Abstract

• The tuber of Stephania glabra (Roxb.) Miers, one of Myanmar indigenous medicinal plants was selected for this research work. The sample was chopped in to small pieces and dried in air. The air dried tuber sample was extracted with 95% of ethanol for about one month. Moreover, it was further extracted with ethyl acetate and ran by different solvents polarities using thin layer and column chromatography. A biologically active pure compound (KLT-1) could be isolated from n-hexane and ethyl acetate solvent ratio (n-hex 19:1EtOAc, 40 mg, and Rf value 0.9). The antimicrobial activity of this pure compound was examined by agar well diffusion method on six selected organisms. It was highly responded on three microorganisms such as Bacillus subtilis, Bacillus pumilus and E. coli. The molecular formula of pure compound (KLT-1) was assigned as C18H30O2 (ester compound) by FT IR (Fourier Transform Infrared), 1H NMR (Proton Nuclear Magnetic Resonance), 13C NMR (Carbon Nuclear Magnetic Resonance), DEPT (Distortion Enhancement by Polarization Transfer), HSQC (Heteronuclear Single Quantum Coherence) and DART (Direct Analysis of Real Time Mass Spectroscopy) mass spectral data. Moreover, the complete structure of pure compound could be elucidated by using advanced spectroscopic methods such as DQF-COSY (Double Quantum Filtered Correlation Spectroscopy) and HMBC (Heteronuclear Multiple Bond Coherence) spectral evidences. The prominent functional groups containing in this compound was assigned and its complete structure was described as follows.