OIA2007 PHYTOCHEMICAL SCREENING

At what temperatures are enzymatic reactions for extraction typically conducted?

Between 15°C to 45°C.

Describe the infusion extraction process.

Drug material is ground into fine powder, placed inside a clean container, and the extraction solvent (hot or cold) is poured on top, soaked, and kept for a short period of time.

Describe the maceration extraction procedure.

Coarsely powdered drug material is placed in a container, covered with solvent, closed, and kept for at least three days, stirred periodically. The micelle is separated from marc by filtration or decantation, then the micelle is separated from the menstruum by evaporation.

Describe the percolation extraction process.

Dried, grinded, and finely powdered plant material is moistened with the solvent, kept for 4h, then transferred into a percolator and allowed to stand for 24h. Solvent is poured from the top until the drug material is saturated, and the liquid is allowed to drip slowly from the bottom.

How are liquid and solid samples identified in infrared spectroscopy?

Liquid samples are identified using sodium chloride plates, while solid samples are milled with potassium bromide and compressed into thin pellets.

How are solvents classified based on polarity?

Solvents are classified from least polar (n-hexane) to most polar (water).

How does cost affect the choice of solvent for extraction?

The solvent should be as cheap as possible to make the extraction process economical.

How does mass spectroscopy (MS) identify compounds?

MS identifies compounds based on chemical structure and molecular weight by bombarding organic molecules with electrons to form charged ions.

How does microwave-assisted extraction enhance solvent penetration?

The heat produced facilitates the movement of solvent into the drug matrix, especially with polar solvents.

How does solvent addition and extraction occur in percolation?

Solvent can be added continuously, and extraction takes place by gravitational force, pushing the solvent through the drug material downward.

How does the mobile phase function in Paper Chromatography?

The solvent poured into the bottom of the container ascends via capillary action, carrying soluble compounds with it.

How does the separation process begin in High Performance Liquid Chromatography (HPLC)?

By injecting the mixture to be separated at the bottom of the HPLC.

How does the Soxhlet extractor work?

The solvent is heated in the bottom flask, evaporates, passes through the condenser, and then flows down to extract the drug in the extraction chamber.

How does ultrasound-assisted extraction affect the extraction process?

It hastens the extraction process by reducing heat requirements.

How is the crude extract prepared for analysis in Gas Chromatography (GC)?

It is diluted with methanol and injected into the system.

How is the extract applied in Thin Layer Chromatography?

The extract is injected into the lower part of the plate and allowed to spread.

How is the presence of tannins tested using Gold Beater's skin?

The skin is soaked in hydrochloric acid, washed, placed in the extract, and then in ferrous sulfate. A color change to brown or black indicates tannins.

How is the retardation factor (Rf) calculated in Thin Layer Chromatography (TLC)?

It is the ratio of the distance travelled by the compound to the distance travelled by the solvent.

How is the retardation factor calculated in Paper Chromatography?

It is the ratio of the distance traveled by the compound to the distance traveled by the solvent.

How much forest coverage is found in Peninsular Malaysia?

6.2 million hectares.

How much forest coverage is there in Sarawak?

9.4 million hectares.

How should solvents be added during fractionation?

They should be added according to the order of increasing polarity.

In which spices has enzyme-assisted extraction been applied?

Ginger, mustard, chili, vanilla, and pepper.

Name some chromatographic techniques mentioned in the notes.

Paper chromatography (PC), thin layer chromatography (TLC), column chromatography (CC), liquid chromatography (LC), gas chromatography (GC), and high-performance liquid chromatography (HPLC).

What apparatus is used in percolation?

A percolator, which is a narrow-cone-shaped glass vessel with openings at both ends.

What are in-vitro and in-vivo studies?

In-vitro studies are conducted outside a living organism, while in-vivo studies are conducted within a living organism.

What are medicinal plants?

Plants traditionally used for medicinal purposes containing active compounds with therapeutic properties.

What are nonpolar solvents used in extraction?

Hexane and dichloromethane are used for extracting nonpolar compounds.

What are phytochemical screenings?

Preliminary tests conducted to detect the presence of primary and secondary metabolites in an extract.

What are phytochemicals?

Natural compounds in plants with potential health benefits, responsible for colors, flavors, and aromas.

What are polar solvents commonly used in extraction?

Water, methanol, and ethanol are used for extracting polar compounds.

What are secondary metabolites, and why are they significant in plant extracts?

Secondary metabolites like alkaloids, terpenes, and flavonoids are important for their potential health benefits and are analyzed in plant extracts.

What are some common methods used for the extraction of medicinal plants?

