JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD B.Pharmacy IV Year QUALITY CONTROL AND STANDARDIZATION OF HERBALS Previous Question Paper (September-2021 - R17)

Macroscopic and microscopic examinations are fundamental initial steps in the pharmacognostic evaluation of herbal drugs to ensure identity and purity.

Macroscopic examination involves the sensory evaluation of the herbal material using the naked eye or a hand lens. It focuses on morphological characteristics such as shape, size, color, surface texture, fracture, odor, and taste. These physical features provide a preliminary identification of the plant part (e.g., leaf, root, bark) and help detect gross adulteration or contamination with foreign organic matter.

Microscopic examination is essential for the identification of powdered drugs or specific tissues. It involves the use of light microscopy to observe internal cellular structures. Key steps include:

• Preparation of thin sections or powder mounts using clearing agents like chloral hydrate to remove cell contents.
• Observation of diagnostic features such as trichomes, stomata, calcium oxalate crystals, starch grains, and vascular elements (xylem vessels).
• Measurement of quantitative microscopic constants, including stomatal number, stomatal index, vein-islet number, and palisade ratio, which are specific to the species and serve as markers for standardization.

Microbial load determination is critical for ensuring the safety of herbal drugs, as they are often susceptible to contamination during cultivation, harvesting, processing, and storage. WHO guidelines mandate testing for total viable aerobic count (TVAC) and specific pathogens.

The procedure typically involves the following steps:

• Sample Preparation: A representative sample is homogenized in a sterile diluent, such as buffered sodium chloride-peptone solution, to release microorganisms from the plant matrix.
• Total Aerobic Microbial Count (TAMC): The sample is plated on suitable media (e.g., Casein-Soybean Digest Agar) using pour-plate or spread-plate methods and incubated to determine the number of colony-forming units (CFU) per gram.
• Total Yeast and Mold Count (TYMC): The sample is plated on selective media like Sabouraud Dextrose Agar and incubated to identify fungal contamination.
• Test for Specific Pathogens: The material is screened for the absence of objectionable organisms such as Escherichia coli, Salmonella species, and Staphylococcus aureus using selective enrichment broths followed by sub-culturing on differential agar media.

The results are compared against WHO-specified limits to ensure the herbal product is free from hazardous microbial levels that could pose health risks to consumers.