Chemical profiling and evaluation of antioxidant, cytotoxic, fibroblast migration-promoting and DNA-protective activities of Orthosiphon pallidus Royle ex Benth. essential oil

The leaf essential oil of Orthosiphon pallidus was studied for its antioxidant, cytotoxic, fibroblast migration-promoting and DNA-protective activities. GC and GC–MS analyses identified fifteen compounds constituting 96.08% of the total oil composition, with ledene oxide-(II) (40.57%) being the major compound. A dose-dependent antioxidant potential was determined for the extracted essential oil. Cytotoxic activity against HeLa cells was observed, with an IC50 value of 102 ± 0.01 µg/mL. A concentration of 100 µg/mL essential oil showed morphological characteristics consistent with apoptosis in HeLa cells. In vitro scratch assay demonstrated that the oil at 50 µg/mL markedly enhanced the migration of chick fibroblast cells. Furthermore, the essential oil showed DNA protection against H2 O2 -induced DNA fragmentation in chick fibroblast cells. The present work reveals that O. pallidus oil is not only a free-radical scavenger and exhibits cytotoxic activity against HeLa cells, but also shows fibroblast migration-promoting and DNA-protective effects under preliminary investigation.