Insights on the Efficacy and Safety of Selected Herbal Teas

1.        Introduction

The World Health Organization made use of traditional medicines, including herbal remedies, in its 2014–2023 strategy to keep populations healthy by providing access to effective and affordable alternatives to medicine and providing healthcare options consistent with people's cultural practices (1). The importance of this review comes from the prevalence of herbal teas as daily beverages among people at home, at work, or in entertainment places. Various medicinal plants will be discussed in this review, including jewel vine, sappan, bale fruit, ginger, licorice, bitter fennel fruit, anise fruit, fenugreek seed, blessed thistle herb, turmeric, and plants of the Cistaceae family. This review shows whether herbal teas are effective and safe or not. Also, this review will focus on the importance of herbal teas in our lives. Herbs have long been used as remedies in traditional medicine. The majority of people on the planet today (between 60 and 80 percent) rely on medicinal herbs for their healthcare. Due to their health-promoting qualities, including anticancer, antibacterial, antidiabetic, anti-inflammatory, and antioxidant properties, herbal teas are widely used in traditional medicine across a wide range of cultures. Along with the expanding health and wellness trend, the market for tea worldwide, particularly herbal teas, is expanding. In many cultures, herbal teas constitute the primary source of dietary antioxidants. Of these antioxidants, polyphenolic chemicals have recently attracted the attention of scientists, along with vitamins and carotenoids. The plant components, preparation method, processing and storage conditions, concentration of bioactive substances, and antioxidant activity of herbal teas all affect these properties. A variety of radical scavenging and reduction capacity assays are used to calculate the in vitro antioxidant potency of a sample and determine the antioxidant activity of herbal teas (2).

2.        Methodology

The author searched a lot of databases including PubMed, Google Scholar, Wiley Online, Scopus, and Science Direct for clinical trials evaluating the efficacy and safety of herbal tea formulations. The reference lists of papers were also hand-searched, and repeatedly to include additional clinical studies. Investigations and Interpretations were made depending on the results of the authors' experiments in previous articles included in this review. Finally, Microsoft Office Excel software was used to design the following charts that classify the number of included clinical trials each year. It is noted that there are few clinical trials and randomized controlled studies evaluating the efficacy and safety of herbal teas formulations, however, we can see a kind of evolution of research focusing on formulations of herbal teas compared to the past but not at the expected high rate (Figure 1).

Figure 1 Number of published articles concerning clinical trials on herbal tea formulations

3.        Herbal Tea formulations

Herbal teas are a widely consumed beverage around the world and are utilized as therapeutic vehicles in many types of traditional medicine. In its most basic form, herbal tea is a blend of herbs produced from various plants' leaves, seeds, and/or roots (3).

3.1         Wang Nam Yen Tea

Women who breastfeed frequently experience inadequate milk supply, especially after Cesarean deliveries. After cesarean delivery, 120 mothers experienced increased breast milk production when drinking Wang Nam Yen herbal tea over 72 hours. Wang Nam Yen herbal tea is used for each meal. Each Wang Nam Yen herbal tea bag contains 500 mg of jewel vine (Derris scandens (Roxb.) Benth), 500 mg of sappan (Caesalpinia sappan Linn.), 500 mg of bale fruit (Aegle marmelos L. Corr.), 500 mg of ginger (Zingiber officinale Roscoe), and 500 mg of licorice (Glycyrrhiza glabra Linn.) (Table 1). Wang Nam Yen herbal tea is a promising traditional medicine used as an alternative to pharmaceutical galactagogues for postpartum women to stimulate milk production (4).

 Table 1 Wang Nam Yen Herbal Tea Ingredients.

Note: The figures were retrieved from PubChem.

3.2         Mother’s Milk® Tea (MMT)

MMT is a known, commercially available herbal tea product that was introduced to the U.S. market for the first time in 1978. Mothers usually consume three to five 1-cup servings of MMT daily. MMT contains 560 mg of bitter fennel fruit (Foeniculum vulgare Miller ssp. vulgare var. vulgare, Apiaceae), 350 mg of anise fruit (Pimpinella anisum L., Apiaceae), 210 mg of fenugreek seed (Trigonella foenum-graecum L., Fabaceae), and 35 mg of blessed thistle herb (Cnicus benedictus L., Asteraceae) (Table 2). It is suggested that this commercially available galactagogue tea is safe for infants and mothers (10).

Table 2 Mother’s Milk Herbal Tea Ingredients.

Note: The figures were retrieved from PubChem.

3.3         Cystus® Tea

Commercially available mouthwashes often contain alcohol and are therefore irritating to patients with mucositis, as they can cause pain and burning. Instead, herbal mouthwashes are often recommended. (15). Cystus® tea could be suitable for clinical practice. Cystus® tea is made from the leaves and small twigs of the Cistaceae family of plants as Halimium halimifolium (16, 17). The Cistaceae family of plants contain polyphenol, flavonoid, and tannin, so they are used as antioxidants (18). Many studies have shown the anti-inflammatory, antioxidant, and antimicrobial properties of Cystus® extracts (19). Cystus® tea is often used for the treatment and prevention of upper respiratory tract infectious diseases (16, 20). A marked decrease in microbial growth in the oral cavity could be noted after mouthrinses with Cystus® tea (16, 21). Cystus® tea has a mild flavor, and it contains no side-effect-inducing ingredients. The current studies with Cystus® tea show good tolerability (17, 22, 23). The local use of Cystus® tea as mouthwash removes expectations of any negative interaction of Cystus® tea with radiotherapy (chemotherapy). Cystus® reduces radiation-induced mucositis in terms of grade, latency, and incidence. Cystus® tea mouthwash can be applied in addition to intensive oral care and hygiene, along with the application of fluorides within the accepted range (24).

Table 3 Cystus® Herbal Tea Ingredients.

Note: The figure was retrieved from PubChem.

4.        Zedoary Tea

Radical scavenging activity of Zedoary rhizome dried powder (ZRDP) (Curcuma zedoaria Roscoe) has a protective role against lipidemic conditions, hypercholesterolemia, and metabolic syndrome due to the high phenolic contents. The ZRDP contains crude protein (13.5 ± 0.68 %), acid detergent fiber (13.22 ± 0.44 %), total dietary fiber (21.86 ± 0.71 %), neutral detergent fiber (18.68 ± 0.53%), and mineral contents. The findings demonstrated that ingesting ZHT samples reduced TC, LDL-cholesterol, and TG considerably (p 0.05) in experimental individuals at day 60 compared to the beginning of the trial. After 12 days of pre-treatment, it was discovered that the zedoary extract at a dose of 200–400 mg/kg b/w was successful in lowering TC levels (17.1%–19.65%), indicating antihyperlipidemic efficacy (26).

 Table 4 Zedoary Herbal Tea Ingredients.

Note: The figures were retrieved from PubChem.

5.        Conclusions

The author is optimistic that shortly, herbal teas will surely find a higher place and interest in pharmaceutical manufacturing as add-on therapies. Herbal teas are effective and safe when they follow good manufacturing practices (GMP) and quality control standards. Some advantages of herbal teas are suitable pharmaceutical dosage form, patient compliance, easy preparation, standardization, and suitability for all ages. However, some disadvantages of herbal teas are adulteration, possible abuse, and drug-drug interaction. Herbal teas should be under strict quality control due to the prevalence of adulteration of medicinal plants for commercial purposes all over the world.