Enhancement of in vitro antioxidant potential of terminalia chebula by various fruit extracts and optimization of concentration by response surface methodology

Abstract

Objective: The main objective of this study was to determine the enhancement of in vitro antioxidant potential of fruits of Terminalia chebula (TC) when used in combination with fruit extracts of Phyllanthus emblica, Ananas comosus, and Punica granatum. Hydroxyl (OH) radical scavenging and 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging assays were used to analyze the antioxidant potential. Method: Formulations of different combinatorial concentrations of fruits to prepare a mixture were achieved with central composite design through response surface methodology. Screening of 300 different combinations of various concentrations was done through hydroxyl radical scavenging assay followed by statistical analysis of data. Further validation of results was done by measuring the antioxidant potential of most bioactive extracts by DPPH method. Results: Screening of 300 samples of different combinations for antioxidant potential revealed the samples with highest percentage inhibition in aqueous (85.2%), ethanolic (92.9%), and aqueous-ethanolic (84.21%) extracts. Data were subjected to analysis of variance and generated a three-dimensional response surface plot for highest activity. Further subjecting these extracts to DPPH assay revealed a significant enhancement in the antioxidant potential of ethanolic extract of TC when used in mixture with other plants. Conclusion: Antioxidant activity of TC was enhanced when used in combination with other fruits extracts. These synergistic studies generating valuable interactions between various phytochemicals could lead to a momentous increase in other associated activities to fight against diseases such as cancer and cardiovascular disorders. Further research on isolation of bioactive compounds in the mixture and their potential to fight various types of cancer could lead to a significant augmentation in the activity of natural compounds.