Carnosinezuur / Carnosic acid

Carnosinezuur is een polycyclisch diterpenoïde (zuurstofhoudend diterpeen) dat voorkomt in planten uit de lipbloemenfamilie, voornamelijk rozemarijn (Rosmarinus officinalis) en echte salie (Salvia officinalis). Gedroogde bladeren van rozemarijn of salie bevatten 1,5 tot 2,5 % carnosinezuur. Carnosinezuur is een krachtige antioxidant.

Carnosinezuur heeft medicinale eigenschappen; het beschermt huidcellen tegen UV-A-straling (fotoprotectie). Bij dierproeven is vastgesteld dat het een bescherming biedt tegen carcinogenen (chemoprotectie).
Carnosinezuur wordt gebruikt als conserveermiddel of antioxidant in voedingswaren en verzorgingsproducten, zoals tandpasta, mondwater en kauwgum, waarbij het een antibiotisch effect zou hebben tegen micro-organismen die verantwoordelijk zijn voor slechte adem.

Bronnen, noten en/of referenties
 Horst Linde, "Ein neues Diterpen aus Salvia officinalis L. und eine Notiz zur Konstitution von Pikrosalvin". Helv. Chim. Acta 47, 1234 (1962). DOI:10.1002/hlca.19640470517
 U.S. Patent 6231896, "Chewing gum base stabilized with carnosic acid" van 15 mei 2001 aan Goodyear Tire & Rubber Company
 T. Masuda, Y. Inaba, Y. Takeda. "Antioxidant mechanism of carnosic acid: structural identification of two oxidation products". J. Agric. Food Chem. 49, 5560 (2001). PMID 11714360
 Elizabeth A. Offord et al. "Photoprotective potential of lycopene, β-carotene, vitamin E, vitamin C and carnosic acid in UVA-irradiated human skin fibroblasts". Free Radical Biology & Medicine 32, 1293 (2002).
 M. Danilenko, X. Wang, G.P. Studzinksi. "Carnosic acid and promotion of monocytic differentiation of HL60-G cells initiated by other agents". J. Nat. Cancer Inst., 93, 1224 (2001). DOI:10.1093/jnci/93.16.1224
 U.S. Patent 5552158, "Skin care composition" van 3 september 1996 aan Norac Technologies

Carnosic acid, a phenolic diterpene specific to the Lamiaceae family, is highly abundant in rosemary (Rosmarinus officinalis). Despite numerous industrial and medicinal/pharmaceutical applications of its antioxidative features, this compound in planta and its antioxidant mechanism have received little attention, except a few studies of rosemary plants under natural conditions. In vitro analyses, using high-performance liquid chromatography-ultraviolet and luminescence imaging, revealed that carnosic acid and its major oxidized derivative, carnosol, protect lipids from oxidation. Both compounds preserved linolenic acid and monogalactosyldiacylglycerol from singlet oxygen and from hydroxyl radical. When applied exogenously, they were both able to protect thylakoid membranes prepared from Arabidopsis (Arabidopsis thaliana) leaves against lipid peroxidation. Different levels of carnosic acid and carnosol in two contrasting rosemary varieties correlated with tolerance to lipid peroxidation. Upon reactive oxygen species (ROS) oxidation of lipids, carnosic acid was consumed and oxidized into various derivatives, including into carnosol, while carnosol resisted, suggesting that carnosic acid is a chemical quencher of ROS. The antioxidative function of carnosol relies on another mechanism, occurring directly in the lipid oxidation process. Under oxidative conditions that did not involve ROS generation, carnosol inhibited lipid peroxidation, contrary to carnosic acid. Using spin probes and electron paramagnetic resonance detection, we confirmed that carnosic acid, rather than carnosol, is a ROS quencher. Various oxidized derivatives of carnosic acid were detected in rosemary leaves in low light, indicating chronic oxidation of this compound, and accumulated in plants exposed to stress conditions, in parallel with a loss of carnosic acid, confirming that chemical quenching of ROS by carnosic acid takes place in planta.

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