High-Performance Thin-Layer Chromatography (HPTLC) is a versatile analytical technique widely used for the analysis of herbal drugs. Let's evaluate the applicability of HPTLC for each of the given options:
- Quantitative estimation of marker compound: HPTLC allows for the qualitative and quantitative analysis of constituents, especially marker compounds in complex matrices like herbal drugs.
- Authentication of extracts: HPTLC can be used for the authentication of herbal extracts by comparing the TLC fingerprint with that of standard reference samples.
- Detection of pesticides: While not its primary use, HPTLC can be employed to detect pesticide residues in herbal drugs through specific development and detection techniques.
- Standardization of herbal drugs: HPTLC is a crucial tool in the standardization process, ensuring batch-to-batch consistency and quality control of herbal products.
Therefore, HPTLC is applicable for all the listed purposes: quantitative estimation of marker compounds, authentication of extracts, detection of pesticides, and standardization of herbal drugs. The correct answer is A, B, C and D.