Antioxidant properties of components extracted from puccoon (Lithospermum erythrorhizon Sieb. et Zucc.)

The petroleum ether extract of puccoon has been separated with thin-layer c hromatography (TLC) and three compounds have been isolated. The structures of the compounds have been identified by spectroscopic methods as beta,beta -dimethyl-acrylshikonin, acetylshikonin and shikonin. Their antioxidant pro perties in lard have been tested with the oxidative stability instrument (O SI). The raw extracts and pure compounds all have obvious antioxidant activ ity, and all have some synergistic effects with D,L-alpha-tocopherol (Ve) a nd butylatedhydroxytoluene (BHT). They all show antioxidant properties in l ard containing Fe3+, and all show synergistic effects with Ve and citric ac id (CA) with different degrees. In the concentration range of 0.01-0.06%, a ntioxidant activity of Ve and BHT, on OSI at 100 degrees C, increases with increase of concentration, but much less than acetylshikonin, shikonin and beta,beta-dimethyl-acrylshikonin. (C) 2000 Elsevier Science Ltd. All rights reserved.