Preparation and Evaluation the Efficacy of Combined Mixture of Finger Root and Robusta Coffee Extracts on Antioxidative Activity

Finger Root (FR) and Robusta Coffee (RC) are natural substances known to be beneficial for human health and used as a traditional medicine in various parts of the world. The efficacy of two commonly used extraction techniques [Ultrasound-Assisted Extraction (UAE) and maceration with stirring (MR)] and four different extraction solvents (50% ethanol, 80% ethanol, 100% ethanol and acetone) on antioxidant activity and the Total Phenolic Content (TPC) in both herbs were investigated. The antioxidant potentials of the samples were determined by reducing capacity with Folin-Ciocalteu reagent, while the radical scavenging activity using 1,1-Diphenyl2-Picryl Hydrazyl (DPPH) and 2,2'-azino-bis (3-ethylbenzothia zoline-6-sulfonic acid) (ABTS) assays. FR and RC extracts from UAE and using 80% and 50% ethanol as an extraction solvent, respectively, showed the highest antioxidant capacity compared to the other extraction processes. The combined mixtures of FR and RC (CFR) in the weight ratios of 1:1 was prepared and evaluated the antioxidant activity. The CFR extract showed a significant increase of TPC and resulted in its strong radical scavenging activity, quite the same level in comparison to the model antioxidant substance, ascorbic acid, compared to when they were assayed independently. Stability results indicated that the TPC of CFR extract was slightly decreased, by around 8.7% and the IC50 values of CFR extract showed slightly increased from 7.13 to 9.06 µg/mL in DPPH assay and from 725.72 to 858.65 µg/mL ABTS assay after storage at room temperature over 1 month. Findings suggested that the extraction methods and different solvent polarity significantly affect polyphenol recovery. The combined mixture of FR and RC extracts, which is quite stable and enhances radical scavenging activity, is interesting to increase economic value and utilization in cosmetic industry.