Tea is an inexpensive, safe, widely consumed, enjoyable, and socially acceptable beverage that hundreds of millions of people on all continents enjoy on a daily basis. Additionally, tea is a dietary source of biologically active substances that aid in the prevention o numerous illnesses (Trevisanato & Kim 2000). Flavonoids and phenolic acids, which are abundant in this common beverage, are the primary sources of phenolic chemicals that give tea infusions their overall antioxidant action (Kim et al., 2011). Hence, tea is a part of the quickly growing category of "wellness beverages" (Byun and Han 2004). The composition of tea is also known to vary depending on the type, climate, horticulture techniques, leaf age and season, and technological advancements (Lin et al., 2003). Due to increased public knowledge of the health advantages of tea intake, there has been a resurgence of interest in tea in recent years (Mckay and Blumberg 2002). Humans have been using herbal teas and beverages for generations to support their lives and livelihoods. These drinks are made from plants that have biological activity (Onaolapo and Onaolapo 2019). Even though non-fermented/aerated green tea, semi-fermented (oolong) tea and fermented black tea makes up the majority of tea produced worldwide, the processing has expanded to include the creation of specialty teas such as white tea, flavoured teas, organic teas, decaffeinated teas, herbal teas, scented teas and numerous other blends (Karori et al., 2007). Tisanes, or herbal teas, are prepared similarly to regular tea (Camellia sinensis). The method of brewing involves steeping (soaking) herbs in hot water for a predetermined amount of time until the water absorbs the bioactive compounds (Onaolapo and Onaolapo 2019). The contents of herbal teas vary greatly; they are primarily made of natural ingredients, mostly herbs, and offer a number of health benefits to people. Herbal tea plant species can provide fresh or dried roots, stems, leaves, fruits, flowers, seeds, bark, or entire plants as ingredients for their teas (Liu et al., 2013). Following the Boston Tea Party in America on December 16, 1773, there was the first known case of widespread tisane drinking in the modern era. This historic incident occurred when many tones of tea were poured into the water (Dwyer et al., 2013). Eastern nations have been employing herbal treatments to cure illnesses, infections, and diseases for millennia. Tea, or an infusion made from dried plant components steeped in boiling water, is a common way that people consume herbal treatments (Chan et al., 2010). Herbal teas are widely consumed due to its aroma, anti-oxidant qualities, and medicinal uses (Naithani et al., 2006). 

TYPES OF HERBAL TEA

Tea's consumption has surged globally as a result of its verified health advantages, it is now an essential component of contemporary life (Cooper et al., 2005). There are numerous varieties of herbal teas, just as there are numerous varieties of actual tea. There are almost as many different herbal tea blends as there are tea connoisseurs, but these blends often contain a few basic ingredients. Herbs that are used to make popular Mediterranean beverages, such as chamomile, peppermint, ginger, Greek mountain tea, eucalyptus, linden, sage, mint, and dictamnus. Some of them are renowned for their delicious flavour and therapeutic qualities (Atoui et al., 2005). There are many different ways to prepare chamomile, but the most common one is in herbal tea, which is drunk in excess of a million cups daily (Srivastava et al., 2010) One of the most often consumed single ingredient herbal teas, or tisanes, is chamomile (Matricaria recutita L., Chamomilla recutita L., Matricaria chamomilla). These tisanes are made from dried chamomile flower heads (McKay & Blumberg 2006). According to Srivastava et al. (2010) chamomile is a herb that has been ingested for centuries and is derived from daisy blooms (Matricaria species), its essential oils are widely utilised in aromatherapy and cosmetic products. According to a study by Chang et al. (2016) it is primarily renowned for its relaxing properties and is regularly used as a sleep aid. Awad et al. (2009) stated that lemon balm tea offers health-promoting qualities and a mild, lemony flavour.

