Pharmacognosy Lab Safety and Definitions

Study Notes

Video links for microscope parts and usage:
- https://youtu.be/YjOdua47pFA?si=R7pBLwvgU0eLsawG
- https://youtu.be/2MsNTrBpw8A?si=9G1cXHVNJDI4srQj
- Additional video link: https://youtu.be/LVS_HQVNIAK?si=UPLY9R3TKHD_OIZKH

Pharmacognosy is the study of medicines derived from natural sources.
It encompasses the study of crude drugs (plant, animal, and microbial origins) that have only undergone collection and drying processes.
The term "Pharmacognosy" originates from the Greek words "pharmakon" (drug) and "gnosis" (knowledge).

Dress appropriately (tie back hair, wear suitable gloves, goggles, and other PPE). Avoid touching your eyes, nose, and mouth.
Know location of emergency numbers and safety equipment.
Do not perform lab experiments without teacher supervision, unless given permission.
Keep the workspace clean.
Avoid obstructing walkways and exits.
Do not eat or drink in the lab, and never taste chemicals.
Be careful handling hot glassware, and dispose of broken glass properly.
Identify hazardous materials before beginning labs.
Be attentive during lab work.
Turn off all heating appliances when not in use and keep flammable materials away from your workspace.
Clean your work area and equipment thoroughly after completing a lab. Wash hands with soap and warm water for at least 20 seconds.

Classification: Dusting powders (fine powders) are categorized into starches and non-starches.

Starch is a polysaccharide carbohydrate.
It's composed of large numbers of glucose units linked together by glycosidic bonds.
General formula: (C₆H₁₀O₅)_n.
Two main components: Amylose (20%) and Amylopectin (80%).
- Amylose is water-soluble and linear.
- Amylopectin is water-insoluble and branched.

Starch granules are polysaccharides composed of two main components: amylose and amylopectin.
These occur in varying sizes in plant organs, frequently in higher amounts in seeds, fruits, rhizomes, and roots compared to leaves and stems.

Starch acts as a reserve food material.
It occurs in granules of varying sizes in almost all plant organs, sometimes accompanied by other reserve food particles (like proteins).

Starch has varied uses, in pharmaceuticals: it acts as an antidote to iodine poisoning, a skin emollient, and a lubricant for surgical gloves.
Use in tablets: binder in tablets which helps in disintegration.

Insoluble in cold water, but becomes a white colloidal solution when boiled and forms a jelly when cooled.
Insoluble in alcohol and organic solvents.
Hygroscopic, capable of absorbing up to 37% moisture.
Stable in the air and when heated to 100°C becomes dry.
Further heating converts starch to a soluble dextrin.
Stained blue with iodine, which disappears on heating and reappears on cooling.
Swells and bursts when heated with chloral hydrate.
Becomes transparent and invisible when heated with phenol.
Charring in concentrated sulfuric acid (H₂SO₄) due to removing water.
Hydrolyzed into glucose and other intermediate components by dilute acids which reduces Fehling's solution.
Swells slowly and forms a small hole (during moist heating) and grows in diameter—this is a process called gelatinization.

Gelatinization occurs at room temperature in the presence of concentrated acids, dilute alkalis, and saturated solutions of heavy metals (e.g., CaCl₂, ZnCl₂).
During gelatinization, starch granules absorb water, swell, and burst if heated for long periods.

Starch appears as irregular, angular masses or as a white powder.
Maize starch is neutral, other types can show slight acidic/alkaline reaction to litmus paper.
Starch is odorless and has a characteristic taste.

Several types of starch exist, including maize, wheat, potato, and rice starches.

The origin of starch granules varies based on the plant source.
- Potato starch comes from tubers of the Solanum tuberosum plant.
- Wheat starch originates from the endosperm of Triticum vulgare grains.
- Maize starch is from the endosperm of Zea mays grains.
- Rice starch comes from the endosperm of Oryza sativa grains.

Provides detailed descriptions of different types of starch grains including distinctive features like size, shape, hilum present/absent, striations, and aggregation patterns.

Images of starch types (e.g., potato, wheat, maize, rice) under a microscope are included, demonstrating the diverse shapes and structures of starch granules.