Effects of Drying Temperature on the Amount of Secondary Metabolites and Antioxidant Activity of Orthosiphon aristatus (Blume) Miq. Tea Extracts

Abstract

Orthosiphon aristatus (Blume) Miq. tea is a traditional herbal tea in Thailand. This herb is used to prevent and treat a wide range of diseases such as diuresis, hypertension, and diabetes. In this study, three different drying temperatures used for herbal tea processing were evaluated (40, 50, and 60 °C) for their secondary metabolites [total phenolic content (TPC), caffeic acid (CA), rosmarinic acid (RA), and total flavonoid content (TFC)] and antioxidant activity. The herbal tea processed at 40 °C showed significantly (P < 0.05) higher TPC [485.26 ± 49.43 mg gallic acid equivalent (GAE)/ 100 g], CA (202.17 ± 1.00 mg/kg), RA (469.99 ± 1.56 mg/kg), TFC [356.86 ± 41.81 mg catechin equivalent (CE)/ 100 g], and 2,2-diphenylpicrylhydrazyl (DPPH) radical scavenging activity than those at other drying temperatures. Therefore, a drying temperature of 40 °C was the optimum condition for the Orthosiphon aristatus(Blume) Miq. leaves because it retained the secondary metabolite content with strong antioxidant potential.

Kadar Total Fenol Dan Antioksidan Teh Daun Sawo Manila (Manilkara Zapota l.) Dengan Variasi Suhu Pengeringan

“…Penelitian serupa yang menyatakan bahwa suhu pengeringan dapat mempengaruhi kadar total fenol pada teh herbal seperti teh kumis kucing [24], teh daun tin [25], dan teh daun mint [26]. Hal ini disebabkan karena suhu tinggi dapat menyebabkan degradasinya sebagian senyawa fenol, sehingga total fenol pada bahan akan menurun.…”