Abstract
A simple, sensitive and precise high-performance thin-layer chromatographic (HPTLC) method was developed and validated for the analysis of ar-turmerone and turmerone, the major constituents of the lipid soluble fraction of the herbal medicament (HM) obtained from the rhizomes of Curcuma longa (turmeric). The separation was carried out on HPTLC aluminum plates precoated with silica gel 60F-254, with n-hexane:ethyl acetate (9.8:0.2 v/v) as mobile phase. Densitometric analysis of ar-turmerone and turmerone was carried out in the absorbance mode at 254 nm. This system was found to give compact spots for ar-turmerone and turmerone (Rf values 0.5 ± 0.05; 0.6 ± 0.04, respectively). A good linear regression relationship between peak areas and the concentrations was obtained over the range of 100–600 ng/spot, with correlation coefficients of 0.997 and 0.998 for ar-turmerone and turmerone, respectively. The limit of detection and quantification was found to be 20 and 40 ng/spot for ar-turmerone and turmerone, respectively. The method was further validated for precision and recovery. The RSD values of the precision were in the range 0.49–1.33% and spike recoveries were 99.9 and 100.0% for ar-turmerone and turmerone, respectively. Analysis of different batches of HM using the above method gave ar-turmerone and turmerone contents in the range of 25–30% and 30–38%. The developed HPTLC method can be applied for identification and quantitative determination of ar-turmerone and turmerone in the lipid soluble fractions of turmeric.