Bioactive triterpenoids from twigs of Betula schmidtii.

Investigation of the MeOH extract of Betula schmidtii twigs resulted in the isolation and identification of three new triterpenoids (1-3), along with ten known ones (4-13). The structures of new compounds (1-3) were elucidated by spectroscopic methods, including 1D, 2D NMR (1H and 13C NMR, COSY, HSQC, HMBC, and NOESY), HR-MS, and chemical methods. All the isolated compounds were evaluated for their cytotoxicity against A549, SK-OV-3, SK-MEL-2, and HCT-15 cell lines. Compound 11 exhibited potent cytotoxic activities against four cell lines, and compounds 5 and 13 significantly induced nerve growth factor secretion in a C6 rat glioma cell line. Their anti-inflammatory effects were also assessed by measuring nitric oxide production in lipopolysaccharide-activated BV-2 cells. Compounds 7 and 12 displayed potent inhibition of nitric oxide production, without significant cell toxicity.