One of the most popular single-ingredient herbal teas, or tisanes, is peppermint (Mentha piperita L.). Traditional medical practices employ peppermint essential oil and tea made from the plant's leaves (Mckay and Blumberg 2006). An amalgam of spearmint and water mint, Mentha piperita is commonly used as peppermint. It's widely used as gum flavouring, toothpaste flavouring, and tea flavouring in Europe and North America (Knowlton, 2011). Hibiscus sabdariffa is frequently used in herbal tea blends, and the dried calyces of this plant are used to make popular drinks all over the world (Mckay, 2009). The vibrant blossoms of the hibiscus plant are used to make hibiscus tea, its colour is pink-red, and its flavour is tangy and refreshing. It tastes good either hot or cold (Majid et al., 2019). According to Marmol et al. (2017) the fruit of the rose plant is used to make rose hip tea. The dried seeds of the rosehip plant are used to make medications. These plants' potential for medicinal application stems from their antioxidant properties, which are linked to or induced by their phytochemical makeup. Rosa rugosa and Rosa canina are the two primary varieties of rose hip seeds used to create tea. These roses are native to Europe, Asia, and North Africa, and are widely grown in the USA.

NUTRITIONAL PROPERTIES OF HERBAL TEA

Herbal teas and beverages are abundant in naturally occurring bioactive substances, including but not limited to carotenoids, phenolic acids, flavonoids, coumarins, alkaloids, polyacetylenes, saponins, and terpenoids (Chandrasekara & Shahidi 2018). According to Carnat et al. (2004) there were 340 mg/l of polyphenolic chemicals in the chamomile tea, with chamaemeloside (155 mg/l) being the most significant. The tea contained only trace amounts of essential oil (7 mg/l). Additionally, the herb and its infusion include organic acids (fumaric, fumaric, malic, quinic, and oxalic acids) that have been shown to have antitumor and antioxidant properties without being harmful to the liver (Rafaela et al., 2013). Several mineral elements were found in chamomile infusion, specifically calcium, potassium, magnesium, zinc, and cadmium (Chizzola et al., 2008). Flavonoids found in lemon balm leaves include quercitrin (a derivative of quercetin), ramnocitrin, luteolin and its derivatives (luteolin 7-o-βd-glucuronopyranoside, luteolin 3'-o-β-d-glucuronopyranoside, apigenin 7-o-β-d-glucopyranoside, and luteolin 7-o-β-d-glucopyranoside-3'-o-β-d-glucuronopyranoside and the main constituents of terpenoids include tannins, ursolic acid, geranyl acetate, and neral were also present in lemon bam leaves (Moradkhani et al., 2010). A study conducted by Ordaz et al. (2018) reported that apigenin, caffeic acid, rosmarinic acid, and phenolic type compounds were among the most prevalent bioactive substances found in the aqueous extracts of lemon balm. Compared to microgreen teas, adult lemon balm tea had higher levels of rosmarinic acid, total flavonoids, total phenolics, and antioxidant capacity. On the other hand, microgreen lemon balm teas have greater concentrations of minerals, such as copper, zinc, phosphorus, magnesium, sodium, potassium, and calcium (Newman et al., 2023). 

Rosmarinic acid and a number of flavonoids, principally eriocitrin, luteolin, and hesperidin, are among the phenolic components of the peppermint leaves (Mckay and Blumberg 2006). A study conducted by Gadaka et al. (2021) on the peppermint tea leaves' methanolic extracts phytochemical screening encompassed the presence of  total phenolic compounds, alkaloids, flavonoids, glycosides, saponin, steroids, tannins, and terpenoids. Peppermint teas are also strong in luteolin and glycosides of apigenin (Kapp et al., 2013). Chen et al. (1998) investigated Roselle tea's volatile component makeup. Four classes of compounds- fatty acid derivatives, sugar derivatives, phenolic derivatives, and terpenoids were identified and over 37 of them were given detailed descriptions. Additionally it is abundant in several nutritionally significant elements, such as calcium, iron, niacin, riboflavin, ascorbic acid, and carotene (Mahadevan et al., 2009). According to Vagiri et al. (2017) the roselle's red calyces are rich in antioxidants, such as sabdaretine, hibiscetine, and flavanoids which is used for tea preparation. Similar to green tea, rosehip (Rosa canina L. Rosaceae) is rich in antioxidants, flavonoids, polyphenolic compounds, and vitamins C, A, and E. It also includes vital minerals and may help prevent oxidation-related diseases (Tumbas et al., 2012). According to Kazankaya et al. (2001) Vitamin C, vitamins A, P, K, B1 and B2, E and minerals including K, Ca, Na, Fe, Mg, and P, and folic acids are all abundant in rose hips. It is estimated that rose hip contains 129 distinct chemical components. A number of significant active ingredients are present in this fruit, including fatty oils, tannins, anthocyanin, phenolic compounds, flavonoids, and organic and inorganic substances (Zahra et al., 2018).

