COMPARATIVE PHARMACOGNOSTICAL AND PHYTOCHEMICAL STUDY OF VARIOUS SPECIES OF THE CONTROVERSIAL DRUG ‘PUNARNAVA'

Objective: Punarnava is a controversial drug i.e. its true botanical identity has not been ascertained, and several different species are used as Punarnava. It is a part of many medicinally important traditional formulations. Ayurvedic Pharmacopoeia of India describes three different species–Roots of Boerhaavia diffusa, Trianthema portulacastrum and Boerhaavia verticillata. The present work deals with the microscopic, macroscopic and phytochemical comparison of the roots of these species of Punarnava, so as to differentiate them and establish their quality parameters.Methods: Roots of these three species were collected, and their comparative morphological, microscopical (transverse section, powder study) and the phytochemical (screening, tannin estimation) study was performed.Results: Roots of Boerhaavia diffusa showed morphological characteristics which clearly distinguished it from the other species. They showed the presence of well developed and stratified cork, abnormal vascular bundles which were discontinuous, and a central cavity, presumably formed due to the disintegration of tissues. Boerhaavia verticillata showed the presence of xylem bundles arranged in the form of a ‘X'-shaped cross in the central region. Thick-walled cork cells and pitted xylem vessels were present only in Boerhaavia diffusa root powder, whereas bundles of fibrovascular tissue were present only in the powder of Boerhaavia verticillata. Tannin content was found to be highest in Boerhaavia diffusa roots.Conclusion: The present investigation will help herbal industries and traditional medicinal practitioners to detect adulteration of the medicinally important immunomodulator Boerhaavia diffusa by Trianthema portulacastrum and Boerhaavia verticillata, which are considered to have no immunomodulatory activity.Â