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Pharmacognosy is the study of crude drugs obtained from medicinal plants, animals, fungi, and other natural sources. [1] The American Society of Pharmacognosy defines pharmacognosy as "the study of the physical, chemical, biochemical , and biological properties of drugs, drug substances, or potential drugs or drug substances of natural origin ...
The exact composition of a herbal product is influenced by the method of extraction. A tea will be rich in polar components because water is a polar solvent. Oil on the other hand is a non-polar solvent and it will absorb non-polar compounds. Alcohol lies somewhere in between. [26] A herb shop in the souk of Marrakesh, Morocco
Most natural essences are obtained by extracting the essential oil from the feedstock, such as blossoms, fruit, and roots, or from intact plants through multiple techniques and methods: Expression ( juicing , pressing ) involves physical extraction material from feedstock, used when the oil is plentiful and easily obtained from materials such ...
It is the most common preparation method in various herbal medicine systems. Decoction involves first drying the plant material; then mashing, slicing, or cutting the material to allow for maximum dissolution; and finally boiling in water to extract oils, volatile organic compounds and other various chemical substances. [ 1 ]
Infusion is the process of extracting chemical compounds or flavors from plant material in a solvent such as water, oil or alcohol, by allowing the material to remain suspended in the solvent over time (a process often called steeping).
Prior to the 1950s, every pharmacy student learned about crude drugs in pharmacognosy class. Pharmacognosy is the study of the proper horticulture, harvesting and uses of the raw medications found in nature. Raising, harvesting and selling crude drugs was how many large pharmaceutical companies started out.
Extraction Profile for Different Types of Extraction. The extraction curve of % recovery against time can be used to elucidate the type of extraction occurring. Figure 4(a) shows a typical diffusion controlled curve. The extraction is initially rapid, until the concentration at the surface drops to zero, and the rate then becomes much slower.
In the acidic extraction, the raw plant material is processed by a weak acidic solution (e.g., acetic acid in water, ethanol, or methanol). A base is then added to convert alkaloids to basic forms that are extracted with organic solvent (if the extraction was performed with alcohol, it is removed first, and the remainder is dissolved in water).