THERAPEUTIC PROPERTIES OF HERBAL TEA

Herbal teas and beverages contain bioactive compounds that have a wide range of biological effects, including antimutagenicity, anti-carcinogenicity, antiaging, antiviral, antibacterial, antiviral, anti-inflammatory, antiallergic, and vasodilatory action (Chandrasekara & Shahidi 2018). According to conventional wisdom, chamomile has antiseptic, antibacterial, disinfecting, bactericidal, fungicidal, and vermifuge properties. It has been utilised for ages as a medicinal herb with antibacterial, anti-inflammatory, moderate astringent, light sedative, and antispasmodic properties (Zhuxin et al., 2007). Shoara et al. (2015) also state that  antibacterial, anti-inflammatory, antimicrobial, antidepressant, antidiarrheal, angiogenesis, anticarcinogenic, hepatoprotective, antidiabetic, and liver-protecting properties are all present in chamomile tea or extract. There is evidence that chamomile is effective against both Gram-positive and Gram-negative bacteria (Kazemian et al., 2018). A study by Chaves et al. (2020) examined the analgesic effects of a crude fraction of chamomile using formalin tests. The findings revealed that using a 30 mg/kg dose of the herb reduced nociception (by 96%) in comparison to the control (10 mL/kg of saline solution), which demonstrated analgesic property. Lemon bam has a mild, lemony flavour and is said to have health-promoting qualities (Awad et al., 2009). There are antiviral properties in the aqueous extract of lemon balm leaves. It prevented HSV-1 (herpes simplex virus 1) from attaching to host cells and from penetrating cells in in vitro experiments (Astani et al., 2014). According to Abdellatif et al. (2014) the growth of bacteria, yeasts, and fungi (Fusarium oxysporum spp., Mucor ramannianus) as well as Gram-positive (Staphylococcus aureus, Bacillus subtilis, Listeria monocytogenes) and Gram-negative (Pseudomonas aeruginosa, Escherichia coli, Klebsiella pneumoniae, Salmonella enterica) bacteria were hindered by the essential oil of Melissa officinalis leaves.

Hibiscus rosa sinensis plants are used to cure a variety of illnesses because of its anti-oxidant, antimicrobial, antidiabetic, anti-ulcer, hepatoprotective, antifertility, antigenotoxic, and anti-inflammatory qualities (Khristi & Patel 2016). Ali et al. (2018) reported that by reducing collagen deposition in the heart following myocardial infarction and enhancing the expression of the collagen III gene, aqueous roselle extract has demonstrated anti-fibrotic action. The minimum inhibitory concentration (MIC) of hibiscus tea shown antibacterial action against strains of Salmonella typhimurium, Pseudomonas aeruginosa, Escherichia coli, and Staphylococcus, regardless of temperature (Paraiso et al., 2021). The plant known by its colloquial name, "nana," peppermint is traditionally utilised in the global pharmaceutical and cosmetic industries as a flavouring ingredient as well as for its antiseptic, stimulant, and antibacterial properties (Mahboubi & Kazempour 2014). Tea with peppermint leaves has powerful antioxidant, antiviral, anticancer, as well as antiallergenic qualities (Dinizdo et al., 2020). Rose hip extracts have shown promise as anti-inflammatory, anti-arthritic, analgesic, antidiabetic, cardioprotective, antibacterial, immunomodulatory, gastroprotective, and skin-improving agents (Patel & Seema 2013). Extensive research has indicated that rose hip possesses pharmacological properties such as anti-obesity, anti-cancer, hepatoprotective, nephroprotective, cardioprotective, antiaging, anti-H. pylori, neuroprotective, and antinociceptive effects. 

