Isolation of Caffeine from Robusta and Arabica Coffee Leaves to Obtain Caffeine Yield

Abstract

Caffeine is a naturally occurring bioactive compound found in various plants, including coffee, tea, and cocoa. Coffee leaves contain caffeine at lower concentrations than coffee beans but have potential as an alternative caffeine source. This study investigated caffeine extraction from Robusta and Arabica coffee leaves using the reflux method. Leaf-to-solvent ratios of 1:3, 1:4, 1:5, 1:6, 1:7, 1:8, and 1:9 and extraction times of 20, 40, 60, 80, 100, and 120 min were evaluated. Caffeine was identified using thin-layer chromatography (TLC) and quantified using UV–Vis spectrophotometry. The results showed that increasing extraction time generally increased the caffeine concentration in the coffee leaf extracts. Robusta coffee leaves produced higher caffeine concentrations than Arabica leaves. The highest caffeine concentration, 3,567.17 ppm, was obtained from Robusta coffee leaves at 120 min extraction time and a leaf-to-solvent ratio of 1:3. However, Arabica coffee leaves produced a caffeine yield of 0.0108%, compared with 0.0083% for Robusta leaves. These results demonstrate that extraction conditions influence caffeine recovery and confirm the potential of coffee leaves as an alternative caffeine source.