Camosic acid from sage

Bailey, D, Richheimwr, S, Bank, V and King, B (1999) High purity camosic acid from rosemary and sage extracts by pH-controlled precipitation. US Patent 5,859,293. 

Fig (11) Camosic acid (89) is an abietane diterpene and has been isolated from the leaves of sage as pale-yellow powder, m.p. 194.5 - 195°C (crystallized from acetic acid). Its oxidation products have been identified as (92), an orange powder, m.p. 129°C and (93), a yellow powder, m.p. 172 - 173°C. 

Masuda, T., Inaba, Y. and Takeda, Y. Antioxidant mechanism of camosic acid Structural identification of two oxidation products. /. Agric. Food Chem. 49, 5560-5565 (2001). Masuda, T., Inaba, Y., Maekawa, T., Takeda, Y., Tamura, H. and Yamaguchi, H. Recovery mechanism of the antioxidant activity from camosic acid quinone, an oxidized sage and rosemary antioxidants. J. Agric. Food Chem. 50, 5863-5869 (2002). 

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. 

An example of the medicinal plant is Rosmarinus officinalis which has chemical components that has significant antioxidant activity [3-6]. Carvalho, Jr. et al., [6] obtained Rosmarinus officinalis extracts via supercritical extraction with CO2 (CO2-SFE) with high antioxidant activity and identified camphor, 1,8-cineole, camosic acid and rosmarinic acid, moreover studied changes in the production scale of extracts. Vincent et al., [7] isolated, by supercritical fluid chromatography, camosic acid (over 80% by mass) from extracts obtained via SFE Rosmarinus officinalis. Camphor, 1,8-cineole, camphene, bomeol, myrcene and a-pinene can be identified as major compounds in extracts via CO2-SFE Spanish sage [8]. 

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