Formulation and evaluation of therapeutic potential of nanoemulsion of a blend of antimicrobial oils

Abstract

This work is aimed at producing an effective self-emulsifying nanoformulation of a combination of 9 antimicrobial edible plant oils against bacterial and fungal infections. The oils are olive, eucalyptus, dill, castor, peppermint, garlic, ginger, sunflower and lemongrass oils. Oil Formulation (OF) was produced by mixing a simple Oil Blend (OB) of the oils with polysorbate 80 at the ratio of 1:4. Particle size distribution, polydispersity index and zeta potential of OF and Nanoemulsion (NE)were determined. The antimicrobial properties of OB and OF were determined using selected bacteria and fungi. The most sensitive bacteria and fungi were then selected for in vivo assay of OB and OF using albino Wistar rats (n = 5). Oral treatment began 4 days post-infection and lasted 5 days. Ciprofloxacin and Ketoconazole were used as positive controls. Safety screenings (hematological, liver function tests (LFT’s) and histological) were then conducted. The results showed that the optimal Oil/Polysorbate 80 ratio was 1:4. NE had mean particle size (151.12 ± 6.21) nm, polydispersity index (0.12) and zeta potential (-13.70 ± 4.40) mV, which after 90 days became (202.50 ± 4.11) nm, 0.09, and (35.00 ± 6.15) mV respectively. OF had mean particle size (158.00 ± 3.08) nm, polydispersity index (0.07) and zeta potential (-15.50 ± 3.01) mV, which after 90 days became (162.90 ± 6.01) nm, 0.08, and (-19.00 ± 0.00) mV respectively. Nanoemulsion formulation of the oil blend significantly (p<0.05) improved antimicrobial activity in infections of Staphylococcus aureus and Aspergillus niger and it was not toxic to the rats.