The standardization and Pharmacognostic parameters (macro and microscopic studies) is an integral part to establish the correct identity of the crude drug. The present investigation revealed Pharmacognostic characters which include morphology, T.S, powder microscopy and phytochemical screening of ephedra stem. The morphological characters of plant part/s or plant provide the diagnostic characters for identification. The macroscopic study revealed that the ephedra stem is woody, greenish or greyish in colour, cylindrical slender, jointed distinct nodes and internodes (2 – 5 mm long and 4 – 6 mm in diameter) having scaly leaves on nodes. slightly aromatic odour and astringent taste. Longitudinal ridges and furrows are present on the stem. The fracture was fibrous, slightly aromatic odour and astringent bitter taste (Fig. 1).
The microscopical or anatomical study gives a preliminary idea about the nature and disposition of cells, tissues and cell inclusions that can be employed for the botanical diagnosis of a drug. The Transverse section of ephedra stem showed a single-layered epidermis composed of quadrangular parenchyma cells with a thick-walled cuticle and vertical rows of sunken stomata and papillae on the outer side. Cortex is composed of thin-walled, radially elongated and loosely arranged collenchymatous cells containing abundant chloroplasts, crystals of calcium oxalate and intercellular spaces form palisade layer. Non-lignified triangular hypodermal cells like a bunch of grapes occur in the ridges. The conjoint, open collateral type of vascular bundle are arranged in a ring near the pericycle region. Vascular bundles are 8 – 11 in numbers. In each vascular bundle, phloem is located towards the outside and xylem is towards the inside between the cambium. Xylem is made up of vessels, tracheids, xylem parenchyma and fibres. Phloem is composed of sieve tubes and phloem parenchyma. The pith is large central region made up of thick-walled parenchymatous cells, some cells are filled with the reddish brown content of tannin. The medullary rays are long and wide and composed of parenchymatous cells.
Powder microscopic investigation provides some important diagnostic characters for rapid and accurate identification of crude drug. Consequently, it is necessary to know the histological characters of genuine drug materials for the detection of adulterants. The results revealed that ephedra powder is greyish green in colour, slightly aromatic odour and an astringent taste. Microscopical studies indicated the presence of fragments of epidermal cells with sunken stomata, crystals of calcium oxalate, parenchyma cells, cortical vascular bundle, pitted vessels and tracheids, groups of phloem fibres, starch grains (light blue in colour) and brown pigment containing cells are some of the diagnostic features.
Each medicinal plant or a specific plant part used as crude drug material contains active chemical constituents with a characteristic profile that can be used for chemical quality control and quality assurance. Various phytochemicals such as terpenoids, saponins, alkaloids, amino acids, glycosides, phenolic compounds, flavonoids, tannins, reducing sugars, carbohydrates, and protein are recorded during preliminary phytochemical screening.
The pharmacognostic profile namely macroscopic and microscopic characters will be helpful for the correct botanical identification, to establish the authenticity of a drug, differentiate the drug from other species and drawing the pharmacopeial standards. Hence Pharmacognostic studies of crude drug play a very important role in identification, purity, and quality of crude drugs.
The pharmacognostic profile of the ephedra stem revealed diagnostic indices that could be helpful in standardization, quality, purity, identification as well as to control adulterations of crude drug. The findings would be helpful in setting standards of the medicinal plant.