Fatty acid profile of new promising unconventional plant oils for cosmetic use

Oils have been used on the cosmetic application since antiquity. With the growing interest in cosmetic formulation of strictly natural origin there has been also an increased interest in the use of alternative oils obtained from nuts, herbs, fruit and vegetable seeds. Due to lack of good scientific reports on the cosmetic plant oils available in Poland, the aim of our research was to characterize fatty acids (FA) profile and oxidative quality of selected unconventional plant oils, which are used as cosmetics or potential cosmetic ingredients.

Oils were purchased from cosmetic health shops in Warsaw (Poland); FA profile was analysed by gas chromatography with flame-ionization detection. Peroxide index (PI), content of hydroperoxides (PV) and free fatty acids (AV) were also determined.

Oxidative quality and FA composition of examined oils varied widely among analyzed oils. Cluster analysis revealed three clusters. Clusters S1 and S3 include only one oil (Perilla and sea buckthorn, respectively). Perilla oil is characterized by relatively small content of both saturated FA (8.5%) and monounsaturated FA (14.2%) and much higher amount of polyunsaturated FA (73.5%) whereas in sea buckthorn these proportions are opposite (saturated FA and monounsaturated FA - 33.5% and 51.0% respectively, and the lowest amount of polyunsaturated FA - 5.2%). In cluster S2 two sub-clusters were distinguished and the content of linoleic (p = 0.0015), α-linolenic (p = 0.0092) and oleic (p = 0.0015) acid caused this distinction. PI ranged from 8.9 in sea buckthorn oil to 135 in Perilla oil. Perilla oil and raspberry seed oil were also characterized by the highest PV (225 ± 14.9 mEq O/kg oil and 232 ± 13.8 mEq O/kg oil, respectively), whereas the lowest PV was determined for walnut oil (0.82 ± 0.18 mEq O/kg oil) and carrot seed oil (0.87 ± 0.21 mEq O/kg oil) oils.

FA composition of cosmetic oils in combination with data concerning their oxidative quality, is very important for determining their safe and effective use. It is very important to standardize and test the FA content in commercially available oils of cosmetic use.