Two New Lactam Derivatives from Micromelum falcatum (Lour.) Tan. with Brine Shrimp Larvae Toxicity.

Chemical investigation of the stems of Micromelum falcatum (Lour.) Tan. led to the isolation of two new lactam derivatives, named 3-(hydroxy(10-hydroxyphenyl)methyl)-4-(16-hydroxyphenyl)-1-methylpyrrolidin-2-one ( 1 ) and 3-(hydroxy(10-hydroxy-9-methoxyphenyl)methyl)-4-(16-hydroxyphenyl)-1-methylpyrrolidin-2-one ( 2 ), along with five known compounds, trans-4-hydroxycinnamic acid ( 3 ), 4-hydroxybenzaldehyde ( 4 ), m-hydroxybenzoic acid ( 5 ), p-hydroxybenzoic acid ( 6 ), and gallic acid ( 7 ). Their structures were determined on the basis of spectroscopic studies, including nuclear magnetic resonance (NMR) spectrum, mass spectrometry (MS) data, ultraviolet (UV) spectrum, infrared (IR) data, and comparison with the literature. All compounds were evaluated for toxicity against brine shrimp larvae and cytotoxicity to HeLa and HepG-2 cells. Compounds 1 - 2 exhibited moderate brine shrimp larvae toxicity with an LC 50 value of 50.6 and 121.8 μg mL -1 , respectively.