Pharmacognostic Evaluation of the Bark of Acacia suma Roxb (Fabaceae)

Purpose: To undertake the pharmacognostic evaluation of Acacia suma Roxb bark for the purpose of identification and differentiation from related species. Methods: The macroscopic and microscopic features of the bark were studied, including the use of powder microscopy with the aid of suitable tools and reagents. Physicochemical parameters such as ash values, extractive values and loss on drying were also determined. The bark powder was successively extracted with different solvents followed by preliminary phytochemical screening of the extracts. Results: Macroand microscopic studies revealed an outer hard and woody exfoliating old bark consisting of dead elements of secondary bast alternating with tangential strips of compressed cork tissue. The outer layer consists of cork cell with lenticels, followed by phellum, phellogen and pheloderm layers. Concentric rings of secondary phloem tissue alternating with regularly arranged polygonal stone cells and radially traversed medullary rays were present. Preliminary phytochemical screening showed the presence of alkaloids, carbohydrates, proteins, tannins and phenolic compounds, gums and mucilages, steroids and triterpenoids, saponins and flavonoids in the bark. Conclusion: The findings of this study will facilitate pharmacognostic standardization of the plant material and aid in the preparation of a herbal monograph for the species.