Unani drugs of plant origin are herbaceous whole plant or their parts. The ever increasing demands of these drugs are leading to the adulteration and substitution of genuine drugs and the poor quality of Unani products. In India, the crude drug supplies are usually obtained through various trade channels and are generally lacking in uniform quality. It is very difficult to authenticate the commercial crude drugs because these are available as dried whole plant or some part of it. The Macro-microscopy & Planar chromatography (TLC/HPTLC) are the basic and important tools for proper identification of adulterants/substitutes of Unani drugs and their quality control.
The macroscopy includes organoleptic characters while the microscopy encompasses the detection of the cell type and cell contents as well as the arrangement of cells in tissues. Banafshan, Bhuamla, Pershiaoashan, Rehan, Resha Khatmi and Zarnab can easily be differentiated from their adulterants/substitutes by observing the surface characters or comparing leaf surface microscopy. Similarly, the arrangement pattern and size of fibres, stone cells, crystals, secretary canals etc in phelloderm and phloem region are valuable parameters for the identification of most of the bark drugs.
However, the quality assurance of Unani drugs still remains a challenge because of the high variability of chemical components viz. alkaloids, phenolics, terpenoids, steroids, glycosides etc. The variation may be diurnal, dioecy, chemotypic, genotypic, ecotypic, seasonal etc. Fingerprint analysis using TLC/HPTLC has become the most potent tools for quality control of Unani medicines because of its simplicity, reliability, rapidity and economy. Not only the general finger print profile but also chemical reference markers can be identified and estimated for quality evaluation and authentication of adulterants/substitutes of Unani medicine viz. asarone in Acorus, phyllanthin & hypophyllanthin in Phyllanthus species, berberine & tinosporaside in Tinospora, glycyrrhizine in Glycyrrhiza, gallic and ellagic acids in Terminalia species etc.