Analysis of antioxidant activity of traditional Sri Lankan herbal formula composed of Phyllanthus Emblica and Tinospora Cordifolia

Abstract

Sri Lanka harbours a diverse range of herbal plants that have long been valued in traditional medicine for their potent bioactive compounds. Phyllanthus emblica and Tinospora cordifolia are two widely used medicinal plants known for their antimicrobial, antioxidant, anti-inflammatory, and immunomodulatory properties. Although these two plants have traditionally been used together in Sri Lankan healing practices, their combined therapeutic effects remain underexplored in scientific literature. Hence, this study aimed to evaluate the antioxidant activity and total phenolic content of water and ethanol extracts of the P. emblica and T. cordifolia combination, using the DPPH radical scavenging assay and Folin-Ciocalteu method. Equal amounts of dried fruits of P. emblica and the dried stems of T. cordifolia were used to prepare traditional 8:1 kashaya preparations. To prepare ethanol extract, the mixture of powdered plant samples was extracted at a solid: solvent ratio of 1:10 in ethanol using a Soxhlet apparatus. Water extract and ethanol extract of the herbal formula composed of P. emblica and T. cordifolia showed excellent antioxidant activity measured by 2,2- diphenyl-1-picrylhydrazyl (DPPH) scavenging assay. The water extract of this combination showed an IC50 value of 0.139 ± 0.001 μl/ml, while the ethanol extract showed a value of 5.47 ± 0.002 μg/ml. Ascorbic acid, used as the reference standard, demonstrated an IC₅₀ of 4.31 μg/ml. The total phenolic contents of the water extract and ethanol extracts were 12.66 ± 0.132 mg Gallic Acid Equivalent (GAE)/ml extract and 233.2 ± 0.12 mg GAE/g extract, respectively, indicating this is a rich source of polyphenols. The results of this study provide evidence that water and ethanol extracts of folkloric herbal formulations composed of P. emblica and T. cordifolia are a potential source of natural antioxidants, which will be valuable in the pharmaceutical and nutraceutical industries. Further detailed studies on varying proportions of this combination and identification of the bioactive compounds responsible for the beneficial effects of this combination are warranted.