Two new iridoid glycosides from Odontonema cuspidatum and their bioactivities

Two new iridoid glycosides, named 6 beta-O-methyl-unedoside (1) and 6 beta-O-methyl-5-deoxythunbergioside (2) along with two known phenyl propanoid glucoside compounds dolichandroside A (3) and verbascoside (4) were isolated from the aerial parts of Odontonema cuspidatum (Nees) Kuntze (Acanthaceae). Structure elucidation of the new compounds was established by interpretation of their 1D and 2D-NMR spectral data by comparing with literatures, HRESIMS and optical activity measurement. The isolated compounds were tested for their in vitro antimicrobial and antimalarial activities. Compound 4 showed a moderate antimicrobial activity against E. coli with IC50 value of 17.5 mu M in comparing with Vancomycin and Cefotaxime.