H. CHEN, S. Li, N. Bai, and C.-T. Ho. Dept. of Food Science, Rutgers, The State Univ. of New Jersey, 65 Dudley Rd., New Brunswick, NJ 08901-8520
Ixeris denticulata, which belongs to genus Ixeris, has been recently found to possess a wide spectrum of therapeutic properties, including cytotoxic, anti-inflammatory, anti-tumor and anticancer activities. Although many previous studies have demonstrated the active components of other Ixeris plants both in vivo and in vitro, relatively few studies have investigated on the chemical components of Ixeris denticulata. This leads to the central objective of our research which is to elucidate the components with potential bioactivities of Ixeris denticulata. The whole plants of Ixeris denticulata were dried and ground into a powder that was extracted with 95% ethanol. After removal of hexane soluble material, the aqueous solution was extracted with ethyl acetate. The ethyl acetate extract was then dried and subjected to successive normal phase silica gel and Sephadex LH-20 gel column chromatography to obtain the pure compounds. In our present study, five compounds were isolated and identified from Ixeris denticulata. Structural characterization was achieved via 1H NMR, 13C NMR and MS techniques. We identified each of the five bioactive compounds as the flavonoids apigenin and luteolin, the plant sterols b-sitosterol and stigmasterol, and an unusual chlorinated iridoid rehmaglutin D. Apigenin has been demonstrated to have anticancer activity and inhibits the growth of several human cancer cells while luteolin has been shown to have potent anti-inflammatory, antioxidant, and anti-cancer activities. As for plant sterol, b-sitosterol and stigmasterol have been reported to lower the concentration of plasma cholesterol in human by inhibiting the absorption of cholesterol from the intestinal lumen. The unusual compound rehmaglutin D has been mostly found in scrophulariaceae plants such as Rehmanniae Radix, which is known as a tonic and an antipyretic in traditional Chinese medicine. No study has been done on the biological activity of this compound. With the exception of luteolin, our research constitutes the first report of the presence of apigenin, b-sitosterol, stigmasterol and chlorinated iridoid rehmaglutin D in Ixeris denticulata.
Session 33F, Nutraceuticals & Functional Foods: Antioxidants and phytochemical analysis