Safety assessment of oats (Avena sativa) extract as a cosmetic ingredient using the threshold of toxicological concern approach

Oves (Avena sativa) je rastlina, ki spada v družino travovcev in predstavlja priljubljeno živilo v različnih predelih sveta. Zaradi njegovega velikega letnega pridelka in uporabe ga kultivirajo v številnih državah. Že od nekdaj je eden izmed glavnih predstavnikov tradicionalne medicine, v zadnjih letih pa je doživel razcvet na področju farmacije, medicine, predvsem pa kozmetične industrije. Najpogosteje se uporablja v obliki rastlinskega izvlečka, pretežno v kozmetičnih izdelkih za nego kože v obliki krem, losjonov, gelov ter šamponov, ki nudijo okluzivno, emolientno, vlažilno, negovalno, antioksidantno ter čistilno delovanje. Zaradi njegove zanimive in pestre kemijske sestave je zelo pomembno, da upoštevamo vsa priporočila za zagotovitev ustreznosti in varne uporabe izvlečka. Zavedati se moramo, da lahko na samo kemijsko sestavo rastline vplivajo tudi različni dejavniki in sicer podnebje, obdobje žetve, proces sušenja in shranjevanja, dobra proizvodna praksa ter ustrezna gojitvena praksa. V diplomski nalogi smo ocenili varnost izvlečka ovsa kot sestavine kozmetičnega izdelka z uporabo pristopa s pragom toksikološkega tveganja (TTC), ki na podlagi kemijskih struktur spojine razvršča v Cramer-jeve razrede toksičnosti s pripisanimi vrednostmi TTC. S pomočjo literature smo preučili kvalitativno in kvantitativno sestavo rastline in izvlečka ploda, slame ter zeli ovsa in na podlagi fizikalno-kemijskih lastnosti spojin in njihovih znanih koncentracij ocenili maksimalni potencialni obseg absorpcije ter sistemsko izpostavljenost. Pri nekaterih spojinah z neznano koncentracijo pa smo ubrali drugačno pot, in sicer smo pri določanju sistemske izpostavljenosti le-to izračunali glede na ocenjeni maksimalni potencialni obseg absorpcije ter vrednost TTC posameznega Cramer-jevega razreda. Za določene spojine smo izračunali tudi dnevni varni odmerek s pomočjo vrednosti NOAEL, ki so močno presegale vrednosti TTC ter vrednosti sistemske izpostavljenosti izvlečka. Glede na dobljene vrednosti in vse podane izračune smo ocenili, da je izvleček ploda, slame ter zeli ovsa varen za uporabo v kozmetičnih izdelkih.Oats (Avena sativa) belongs to the Poaceae family, which represents a popular dietary staple in various parts of the world. Due to its large annual harvest and use it is cultivated in many countries. Its use dates back to traditional medicine, but in the recent years it has also flourished in the field of pharmacy, medicine and cosmetic industry. Oat extract can be found in countless skincare formulations in the form of creams, lotions, gels and shampoos, which offer occlusive, emollient, moisturizing, nourishing, antioxidant and cleansing properties. Because of the plant\u27s interesting chemical composition, extra care needs to be taken and all the recommendations to ensure safe use of the extract need to be followed. The chemical composition of the plant itself can also be affected by different factors such as climate, harvest period, drying process, storage process and good manufacturing practice. In this thesis, we have conducted a safety assessment for the Oats extract as an ingredient of a cosmetic product by employing the threshold of toxicological concern (TTC) approach, which evaluates the compounds based on chemical structures and classifies them according to the Cramer classification scheme thus providing the predetermined exposure limits (TTC values). With the use of available literature, we have examined the qualitative and quantitative compositions of the actual plant and extract of oat grain, hay and herb. Based on the physicochemical properties of each known compound, we estimated its maximum potential absorption and systemic exposure when using such cosmetic product. In case the concentration of compound in the extract was unknown, we determined the acceptable systemic exposure based on maximum estimated potential absorption and exposure limits (TTC values) obtained with the help of Cramer classification scheme. For some of the compounds, we have also calculated a safe daily exposure by employing the NOAEL values, which exceeded TTC values and systemic exposure values of the compounds brought about by the use of the cosmetic product. Based on all calculations and examined properties, we have concluded that the extract of oat grain, hay and herb is safe for use in cosmetic products