Abstract
Phytochemical study directed by antimicrobial activity testing of the root extract of Salvadora persica known as Siwak was conducted to identify the antimicrobial components. Fresh roots were extracted with ethanol and the total extract was fractionated with CHCl3 and EtOAc. The antimicrobial activity was trapped to the CHCl3 soluble fraction. Column chromatography followed by CPTLC resulted in the isolation of three active compounds. In addition to the major compound benzyl isothiocyanate two new minor derivatives 3-methoxy benzyl isothiocyanate (1) and 3-hydroxy benzyl isothiocyanate (2) were identified. Structures were elucidated using different spectroscopic tools including UV, MS, 1D- and 2D-NMR. The isolated compounds were active against gram positive, gram negative bacteria and fungi.