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<i>Psidium guajava</i> (Guava tree) is one of the most widely known species in the family Myrtaceae. The Guava tree has been reported for its potential antioxidant, anti-inflammatory, antimicrobial, and cytotoxic activities. In the current study, the chemical compositions of the <i>n</i>-hexane extract and the essential oil of <i>P. guajava</i> were investigated using the GC/MS analysis, along with an evaluation of their antioxidant potential, and an investigation into the enzyme inhibition of acetylcholinesterase (AChE), butyrylcholinesterase (BchE), tyrosinase, α-amylase, and α-glucosidase. Moreover, molecular docking of the major identified active sites of the target enzymes were investigated. The chemical characterization of the <i>n</i>-hexane extract and essential oil revealed that squalene (9.76%), <i>α</i>-tocopherol (8.53%), and <i>γ</i>-sitosterol (3.90%) are the major compounds in the <i>n</i>-hexane extract. In contrast, the major constituents of the essential oil are D-limonene (36.68%) and viridiflorol (9.68%). The <i>n</i>-hexane extract showed more antioxidant potential in the cupric reducing antioxidant capacity (CUPRAC), the ferric reducing power (FRAP), and the metal chelating ability (MCA) assays, equivalent to 70.80 ± 1.46 mg TE/g, 26.01 ± 0.97 mg TE/g, and 24.83 ± 0.35 mg EDTAE/g, respectively. In the phosphomolybdenum (PM) assay, the essential oil showed more antioxidant activity equivalent to 2.58 ± 0.14 mmol TE/g. The essential oil demonstrated a potent BChE and tyrosinase inhibitory ability at 6.85 ± 0.03 mg GALAE/g and 61.70 ± 3.21 mg KAE/g, respectively. The <i>α</i>-amylase, and <i>α</i>-glucosidase inhibitory activity of the <i>n</i>-hexane extract and the essential oil varied from 0.52 to 1.49 mmol ACAE/g. Additionally, the molecular docking study revealed that the major compounds achieved acceptable binding scores upon docking with the tested enzymes. Consequently, the <i>P. guajava n</i>-hexane extract and oil can be used as a promising candidate for the development of novel treatment strategies for oxidative stress, neurodegeneration, and diabetes mellitus diseases.