Thesis (M.Sc.In Pharm)--Chulalongkorn University, 2010

Chemical investigation of the roots of Maerua siamensis (Kurz) Pax. (family Capparidaceae) led to the isolation of two new indole alkaloids named 7-hydroxy-6-methoxycyclobrassinone and 7-hydroxycyclobrassinone, together with three known compounds i.e. β-sitosterol, vanillin and lupeol. The structures of these isolated compounds were determined by spectroscopic analyses, including UV, IR, MS and NMR, and comparison with previously reported data. 7-Hydroxy-6-methoxycyclobrassinone was strongly active (IC50 = 1.51 µg/ml), while 7-hydroxycyclobrassinone was moderately active (IC50 = 8.31 µg/ml), against human small-cell lung cancer cell line (NCI-H187). In addition, 7-hydroxy-6-methoxycyclobrassinone also exhibited anti-tuberculosis activity against Mycobacterium tuberculosis with a minimum inhibitory concentration of 25 µg/ml.