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HIMANSHI 23MSB10013 PLANT RESOURCES.pptx

The document discusses the roles and production of steroids and glycosides in plants, including their definitions, biosynthesis, therapeutic uses, and extraction methods. It highlights the significance of steroids in human health and their commercial production, particularly focusing on cardiac glycosides like digitalis. Additionally, it outlines the methods for extracting glycosides, their use in plant defense, growth regulation, and their influence on attracting pollinators.

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UNIVERSITY INSTITUTE OF BIOTECHNOLOGY DEPARTMENT BIOSCIENCES Master of Science: Botany TOPIC : STEROIDS AND GLYCOSIDES SUBMITTED TO: D.R SHAILIKA SUBMITTED BY: HIMANSHI UID: 23MSB10013
2 Content: Steroids • Introduction • Uses of steroids • Commercial production • Plant sterols • Biosynthesis of sterols Glycosides • Introduction • Digitalis : a cardiac glycoside • Extraction of glycosides
3 Steroids • Steroids may be defined as: “Any of numerous naturally occurring or synthetic fat soluble organic compounds having as a basis 14 Carbon atoms arranged in four rings. They include sterols, bile acids, adrenal and sex hormones, certain natural drugs such as Digitalis compounds and precursors of certain vitamins.” • Different steroids vary slightly in their structure, but they all have 4 fused carbon rings.
4 The diversity of biologic activities of steroids includes: • Plant steroids are natural products which influence the development and control of the reproductive tract in humans(estradiol, progesterone, testosterone) • The induction of sexual reproduction in aquatic fungi. In additions, steroids contribute to a wide range of therapeutic applications, such as; 1. Cardiotonics (digitoxin) 2. Vitamin D precursors (ergosterol) 3. Oral contraceptive agents (semisynthetic estrogens and progestins) 4. Anti-inflammatory agents (corticosteroids)
5 Commercial production of steroids • The steroid hormones and their semisynthetic analogues represent a multi-million-dollar annual business for the American drug industry • In the past, the source of steroid hormones was from the gonads and adrenal glands of animals • The amount of hormones present in these glands was extremely small; consequently, it was not practical to use the pure hormone in the therapy • At the present time, the principal source of the steroid chemical nucleus used in the drug industry is the plant kingdom
6 Plant Sterols • Sterols, also known as steroid alcohols, are a subgroup of the steroids • Steroidal alcohols C27 – C29 are present in the lipid fraction of many tissues. These are solids therefore named as sterols. • The most widely occurring sterol is cholesterol. It has been identified in algae, fungi, bacteria, ferns, animals and higher plants.
7 Biosynthesis Of Sterols In Plant • Acetyl-CoA Formation: The pathway begins with acetyl-CoA, which is derived from carbohydrates, fatty acids, or amino acids. • Mevalonate Pathway: Acetyl-CoA is converted into mevalonate through a series of enzymatic reactions. This occurs in the cytosol and involves the enzymes HMG-CoA synthase and HMG-CoA reductase. • Isoprenoid Synthesis: Mevalonate is then phosphorylated and decarboxylated to produce isopentenyl pyrophosphate (IPP) and its isomer, dimethylallyl pyrophosphate (DMAPP). These are the building blocks for isoprenoid synthesis. • Squalene Formation: IPP and DMAPP are condensed to form larger isoprenoid units, eventually leading to the production of squalene through several condensation reactions. • Cyclization and Modification: Squalene undergoes cyclization to form lanosterol, which is then converted into various sterols through a series of enzymatic modifications. This includes the formation of sterol side chains and the introduction of double bonds. • Final Sterol Products: Common plant sterols include sitosterol, stigmasterol, and campesterol. These sterols play crucial roles in maintaining membrane integrity and fluidity, as well as serving as precursors for signaling molecules.
8 Glycosides: •Organic natural compounds present in a lot of plants and some animals, these compounds upon hydrolysis give one or more sugars (glycone) moieties and non sugar (aglycone) moiety. Glycoside=sugar group+ nonsugar group (glycone) (aglycone or genin) Glycone and aglycone are linked by glycosidic linkage. Colorless, solid, amorphous, nonvolatile (flavonoid- yellow, anthraquinone-red or orange.) They are water soluble compounds, insoluble in organic solvents
9 Glycosides: • Glycosidic linkage is formed between – OH group of sugar and –H group of non sugar moieties OR other sugar with loss of water molecule. • glycoside=glycone{---o---}aglycon
10 • Glycosides can be alpha or beta but plants contains only beta glycosides • Therapeutic effect of glycosides is only due to aglycon part only and suger moiety facilitate absorption of glycoside, transportation of aglycone to site of action. •Glycosides have therapeutic effect in human and animalsthey are used in traditional and modern medicines as 1. cardio tonic 2. purgative 3. Analgesic 4. anti- rheumatic 5. Demulcent 6. many other uses.
