Pharmacognostic and Taxonomic Studies of Leaf and Stem of Launaea taraxacifolia (Willd) Amin Ex C. Jeffrey (Compositae)

Launaea taraxacifolia from the family Compositae is used in the treatment of diabetes mellitus, hypertention, cancer, malaria, bacterial infections and arthritis. The aim of this study was to evaluate pharmacognostic and taxonomic parameters such as microscopy, micromeritics, chemomicroscopy, fluorescence, soluble-extractive values and ash values of the leaves and stems of this plant. The plant was collected, identified, air-dried, weighed and subjected to evaluation using standard procedures. The results showed that, from microscopy: the stomatal distribution was amphistomatic and the stomatal type were anisocytic and anomocytic on the abaxial surface and anomocytic on adaxial surface with T-pieces on the stomata. The stomatal index was 18.7% on the abaxial surface and 11.9% on the adaxial surface. The stomatal number on the abaxial surface was 13.2 (15.6±0.55) 18.1 and 18 (26.5±2.08) 36 for adaxial surface. Results of the micromeritics properties of the powdered leaf and stem samples were bulk volume of 38.67±0.17 and 51.33±0.33, tapped volume of 29.83±0.17 and 34.0±0.00, bulk density of 0.26±0.00 and 0.20±0.00, tapped density of 0.34±0.00 and 0.29±0.00, angle of repose of 36⁰ and 43⁰, Carr’s index of 22.7% and 33.78%, Hausner’s ratio of 1.30±0.01 and 1.15±0.01. The micromeritics indicated that the powder had a fair flow and for chemomicroscopy the powder contained lignin, mucilage, oil and protein. The fluorescence properties determined revealed different colours under different ultraviolet lights. The water-soluble, methanol-soluble, ethanol-soluble extractive values were 35% w/w, 14% w/w and 16%w/w for leaf and 18% w/w, 8% w/w, and 9% w/w for stem respectively. The moisture content of the leaf and stem were 16% w/w and 11% w/w. Total, acid-insoluble and water- soluble ash values were 17.7% w/w, 1.3% w/w and 8.3% w/w for leaf and 6.3% w/w, 0.3% w/w and 4.7% w/w for the stem respectively. This data obtained from the pharmacognostic and taxonomic studies provide information for the identity, purity and quality of L. taraxacifolia.