# Plant-Origin Additives from _Boswellia_ Species in Emulgel Formulation for Radiotherapy Skin Care
## 4 Discussion
### Correlation Matrix of Instrumental Analysis Results and Sensory Analysis
Moreover, according to [PERSON] et al., the presence of thickening substances in the system, especially carbomer in emulgels and cetyl alcohol in emulsions, can affect the perception of odor by the probands [60]. The cetyl alcohol present in the formulation of products also enhances the odor of the product and perfumes the skin. \begin{table}
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The strongest correlation (correlation coefficient closest to \(1\)\(p\geq 0.01\)) was obtained for the cushion effect and oiliness (0.920) and for the cushion effect and absorption (correlation coefficient \(-0.919\)). The cushion effect is the amount of product felt between the fingers (forefinger and thumb) when rubbing them together. The more product you feel between your fingers, the stronger the cushion effect. The strongest cushion effect was reported by the probands for emulsions and was smallest for emulgels, which is related to their physicochemical form. This effect is typical for emulsions and less noticeable for emulgels due to their excellent spreading properties combined with fast and easy absorption [61], hence the negative correlation observed; the smaller the cushion effect (lower numerical value), the higher the absorption (higher score from the probands), as less formulation between the fingers will result in faster absorption. The smaller the amount of preparation between the fingers, as in the case of emulgels, the less oiliness felt, i.e., the degree of oily deposit left on the skin immediately after application. Oiliness is correlated with absorption (correlation coefficient \(-0.808\)\(p\geq 0.05\)). Samples of preparations that are too viscous and oily in feel may have poorer absorption for the probands. Hence, the lowest oiliness values were recorded for emulgels. This is desirable because the skin affected by radiodermatitis is sore, and patients with dermatoses and skin injuries have a negative opinion of oily, sticky preparations such as ointments and creams that they have to use [32; 34]. The obtained tests results also showed that oiliness is correlated with the % inhibition of the sample. The % inhibition of the sample value is related to the presence of active substances in its composition. They are capable of neutralizing free radicals, the main sources of which are essential oil and select CO\({}_{2}\) extract, with an inhibition capacity of 49.9% and 54.8%, respectively. These raw materials themselves are not greasy because they are volatile; the essential oil evaporates without leaving a greasy stain. However, in this research, they have been introduced into the recipe of emulsions and emulgels. Low oiliness was recorded for emulgels where the essential oil and select CO\({}_{2}\) extract were added to the hydrogel. Moreover, according to [PERSON] et al. [57], in the case of carbomer-based emulgels containing plant extracts with antioxidants and lipid lowering activity, such as _Boswellia_[62], it is possible to decrease the production of sebum. The obtained research results are surprising, and it should be emphasized that correlations of sensory-assessed features with the results of physicochemical tests of preparations for topical use are not a common topic of scientific studies. Hydration is also correlated with the % inhibition of the sample, as confirmed by the moisturizing effect of plant-origin additives from _Boswellia_ species, mentioned earlier and proven in the literature. However, the polyphenol content was correlated with the pH of the formulation (correlation coefficient: \(-0.644\), \(p\geq 0.1\)). This is a further confirmation of the research results by [PERSON] et al. [63], i.e., that an increase in pH--and hence the deprotonation of hydroxyl groups--increases the antiradical activity of polyphenols. The correlation coefficient of the polyphenol concentration with the mean droplet size of the dispersed phase was \(-0.628\) (\(p\geq 0.1\)).