Quantitative analysis of benzyl isothiocyanate in Salvadora persica extract and dental care herbal formulations using reversed phase C18 high-performance liquid chromatography method

Context: Benzyl isothiocyanate is the active antimicrobial agent in Salvadora persica (siwak) widely used in Islamic countries for oral hygiene. Aims: Quantification of benzyl isothiocyanate in the ethanol extract of S. persica and some dental care herbal formulations labeled to contain siwak. Settings and Design: Simple and sensitive high-performance liquid chromatography method was designed. Subjects and Methods: Separation was achieved on reverse phase C₁₈ (250 mm × 4.6 mm, 5 μ ) column with a mobile phase comprising acetonitrile and water (1:1). The detection was carried out at 190 nm using ultra violet-visible detector. The flow rate was kept at 1 mL/min. Results: A sharp and well-defined peak was obtained at the retention time of 9.322 ± 0.3 min. Linear regression analysis data for the calibration plot showed a good linear relationship between response and concentration in the range of 0.5–500 μg/mL with a regression coefficient (r²) of 0.9977. The method was validated for accuracy, precision, robustness, and sensitivity. All the parameters examined met the current recommendations for the International Conference on Harmonization guidelines for method validation. Conclusions: The method was applied for the quantification of benzyl isothiocyanate in siwak extract, dental care powder, mouth wash, and toothpaste claimed to contain siwak. The developed method was found specific, simple, selective, and reliable for routine use in quality control analysis of different commercially available herbal care products.