Comparative pharmacognostic study and establishment of quality parameters of leaves of two species of Karen: Thevetia peruviana and Nerium indicum

Abstract

Background: Two species of Karen - Nerium indicum and Thevetia peruviana are found distributed throughout tropical parts of India. Their leaves are used as cardiotonic and diuretic. Objectives: The present investigation deals with the comparative pharmacognostical study of the leaves of the two species and establishment of its quality parameters. Methods: Detailed morphological and qualitative as well as quantitative microscopic study was carried out. This was followed by phytochemical screening of the two species. Results: Leaf surface microscopy of N. indicum leaf shows straight-walled epidermal cells and anomocytic stomata whereas T. peruviana leaf shows wavy-walled epidermal cells and anisocytic stomata. The chief powder characterisics of N. indicum powder are horse-shoe shaped and annular xylem vessels, pericyclic fibres, hooked-top covering trichomes and calcium oxalate rosette crystals, whereas T. peruviana powder shows mainly the presence of rosette crystals, thereby making it easy to differentiate the two leaves. Various quantitative microscopic parameters were also established. Phenolics, cardenolides, and sterols were detected in both the species, but alkaloids were detected only in T. peruviana . Conclusion: The present work can serve as a useful tool in the identification, authentication and standardization of the plant material and distinguishing the two species from each other.