Botanical Pharmacognosy of Bacopa monnieri (Linn.) Pennell

Backgound: B. monnieri (Linn.) Pennell is a slender, creeping and mat forming herb well adapted to grow in both terrestrial and submersed conditions. It is an important medicinal plant belongs to the family Plantaginaceae and espoused as a source for the Ayurvedic drug brahmi. Objectives: The present study aims to delineate the morphological and histomorpho diagnostic profile of the stem, root and leaves of brahmi and analyze their qualitative and quantitative anatomical peculiarities to support the pharmacobotanical characterizations using digital, stereo and polarized microscopic techniques. Results: Cross section of lamina had shown a homogeneous mesophyll fails to differentiate into palisade and spongy tissues. Lamina was amphistomatic which contained three different types of stomatal complexes vz., diacytic, anisocytic and anomoteracytic. The mean number of stoma per square millimeter of leaf area was found to be higher in adaxial surface (656.9/mm2) than abaxial (433.3/mm2) with a corresponding stomatal index of 15.2 and 9.4 respectively. Adventitious root in cross section gave ‘spokes in a wheel’ appearance and shoot cortex architecture had shown honey-comb pattern of aerenchyma chambers. Vascular bundles were many, conjoint and closed, where a centra solid core of xylem encircled by phloem. Crystal ideoblasts of calcium oxalate were observed in characteristic tissues of epidermis of the leaves, mesophyll, cortical tissues of stem, and intervening walls of the file of cells of diaphragms in stem and adventitious roots. Conclusion: The above delineated anatomical characteristics in conjunction with aerenchyma in root and shoot tissues as an effective water tolerance mechanism to thrive prolonged submergence in water logged conditions could provide valuable tags as useful markers for pharmacological identification of the taxon.