Formulation and Characterization of Caesalpinia decapetala Seed Oil Nanoemulsion: Physicochemical Properties, Stability, and Antibacterial Activity

Nanoemulsions contain acceptable O/W or W/O dispersions, with droplet sizes ranging from 100 to 500 nm. In the current study, we formulated O/W nanoemulsion using Caesalpinia decapetala seed oil, Tween 20, and Tween 80 surfactant through ultrasonic and spontaneous emulsification methods. C. decapetala is a climbing shrub thorny tree. C. decapetala seed oil contains different chemical constituents predominantly unsaturated fatty acid and has antibacterial, and antioxidant activity. Then physicochemical properties of the prepared nanoemulsion were evaluated using different methods. As a result, the prepared nanoemulsion came to be 132.56 ± 0.49 - 290.033 ± 1.95nm average particle size, 0.028 ± 0.038 - 0.3006 ± 0.04 polydispersive index, -32.27 to -58 mV zeta potentials, 1.334 - 1.380 refractive index, 75 - 90.81% percent of transmittance, 4.38 - 6.5 pH value, 3.922 – 5.2468 mPa.s viscosity value with spherical shape, excellent physical stability and also had good oxidative stability of the molecule. Subsequently, gram-positive and gram-negative bacterial strains were employed to assess the nanoemulsion's antibacterial efficacy. Therefore, the results indicate that C. decapetala seed oil nanoemulsion has excellent antibacterial activity on both gram-positive and gram-negative bacteria strains. This nanoemulsion that was formulated using Tween 80 had higher inhibition zones like 13.5,13, 12, and 11 mm than the other methods on S.aureus E.coli S.pyogenes P. aeruginosa resepectively. Generally, smaller particle size, polydispersive index, stable surface charge, and low value of viscosity indicate that formulated nanoemulsion had better stability and bioavailability activity for antibacterial activity.