Pridobivanje in analiza neumiljivih snovi izbranih rastlinskih olj ter preverjanje njihove antioksidativne aktivnosti

Podvratnik, Kaja (author), Kočevar Glavač, Nina (mentor), Schoss, Katja (co-mentor)

Rastlinska olja so lipidi, ki jih pridobivamo iz semen ali redkeje iz drugih delov rastlin s hladnim stiskanjem ali s postopkom ekstrakcije s topilom. Vsebujejo trigliceride (95-98 %) in neumiljive snovi (< 5 %), ki pomembno prispevajo k bioaktivnim lastnostim rastlinskih olj. Najbolj zastopane neumiljive snovi so fitosteroli, fenolne spojine, skvalen, rastlinski pigmenti in vitamin E. Rastlinska olja so vedno bolj priljubljena tudi v farmacevtski industriji, ker kažejo ugodne učinke pri kožnih in srčno-žilnih boleznih. V magistrski nalogi smo analizirali sestavo neumiljivih snovi izbranih rastlinskih olj in ugotavljali njihovo antioksidativno aktivnost. Na voljo smo imeli 66 vzorcev različnih rastlinskih olj, ki smo jih po modificirani farmakopejski metodi pripravili na analizo s plinsko kromatografijo, sklopljeno z masno spektrometrijo. Analizirali smo njihovo sestavo in vsebnost posameznih neumiljivih snovi. V naslednjem koraku smo z modificirano metodo DPPH ugotavljali njihovo antioksidativno aktivnost, ki smo jo primerjali z α-tokoferolom. Ugotovili smo, da večina olj vsebuje različne fitosterole, v nekaterih pa se pojavlja tudi holesterol, ki ga je sicer v rastlinah zelo malo. Najbolj raznoliko sestavo neumiljivega dela je imelo ognjičevo olje, kjer smo detektirali kar 12 različnih komponent. Te snovi so bile skvalen, γ-tokoferol, holesterol, kampesterol, stigmasterol, β-sitosterol, lanosterol, holest-7-en-3-ol, 9,19-ciklolanost-24-en-3-ol ter še tri neidentificirane komponente. Prevladujoči fitosterol je bil β-sitosterol, ki se je pojavljal v vseh vzorcih, razen v kivijevem olju. Edini tokoferol, ki smo ga zaznali v naših vzorcih, je bil γ-tokoferol. Največjo antioksidativno aktivnost je imelo borečevo olje, saj je vsebovalo visok delež cikloartenola, pri katerem smo potrdili statistično značilno korelacijo z antioksidativno aktivnostjo. Korelacijo smo potrdili tudi med antioksidativno aktivnostjo in dezmosterolom ter γ-tokoferolom. Zaključujemo, da so naše metode ustrezne in zanesljive, saj so rezultati v večjem delu primerljivi z literaturnimi. Sestava neumiljivih delov olj je sicer podvržena veliki variabilnosti zaradi različnih procesov gojenja rastline, pridobivanja olja in izolacije neumiljivega dela, česar se moramo zavedati ob izbiri olja za uporabo v prehranske, kozmetične ali farmacevtske namene.

• Language: Slovenian
• Keywords: rastlinska olja, neumiljive snovi, plinska kromatografija, GC-MS, antioksidativna aktivnost, DPPH
• Work type: Master's thesis/paper
• Organization: FFA - Faculty of Pharmacy
• Year: 2022
• PID: 20.500.12556/RUL-135894
• Publication date in RUL: 31.03.2022

Secondary language

• Language: English
• Title: Extraction and analysis of unsaponifiable compounds of selected vegetable oils and determination of their antioxidative activity

Abstract

Vegetable oils are lipids obtained from seeds or less frequently from other parts of plants by cold pressing or solvent extraction. They contain triglycerides (95-98 %) and unsaponifiable matter (< 5 %), which significantly contribute to the bioactive properties of vegetable oils. The most common unsaponifiable substances are phytosterols, phenolic compounds, squalene, pigments and vitamin E. Vegetable oils are also becoming popular in the pharmaceutical industry due to beneficial effects in skin and cardiovascular diseases. In this master's thesis we analayzed the composition of unsaponifiable matter of selected vegetable oils and determined their antioxidative activity. We had 66 different samples of different vegetable oils available, which were prepared for analysis by gas chromatography coupled with mass spectrometry according to a modified pharmacopoeial method. We analyzed their composition and the content of unsaponifiable matter. In the next step, we used a modified DPPH method to determine the antioxidative activity, with α-tocopherol as a control. We found out that most oils contain various phytosterols and some also contain cholesterol, which is typically very low in plants. Marigold oil had the most diverse composition of the unsaponifiable matter; we detected 12 different components: squalene, γ-tocopherol, cholesterol, campesterol, stigmasterol, β-sitosterol, lanosterol, cholest-7-en-3-ol, 9,19-cyclolanost-24-en-3-ol and three other unidentified components. The predominant phytosterol was β-sitosterol, which appeared in all samples except kiwi oil. The only tocopherol detected in our samples was γ-tocopherol. Borage oil had the highest antioxidative activity, as it contained a high proportion of cycloartenol, for which we confirmed a statistically significant correlation with the antioxidative activity. A correlation was also confirmed for desmosterol and γ-tocopherol. We conclude that our methods are relevant and reliable, as the results are largely comparable to the literature. The more precise composition of unsaponifiable matter is still subject to great variability due to different processes of plant cultivation, oil production and isolation of unsaponifiable matter, which we must consider when choosing oils for food, cosmetic and pharmaceutical purposes.

• Keywords: vegatable oils, unsaponifiable matter, gas chromatography, GC-MS, antioxidative activity, DPPH