Bio-functional nanoemulsion of Plectranthus amboinicus Essential oil: Molecular insights into obesity control

This study explored the bioactive potential of Plectranthus amboinicus essential oil (PAEO) and its nanoemulsion (PANE). PAEO, extracted via hydro-distillation, contained 71.3 % carvacrol (GC–MS). PANE exhibited a Z-average diameter of 200.3 nm, ζ-potential of -9.54 mV, and FT-IR-confirmed encapsulation. Although PAEO showed larger antimicrobial zones (20–23 mm) against S. aureus and E. coli , PANE demonstrated lower MICs (96 μ L/mL vs. >96 μ L/mL). PANE was better than PAEO in controlling obesity, with enhanced lipid peroxidation inhibition ( IC₅₀ : 147.91 vs. 189.47 μ L) and DPPH radical scavenging ( IC₅₀ :115.47–140.21 vs. 203.38 μ L). PANE ( IC₅₀ : 350.00 μ L) showed reduced lipase inhibition versus crude form (163.23 μ L) due to encapsulation. MTT assays revealed PANE’s enhanced bioavailability ( IC₅₀ : 1 ± 0.01 μ L PANE vs. 2.5 ± 0.01 μ L PAEO), supporting adipocyte gene modulation. PAEO induced stronger PRDM16 up-regulation (5.03-fold, p = 0.001), a key adipocyte browning marker, but pungency and instability limits therapeutic utility. In contrast, PANE, a stable nanoemulsion, achieved significant PRDM16 activation (3.91-fold, p = 0.006) without stability concerns, positioning it as a viable phytochemical alternative to Orlistat in obesity management.