Chem. Pharm. Bull., 54(8),1219-1222, August 2006

Notes

Degraded and Oxetane-Bearing Limonoids from the Roots of Melia azedarach

Yoshiyasu FUKUYAMA,^* Momoko NAKAOKA, Tomoko YAMAMOTO, Hironobu TAKAHASHI, and Hiroyuki MINAMI

Institute of Pharmacognosy, Faculty of Pharmaceutical Sciences, Tokushima Bunri University; Yamashiro-cho, Tokushima 770-8514, Japan. * To whom correspondence should be addressed. e-mail: fukuyama@ph.bunri-u.ac.jp

Brine shrimp lethality test (BST)-guided fractionation of a methanol extract of the roots of Melia azedarach resulted in the isolation of two new limonoids, 9α-hydroxy-12α-acetoxyfraxinellone (1) and 7,14-epoxy-azedarachin B (2), together with the known compounds, 12α-hydroxyfraxinellone (4), 9α-hydroxyfraxinellone (5), azedarachin B (6), and neoazedarachin B (7). The structures of 1 and 2 were elucidated by analysis of spectroscopic data and comparison of their NMR data with those of the known compounds. Compounds 1, 2 and 4-7 exhibited significant activity in the BST, in particular, azedarachin B (6) showed remarkable BST activity with an LC₅₀ value of 0.0098 μM.

Key words Melia azedarach; limonoid; fraxinellone; azedarachin; brine shrimp lethality; cytotoxicity