Chemical components and antioxidant activity of the volatile oil from Cassia tora L. seed prepared by supercritical fluid extraction

The seed of Cassia tora L. has been used as a traditional Chinese medicine for a long time and it is also an herbal tea in China. In this research, its volatile oil was recovered by employing supercritical fluid extraction using carbon dioxide and analyzed by gas chromatography (GC) and GC-mass spectrometry. The main components of the volatile oil were elucidated as (Z,Z)-9,12- octadecadienoic acid (26.74%), oleic acid (24.15%), n-hexadecanoic acid (13.99%), chrysophanol (7.26%), (E)-9-octadecenoic acid (4.52%) and octadecanoic acid (4.44%). This volatile oil was characterized by a high content of aliphatic acids (75.90%) and anthraquinones (7.26%). In the antioxidant assays, the volatile oil from C. tora L. seed demonstrated 2,2′-diphenyl-1- picryhydrazyl radical-scavenging activity in the concentration range from 20 to 500 g/mL, with the 50% inhibitory concentration (IC 50) value at 137 g/mL; it also showed a significant inhibitory effect against hydroxyl radicals with an IC 50 value of 67 g/mL, lower than that of quercetin (IC 50 = 8.15 g/mL), but superior to that of 4-terpineol (IC 50 = 87.5 g/mL). The observed antioxidant activity of this volatile oil is probably caused by the presence of high levels of chrysophanol and, possibly, (Z,Z)-9,12-octadecadienoic acid. © 2007, Blackwell Publishing.link_to_subscribed_fulltex