Impact of leaf growth stages on essential oil composition and bioactivity in lemongrass (Cymbopogon citratus)

Lemongrass (Cymbopogon citratus) essential oil plays a crucial role in managing digestion, blood cholesterol levels, inflammation, and the immune system. It also has a calming effect on the mind and body in aromatherapy. Among its constituents, β-myrcene has been reported as a potent analgesic, antidiabetic, antioxidant, anti-inflammatory, and anticancer agent. This study aimed determine the optimum leaf development stage for extracting essential oil enriched with therapeutic phytochemicals such as citral, β-myrcene, and perillaldehyde. In lemongrass, essential oil is produced by glandular trichomes. Microscopic analysis revealed the presence of capitate-stalked trichomes on the abaxial epidermis of the leaves. GC-MS analysis identified key phytochemicals such as citral and β myrcene in significant amounts across all leaf growth stages, with essential oil yields of 52.03% (lag phase), 64.26% (log phase), and 69.27% (stationary phase). Antioxidant activity was evaluated at 50 µL/mL, with the highest value (84.42 ± 0.03%) observed in the lag phase. Total phenolic content was also highest in the lag phase (1123.61 ± 16.71 µg GAE/g), whereas total antioxidant capacity reached its maximum in the stationary phase (0.7 ± 0.15).  The stationary phase exhibited the highest anti-inflammatory potential (82.12 ± 0.04%). Both the stationary and lag phases demonstrated the highest anti-diabetic potential compared to the commercial drug sitagliptin-metformin. The stationary phase exhibited the highest biofilm inhibitory potential against S. aureus (38.78 ± 0.12%) and R. solanacearum (91.00 ± 0.07%), while the lag phase showed the strongest inhibition against X. oryzae (89.57 ± 0.01%). GC-MS analysis identified citral, β myrcene,  and perillaldehyde. These findings suggest that Cymbopogon citratus is a valuable source of citral, β-myrcene, and perillaldehyde, particularly in the log and stationary phases of leaf development.