PHARMACOGNOSTIC EVALUATION AND STANDARDISATION OF THE STEM BARK OF TERMINALIA TOMENTOSA ROXB.

Background: Terminalia tomentosa Roxb. (Combretaceae), commonly known as the crocodile-bark tree, is a large deciduous tree whose stem bark occupies a prominent place in Ayurvedic, Siddha and folk medicine systems across India for the management of diarrhoea, bronchitis, fractures, haemorrhages and inflammatory conditions. Despite this long traditional use, the stem bark has not been subjected to a systematic pharmacognostic and physicochemical evaluation, leaving an important gap with respect to its authentication and quality control. Objective: The present study was undertaken to perform a comprehensive pharmacognostic and preliminary phytochemical standardisation of the stem bark of T. tomentosa, generating reference parameters for its identification and quality assessment. Methods: Authenticated stem bark collected from the Dandeli-Tinaighat forest Karnataka, was evaluated for organoleptic and morphological characteristics, transverse-section and powder microscopy and standard physicochemical parameters including moisture content, ash values, extractive values, fibre dimensions and foaming index. A 70% ethanolic extract was screened qualitatively for major phytoconstituents and quantitatively for total phenolic, flavonoid and tannin content using validated spectrophotometric assays referenced against gallic acid, quercetin and tannic acid standards, respectively. Results: The bark was dark grey to black, odourless, bitter and granular in fracture. Microscopy revealed a multilayered cork of 25-30 rectangular cell layers, prismatic calcium oxalate rosettes, simple and compound starch grains, phloem fibres and uniseriate to occasionally biseriate medullary rays. Moisture content was 6.6% w/w; total, acid-insoluble and water-soluble ash were 0.615 g, 0.35 g and 0.585 g respectively. Alcohol-soluble and water-soluble extractive values were 8.2% w/w and 3.8% w/w. Mean fibre length and width were 18.67 mm and 1.58 mm and the foaming index was below 100. Qualitative screening indicated the presence of tannins, triglycerides, flavonoids, saponins, carbohydrates and phenolic compounds, with alkaloids, proteins, steroids and glycosides absent in both extracts. Regression analysis yielded strong linearity for total phenolic (R² = 0.956), flavonoid (R² = 0.908) and tannin (R² = 0.985) content. Conclusion: The morphological, microscopical and physicochemical parameters established in this study provide a reliable reference profile for the identification, authentication and quality control of T. tomentosa stem bark and may serve as a foundation for future pharmacopoeial standardisation and pharmacological investigation.