Medicago sativa and Medicago truncatula as plant sources of the chemopreventive flavone tricin

In recent years many data have been published on health benefits of flavonoids present in human diet. Many studies were performed to characterize potential cancer chemopreventive properties of various plant phytochemicals, including flavonoids. Among this group of secondary metabolites tricin (4',5,7-trihydroxy-3',5'-dimethoxyflavone) has shown cancer preventive activity. The growth inhibitory and cell cycle-arresting properties of tricin in human MDA-MB-468 breast cancer and in nude mice were documented. The ability of tricin to inhibit cyclooxygenase enzymes and to modulate the cyclooxygenase-mediated prostaglandin production may contribute to its chemopreventive efficacy on intestinal carcinogenesis and prostate cancer. Few studies have focused on other pharmacological activities of tricin, and those performed used tricin monomer, which derives from chemical synthesis. Plant derived tricin products were not explored so far. The tricin glycosides are commonly distributed in the plant kingdom. However, there are few plant species with a concentration of tricin which may be of commercial value. Our recent work on flavonoids from Medicago sativa (common name alfalfa) and Medicago truncatula showed that tricin glucuronides were the main components of the flavonoid fraction of these two species [1, 2]. The total concentration of tricin glycosides in M. sativa was 1.4–1.7% of dry matter (whole shoots) depending on variety. M. truncatula var truncatula, M. truncatula var longispina and M. truncatula var Jemalong A17 (leaves) contained 3.23, 2.37 and 3.34% dry matter, respectively. Thus, we suggest that these two species (other Medicago species should be studied) can be considered as natural, commercial herbs with high tricin concentration.

References: [1] Stochmal A. et al. (2001) J. Agric. Food Chem. 49: 5310–5314. [2] Kowalska I. et al. (2007) J. Agric Food Chem. 55: 2645–2652.