Assessment of Chemical Stability of Constituents in Thiosulfinate derivative-rich Extract of Garlic by a Validated HPTLC Method

Garlic (Allium sativum) is a plant known since ages for its beneficial properties. This study was carried out to develop and validate a simple, specific and robust high performance thin layer chromatography method for analysis of constituents present in a thiosulfinate derivative-rich extract of garlic. High performance thin layer chromatography analyses were carried out using aluminium backed silica gel 60F-254 plates as the stationary phase and toluene: ethyl acetate: chloroform: methanol (8:20:12:60% v/v/v/v) as the mobile phase. The method was validated as per ICH Q2 guidelines. The stability of eight components present in the extract of garlic under stress conditions like increased temperature, varying pH and presence of oxidant was also investigated as per the ICH Q1A (R2) guidelines. It was observed that the stability of all constituents present in the extract was majorly dependent on pH, illumination and temperature. The high performance thin layer chromatography method developed was able to estimate changes in content of all constituents present in the extract of garlic when it was subjected to stress conditions, which proves the stability-indicating nature of the method. Results of the study suggested that thiosulfinate derivative-rich extract of garlic should be stored at -20 degrees in a well-closed container, away from light at a pH range of 4-7 to avoid degradation of components present in the extract.