Rosemary, antioxidant

The effectiveness of the two natural antioxidants rosemary and sage increases with the content of the active phenolic diterpenes [2-3]. New and improved extraction techniques based on supercritical C02-extraction (see chapter 2.1.2) resulted not only in concentrated and very active, but also in well desodourized and almost neutral tasting antioxidants. 

For use as an antioxidant, rosemary resin is usually fractionated from the essential oil because of the oil s strong eucalyptus-like note. This is a commercial process for CO2 extraction, but the extract has to compete commercially with solvent extraction of antioxidant, as the major advantage of capturing top notes that CO2 extraction has, is negated because of evaporation of the essential oil. A solvent extracted and fractionated antioxidant is as functional as a S.CO2 extract (reviewer s comment). 

Like many other antioxidants, rosemary and its polyphenols possess not only antioxidative activities, but also antitumorigenic activities. Huang et al. (5) investigated the inhibitory effects of rosemary extract, carnosol and ursolic acid on tumor formation in mouse skin. They found that topical application of rosemary inhibits B(a)P- and DMBA-induced initiation of tumor and TPA-induced tumor promotion in DMBA-initiated mice. Carnosol and ursolic acid were found to be strong inhibitors of TPA-induced inflammation, ornithine decarboxylase activity and tumor promotion in mouse skin (5). It was suggested that carnosol acted like other nonsteroidal phenolic anti-inflammatory agents, such as curcumin, which inhibited the metabolism of arachidonic acid. 

Several other naturally occurring antioxidants have been identified in oils. Sesamol [533-31-3] (6) occurs as sesamoline [526-07-8], a glycoside, in sesame seed oil. FemUc acid [1135-24-6] (7) is found esterified to cycloartenol [469-38-5] in rice bran oil and to 3-sitosterol in com oil. Although it does not occur in oils, rosemary extract has also been found to contain powerful phenoHc antioxidants (12). 

A few spices, particularly rosemary and sage, are known to act as antioxidants which prevent rancidity due to oxidation in fats and fatty foods. 

The most popular natural antioxidants on the market are rosemary extracts and tocopherols. Natural antioxidants have several drawbacks which limit use. Tocopherols are not as effective ia vegetable fats and oils as they are ia animal fats. Herb extracts often impart undesirable colors or flavors ia the products where used. In addition, natural antioxidants cost considerably more than synthetic ones. Despite this, the pubHc s uncertainty of the safety of synthetic antioxidants continues to fuel the demand for natural ones (21). 

Nowadays, consumers would like those antioxidants present in food products not only to stabilise food lipids, but also to be absorbed through the intestinal wall and protect the lipids of blood plasma against oxidation. This effect is relatively evident in the case of tocopherols (which are liposoluble) or ascorbic acid (which is hydrophilic), but much less evidence is available on antioxidants of medium polarity, such as flavonoids, rosemary oleoresins or green or black tea catechins. 

CHANG s s, osTRic-MATiJASEVic B, HSIEH o A L and HUANG c L (1977) Natural antioxidants from rosemary and sage, J Food Sci, 42 (4), 1102-6. 

CHEN z-Y, WANG L Y, CHAN p T, ZHANG z, CHUNG H Y and LIANG c (1998) Antioxidative activity of green tea catechin extract compared with that of rosemary extract, JAOCS, 75 (9), 1141-5. 

Synthetic analogues or derivatives of a-tocopherol which have better antioxidant properties can be introduced. Many natural antioxidants such as flavonols, flavones, tea leaf catechins, rosemary antioxidants and spice extracts have been reported to be more active than BHA, BHT or the tocopherols in model systems. The food applications of these compounds need to be explored further. 

The antioxidant activity of rosemary and sage (leaves and extracts) were most effectively investigated [96,97], Traditional extracts of spices and herbs are obtained by steam distillation (essential oil) or by extracting the botanical with solvents such as alcohol, hexane, or acetone, and removing the solvents by evaporation. The SFE process for production of the inherent natural antioxidants is now the most gentle and effective method [70],... 

In the year 1952, Chipault et al. mentioned that rosemary and sage have the best antioxidant activities, followed by oregano, thyme, clove, allspice and black pepper [28], By using the CO2 extraction the camosolic acid, the most effective substance in this respect, can be enriched to high concentrations. 

Rosemary and sage have been shown to have effective antioxidant properties. The extracts in the past have been of strong odor and bitter taste and thus unsuited for use in most food products. However, solvent extraction procedures have been developed to produce purified antioxidants fiom rosemary and sage. 

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. 

Several spices possess antioxidative properties — a turmeric extract (curcuminoid), a hexane extract of rosemary, and the a-tocopherol-supplemented capsicum pigment exhibit their antioxidative effects in vivo by dietary supplementation. Turmeric extract has demonstrated the ability to reduce liver triacylglycerol deposition as well as cholesterol. 

Asai, A., Nakagawa, K., and Miyazawa, T., Antioxidative effects of turmeric, rosemary and capsicum extracts on membrane phospholipid peroxidation and liver lipid metabohsm in mice, Biosci. Biotechnol. Biochem., 63, 2118-2122, 1999. 

Bicchi, C., Binello, A., and Rubiolo, P. 2000. Determination of phenolic diterpene antioxidants in Rosemary (Rosmarinus officinalis L.) with different methods of extraction and analysis. Phytochem. Anal. 11, 236-242. 

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)... 

Baratta, M.T., Dorman, H.J.D., Deans, S.G., Biondi, D.M. and Ruberto, G. (1998) Chemical composition, antimicrobial and antioxidative activity of laurel, sage, rosemary, oregano and coriander essential oils. Journal of Essential Oil Research 1 0(6), 61 8-627. 

Wade et al. (1986) reported that BHA and BHT were effective in retarding oxidation of anhydrous milk fat but DL-a-tocopherol acted as a pro-oxidant. Natural antioxidants in betel and curry leaves have also been reported to retard oxidation of anhydrous milk fat (Sharma, 1981 Parmer and Sharma, 1986). Amr (1991) reported that turmeric and wheat grits were as effective as BHA and BHT in controlling oxidative rancidity in sheep s anhydrous milk fat for up to 4 months. However, rosemary, sage, rue and fennel exerted pro-oxidant effects. Quercetin and rutin are reported to be efficient antioxidants in butter (Eriksson, 1987). 

Natural antioxidants include gum guaiac, tocopherols (including vitamin E), and oil of rosemary (containing rosmaridiphenol). 

Natural antioxidants are present in many spices and herbs (Lacroix et al. 1997 Six 1994). Rosemary and sage are the most potent antioxidant spices (Schuler 1990). The active principles in rosemary are car-nosic acid and camosol (Figure 11-3). Anti-... 

Figure 11-3 Chemical Structure of the Active Antioxidant Principles in Rosemary...

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