Common methods include maceration, infusion, decoction, percolation, digestion, Soxhlet extraction, superficial extraction, ultrasound-assisted, and microwave-assisted extraction.

What are some examples of toxic heavy metals that must be tested for in herbal preparations?

Examples include arsenic, cadmium, lead, and mercury.

What are some forms of herbal pharmaceuticals?

Tablets, capsules, syrups, powders, and extracts.

What are some techniques used in phytochemistry analysis?

Chromatographic and spectroscopic techniques.

What are the advantages and disadvantages of alcohol as a solvent?

Advantages: self-preservative above 20% concentration, non-toxic at low concentrations, requires less heat for concentration. Disadvantages: does not dissolve fats, gums, and wax; flammable and volatile.

What are the advantages and disadvantages of chloroform?

Advantages: colorless, sweet smell, soluble in alcohols, well absorbed in the body. Disadvantages: has sedative and carcinogenic properties.

What are the advantages and disadvantages of ethyl acetate?

Advantages: low toxicity, high volatility, high purity, good solvency. Disadvantages: high flammability, low boiling point, potential health hazards.

What are the advantages and disadvantages of ionic liquids?

Advantages: excellent for microwave-assisted extraction, non-flammable. Disadvantages: not ideal for preparing tinctures.

What are the advantages of maceration?

Simple extraction method, suitable for thermolabile plant material, and one of the cheapest ways to obtain several plant extracts and bioactive compounds.

What are the advantages of microwave-assisted extraction?

It minimizes solvent and extraction time while increasing the yield.

What are the advantages of Paper Chromatography?

Simplicity, cost-effectiveness, and high sensitivity to small quantities of material.

What are the advantages of Soxhlet extraction?

It allows for large amounts of drug extraction with smaller solvent volumes, is applicable to heat-stable materials, and requires no filtration.

What are the advantages of Thin Layer Chromatography (TLC)?

It is less time-consuming, produces clear spots, and is stable to acid as a solvent.

What are the advantages of ultrasound-assisted extraction?

It is applicable to small samples, reduces extraction time and solvent use, and maximizes yield.

What are the advantages of using Gas Chromatography (GC)?

It can separate plant material contaminated with volatile pesticides and is used in quality control testing.

What are the advantages of using water as a solvent for extraction?

Water is cheap, nontoxic, non-flammable, and highly polar, dissolving a wide range of substances.

What are the benefits of using high-performance liquid chromatography (HPLC) in herbal quality control?

HPLC is used for separating, identifying, and quantifying the chemical constituents in herbal products, ensuring quality and consistency.

What are the common forms in which botanical materials are purchased?

Botanical materials are most often purchased in processed form, such as powdered herbs or dry extracts.

What are the disadvantages of maceration?

Long extraction time and low extraction efficiency.

What are the disadvantages of microwave-assisted extraction?

It is suitable only for phenolic compounds and flavonoids; compounds like tannins and anthocyanins may degrade due to high temperatures.

What are the disadvantages of Paper Chromatography?

It is time-consuming and the filter paper can be fragile and destroyed by chemicals.

What are the disadvantages of Soxhlet extraction?

Regular shaking is not possible, and it is not suitable for thermolabile materials.

What are the disadvantages of ultrasound-assisted extraction?

It is difficult to reproduce and high energy application may degrade phytochemicals by producing free radicals.

What are the disadvantages of using water as a solvent for extraction?

It promotes bacterial and mold growth, may cause hydrolysis, and requires a large amount of heat to concentrate the extract.

What are the key components of quality control in herbal products?

1. Plant identification, 2. Batch-to-batch consistency, 3. Safety procedures for microbes, pesticides, and heavy metals.

What are the major stages in the extraction and characterization of bioactive compounds?

1) Selection of an appropriate solvent, 2) Extraction methods, 3) Phytochemical screening procedures, 4) Fractionation & purification methods, 5) Identification techniques.

What are the potential sources of raw materials for extraction?

Raw materials can come from both wild and cultivated plants.

What are the properties of alcohol as a solvent for extraction?

Alcohol is polar, miscible with water, and can extract polar secondary metabolites.

What are the steps in phytochemical screening?

Procurement of raw material, extraction, isolation & purification, characterization of pure compounds, and bioassay-guided isolation.

What are the steps involved in the extraction process after filtration?

The extract is separated by filtration, followed by decantation, and the marc is expressed with the final amount of solvent added to achieve the required volume.

What are the steps involved in the overview of extraction, isolation, and purification of phytoconstituents?

Steps include identity and quality assessment, extraction, filtration, pharmacological screening, characterization, isolation, and purification.

