Abstract
Parthenium hysterophorus L. (Congress grass, family Asteraceae) is found throughout the global agricultural and vacant lands. In the present work, the pharmacognostic, pharmacological and allelopathic traits of various parts (root, stem and leaves) of P. hysterophorus grown in Pakistan were investigated. P. hysterophorus growing/flowering season starts from March-April till August-September. The plant has tap root with numerous rootlets and root hairs. Stem is straight, with light groove, covered with hairs and numerous profusely branches, wherein the stem reaches up to 150 cm in height. The leaves are simple, dull green in color, alternate, leaflets with profusely dissected regions and hairs are present on the lower surface of leaf. Transverse section (TS) of root revealed epidermis, cortex, endodermis, xylem, phloem and medullary rays running from endodermis towards the center. TS of stem was circular in outline with shallow ridges covered with hairs. TS of leaf consisted of epidermis, which is intermitted by simple, glandular, branched and multicellular trichomes. Powder drug microscopy of roots revealed the presence of epidermal cell, phloem elements, fiber, cluster/group of fibers, root hairs, xylem vessels and medullary rays. The stem powder drug microscopy showed the presence of trichomes, fibers, parenchymatous cells, lignified vessel, group/cluster of vessels, secretory gland with epidermal cells, prismatic crystal of Ca oxalate and phloem elements with parenchyma cells. Phytochemical screening of diethyl ether, ethanol and aqueous extracts of root, stem and leaves showed the presence of amino acids, fixed oils, alkaloids, flavonoids, phenols, carbohydrates, proteins and triterpenoids, while steroidal glycosides, gum and mucilage were absent in all plant parts. Chemical composition showed that moisture, lipids, protein contents and total gross energy were higher in plant grown in summer season as compared to winter season. On the other hand, ash, fibers and carbohydrate contents were higher in winter and declined in summer season.