Seasonal variations of rosmarinic and carnosic acids in rosemary extracts. Analysis of their in vitro antiradical activity

Abstract

Rosemary plants were analysed using HPLC and eight different compounds (vanillic acid, caffeic acid, rosmarinic acid, naringin, hispidulin, cirsimaritin, carnosol and carnosic acid) were identified and quantified. The analysis of the DPPH (1,1-diphenyl-2-picrylhydrazyl) radical scavenging activity revealed that rosmarinic and carnosic acids were the best rosemary scavengers with IC sun(50) values of 27 and 32 micro M, respectively. Environmental influences on rosmarinic and carnosic acids content in rosemary plants were studied over a period of one year under southern UK conditions. Carnosic acid reached the maximum concentrations in December, decreasing by 50% during the summer months, while rosmarinic acid showed a constant concentration during the year. The significance of these results has been discussed later in this paper.

Carnosic Acid and Carnosol, Two Major Antioxidants of Rosemary, Act through Different Mechanisms

“…Food material such as oil, raw and cooked meat, and cooked meat patties were protected from oxidation by carnosic acid, in most cases with a higher efficiency than synthetic antioxidants (Erkan et al, 2008;Zhang et al, 2010;Naveena et al, 2013;Jordán et al, 2014). Carnosic acid also was described as a scavenger of hydroxyl and 2,2-diphenyl-1-picrylhydrazyl radicals (Aruoma et al, 1992;Luis and Johnson, 2005). While the potential antioxidative activity of carnosic acid is well documented, its exact mechanism of action has not been studied extensively.…”

“…Carnosic acid is present at very high concentrations, up to several percent of dry weight, in leaves of the Mediterranean half-shrub rosemary (Munné-Bosch and Alegre, 2001;del Baño et al, 2003;Luis and Johnson, 2005). Carnosic acid biosynthesis and accumulation take place exclusively in young rosemary leaves at the branch apices, with the diterpene molecule being partially consumed during leaf development and aging (Hidalgo et al, 1998;Brückner et al, 2014;Bo zi c et al, 2015).…”

“…The antioxidative activity of the latter compound, produced spontaneously from carnosic acid by nonenzymatic reaction, has been seldom investigated (Aruoma et al, 1992;Zeng et al, 2001). Diterpene levels in field-grown rosemary plants displayed seasonal changes, with a tendency for carnosic acid losses in response to environmental stress conditions (Luis and Johnson, 2005). In particular, carnosic acid concentrations in rosemary leaves under natural conditions were found to decrease at high temperatures and low precipitation rates in summer with concomitant increases in oxidized derivatives, suggesting that cellular oxidative stress is accompanied by the consumption of carnosic acid (Munné-Bosch et al, 1999;Munné-Bosch and Alegre, 2003).…”

“…Carnosic acid and carnosol are present in photosynthesizing green tissues only (Munné-Bosch and Alegre, 2001;Luis and Johnson, 2005) and, in leaves, they have been found in the chloroplasts (Munné-Bosch and Alegre, 2001). However, carnosic acid and carnosol also have been reported to partition between trichomes at the leaf surface and internal leaf tissues (Bo zi c et al, 2015).…”

New genre of antioxidants from renewable natural resources: Synthesis and characterisation of rosemary plant-derived antioxidants and their performance in polyolefins

“…Literature studies on quantification of the amount of phenolic compounds in extracts of rosemary leaves have shown that the most abundant compounds were carnosic acid (CA) and rosmarinic acid (RA) followed by carnosol (CA-OH); the concentrations of the three compounds were found to be 12.18, 2.15 and 0.53 mg g -1 fresh weight biomass [24] and these were estimated to account for >90% of the antioxidant activity of the plant [25,26]. Commercial rosemary extract containing rosmarinic acid (93.4% pure) was used as the starting material for the synthesis of the rosmarinates esters investigated and reported here.…”