Phytochemical Diversity and Biological Effects of Juniperus Thurifera L., Essential Oil : A Comparative Study using In Vitro and In Silico Methods.

Juniperus thurifera L., a plant endemic to the Moroccan High Atlas Mountains, thrives in extreme climatic conditions, resulting in the production of valuable secondary metabolites. This study aims to elucidate the phytochemical diversity and biological activities of J. thurifera essential oil (JTEO) through a comparative analysis of samples from two distinct regions: Tensift-Al Haouz and Azilal, using both in vitro and in silico methods. Gas Chromatography-Mass Spectrometry (GC-MS) analysis revealed 21 components in the Tensift-Al Haouz JTEO (99.99 % of the oil) and 23 components in the Azilal JTEO (99.58 % of the oil), with oxygenated monoterpenes being the predominant compounds in both. The biological activities were assessed in vitro. Antioxidant properties, evaluated using DPPH, FRAP, and ABTS assays, showed significant activity in both oils. Antibacterial activity was tested against two strains of Gram-positive and two strains of Gram-negative bacteria, with both oils demonstrating notable bacterial growth inhibition. Enzymatic assays assessed the antidiabetic (α-amylase and α-glucosidase), dermo-protective (tyrosinase and elastase), and neuroprotective (AChE and BChE) activities. Both oils displayed substantial inhibitory effects across all tested activities, with variations attributed to their distinct chemical compositions. In silico analyses of six target enzymes confirmed significant binding affinities of the major compounds. Notably, 2,2'-Thiobis(6-tert-butyl-p-cresol) exhibited strong binding affinities with AChE, BChE, α-amylase, α-glucosidase, tyrosinase, and elastase, with binding energies ranging from -10.0 to -6.2 kcal/mol. These findings indicate that JTEO is a rich source of bioactive compounds with promising potential in pharmacological and cosmetic applications.