Decoding Ocimum basilicum L.'s Medicinal Potential Through Growth Phase Profiling: A Conservation Perspective

Ocimum basilicum L. is widely documented for its medicinal properties, primarily attributed to essential oils (EOs) produced by glandular trichomes on its leaves. The present study investigates how different leaf growth phases lag, log, and stationary affect EO yield and pharmacological activity. Microscopic analysis revealed that trichome density was highest during the lag phase, while trichome size peaked was greatest in the stationary phase. EO yield was greatest in the lag phase (1.26 mL/5 g fresh weight); however, GC-MS profiling indicated that the stationary phase EO contained the highest concentrations of key bioactive compounds, notably eriodictyol and 2,5-dioxoimidazolidin-4-yl urea. Bioactivity assays demonstrated that EO from the log phase exhibited the strongest DPPH radical scavenging activity (63.87 ± 2.95%), whereas the stationary phase EO showed highest total phenolic content (982.61 ± 62.45 mg GAE/g), antioxidant capacity (0.79 ± 0.01 mg EAA/g), anti-inflammatory activity (91.89 ± 10.28%), and antidiabetic potential (95.56 ± 0.00%). Antimicrobial testing confirmed the stationary phase EO as the most potent, with the lowest MIC and MBC values against Staphylococcus aureus (6.25 and 3.125 µL/mL), Ralstonia solanacearum (12.5 and 3.125 µL/mL), and Xanthomonas oryzae (50 and 3.125 µL/mL). These findings suggest that while EO yield is highest in the lag phase, the stationary phase offers the most comprehensive pharmacological potential, making it the optimal harvest stage for medicinal applications.