Simultaneous high-performance thin-layer chromatographic method for the estimation of guggulsterones E and Z in AYUSH guggul formulations and confirmation of the antioxidant potential of guggul by thin-layer chromatographic-bioautographic method

Guggulsterone (GS) is a bioactive phytosteroid found in the oleo-gum resin of guggul (Commiphora wightii). In Indian system of medicine, there is a long history of the use of gum and plant extract of guggul for treating various ailments. Due to the complex nature, low availability, and inconsistency of phytosteroids, their analysis is a difficult task. A fast, sensitive, selective, and robust densitometric high-performance thin-layer chromatographic method was developed to determine guggulsterones E and Z (GS-E and GS-Z) quantitatively in six different guggul-based formulations used in AYUSH (Ayurveda, Yoga and Naturopathy, Unani, Siddha, and Homeopathy) systems of medicine, which are used as chemical markers for the standardization of different guggul-based formulations. Separation was done on silica gel 60F(254) aluminum plates using n-hexane-ethyl acetate (5:5, V/V) as the mobile phase. Quantification of GS-E and GS-Z was carried out using densitometry at 254 nm. A precise and accurate quantification method was developed in the linear working concentration range of 6.43-24.12 mu g/mL, 13.06-42.43 mu g/mL with good correlations, r(2) 0.9971 and 0.9994, respectively, for GS-E and GS-Z. The contents of GS-E and GS-Z were in the range of 50-2240 mu g/g and 70-3330 mu g/g, respectively, in different guggul-based formulations. The method was validated for precision, robustness, accuracy, limit of detection and limit of quantification, etc., as per the International Council for Harmonization guidelines. Specificity was confirmed using retention factor and spectra correlation of standard and sample tracks. Further, antioxidant profile of oleo-gum resin of guggul was carried out by using the TLC-bioautography approach. TLC-bioautography showed prominent spots of GS-E and GS-Z with other compounds in yellowish color against purple background of the developed plate. The developed method is economical and can be applied for the routine analysis of marketed polyherbal guggul-based formulations.