Essential oils from the leaves of <i>Mitrephora calcarea</i> Diels ex Weeras. &amp; R.M.K.Saunders and <i>M. maingayi</i> Hook.f. &amp; Thomson: Chemical analysis, biological activity, and molecular docking

The current study first describes the chemical profile of the leaf essential oils from two Annonaceous plants. Hydro-distillation and sequential GC-FID/ MS analyses resulted in the identification of (<i>E</i>)-caryophyllene (29.35%), γ-curcumene (22.91%), β-pinene (12.37%), and bicyclogermacrene (6.16%) as the major compounds in <i>Mitrephora calcarea</i> leaf essential oil. In the meantime, <i>M. maingayi</i> leaf essential oil was associated with the appearance of the main compounds (<i>E</i>)-caryophyllene (31.94%), (<i>E</i>)-β-ocimene (12.23%), α-humulene (9.00%), γ-elemene (6.82%), germacrene B (7.57%), and δ-cadinene (5.79%). These two essential oils had moderate cytotoxicity towards A549 cancer cells with IC₅₀ values of 56.85±0.35 - 59.16±0.43 μg/mL. <i>M. calcarea</i> leaf essential oil showed strong antimicrobial activity against the yeast <i>Candida albicans</i> ATCC 10231 with a MIC value of 32 μg/mL. Both essential oils also strongly exhibited mosquito larvicidal activity against the third-instar stage of <i>Aedes aegypti</i> and <i>Culex quinquefasciatus</i> larvae with 24-h and 48-h LC₅₀ values of less than 50 μg/mL. The molecular docking study highlighted (<i>E</i>)<i>-</i>caryophyllene to exert the highest binding affinity for the target protein <i>C. albicans</i> sterol 14α demethylase (CYP51), while bicyclogermacrene demonstrated a strong affinity for <i>Cx. quinquefasciatus</i> odorant-binding protein (OBP). The key interactions driving these affinities were predominantly hydrophobic.