Optimizations of antioxidants-rich herbal tea formulation from selected medicinal plants for the enhancement of Psidium guajava tea

Abstract

Herbal teas are simple, effective, inexpensive, drugfree, and caffeine-free ways to enjoy the flavor and benefits of herbs and spices, which are commonly consumed by people since they are natural, harmless, and can assist in treating or controlling various therapeutic illnesses. The purpose of this study was to develop guava leaf-based herbal tea with a combination of supporting and activating herbs such as Cinnamomum zeylanicum (cinnamon) leaf and bark, Senna auriculata (avaram senna) flower, Gymnema sylvestre (gurmar), Ocimum tenuiflorum(holy basil) leaf, and Citrus limon (lemon) leaf in order to improve guava tea. Herbal teas were prepared using nine various combinations of the above-mentioned plant materials along with guava tea for comparative purposes. The extraction of tea was done by infusing tea bags, and phytochemicals were screened with a standard procedure. Total polyphenolic content (TPC) and total flavonoid content (TFC) were determined using the Folin-Ciocalteu approach and the aluminum chloride spectrophotometric method, respectively. Total antioxidant capacity was determined by the ferric reducing antioxidant power (FRAP) assay, while radical scavenging activity was determined by the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay. The toxicity of developed tea bags was assessed using a brine shrimp micro-well cytotoxicity assay. According to the findings, all of the prepared herbal teas and guava tea are rich in essential phytochemicals. Moreover, the combination of guava leaf, cinnamon bark, cinnamon leaf, avaram senna flower, gurmar leaf, holy basil leaf, and lemon leaf (35:20:1:1:1:1:1) exhibited the highest TPC (2027.12 mg GAE/ml) and antioxidant capacity (82.33 mg ascorbic acid eq/ml). During sensory evaluation, this composition was most preferred to guava tea by the semi-trained panel, and it showed nontoxicity to brine shrimp (LC50 values higher than 1000 mg/L). In conclusion, even though guava tea has already been developed and proven to have anti-diabetic and antioxidant properties, the herbal tea formulation from seven medicinal plants showed the greatest preference due to the highest TPC and highest antioxidant capacity. Further studies are needed to determine the antidiabetic properties of developed herbal teas and compare the anti-diabetic properties of guava tea.