Modernizing Analytical Standards in Ayurvedic and Botanical Products: Re-evaluating the Suitability of High-performance Thin-layer Chromatography-based Planar Chromatographic Fingerprinting for Identity and Plant-part Determination

Dear Editor, The analytical evaluation of herbal and botanical products presents a unique scientific challenge, reflecting the intrinsic complexity and variability of plant-derived matrices. As global regulatory expectations continue to evolve toward enhanced specificity, reproducibility, and traceability, the principle of “fit-for-purpose” analytical methodology has become increasingly central to ensuring the reliability of quality assessment systems. High-performance thin-layer chromatography (HPTLC) has historically contributed as a rapid technique for qualitative fingerprinting. Its utility in preliminary screening is well recognized, particularly in academic and exploratory contexts. However, the expanding complexity of botanical supply chains and the need for precise identity confirmation necessitate careful consideration of its analytical scope and limitations. A particularly challenging aspect of botanical analysis is the differentiation of plant parts (e.g., roots, leaves, stems, and bark) based on their chemical composition. Plant tissues are governed by organ-specific biosynthetic pathways, yet they frequently contain overlapping classes of metabolites, differing primarily in concentration, ratios, and minor constituents rather than the presence of entirely unique chemical markers. This makes differentiation based solely on chemical presence inherently complex. These intrinsic characteristics are further influenced by geographical origin, soil composition, climatic conditions, altitude, seasonal variation, cultivation practices, and postharvest processing, all of which can significantly alter phytochemical expression and stability.[1,2] Consequently, the chemical identity of a given plant part is not fixed, but exists within a continuum shaped by both biological and environmental variables. Within this context, reliance on planar chromatographic fingerprints for definitive interpretation warrants careful scrutiny. Chromatographic patterns generated under such conditions may appear visually similar despite meaningful molecular differences, or conversely, may differ due to environmental or methodological variability rather than true compositional divergence. In the case of plant-part differentiation, where shared metabolites are common, visual band patterns or relative intensity alone may not provide sufficient specificity for reliable identification. Evidence from the literature further reinforces this concern. Studies evaluating commercial herbal products have demonstrated that materials conforming to expected chromatographic profiles may still contain substituted species or exhibit compositional discrepancies when assessed using higher-resolution analytical techniques.[3,4] These findings highlight that apparent conformity in chromatographic fingerprinting does not necessarily reflect chemical authenticity or functional equivalence. Advances in analytical science provide more suitable alternatives for addressing these challenges. Techniques such as liquid chromatography coupled with mass spectrometry enable detailed characterization of phytochemical constituents, including minor compounds and structurally related analogues critical for distinguishing plant parts.[5] Similarly, nuclear magnetic resonance-based metabolomic approaches offer comprehensive chemical profiling and improved discriminatory power when combined with multivariate analysis.[6] These techniques provide the level of molecular specificity and quantitative resolution required for reliable botanical identification. Molecular tools, including DNA-based approaches, may offer an additional layer of verification for species-level identification; however, their applicability to plant-part differentiation remains limited. Their greatest value lies in complementing chemical analysis within an orthogonal, multimethod framework, rather than functioning as standalone solutions.[4] From a regulatory perspective, the International Council for Harmonization Q2(R2) guideline emphasizes that analytical methods must be demonstrably fit-for-purpose, with validated parameters including specificity, accuracy, precision, system suitability, and robustness.[7] For botanical matrices, this necessitates analytical approaches capable of resolving not only species identity but also plant-part specificity and variability arising from environmental and processing factors. In parallel, pharmacopoeial evolution and international frameworks highlight the importance of good agricultural and collection practices and good manufacturing practices, with emphasis on traceability through documentation of geographical origin, cultivation conditions, harvesting parameters, and postharvest handling.[2] In light of these considerations, it becomes increasingly evident that while HPTLC remains valuable as a rapid and accessible screening tool, its interpretative limitations constrain its suitability for more definitive analytical roles. Its continued use in academic or exploratory contexts is well justified; however, in commercial quality control and regulatory decision-making, where analytical specificity and reproducibility are critical, reliance on such approaches as a sole determinant – particularly for plant-part identification – may not fully align with contemporary scientific expectations. Accordingly, a tiered, fit-for-purpose analytical framework, integrating chromatographic, spectrometric, and complementary methodologies, offers a more robust and scientifically defensible approach. Within such frameworks, HPTLC may serve as a supportive preliminary tool, but not as a standalone basis for critical pass–fail decisions. In conclusion, advancing the scientific credibility and regulatory acceptance of herbal and botanical products requires alignment between analytical methodology and the true complexity of plant systems. Recognizing the limitations of planar chromatographic approaches in plant-part identification, and embracing integrated, validated analytical strategies, will be essential for ensuring authenticity, consistency, and global confidence in botanical products. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.