Isolation and 1H-NMR identification of a tiliroside from Odontonema strictum (Acanthaceae)

Abstract

The dried leaves (310g) ofOdontonema strictum (OSM) were poured and extracted in MeOH/DCM (1/1//v/v) for 48 hours to yield 25g of dry residue which were purified using chromatographic methods (vacuum liquid chromatography column (VLC), Sephadex LH-20 column and Thin Layer Chromatography (TLC)). Fractions containing flavonoids were mixed for further purifications. Compound 1, yellow amorphous powder (8 mg) was re-dissolved in MeOH and developed in EtAOc/MeOH (2:1) to give an Rf value of 0.27 and mp 301-303°C. The compound reacted positively to HCl-Mg and Molish reactions. The 1 H-NMR (400 MHz, CDCl3) spectrum displayed the typical signals for tilirosides. The presence of glycosidic flavonoids may possibly contribute to the pharmacological properties of OSM.