Effects of processing method and age of leaves on phytochemical profiles and bioactivity of coffee leaves

[Display omitted] •Processing method affects antioxidant and anti-inflammatory activities of coffee leaves.•JGTP young coffee leaves have the greatest antioxidant and anti-inflammatory activities.•BTP mature coffee leaves have the least antioxidant and anti-inflammatory activities.•BTP mature coffee leaves have dual function on inflammation.•Mature coffee leaves oxidized 48 h have both nitric oxide inhibition and induction effects. The use of coffee leaves as a novel beverage has recently received consumer interest, but there is little known about how processing methods affect the quality of final product. We applied tea (white, green, oolong and black tea) processing methods to process coffee leaves and then investigated their effects on phytochemical composition and related antioxidant and anti-inflammatory properties. Using Japanese-style green tea-processing of young leaves, and black tea-processing of mature (BTP-M) coffee leaves, produced contrasting effects on phenolic content, and associated antioxidant activity and nitric oxide (NO) inhibitory activity in IFN-γ and LPS induced Raw 264.7 cells. BTP-M coffee leaves also had significantly (P