HERBAL TEA USED FOR PREVENTION OF DISEASES

Li et al. (2013) report that an increasing number of people drink these infusions on a daily basis for health reasons.   Chamomile tea is said to strengthen the immune system and aid in the battle against cold-related diseases, demonstrating its health-promoting properties (Srivastava & Gupta 2009). In the past, chamomile has been used to treat a variety of conditions, including rheumatic pain, hemorrhoids, menstrual disorders, ulcers, sleeplessness, inflammation, and hay fever (Srivastava et al., 2010).  One of chamomile's primary functions is as a versatile digestive aid. Additionally, it can be used to treat a variety of gastrointestinal disorders, including motion sickness, indigestion, anorexia, flatulence, nausea, vomiting, and diarrhea. In addition to being an herbal bitter that stimulates the liver, chamomile also has the ability to treat ulcers (Mann and Staba 1986). Lemon balm herbal tea has been shown to be effective for a variety of conditions, including bronchial problems, stomach issues, hypertension, nervous system abnormalities, and sleeplessness (Skotti et al., 2014). Mexican traditional medicine makes extensive use of lemon balms (melisa or balm) dry leaves to cure a variety of conditions, including mental illness, gastrointestinal issues, liver and biliary ailments, central nervous system abnormalities, respiratory and cardiovascular issues, and various cancers (Shakeri et al., 2016). Lemon balm is used widely in ophthalmology, gynaecology, cancer, gastroenterology, and cardiology. It is also used to treat neurological illnesses, obesity, and sleep disturbances (Katarzyna et al., 2019).

The decoctions or infusions of Roselle offer important therapeutic alternatives against a wide range of degenerative diseases, including cancer, diabetes, hypertension, hyperlipidemia, hepatoprotection, nephroprotection, and many more (Arslan et al., 2021). According to Guardiola & Mach (2014) Patients with type 2 diabetes and those who are prehypertensive or slightly hypertensive can benefit greatly from using H. sabdariffa extract on a regular basis. Hibiscus leaves and blossoms are used in India as a cough, emmenagogue, demulcent, menorrhagia, antifertility, diuretic, and menorrhagia therapy (Jadhav et al., 2009). Daily intake of peppermint tea has been shown in a study by Connelly et al. (2014) to alleviate osteoarthritis, modify hormone levels, particularly testosterone, and reduce headaches and insomnia. It has been demonstrated that luteolin, one of the polyphenolic components of peppermint, reduces lung tissue inflammation, the production of antibodies specific to C. pneumoniae, and the presence of Chlamydia (Tormakangas et al., 2005). For irritable bowel syndrome, flatulence, indigestion, nausea, and vomiting, peppermint is used as a folk cure or alternative medical treatment (Grigoleit & Grigoleit 2005).  In Iran, people drink rose hip tea and utilise it as traditional medicine for ailments like dropsy, constipation, gallstones, stomach disorders, and the common cold (Montazeri et al., 2011). Specifically, there have been reports of beneficial effects on arthritis from rose hip powder and extract (Zahra et al., 2018). Vitamin C deficiency and the flu can be avoided with rose hip tea. Additionally, it is used to address issues with the stomach, such as inflammation, ulcers, and acidity. However, it is also used to treat gout, kidney problems, excessive cholesterol, and weight reduction (Tseng et al., 2005). 

Priya P. and Beela G.K. (2024). Nutritional and Therapeutic Potentials of Herbal Tea. Biological Forum – An International Journal, 16(3): 50-55.