Carnosic acid antioxidant activity

Frankel, E.N., Huang, S.W., Aeschbach, R., and Prior, E. 1996 Antioxidant activity of a rosemary extract and its constituents, carnosic acid, carnosol and rosmaric acid in bulk oil and oil-in-water emulsion. J. Agric. Food Chem. 44 131 -136. 

Rosemary (Rosmarinus officinalis, Labiatae) is native to southern Europe. Rosemary acts as a mild analgesic and antimicrobial agent in traditional herbal use [95]. The relative amount of carnosol (Di25) in dried rosemary leaves is 3.8-4.6%. Among the antioxidant compounds in rosemary leaves, 90% of the antioxidant activity can be attributed to Di25 and carnosic acid (ll,12-dihydroxy-8,ll,13-abietatrien-20-oic acid)... 

The abietane diterpene carnosic acid (89), a derivative of ferruginol, is found in the popular Labiatae herb, sage and rosemary and is considered a precursor of other diterpenoid constituents in the herb [20,21]. Wenkert et al [22] have established the structure of carnosic acid (89). Carnosic acid (89) and related diterpenes such as camasol (90) and rosemanol (91) Fig. (11) possess powerful antioxidant activities [23] but carnosic acid (89) is the most powerful potency among these diterpenes. Carnosic acid (89)... 

Dapkevicius et al. (1998) compared yields and antioxidant activities of four different extracts from rosemary and sage leaves an acetone, a water extract (both from deodorized plant material), and an acetone and SFC C02 extract (both from nondeodorized plant material). The yields (g per kg dry matter) ranged from 50.2 for the SFC C02 to 90.8 for the water extract from deodorized plant material. High antioxidant activity was found for the SFC C02 and the acetone extracts, but low activity was determined for all water extracts. This emphasizes the importance of camosol and carnosic acid that are extracted from leaves with water-ethanol solvent... 

The use of extracts from rosemary as food preservatives is well established [25] the phenolic compounds obtained from this source have been shown to act as antioxidants in vitro and reduce the oxidation of dietary lipids in a dose-dependant manner [26]. The constituents of rosemary considered responsible for the majority of this antioxidant activity are rosmarinic acid, carnosol, and carnosic acid [14]. 

Aruoma 01, Halliwell B, Aeschbach R, Loligers J. Antioxidant and pro-oxidant properties of active rosemary constituents carnosol and carnosic acid. Xenobiotica 1992 22 257-268. 

Common sage and rosemary (see Table 8.32), plants of the Lami-aceae family, contain the diterpenes camosic acid, also known as rosmaricin (8-259), derived from ent-caurene, and bitter carnosol (picrosalvin, 8-260), which are potent antioxidants. Carnosic acid is a major component of fresh rosemary tops (1-2%), but is unstable and is enzymatically transformed into carnosol. These two diterpenoids represent about 15% w/w of plants haulm extracts and exhibit about 90% of extract antioxidant activity. Other transformation products of carnosic acid are rosmanol (7a-hydroxy derivative, 8-261), epirosmanol (7P-isomer, 8-262) and similar compounds. 

Mint plants (Lamiaceae), for example in common thyme (ThymtAS vulgaris), contain substituted biphenyls derived from monoter-penic alcohol thymol, their o-quinones (10-178) or p-quinones (10-179), which exhibit marked antioxidant activities. Among the most active natural antioxidants with anti-inflammatory effects is carnosic acid, also known as rosmaricine (10-180), which is accompanied by carnosol (picrosalvin, 10-181). These two antioxidants represent about 15% by weight of commercial extracts of rosemary... 

Rosmarinus officinalis) and more than 90% of their antioxidative activity. The carnosic acid content in fresh spices is about 1-2%. 

Frankel, E. N., S. H. Huang, E. Prior, and R. Aeschbach. 1996. Evaluation of antioxidant activity of rosemary extracts, carnosol and carnosic acid in bulk vegetable oils and fish oil and their emulsions. /. Sci. Food Agric. 72(2) 201-208. 

Sage extracts, like those of rosemary, have strong antioxidant activities in vitro and in vivo labiatic acid, carnosic acid, and the phenolic acids are reported to be the active compounds (see rosemary). Sage oil displayed chemopreventive activity against... 

Huang, S, Frankel, E, Schwarz, K, Aeschbach, R and German, J (1996) Antioxidant activity of carnosic acid and methyl camosate in bulk oils and oU-in-water emulsions. J. Agric. Food Chem., 44, 2951-2956. 

The antioxidant activity of the four phytochemicals isolated from rosemary were assayed in a DPPH free radical scavenge system. Carnosic acid, camosol and rosmarinic acid showed concentration-dependent scavenging ability. These phytochemicals were more potent than vitamin C and vitamin E. The 50% DPPH... 

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