Pharmacopoeial chemical values, fatty acid composition, unsaponifiable matter and antioxidative activity of selected vegetable oils

Rastlinska olja so zaradi svojih lastnosti pomembna v prehrani, kozmetiki, farmaciji in medicini. Po sestavi so trigliceridi, manjši delež pa predstavljajo neumiljive snovi. Naše delo je del širše raziskave o sestavi rastlinskih olj in njihovemu delovanju na koži. V raziskavi smo ugotavljali in vrednotili sestavo sedmih rastlinskih olj ter njihovo antioksidativno aktivnost. Uporabili smo pet rastlinskih olj, ki smo jih izbrali glede na njihovo značilno maščobnokislinsko sestavo trigliceridov, in sicer olje granatnega jabolka (prevladujoča punicinska kislina), laneno olje (prevladujoča α-linolenska kislina), kokosovo olje (prevladujoča lavrinska kislina), olivno olje (prevladujoča oleinska kislina) in makovo olje (prevladujoča linolna kislina). Z ekstrakcijo lipovih in ognjičevih semen z n-heksanom smo pridobili dve manj znani rastlinski olji, lipovo olje in ognjičevo olje. Lipovo olje vsebuje največji delež linolne kisline, ognjičevo olje pa kalendinske kisline. Metode ugotavljanja farmakopejskih kemijskih števil (1) in izolacijo neumiljivih snovi (2) smo izvedli po Ph. Eur. 7.0 in 8.0. Večina olj je bila ustreznih. Peroksidno število je bilo pri večini olj nizko (od 0,6 do 19,3), jodno in hidroksilno število sta bila najvišja pri olju granatnega jabolka (II=192 in IOH=36,10). Jodno število je najvišje pri tem olju, zaradi visoke vsebnosti nenasičenih maščobnih kislin. Kislinsko število je bilo najvišje pri olju granatnega jabolka (IA=3,56), saponifikacijsko in estrsko število pa pri kokosovem olju (IS=265 in IE=265). S pomočjo analize GC-MS smo ugotovili maščobnokislinsko sestavo trigliceridov, ki je bila skladna z literaturnimi podatki. Določili smo tudi vsebnost neumiljivega dela, ki se za proučevana olja giblje v razponu od 0,55 % do 2,26 %, in vrednost njihovega antioksidativnega potenciala. Najvišjo vrednost smo ugotovili pri olju granatnega jabolka (okoli 49 %), okoli 30 % pa so imeli lipovo, ognjičevo in olivno olje. Pri ostalih oljih so bile vrednosti nižje. Na podlagi maščobnokislinske sestave in visoke antioksidativne aktivnosti smo ugotovili, da bi bile smiselne nadaljnje raziskave zlasti lipovega in ognjičevega olja, saj sta olji še neraziskani in njuna potencialna uporaba neuveljavljena. Uporaba je verjetno še neuveljavljena, zaradi rabe drugih delov teh dveh rastlin v medicini in farmaciji in dolgotrajnega procesa pridobivanja obeh olj.Vegetable oils play a very important role in the cosmetic and pharmaceutical industries and medicine. Vegetable oils are manly triglycerides, a small amount in their composition is represented by unsaponifiable matter. Our research is a part of another research, in which we are studying characteristics of vegetable oils and their effect on human skin. In our research, we determined the fatty acid composition of triglycerides and antioxidative activity of seven vegetable oils. We selected five vegetable oils, based on their fatty acid composition of triglyceridesthese were pomegranate seed oil (characterised by punicic acid), flax seed oil (α-linolenic acid), coconut oil (lauric acid), olive oil (oleic acid) and poppy seed oil (linoleic acid). In addition, two less-known oils were extracted by n-hexane extraction out of their seeds, i.e. Tilia and Calendula seed oils. Tilia seed oil contains a high amount of linoleic acid, while Calendula seed oil contains a high amount of calendic acid. Determination of chemical numbers and isolation of unsaponifiable matter was performed according to Pharmacopoeial procedures (1, 2). Most of the oils were suitable. Peroxide value was low in most cases (from 0,6 to 19,3). Iodine and hydroxyl values were the highest in pomegranate oil (II=192 and IOH=36,10). We can conclude that high iodine value is due to high amount of unsaturated fatty acids. Acid value was also the highest in pomegranate oil (IA=3,56), while saponification and ester values were the highest in coconut oil (IS=265 in IE=265). Using GC-MS analysis we determined the fatty acid composition, which was in accordance with literature data. We also determined the content of unsaponifiable matter and antioxidant activity. The highest antioxidant activity was found for pomegranate seed oil (around 49 %) and around 30 % for Tilia seed oil, Calendula seed oil and olive oil. Based on the fatty acid composition of triglycerides and high value of antioxidative activity, we concluded that Tilia seed oil and Calendula seed oil are most interesting for further studies to find potential use of these two oils. Current lack of usage of these two oils are probably due to other uses in medicine and pharmacy and time-consuming extraction