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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 ...
Plant extracts may interact with conventional drugs, both because they may provide an increased dose of similar compounds, and because some phytochemicals interfere with the body's systems that metabolise drugs in the liver including the cytochrome P450 system, making the drugs last longer in the body and have a cumulative effect. [125]
Complexation with phospholipids has been applied to a number of popular herbal extracts and active molecules including Ginkgo biloba extract, [4] bilobalide isolated from Ginkgo biloba, [5] silybin isolated from milk thistle (Silybum marianum), [6] curcumin isolated from turmeric, [7] and green tea extract (Camellia sinensis).
Ethnomedicine is a study or comparison of the traditional medicine based on bioactive compounds in plants and animals and practiced by various ethnic groups, especially those with little access to western medicines, e.g., indigenous peoples.
It is a popular misconception that herbal medicines are safe and side-effect free. [34] Consumption of herbs may cause adverse effects . [ 35 ] Furthermore, "adulteration, inappropriate formulation, or lack of understanding of plant and drug interactions have led to adverse reactions that are sometimes life threatening or lethal."
Secondary metabolites and pigments may have therapeutic actions in humans, and can be refined to produce drugs; examples are quinine from the cinchona, morphine and codeine from the poppy, and digoxin from the foxglove. [1] In Europe, apothecaries stocked herbal ingredients as traditional medicines.
Native American traditional herbal medicine introduced cures for malaria, dysentery, scurvy, non-venereal syphilis, and goiter problems. [20] Many of these herbal and folk remedies continued on through the 19th and into the 20th century, [ 21 ] with some plant medicines forming the basis for modern pharmacology.
The drug must be found to be effective against the disease for which it is seeking approval (where 'effective' means only that the drug performed better than placebo or competitors in at least two trials). The drug must meet safety criteria by being subject to animal and controlled human testing. Gaining FDA approval usually takes several years.