What are the two basic classifications of fractionation techniques?

Physical methods and chemical methods.

What are the various mechanisms involved in chromatographic separation?

Adsorption, partition, affinity, ion exchange, or size exclusion.

What can be developed after identifying active plant substances?

Standardization of a plant preparation or structure-activity relationship studies can be initiated.

What challenges are associated with quality control in herbal preparations?

Challenges include ensuring consistency and safety at all production stages.

What challenges exist in identifying the active compounds in herbal ingredients?

Many molecules act in ways that are sometimes known, but often not understood, requiring expertise and specific instruments for analysis.

What components make up the HPLC apparatus?

A solvent reservoir, sample injector, pressure pump, HPLC tube, and diode detector.

What determines the choice of extraction method for a plant material?

The choice depends on the nature of the plant material, the solvent used, pH of the solvent, temperature, and solvent-to-sample ratio.

What does a white precipitate in Gelatin's test indicate?

The presence of tannins.

What does a white precipitate in the Gelatin test indicate?

The presence of phenols.

What does a yellow precipitate in the Lead acetate test signify?

The presence of flavonoids.

What does Dragendorff's test indicate?

The presence of alkaloids, indicated by an orange-red precipitate.

What does Hager's test indicate?

The existence of alkaloids, indicated by a yellow-colored precipitate.

What does Keller-Killiani test imply?

The presence of digitoxose, indicated by a reddish-brown layer that turns bluish-green.

What does Legals test signify?

The existence of cardiac glycosides, indicated by a pink-to-blood-red precipitate.

What does Mayer's reagent test for?

The existence of phenolic compounds.

What does Mayer's test imply?

The presence of alkaloids, indicated by a whitish or cream precipitate.

What does nuclear magnetic resonance spectroscopy (NMR) focus on?

NMR focuses on the physical properties of bioactive molecules, such as the number and arrangement of carbon atoms and the presence of isotopes.

What does selectivity refer to in solvent extraction?

Selectivity is the ability of a solvent to extract active constituents while leaving inert material.

What does the Alkaline reagent test reveal about flavonoids?

Emergence of an intense yellow color that turns colorless after adding dilute acid.

What does the Lead acetate test indicate when a red-to-blue color forms?

The occurrence of phenols.

What does the Ninhydrin test signify?

The presence of proteins when a blue color forms after boiling.

What does the term 'characterization' refer to in the context of phytoconstituents?

Characterization refers to the identification and analysis of the chemical composition and structure of phytoconstituents.

What does ultraviolet spectroscopy (UV) analyze?

UV analyzes compounds in plant extracts for qualitative and quantitative analysis, detecting secondary metabolites like phenols and anthocyanins.

What does Wagner's test signify?

The existence of alkaloids, indicated by a reddish-brown precipitate.

What factors affect the speed of separation in Paper Chromatography?

The type of filter paper used; thick paper speeds up the process, while porous paper slows it down.

What factors enhance the efficiency of extraction?

Factors include properties of the extraction solvent, particle size of raw materials, solvent-to-solid ratio, extraction temperature, and extraction duration.

What factors influence the choice of an extraction method?

The choice depends on the nature of the plant material, solvent used, pH of the solvent, temperature, solvent to sample ratio, and intended use of the final products.

What factors should be considered when choosing a plant extraction method?

Stability to heat, nature of solvent, cost of the drug, duration of extraction, final volume required, and intended use.

What factors should be considered when selecting solvents for extraction?

Factors include selectivity, safety, cost, reactivity, recovery, viscosity, and boiling temperature.

What frequency range is used in microwave-assisted extraction?

Electromagnetic radiation in frequencies between 300 MHz and 300 GHz.

What happens to the column after the extract is added in Column Chromatography (CC)?

The bottom of the column is opened, and various fractions of n-hexane are collected at intervals.

What happens when nonpolar solvents are used in microwave-assisted extraction?

The microwave radiation produces only small heat, which does not favor the extraction process.

What happens when the solvent level reaches the top of the siphon in Soxhlet extraction?

The solvent and extracted plant material flow back to the flask, continuing the extraction process.

What indicates that the plant sample is completely extracted in Soxhlet extraction?

The solvent flowing from the extraction chamber does not leave any residue behind.

What indicates the presence of flavonoids in Shinoda's test?

Emergence of pink coloration after adding hydrochloric acid and mRimandoium turnings.

What indicates the presence of peptide linkages in the Biuret test?

Appearance of violet color after adding sodium hydroxide and copper sulfate.

What indicates the presence of phenolics in the Prussian Blue test?

Development of blue color after adding FeCl3 and K3[Fe(CN)6].