Development and validation of TLC-densitometry method for quantification of tetraprenyltoluquinone in the stem bark hexane extract of Garcinia cowa roxb.

A thin layer chromatography (TLC) method coupled with densitometry was optimized and established to quantify tetraprenyltoloquinon (TPTQ) in the hexane extract of Garcinia cowa roxb stem bark. The stationary phase was TLC plates of silica gel 60 F254, with a thickness of 250 μm, while a mobile phase was the mixture of hexane: chloroform: ethyl acetate: formic acid in the ratio of 20:70:9:1 was selected for the chromatographic system. TLC separation of the components was followed by densitometric analysis at 230 nm. The chromatogram revealed a tight spot for TPTQ at the Rf = 0.41 ± 0.03). The value of the regression equation (r2 = 0.992) demonstrated an excellent linear association between peak area and TPTQ amount in the 250-750 μg.spot-1 range. The precision, specificity, and accuracy of the approach were all validated. The 72.65 and 242.15 μg.spot-1 were found as the limit of detection and quantification, respectively. The proposed TLC method can be considered for identifying and quantifying TPTQ in Garcinia cowa Roxb bark hexane extracts.