They have penetrated into an emerging niche market along with other popular beverages such as tea, coffee and cocoa which are also prepared using plant materials.
For instance, herbal teas prepared from Aegle marmelos (Bael), Cassia auriculata (Ranawara), Aerva lanata (Polpala), and Hemidesmus indicus (Iramusu) are common social beverages of food cultures in India and Sri Lanka.
These herbal beverages may provide some therapeutic medicinal value. Those herbal beverages for which therapeutic properties are claimed may vary widely in their potency; therefore, a desired effect may be obtained. In addition, reaction to a particular herb can vary greatly form one person to another.
The potency of herbal beverages and hence their effectiveness, cannot be accurately predicted because the concentration of active ingredients in the plant material can vary enormously. Several factors can influence the potency of a herb, such as age of the plant, growing conditions, growing locations, storage and handling procedures, extraction methods and post-harvest processing. Any of these factors may produce a wide variation in the properties associated with an herbal tea.
Alongside the ever-popular green and black tea varieties, herbal beverages can be made with water infusions of the stems, roots, fruits, buds, leaves, flowers and other component parts of a hugely diverse range of plant species.
Herbal teas/beverages are rich sources of natural bioactive compounds such as carotenoids, phenolic acids, flavonoids, coumarins, alkaloids, polyacetylenes, saponins and terpenoids, among others.
They have been shown to possess, among other things, antioxidant, immunomodulatory, and antidiabetic properties, mainly due to their phenolic compounds.
The oral use of the upper parts of Echinacea purpurea are recognized a beneficial for colds and respiratory infections, whereas it is root and the upper parts of Echinacea pallida that are useful for the treatment pf influenza-like infections.
Chamomile and peppermint are the basis of some of the most popular herbal teas, with the anti-inflammatory and anti-mutagenic responses to chamomile, and relaxation effects of peppermint oil on the gastrointestinal tract being characterized.
Herbal beverages and therapeutic value
