Dehnh Leaf Essential Oil from Palestine Exhibits Antimicrobial and Antioxidant Activity but No Effect on Porcine Pancreatic Lipase and α-Amylase.

Dehnh is a tree species that is commonly used for various purposes, including forestry, agroforestry, and conservation. The present investigation was designed to determine the composition of leaves essential oil and estimate its free radicals, porcine pancreatic lipase, α-amylase inhibitory, and antimicrobial properties in vitro. The chemical constituents were analyzed using the gas chromatography-mass spectrometry (GC-MS) technique. DPPH (2,2-diphenyl-1-picrylhydrazyl), p-nitrophenyl butyrate, and 3,5-dinitro salicylic acid (DNSA) methods were employed to estimate the antioxidant, antiobesity, and antidiabetic effects of the essential oil. The microdilution assay was employed to assess the antimicrobial efficacy of the substance against a total of seven distinct microbial species. The GC-MS results revealed that essential oil contains 52 components that makeup 100% of the entire oil. The main chemical constituents in essential oil are -cymene (38.64%), followed by aromadendrene (29.65%), and 1,8-cineol (6.45%), with monocyclic monoterpene being the most abundant phytochemical group, followed by the sesquiterpene hydrocarbon group, representing 44.27 and 31.46%, respectively. The essential oil showed a weak antioxidant effect and had no antilipase or antiamylase effects. At the same time, the oil showed a strong antimicrobial effect against methicillin-resistant (MRSA), , and , which was even more potent than the positive controls, ciprofloxacin and ampicillin, which had MIC doses of 0.2 ± 0.01, 0.2 ± 0.01, and 6.25 ± 0.1 µg/mL, respectively. It also has a strong anti- effect with a MIC of 0.2 ± 0.01 µg/mL. In light of these findings, in vivo studies should be conducted to determine the efficiency of the essential oil in treating microbial infections.