Response of total phenolic content and antioxidant activities of bush tea and special tea using different selected extraction solvents
The positive health benefits associated with tea are made possible by the antioxidant activity of phenolic compounds present in tea. The total phenolic content and antioxidant activity of bush tea (Athrixia phylicoides DC.) and special tea (Monsonia burkeana) were studied. The extractions were done in triplicate using cold water (5, 10 and 15 minutes), hot water (5, 10 and 15 minutes), 95% acetone, 95% methanol and 95% hexane. The experiments were arranged in a complete randomised design (CRD), and samples were extracted in triplicates in each treatment. Results demonstrated that total phenolic content ranged from 2.83 mg GAE / 100 g to 4.93 mg GAE / 100 g for bush tea and 2.60 mg GAE / 100 g to 6.24 mg GAE / 100 g for special tea. The ABTS antioxidant activity ranged from 34.41 µmol TE / g to 58.34 µmol TE / g in bush tea and 86.49 µmol TE / g to 197.46 µmol TE / g in special tea. The DPPH antioxidant activity in bush tea ranged from 59.87 µmol TE / g to 77.17 µmol TE / g and in special tea from 93.78 µmol TE / g to 109.13 µmol TE / g. Special tea had significantly higher total phenols and antioxidant activity (p<0.05) than bush tea. Hot water extractions were found to be comparable to chemical solvent extractions. This suggests that the potential benefits associated with consumption of beverages containing phenolic compounds can be expected from the consumption of these teas.