Pharmacognosy 2 PHG 203 Week (5) 2018-2019 Dr Heba

WOOD

Intended Learning Outcomes (ILOs) a1- The basic concepts of Pharmacognosy through principles of the morphological, histological and taxonomical features of medicinally important plant organs including fruits, herbs, barks, woods and subterraneans. a2- The natural drugs characteristics (belonging to fruits, herbs, barks, woods and subterraneans) as sources for pharmaceutical active ingredients. a3- The different medicinal applications of the selected drugs in the alternative and complementary therapy in relation to their active constituents. c1- Select the most appropriate methods for identification and purification of the selected drugs based on macroscopical, microscopical and/or chemical criteria. c2- Suggest the most suitable natural drugs (from the selected ones) as remedies for treatment of several diseases and disorders. d1- Express well all studied information with their clear special terminological principles. d2- Draw skillfully all scientific drawings related to the studied course.

Definition: The wood drug consists of all tissues inside the cambium in either the trunk or root of the medicinal plant.

Types of wood: Item Sap woods Heart wood White or yellowish white 1. Color: White or yellowish white Dark color 2. Reserve food materials Present Absent 3. Function Conductive and support Support 4. Presence of coloring materials [oils, gums, prisms of tannins ]: Absent. Present. 5. Durability: less durable More durable

Structure of the Wood: 1-Large wood vessels 2-Tracheids 3-Wood fiber 4-Wood parenchyma 5-Medullary rays. 6-All the elements are lignified

Vessels and Tracheids: Vessels Tracheids A,B annular , C ,D reticulated, E, pitted

Gymnospermous wood : formed mainly of tracheids and characterized by absence of vessels. Angiospermous wood [ dicotyledonous wood] : It is a typical wood and consists of: Wood fiber. Tracheas. Vessels. Wood parenchyma cells. Medullary rays.

True annular rings or (Growth layer) Def. : due to periodical seasonal activity of the cambium results in the formation of successive layers of the wood known as growth layers (annular rings). Each layer corresponds to one year of growth. Each layer is formed, of 2 parts: The inner layer (spring or early wood): which is characteristic by high proportion of wide vessels and less amounts of less thickened fibers. The outer layer (summer or late wood): which is darker and characterized by presence of small amounts of narrow vessels and large amounts of highly thickened fibers.

annular rings:

The arrangement of wood parenchyma Diffuse: wood parenchyma cells are equally scattered with no special arrangement. Metatracheal: the wood parenchyma cells are running transversely between medullary rays Paratracheal: when adjacent to the vessels and incompletely surrounding them. Terminal: the wood parenchyma cells are localized at the end of the growth layer. Vasicentric: the wood parenchyma cells are completely surrounding the vessels.

Quassia wood الخشب المر: Origin: The dried wood of the trunk and branches of Picrasma excelsa known as Jamaica quassia or of Quassia amara known as Surinam quassia F. Simarubaceae

Active constituents and Uses: Bitter principles: Picrasmin. Quassin. Neoquassin Uses: In small doses used as bitter stomachic. In large dose used as anthelmintic for thread worms.

Powder+ alcohol alc. Extract + phloroglucin + conc. Hcl red color Special test: Powder+ alcohol alc. Extract + phloroglucin + conc. Hcl red color

Powder:

Item Jamaica quassia Surinam quassia 1-Medullary rays Bi to tri serriate. Most are uniserriate 2-Prisms of ca.ox: Present in wood parenchyma and medullary ray cells Absent. 3-Bitter principles Picrasmin. Quassin. Neoquassin.