Antioxidant Analysis of Kawa Daun (Coffea canephora) Beverage by In Vitro and In Silico Approaches

In Tanah Datar Regency, West Sumatra, Indonesia, the waste of pruning coffee leaves (Coffea canephora) is utilized as a traditional beverage called "Kawa Daun". For a consistent quality of Kawa Daun functional beverage, we evaluated the effect of different smoking times (0, 2, 4, and 6 h) on its in vitro DPPH antioxidant activity. Estimation of antioxidant components from the coffee leaf was conducted in silico using Peroxiredoxin V (PrxV) with 3MNG code as a receptor, and 33 phytochemicals were reported to be present in the coffee leaves as ligands. As a result, Kawa Daun, with a 2-h smoking time, had the highest antioxidant activity. Molecular docking between PrxV and the 33 compounds resulted in the ten most potential compounds based on the affinity energy. They were xanthone (-4.9 kcal/mol), uric acid (-4.8 kcal/mol), xanthosine (-4.8 kcal/mol), caffeine (-4.6 kcal/mol), 3-methylxanthine (-4.6 kcal/mol), 7-methylxanthosine (-4.6 kcal/mol), theobromine (-4.5 kcal/mol), theophylline (-4.5 kcal/mol), caffeic acid (-4.5 kcal/mol), and xanthine (-4.4 kcal/mol). These ten ligands had stronger interactions than the control ligand 1.2-dithiane-4.5-diol (-3.6 kcal/mol). This research showed the potential of Kawa Daun as a functional beverage with antioxidant activity. Further confirmation on the antioxidant potential of this beverage using an in vivo method is recommended.