High-performance thin-layer chromatographic method for the estimation of benzyl isothiocyanate in salvadora persica root extract and dental care herbal products

A novel, simple, and sensitive high-performance thin-layer chromatography (HPTLC) method has been successfully developed and validated for the quantification of benzyl isothiocyanate in Salva-dora persica (Miswak or Siwak) extract and some dental care herbal products labeled to contain Siwak extract. A modified HPTLC method was carried out using glass-coated silica gel 60 F₂₅₄ plates and mobile phase consisting of n-hexane-ethyl acetate (9:1) furnished compact spots at R_F 0.61 ± 0.01. The developed plate was scanned and quantified densitometrically at 191 nm. Linear regression analysis revealed a good linear relationship between peak area and amount of benzyl isothiocyanate in the range of 100-600 ng band^-1 (r² = 0.9991). The method was validated in accordance with the International Conference on Harmonization (ICH) guidelines for precision, accuracy, and robustness. The proposed method will be useful to evaluate the therapeutic efficacy of Siwak extracts and dental care herbal formulations containing Siwak.