Phenolic Compounds, Antioxidant and Antibacterial Activities of Cedrus Atlantica Stem Barks

Stem barks of Cedrus atlantica were investigated for their antioxidant and antibacterial activities and their chemical composition. The phenolic ingredients of the extracts were studied using LC-MS/MS against twenty-seven phenolic compounds. The antioxidant activity was evaluated by DPPH, O₂-DMSO-alkaline, ABTS, β-carotene-linoleic acid and CUPRAC assays, while the antibacterial activity was performed using the disk diffusion and MIC assays. In addition, the phenolic and flavonoid contents were determined as gallic acid and quercetin equivalents, respectively. Ethyl acetate extract exhibited the highest activity in DPPH, O₂-DMSO alkaline, ABTS, β-carotene linoleic acid and CUPRAC assays (IC₅₀ = 10.85 ± 1.41, 3.36 ± 0.40, 0.74 ± 0.03, 10.03 ± 0.01, A_0.50 = 23.56 ± 1.67 μg/mL, respectively), followed by n-butanol and hydromethanol extracts. In addition, the ethyl acetate and n-butanol extracts showed remarkable antibacterial activity against Enterobacter aerogenes and Staphylococcus aureus (ATCC 43300), respectively. The LC-MS/MS analyses of all extracts afforded high amounts of quinic acid, malic acid, rosmarinic acid, protocatechuic acid, chlorogenic acid, coumarin, vanillin, and quercetin, exhibiting antioxidant activity.