Insulin Plant (Costus pictus) Leaves: Pharmacognostical Standardization and Phytochemical Evaluation

To explore the micro morphology and physicochemical parameters of the leaves of Costus pictus D. Don (Costaceae). Macroscopy, microscopy, physicochemical analysis, preliminary phytochemical screening and other WHO recommended parameters for standardizations were performed. Costus pictus D. Don is a perennial herb and hardy vigorous growing ginger. The leaves are simple, spirally arranged, oblong-lanceolate with the length 10 to 25cm and width 2.5 to 6cm. The midrib consists of thin epidermal layer of small squarish cells on the adaxial side and fairly thick cylindrical epidermal cells on the abaxial side. The vascular system of the midrib includes an abaxial band of three vascular bundles and adaxial single median bundle. The adaxial epidermal layers of the lamina consist of thick, cylindrical cells. The abaxial epidermis is thin which consists of narrow tubular cells. The adaxial epidermis is apostomatic and abaxial side is stomatiferous. Calcium oxalate crystals of minute particle are aggregated into large masses in the mesophyll cells. Hexacytic type stomata are present. Vein islet numbers, vein termination numbers, stomatal number, stomatal index and other physico chemical tests like ash values, loss on drying and extractive values were determined. Preliminary phytochemical screening showed the presence of carbohydrates, triterpenoids, proteins, alkaloids, tannins, saponins, flavonoids, sterols and volatile oil. Powder microscopy of the leaf showed fragments of unicellular trichomes, hexacytic stomata, abaxial solitary bundle and calcium oxalate crystals. Microscopic analysis was informative and provides useful information in the botanical identification, standardization for purity & quality and immense value in authentication of the leaf.