Questions and Answers
What is the main purpose of identifying raw plant material in the pharmaceutical industry?
To ensure quality, safety, and efficacy
Which method of identification involves observing physical features like shape, size, color, and texture?
Morphological examination
What type of examination involves analyzing tissue structure at a microscopic level?
Histological examination
Which method of identification involves preparing temporary mounts to view cellular details?
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What do diagnostic chemical tests in the identification process aim to identify?
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Why is it important to perform chemical tests during the identification of plant material?
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What is the main function of cellulose in plant cell walls?
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Which substance provides gel-like consistency in some plant cells?
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Where can you find aromatic compounds like essential oils in plants?
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Which component of plant cells mainly provides rigidity to the cell walls?
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What is the function of the living part of the cell known as?
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Which compound is used for energy storage in plant cells?
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What is the purpose of adding Toluidine Blue O solution to the plant sample?
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Which substance, often found in plant cells, gives a gel-like consistency to certain plant tissues?
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What is the primary role of lignin in plant cell walls?
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Where are essential oils, commonly used in fragrances and medicinal products, primarily located in plants?
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Which plant cell component contains various organelles and is responsible for most cellular functions?
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What substance, primarily found in the cell walls of plants, provides resistance to tensile forces and contributes to the rigidity of plant structures?
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Which component of plant cell walls is responsible for providing impermeability to water and acts as a barrier to pathogens?
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In plant cells, which substance is responsible for providing a gel-like consistency to certain tissues and acts as a lubricant for seed dispersal?
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What are some additional solutions that could be used as stains?
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What is the purpose of soaking tissue in a 40% to 60% nitric acid solution at 60oC for 3-4 minutes in the alternative method A?
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In alternative method B, what is the purpose of heating a leaf fragment in chloral hydrate solution for 15 minutes?
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What should be done with excess, unused, or contaminated chloral hydrate according to alternative method B?
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Which step is a common practice in both alternative method A and alternative method B for preparing plant samples?
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What is the fundamental difference between the clean-up procedures in alternative method A and alternative method B?
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What is the primary difference in the procedure for determining stomatal number and stomatal index?
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Why is it important to calculate the mean stomatal value from at least 10 different sites of the specimen?
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Which term describes the upper surface of leaves or plant structures when referring to stomatal observation?
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What is the purpose of determining the stomatal index rather than just the stomatal number?
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How does the size of the surface area play a role in determining stomatal index?
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Explain how the stomatal number is determined in a specimen.
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What is the procedure for calculating stomatal index in a specimen?
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Why is it recommended to calculate the mean stomatal value from at least 10 different sites of a specimen?
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What is the difference between determining stomatal number and stomatal index in plant specimens?
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What is the significance of counting palisade mesophyll cells that are at least 50% covered by epidermal cells?
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What does the palisade mesophyll ratio represent?
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Why is it necessary to use a sharp razor blade and cut at an angle when obtaining tissue sections?
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How can one improve the success rate of obtaining sections thin enough for microscopy?
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What is a USP Authenticated Reference Material?
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What reagents and/or optical devices can be used to detect different plant cell structure/metabolites?
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What can you observe once these reagents (from the other devices that detect the plant cells) react with the target structure/metabolites?
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What is the primary focus of phytochemical screening?
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In the context of chemical evaluation, what does the process of 'characterization' primarily involve?
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What is NOT a crucial consideration when preparing crude extracts of plants?
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Which process is NOT a part of the evaluation of chemical constituents of a plant?
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What is the significance of 'Instrumental Analysis' in the evaluation of plant chemical constituents?
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What is the main significance of phytochemical analysis in the drug discovery process and quality control of herbal preparations?
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What is the primary purpose of performing chromatographic separation of a plant's phytochemical constituents?
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Why is it essential to have proper knowledge of the chemical constituents in natural sources when isolating compounds?
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In phytochemical analysis, what is the significance of chemical identification of herbal preparations or crude drugs from a regulatory standpoint?
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What role does phytochemical screening play in identifying compounds with potential biological activity?
