Structural characterization of phenolic content, antioxidant and antibacterial activities of Coffea arabica green seeds

This study concerns the evaluation of the antioxidant and antibacterial activities of Coffea arabica green seed extract. The chemical compositions were analyzed by RP-HPLC-PDA spectroscopy. Antioxidant activities were assessed using 2,2-diphenyl-1-picrylhydrazyl scavenging, 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid), reducing power and phenanthroline assays. The antibacterial activity was tested against 14 bacterial strains as per CLSI recommendation. The RP-HPLC-PDA revealed the presence of resorcinol, ferulic acid, rutin, catechin, gallic acid, caffeic acid, quercetin, chlorogenic acid and p-coumaric acid. The n-butanolic extract has the highest activity with 2,2-diphenyl-1-picryl-hydrazyl-hydrate (20.09 ± 0.40 µg/ml) and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (5.27 ± 0.19 μg/ml) assays. The A0.5 of the methanolic crude extract was 8.18 ± 0.63 μg/J ml for reducing power and 2.54 ± 0.06 μg/ml for phesnanthroline assay. The n-butanol extract showed an interesting antibacterial activity against Citrobacter freundii ATCC 8090 and Staphylococcus aureus ATCC 6538 with minimal inhibitory concentration of 13.02 µg/ml. Our finding provides an effective and specific natural approach to search for classes of antioxidant and antibacterial compounds for different uses. © 2020, Society for Plant Research.