Effect of infusion conditions on total phenolic content and antioxidant activity in Centella asiatica tea

The effect of different infusion conditions (water temperature, steeping time and multiple infusions) on the total phenolic content (TPC) and antioxidant activity (AOA) of Centella asiatica tea were studied. Total phenolic content and antioxidant activity were determined spectrophotometrically using Folin-Ciocalteau method and 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay respectively. The extraction efficiency of these compounds strongly depends on the infusion conditions. The results indicated that higher water temperature and shorter steeping time are the best combination for the extraction of TPC and AOA of C. asiatica. The highest TPC and AOA were detected in C. asiatica tea infused at 100 °C for 5 min and 80 °C for 10 min, while the lowest TPC and AOA were detected in infusions at 60 °C for 3 min. The study also showed that TPC and AOA were higher in the first infusion rather than second and third infusions. However, C. asiatica tea can be re-infused with the same leaves although the TPC and AOA decreased in the later infusions.