Chemotaxonomy and Bioactivity of <i>Cupressus sempervirens</i> Varieties Essential Oils: Insights Into Their Antioxidant and Enzyme Inhibitory Potential

Collagenase and tyrosinase are key enzymes involved in skin aging and melanin synthesis, making the search for effective natural inhibitors increasingly important in cosmetic and pharmaceutical fields. In this context, the present study explores the chemotaxonomy, antioxidant capacity, and enzyme inhibitory potential of essential oils (EOs) from three Tunisian varieties of Cupressus sempervirens: var. horizontalis, var. numidica, and var. pyramidalis. Gas chromatography-mass spectrometry (GC-MS) analysis of leaf EOs identified 47 compounds, predominantly monoterpenes, with α-pinene and 3-carene as major constituents. Principal component analysis (PCA) and hierarchical cluster analysis (HCA) distinguished two chemical groups: Group 1 (C. sempervirens var. pyramidalis), from a sub-humid bioclimate, rich in cedrol, cryptopinone, and totarol; and Group 2 (var. horizontalis and numidica), from a semi-arid bioclimate, characterized by high levels of α-pinene and limonene. Antioxidant assays showed that var. pyramidalis had the strongest activity (IC₅₀: 45.49 µg/mL for DPPH; 127.7 µg/mL for ABTS). Enzyme inhibition tests revealed that var. horizontalis exhibited the best antityrosinase (IC₅₀: 178.5 µg/mL) and anticollagenase (IC₅₀: 229.59 µg/mL) activities. These results highlight the potential of C. sempervirens EOs, particularly from var. pyramidalis and horizontalis, as promising natural ingredients for cosmetic and pharmaceutical applications targeting skin aging and hyperpigmentation.