Phytochemical characterization, antioxidant, and antimicrobial properties of Cedrus atlantica (L.) : In vitro and in silico studies

Among the medicinal plants that make up Morocco's plant cover, the Atlas cedar (Cedrus atlantica L.), a species endemic to the mountains of North Africa, occupies a fragmented geographical range. However, research into its biological activities remains limited. In this context, the present study aims to evaluate the antibacterial (disc method) and antioxidant (DPPH, FRAP, TAC) activities of ethanolic extracts from C. atlantica (EECA) needles, following the phytochemical characterization of this extract by HPLC-DAD-MS. The ethanolic extraction of the needles resulted in a notable yield of approximately 17.84 % HPLC-DAD-MS analysis revealed the presence of 16 phenolic compounds, categorized into phenolic acids and flavonoids, including the isomer apigenin-7-O-glucoside, catechin, and ellagic acid-deoxyhexose. The in vitro assessment of antioxidant potential, using DPPH, FRAP, and TAC tests, showed an activity proportional to the increase in extract concentration. EECA demonstrated significant free radical-scavenging potential, with an IC₅₀ of 61.84 ± 3.59 µg/mL, an EC₅₀ of 269.79 ± 10.58 µg/mL, and a total antioxidant capacity (TAC) of 913.94 ± 18.46 µg AAE/mg. In vivo tests revealed antimicrobial activity against both Gram-positive and Gram-negative bacteria, with inhibition diameters ranging from 10.87 mm to 23.91 mm, as well as antifungal activity, with inhibition diameters ranging from 10.58 mm to 22.59 mm. Furthermore, the in silico study showed that among the identified molecules, tetragalloylglucose, apigenin-7-O-glucoside, and digalloylglucose exhibited the highest inhibitory affinity toward NADPH oxidase, with docking scores of -7.723, -7.424, and -7.374 kcal/mol, respectively. These findings highlight the pharmacological and biological potential of Cedrus atlantica L. needles and open up promising prospects for their use in therapeutic and biotechnological applications.