Antioxidant Activity of a Rosemary Extract and Its Constituents, Carnosic Acid, Carnosol, and Rosmarinic Acid, in Bulk Oil and Oil-in-Water Emulsion

Abstract

This study was aimed at evaluating the antioxidant activity of a commercial rosemary extract and the active constituents carnosol, carnosic acid, and rosmarinic acid, in inhibiting the formation and decomposition of hydroperoxides in tocopherol-stripped corn oil and in the corresponding corn oilin-water emulsions. In bulk corn oil, the rosemary extract, carnosic acid, rosmarinic acid, and R-tocopherol were significantly more active than carnosol. In contrast, in corn oil-in-water emulsion, the rosemary compounds were less active than in bulk oil, and the rosemary extract, carnosic acid, carnosol, and R-tocopherol were more active than rosmarinic acid. Similar results were obtained in corn oil-in-water phosphate buffer emulsion at pH 5, but R-tocopherol was less active. Carnosol and carnosic acid were much more active antioxidants in corn oil-in-water emulsions buffered at pH 4 and 5 than at pH 7. The decreased antioxidant activity of the polar hydrophilic rosemary compounds in the emulsion system may be explained by their interfacial partitioning into the water, thus becoming less protective than in the bulk oil system. The effect of pH may be related to the stability of the rosemary antioxidants.

Métodos para avaliação do grau de oxidação lipídica e da capacidade antioxidante

“…O grau de eficácia dos antioxidantes, medido a alta temperatura, pode também refletir a maior ou menor estabilidade térmica dos compostos 4,7,10 . Estes fatos explicam alguns dos resultados contraditórios obtidos relativamente à eficácia antioxidante de certos compostos 4,48 .…”

Ultrasound versus microwave as green processes for extraction of rosmarinic, carnosic and ursolic acids from rosemary

“…1). This polyphenol profile induces antioxidant [3][4][5], antibacterial [5,6] and antimutagenic properties to rosemary extracts. RA and CA are more specifically used in the food industry as natural antioxidants [7,8].…”

Chemical Analysis and Growth Inhibitory Effect Of Rosemary Plant on Aspergillus niger

“…This plant recently has been used in sanitary, pharmaceutical and cosmetic industry and it's fresh and dried leave used as a flavor for meats and soups [1]. Rosemary is known as an antioxidant plant and this activity associated to two phenolic diterpenes: carnosic acid and carnosol [8].Furthermore, caffeic acid and its derivatives such as rosmarinic acid are component of Rosemary and are recognized as antioxidant compounds. The phenolic compound, rosmarinic acid, obtains one of its phenolic rings from phenylalanine via caffeic acid and the other from tyrosine via dihydroxyphenyl-lactic acid.…”