Gender and aridity drive essential oil chemodiversity in Tunisian Pistacia lentiscus for tailored bioresource valorisation

The essential oil composition of Tunisian female and male Pistacia lentiscus leaves from semi-arid to arid bioclimates was investigated across three phenological stages using gas chromatography-mass spectrometry-flame ionization detection (GC-MS/FID). Monoterpene hydrocarbons (44.67–60.59%) and sesquiterpene hydrocarbons (8.18–29.72%) were dominant, with limonene, sabinene, α- and β-pinene, terpinen-4-ol, germacrene D, γ-terpinene and β-caryophyllene as major components. Principal component analysis (PCA) revealed significant chemical differentiation based on plant gender and climatic factors. Male samples showed higher α-pinene and β-pinene content while female samples were enriched in limonene and germacrene D. Semi-arid male samples contained more sabinene, terpinene-4-ol and γ-terpinene than the arid samples. Female specimens from semi-arid zone accumulated higher limonene than arid counterparts. Phenological stage had minor effects. Our study provides three novel findings: (1) We examined sex, climate, and phenology together for the first time. (2) Aridity drives a clear chemotype shift in males—semi-arid males produce sabinene/terpinen-4-ol, arid males produce α/β-pinene. (3) In females, aridity causes a 3- to 10-fold limonene reduction while sesquiterpenes persist, revealing a metabolic trade-off. These findings advance understanding of how this Mediterranean shrub adjusts its chemistry to climate and provide a basis for sex- and climate-based harvesting of tailored essential oils.