Antibacterial compounds of the cultivated Robusta coffee: Coffea canephora Pierre ex A. Froehner

Abstract

The stems and leaves of robusta coffee, Coffea canephora Pierre ex A. Froehner, one of the traded Coffea species, yielded caffeine (1), lupeol (2), ursolic acid (3), 3β-acetyl oleanolic acid (4), friedelin (5), asperphernamate (6), squalene (7), stigmasterol (8), stigmasterol-3-O-β-D-glucopyranoside (9) and chlorophyll a (10). The structures of the compounds were determined using 1D, 2D NMR experiments, IR and MS. Ursolic acid, 3β-acetyl oleanolic acid, caffeine and chlorophyll a, were studied for their antibacterial inhibition effects against methicillin resistant Staphylocccus aureus (MRSA) clinical strains SA1199B, XU212, ATCC25923, MRSA 340702 and MRSA 27819. Ursolic acid showed highest antibacterial activity against all the tested organisms with the MIC of 8–16 µg/ml. Ursolic acid showed 1-to-4-fold better activity when compared to norfloxacin against SA1199B, XU212, ATCC25923, MRSA 340702 and MRSA 27819.

Keywords

• Coffea canephora Pierre ex A. Froehner
• Rubiaceae
• Ursolic acid
• Caffeine
• Antibacterial activity
• MRSA