Antioxidant activity and chemical composition of Origanum spp. essential oils.

RODRIGUEZ, SILVANA; BELLADONNA, DAMIÁN; RODRIGUEZ, ROBERTO; ANA PAULA MURRAY

Rosario

Congreso; 4º Reunión Internacional de Ciencias Farmacéuticas; 2016

UNR

Origanum spp. commonly known as ?oregano? and its essential oil are widely used in agriculture and in the pharmaceutical and cosmetic industries.The objectives of this study were to analyze the chemical composition of hydrodistilled essential oils of two varieties O. vulgare subp. vulgare known as ?Don Bastías? and ?Mendocino? ecotypes, collected from Bahia Blanca, Bs. As. Province. Their essentials oils were analyzed by GC/MS in order to determine the essential oil chemotype. Also, their antioxidant activities against DPPH were investigated.The GC/MS analysis of the Don Bastías oil resulted in the identification of 24 compounds representing about 98.3% of the oil. Thymol (35.30%) and p-menth-2-en-1-ol (16.59%) were the main compounds, followed by ɣ-terpinene (11.47%) and terpinen-4-ol (10.80%).From the analysis of Mendocino essential oil 22 compounds were identified, representing 95.84% of the oil, with thymol (28.07%), p-menth-2-en-1-ol (18.66%), terpinen-4-ol (11.76%) and carvacrol (9.69%) as the major ones.The antioxidant activity studies show that Don Bastías oil is a strong free radical scavenger (IC50 = 7.78 ± 0.36 µg/ml), whereas the Mendocino oil is moderately active (IC50 = 21.92 ± 0.94 µg/ml).Carvacrol and thymol have been reported to contribute to the antioxidant activity and quality of the essential oils in Origanum spp. Those results show very strong antioxidant activity for radical scavenging ability which could be attributed to the high content of phenolic compounds, as carvacrol and thymol, in those oils. Comparison of the IC50 values revealed that our oils have stronger activity in DPPH radicals scavenging than BHT and Trolox. It could be concluded that these oils can be categorized in ?thymol? chemotype according to their chemical composition. Also, due to their strong antioxidant activity they could be considered as a suitable natural antioxidant preservative.