Pharmacognostic evaluation of the leaf of Microtrichia perotitii DC. (Asteraceae)

Microtrichia perotitii DC. belongs to the family Asteraceae (Compositeae) and it is a herb found in the West African countries. The aim of this research was to establish pharmacognostic standards for M. perotitii through macroscopic, microscopic, chemo-microscopic and physico-chemical investigations. The macroscopic studies revealed the shape of the leaf as small with acute apex, asymmetric base, pubescent surface with long petiole and a serrated margin. Organoleptically, the leaf is green, slightly bitter and pepperish with an unpleasant odour. The microscopic studies of the leaf showed epidermal cells with irregularly thickened walls, numerous anomocytic stomata, and multicellular covering trichomes on both upper and lower epidermis. The transverse section of the leaf showed that it was dorsiventral with separated elements of vascular bundle. The powdered leaf revealed calcium oxalate crystals (prism and rosette), starch (oval) and xylem (spiral). Quantitative-leaf microscopy revealed the leaf constants as palisade ratio (3.2-3.4); stomatal number (258-285); stomatal index (19.5-24.7); vein-islet number (6.0-8.0) and vein-let termination number (8.0-11.0). The physico-chemical constants of the leaf showed moisture content (12.67 %), total ash (20.33 %), acid –insoluble ash (27.3 %), water- soluble ash (81.18 %), water extractive values (40.9 %) and alcohol extractive values (25.45 %). This is the first time the pharmacognostic parameters of the leaf of M. perotitii were studied and it will be quite useful for its identification, standardization and inclusion in various pharmacopoeias. Key words: Microtrichia perotitii, macroscopical, microscopical, physico-chemical, pharmacognostic.