven antioxidant properties. Although the essential oil itself had a higher polyphenol content, among the formulations, the highest concentration of polyphenols were had by sample E_SCO\({}_{2}\) (3.88 mg/dm\({}^{3}\)) and sample Em_SO (3.64 mg/dm\({}^{3}\)). This may be related to the fact that in recipe of emulsion, one of the components is milk thistle oil, which has polyphenols in its composition [25]. When comparing the % inhibition of the preparations, the E_SO containing essential oil had the highest value (18.5%). All preparations--except Em_hSO (its % inhibition of the DPPH radical was 7.29)--showed a higher % inhibition of the DPPH radical compared to the placebo preparations. In the case of polyphenol content, the statistical differences was shown for placebo formulation and samples: E_SCO\({}_{2}\), E_SO, Em_SO, and Em_hSO. This means that the addition of extracts and essential oil increased the antioxidant activity and polyphenol content in preparations containing plant-origin additives from the _Boswellia_ species. Figure 4: Results of antioxidant activity and polyphenols concentration in plant-origin additives from _Boswellia_ species and topical formulations for skin care. ExS—Soxhlet extract; ExCO\({}_{2}\)—CO\({}_{2}\) extract; OE—essential oil; E—emulsion; Em—emulugel; P—placebo; CO\({}_{2}\)—addition of CO\({}_{2}\) extract; O—addition of essential oil; S—addition of Soxhlet extract; h—plant raw material was introduced to the hydrogel. Different letters in the same category (separately for raw materials and separately for preparations) indicate significant difference between samples at \(p<0.05\).