Lithocarpic acids O–S, five homo-cycloartane derivatives from the cupules of Lithocarpus polystachyus.

Chemical investigation of the cupules of Lithocarpus polystachyus resulted in the identification of four 3,4- seco -homo-cycloartane and one homo-cycloartane derivatives named lithocarpic acids O–S. Their structures were determined based on extensive 1D/2D NMR, IR, MS spectroscopic analyses and chemical methods. Lithocarpic acid O ( 1 ) exhibited inhibitory activities on mouse and human isozymes of 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) with IC 50 values of 0.49 and 1.1 μM, respectively. [ABSTRACT FROM AUTHOR]