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Study Notes
Introduction to the Experiment
- The purpose of identification is to ensure quality, safety, and efficacy of plant materials used in pharmaceuticals, excipients, or dietary supplements by verifying botanical and chemical characteristics.
- The goal is to distinguish different plant parts (root, stem, leaf, flower, fruit, seed) and identify specific compounds (e.g., alkaloids, flavonoids, tannins).
Morphological Examination
- Involves observing physical features like shape, size, color, and texture.
- Helps distinguish different plant parts (root, stem, leaf, flower, fruit, seed).
Histological Examination
- Analyzes tissue structure at a microscopic level.
- Can be done on whole plant material or plant powder.
- Prepares temporary mounts to view cellular details (e.g., root, stem, leaf, flower, fruit, or seed).
- Uses stains or reagents to visualize specific features.
Histological Features Examined
- Cellulose: a major component of plant cell walls.
- Cytoplasm: the living part of the cell.
- Essential Oils: aromatic compounds found in certain plant tissues.
- Lignin: provides rigidity to cell walls.
- Mucilage: a gel-like substance in some plant cells.
- Starch: energy storage in plant cells.
- Tannins and Other Polyphenols: bioactive compounds.
Staining Fresh Sample
- Parker et al. (1982) method:
- Sample preparation: cut a cross-section of the sample as thinly as possible.
- Initial wash and soaking: flush the section from the razor blade into a Petri dish filled with water, and soak the section in tap water for 2-3 minutes.
- Staining with Toluidine Blue O: transfer the section to a second Petri dish, add 2-3 drops of Toluidine Blue O solution, and soak the section in the solution for 1 minute.
- Final rinse: transfer the section to the last Petri dish, and rinse the section under gently running water for 2 minutes.
- Mounting and examination: place the stained section on a clean glass slide, add a drop of tap water, cover the section with a coverslip, and examine the stained sample under a microscope.
Alternative Methods
- Alternative method A: soak the tissue in a 40% to 60% nitric acid solution at 60°C for 3-4 minutes, wash the tissue in water, neutralize in a 1% NaOH solution, and wash again in water.
- Alternative method B: heat a leaf fragment in chloral hydrate solution in a water bath.
- Clean-up: neutralize excess nitric acid with 10% Sodium Carbonate, and neutralize excess NaOH solution with 10% HCl or 10% H2SO4.
Stomatal Number and Stomatal Index
- Stomatal number: determined by counting the number of stomata per unit area of a microscopic field.
- Stomatal index: calculated by observing the specimen under a microscope at a low magnification, determining the size of the surface with a calibrated micrometer ocular, and counting the number of stomata and epidermal cells.
Determination of Tissue Arrangements
- Lay the appendage to be sectioned on a microscope slide, place another microscope slide over the appendage, and cut straight down along the edge of the upper slide.
- Without moving the upper slide, cut down again at an angle to obtain sections thin enough to determine tissue arrangements.
Palisade Mesophyll Ratio
- Use the cross-section of leaf tissue to determine the palisade mesophyll ratio.
- Boil leaf fragments in chloral hydrate solution, stain and mount as indicated, and examine under the microscope.
- Identify groups of four adaxial epidermal cells and count the palisade mesophyll cells that are lying below and are at least 50% covered by the epidermal cells.
- This value divided by 4 is the palisade mesophyll ratio.
Phytochemical Analysis
- Phytochemical analysis is significant in both the drug discovery process and in the quality control of herbal preparations.
- It involves isolation, separation, and purification of compounds from natural sources to identify those responsible for biological activity.
- Chemical evaluation involves qualitative and quantitative chemical tests, chemical assays, or instrumental analysis.
- Phytochemical screening is the qualitative testing of the chemical constituents of plants, usually done in the crude extract of the plant of interest.
Considerations for the Preparation of Crude Extracts
- Considerations include the choice of solvent, extraction process, and presence of interfering compounds.
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Description
Learn about the purpose and methods of identifying raw plant materials used in pharmaceuticals, excipients, and dietary supplements. Understand how morphological examination helps in verifying botanical and chemical characteristics for ensuring quality, safety, and efficacy.
