Antioxidant activity and total phenolic compounds in the extracts of young and mature leaves of Robusta coffee collected from coffee gardens in Kosamphi Nakhon District, Kamphaeng Phet Province, and the extracts of young and mature leaves of Arabica coffee collected from coffee gardens in Mueang District, Tak Province

Abstract

This research aimed to study antioxidant activities and total phenolic content in coffee leaf extracts from Coffea canephora Pierre ex A. Froehner (Young leaves), Coffea canephora Pierre ex A. Froehner (old leaves), Coffea arabica L. (young leaves) and Coffea arabica L. (old leaves). The leaves were extracted with 65 % ethanol, and the mixture was concentrated using rotary evaporation. The Coffea arabica L. (old leaves) extract provided the highest yield of 13.23%, while Coffea canephora Pierre ex A. Froehner (Young leaves) extract had the lowest yield of 2.44%. Antioxidant properties using DPPH assays demonstrated that Coffea canephora Pierre ex A. Froehner (old leaves) extract showed the highest DPPH scavenging activity with IC50 11.397 µg/ml, while the Coffea arabica L. (young leaves) extract showed the lowest value with IC50 57.053 µg/ml. The highest total phenolic content of Coffea canephora Pierre ex A. Froehner (Young leaves) extract was observed at 558.54 GAE/g extract.