LC-HRMS- and TLC-based metabolomics for the identification and authentication of Sida rhombifolia

Ensuring the authenticity and quality of Sida rhombifolia raw materials is crucial for its herbal medicinal product's consistent efficacy, quality, and safety. In this study, we developed an identification and authentication method for identifying and authenticating S. rhombifolia from Turnera subulata. T. subulata has the same leaf morphology as S. rhombifolia, so that it could be used as an adulteration raw material for S. rhombifolia. We employed liquid chromatography-high resolution mass spectrometry (LC-HRMS)- and thin-layer chromatography (TLC)-based metabolomics for that purpose. Distinct chemical fingerprints of S. rhombifolia from T. subulata were obtained using LC-HRMS and TLC fingerprint analysis. Mixtures of S. rhombifolia and T. subulata powdered samples at varying concentrations (5 %, 25 %, and 50 % w/w) were analyzed using principal component analysis (PCA) and orthogonal partial least squares discriminant analysis (OPLS-DA) to see differences of each group. The PCA score plot from the TLC analysis explained over 70 % of the total variance, while LC-HRMS data provided the highest classification accuracy at 97.05 %. This integrated approach enhances the reliability of S. rhombifolia authentication by combining TLC's rapid profiling capability with LC-HRMS's analytical precision. This study provides a robust analytical framework for the quality control of herbal medicines, specifically addressing challenges related to adulteration.