11 Digitalis : a cardiac glycoside • Botanical origin: Digitalis purpurea • Part used: dried leaves • Family: Scrophulariaceae • Constituents: The drug contains a large number of steroidal glycosides (neaely 30) of which the most important from medicinal point of view are Digitoxin, Gitoxin, Gitaloxin. • Uses: Digitalis is used in the form of tablets or capsules to treat congestive heart failure, supraventricular tachycardia, atrial flutter and atrial fibrillation.
12 • Characterstics: 1. Colour: Dark grayish green 2. Odour: Odourless 3. Taste: Distinctly bitter 4. Size: Length 10-30 cm Width 04-10 cm 5. Shape: Ovate, lancolate, petiolate. 6. Length 10-30cm • Marketed products: It is one of the ingredients of preparations known as Lanoxin Tablets
13 Extraction of glycosides 1. Selection of Plant Material Choose the appropriate plant source known for its glycoside content (e.g., elderberry, ginseng, or certain fruits). 2. Preparation of Plant Material Drying: If using fresh plant material, consider drying it to reduce moisture content. Grinding: Grind the dried plant material into a coarse powder to increase the surface area for extraction. 3. Extraction Method Solvent Extraction: Choosing the Solvent: Use polar solvents like water, ethanol, methanol, or acetone, depending on the solubility of the glycosides. Maceration: Soak the ground plant material in the solvent for several hours to several days. Filtration: After soaking, filter the mixture to separate the liquid extract from the solid plant material.
14 • Ultrasonic Extraction: Apply ultrasonic waves to enhance the extraction efficiency, particularly for thermolabile compounds. • Steam Distillation : While primarily used for volatile compounds, this method can also extract glycosides by passing steam through plant material, which can help in releasing water-soluble glycosides. • Soxheld extraction : 1. Preparation: Grind the plant material and place it in a thimble. 2. Setup: Assemble the Soxhlet apparatus, connecting the thimble to the extractor and the flask containing the solvent. 3. Extraction: Heat the solvent; it vaporizes, rises, and condenses in the extractor. The solvent percolates through the plant material, dissolving glycosides. Once full, the solvent siphons back into the flask, repeating the cycle. 4. Duration: Typically run for 4–8 hours. 5. Collection: After extraction, use rotary evaporation to remove the solvent, yielding concentrated glycosides.
15 • 4. Concentration • Use methods like rotary evaporation to remove the solvent from the filtered extract, concentrating the glycosides. • 5. Purification • Chromatography: Techniques such as column chromatography or high- performance liquid chromatography (HPLC) can be employed to further purify glycosides from the extract. • 6. Characterization • Use analytical methods (like mass spectrometry or nuclear magnetic resonance) to confirm the presence and structure of the glycosides. • 7. Storage • Store the purified glycosides in a cool, dark place, ideally in airtight containers to prevent degradation.
16 Soxhlet Apparatus
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18 Uses of glycosides in plants 1. Defense Mechanisms Glycosides, especially cyanogenic glycosides, saponins, and cardiac glycosides, are often involved in the plant's defense against herbivores, pathogens, and other environmental stresses. Cyanogenic glycosides release toxic cyanide when hydrolyzed, deterring herbivores from feeding on the plant. Saponins can have toxic effects on fungi, bacteria, and herbivores by disrupting cell membranes. Cardiac glycosides (such as those found in foxglove and oleander) are toxic to animals and can deter grazing. 2. Plant Growth Regulation Some glycosides function as signaling molecules, influencing plant growth and development. For example: Auxin-like glycosides can regulate plant growth by influencing processes like cell elongation and division.
19 3. Attraction of Pollinators and Seed Dispersers Some glycosides are involved in the attraction of pollinators or seed dispersers by contributing to the plant's scent or color. The sugars in glycosides can enhance the palatability of plant tissues, while the aglycones may provide attractive odors or flavors. For example, flavonoid glycosides can impart vibrant colors to flowers, which attract pollinators like bees, butterflies, and birds. 4. Protection from UV Radiation and Oxidative Stress Glycosides like flavonoid glycosides and phenolic glycosides act as antioxidants. They help protect plants from damage caused by ultraviolet (UV) radiation and oxidative stress. These compounds can absorb UV light and neutralize free radicals, reducing cellular damage.
20 Chemical test of digitoxin: Baljet Test: • Glycoside(small amount)+ 1ml of 50% ethanol + 0.1 ml of 1% solution of dinitrobenzene in methanol + 2 – 3 drops of 20% sodium hydroxide solution • Result : violet color changes to blue color Legal test : Glycoside + few drops of pyridine and 1 drop of 2% sodium nitroprusside and a drop of 20% NaOH is added. • Result : Deep red color occur
21 Killer-Killiani test : • Drug + 10ml of 70% alcohol for few minute and filtered. To 5ml filtrate 10ml of hydrogen peroxide and 0.5 ml of strong solution of lead acetate is added. To this mixture 1 or 2 drop of concentrated sulphuric acid is added. • Result: Appearance of blue color confirms presence of deoxy sugar.
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