Phytochemistry General Introduction PDF

Phytochemistry General introduction  Course objectives 1. To describe the chemistry and biological activity of volatile oils, resins, carbohydrates, alkaloids, glycosides and tannins. 2. To describe the structure activity relationship of the biologically active componen...

Phytochemistry General introduction  Course objectives 1. To describe the chemistry and biological activity of volatile oils, resins, carbohydrates, alkaloids, glycosides and tannins. 2. To describe the structure activity relationship of the biologically active components. 3. To recognize and draw the chemical structures of such active components. 4. To describe the physical and chemical properties of active and inactive components. 10/21/2024 MOSA ELHADY 2  Course outline General introduction to phytochemistry, extraction and isolation of natural products, techniques commonly used in phytochemistry. Volatile oil (terpene, oxygenated terpene, phenolic compound) Alkaloids (proto-alkaloids, true alkaloids, tropane alkaloids) Carbohydrates Glycosides (alcoholic glycosides, anthraquinone, flavonoids, saponin). Tannins Bitter principles Resin and its combination 10/21/2024 MOSA ELHADY 3  What is phytochemistry? Phytochemistry is the study of plants and their phytochemicals, this involve the following: Authentication and extraction of the plant material. Separation and isolation of the constituents of interest. Characterization of the isolated compounds. Investigation of the biosynthetic pathways to particular compounds. Quantitative evaluations. Pharmacological assessment of the separated components. 10/21/2024 MOSA ELHADY 4 Historical development of phytochemistry Cpds like cane sugar, starch, K.W. Scheel (German camphor, benzoic acid, fats, apothecary) isolate citric, Chemical nature of fats volatile oils, resin their gallic, prussic, oxalic and and fixed oils was aqueous extraction and tartaric acids. elucidated. evaporation were known. Twentieth Before 1645 -1715 1742 1803 1813 -1823 cent. A French apothecary (Nicholas Narcotine; the first alkaloid was At this time attention was Lemery) extend use of isolated, morphine, strychnine, turning to the elucidation of extraction process and made use emetine and many other are the actual biosynthetic way. of alcohol and solvents. followed rapidly. this emphasis has continue today.  The recent interest: Active principles (usually alkaloids or specific glycosides) with pronounced pharmacological properties were receive special attention. The plant as source of new drugs, the strategies for fractionation of plant extract based on biological activity rather than on particular class. The chemical examination follow after the isolation of active fraction. 10/21/2024 MOSA ELHADY 6  Techniques used in phytochemistry 10/21/2024 MOSA ELHADY 7  What is the preliminary phytochemical screening test? is a process of tracing plant constituents. Phytochemistry is widely used in field of herbal medicine. Phytochemical techniques mainly applied to the quality control of Chinese herbal medicine or herbal medicine for various chemical components such as alkaloid, saponins, flavonoids,… In most cases biologically active cpds in herbal medicine have not been determined. 10/21/2024 MOSA ELHADY 8  Therefore, it is important to use the phytochemical method to screen and analyze bioactive cpds. The study paves the way to discovery of new therapeutic cpds as needed by modern scientific approach of producing medicines. 10/21/2024 MOSA ELHADY 9  Preliminary phytochemical screening test Test for tannins: To 2 ml water extract of different plant parts, 2 ml of 10% ferric chloride solution was added in a test tube. Blue-black precipitate indicates the presence of tannins. 10/21/2024 MOSA ELHADY 10  Test for alkaloids To 2 ml methanolic extract of different plant parts, 1 ml of 1 % hydrochloric acid was added in a test tube, and heated in a water bath for 10 minutes. 1 ml from each solution was taken and 6 drops of Dragendorff’s reagent / Wagner’s reagent / Mayor’s reagent were added and mixed separately. Orange precipitate / brownish-red precipitate / creamish precipitate respectively indicate the presence of alkaloids. 10/21/2024 MOSA ELHADY 11  Test for cardiac glycosides (Keller-Kiliani test) To 2 ml methanolic extract of different plant parts, 1 ml glacial acetic acid, 6 drops of 10% ferric chloride solution and 6 drops of concentrated Sulphuric acid were added in a test tube. Green-blue color indicates the presence of cardiac glycosides. 10/21/2024 MOSA ELHADY 12  Test for steroids and terpenes (Liebermann-Burchard reaction) To 2 ml chloroform extract of different plant parts, 2 ml acetic anhydride and few drops concentrated Sulphuric acid were added in test tube. Blue- green ring between layers indicates the presence of steroids and pink- purple ring indicates presence of terpenes. 10/21/2024 MOSA ELHADY 13  Test for Cyanogenic glycosides To 3 ml ethanol extract of different plant parts, 2 ml sterile water was added in a conical flask. Freshly prepared sodium picrate paper was placed at stopper and the solution was heated to boil. Change of color of sodium picrate paper from yellow to different shades of red indicates the presence of Cyanogenic glycosides. 10/21/2024 MOSA ELHADY 14  Free anthraquinones test: To 5 ml the ethanol extract of different plant parts, 10 ml of water was added, boiled and allowed to cool. Then 2 ml of the solution was shaken with 5 ml chloroform. The chloroform layer separated and concentrated to about 2 ml. 2-3 ml ammonia solution was then added. Pink-red color acquired by the alkaline layer indicates the presence of free anthraquinones 10/21/2024 MOSA ELHADY 15  Anthraquinone glycosides test: To 2.5 g powdered material of different plant parts, 10 ml of 20% sulphuric acid and 2 ml of 2% ferric chloride solution were added in a test tube, boiled in a water bath (refluxed) for 30 minutes, allowed to cool, and filtered. The solution then extracted with 10 ml chloroform in separating funnel. Chloroform layer separated and concentrated to about 4 ml and 2.5 ml of 10 % ammonia solution added. Pink-red color acquired by the alkaline layer indicates the presence of anthraquinone glycosides. 10/21/2024 MOSA ELHADY 16  Test for flavonoids (Shinoda’s test) To 2 ml ethanol extract of different plant parts, 0.5 ml concentrated Hydrochloric acid and few pellets of magnesium turning were added in a test tube. Pink- tomato red color indicates the presence of flavonoids. 10/21/2024 MOSA ELHADY 17  Test for Volatile oils ◼ Menthol Vanillin Methyl salicylate Thymol E ugenol 10/21/2024 MOSA ELHADY 18  The end 10/21/2024 MOSA ELHADY 19