Phenolic compounds, antioxidant and antibacterial activities of three Ericaceae from Algeria

• Arbutus unedo presents a higher total phenolics and flavonoids.
• Arbutus unedo has a higher antioxidant and antibacterial activities.
• Arbutus unedo contains epicatechin, caffeic acid, ρ-coumaric acid, quercetin, t-cinnamic acid, kaempferol.
• Erica arborea contains caffeic acid, ρ-coumaric acid, quercetin and t-cinnamic acid.
• Erica multiflora contains caffeic acid, ρ-coumaric acid, quercetin and kampferol.

Herbs of the Ericaceae family are commonly found in Algeria and used in traditional medicine as antiseptic, diuretic, astringent, depurative, and to treat scalds and wounds. The methanolic extracts of three species, Arbutus unedo L. (A. unedo, leaves), Erica arborea L. (E. arborea, flowered aerial parts), and Erica multiflora L. (E. multiflora, flowered aerial parts), were compared regarding their content in phenolic compounds, their antioxidant, and antibacterial activities. A. unedo harbors the highest content in total phenolics and flavonoids, followed by E. arboreaE. multiflora. The contents in total phenolics and flavonoids showed a correlation with the measured antioxidant (hydrogen-donating) activities; this was particularly the case for flavonoids content. The A. unedo extract showed antibacterial activity against all the tested strains (Staphylococcus aureus ATCC 6538, S. aureus C100459, Escherichia coli ATCC 25922, and Pseudomonas aeruginosa ATCC 9027); however, the E. arborea and E. multiflora extracts showed antibacterial activity only against Gram positive bacteria. Some polyphenols were identified in the three herbs by thin-layer chromatography and high-performance liquid chromatography coupled with diode array and mass spectrometry detection; from these, caffeic acid, p-coumaric acid, naringin, quercetin and kaempferol are reported for the first time in E. multiflora.