Evaluation of Physicochemical and Antifungal Properties of Microemulsions of Lemongrass Oil (Cymbopogon citratus) and Clove Oil (Syzygium aromaticum)

doi.org/10.26538/tjnpr/v5i2.13

Abstract

Onychomycosis is a nail infection caused by the fungus Trychophyton rubrum. Current treatments are sometimes ineffective due to poor patient compliance during the long duration therapy, besides their undesired side effects. Owing to the potency of some natural ingredients as antifungals, topical herbal formulations may be an alternative treatment as they can be applied directly to the infected nails providing an intra-dermal action with minimum side effects. This study aims to develop microemulsion formulations of lemongrass oil (Cymbopogon citratus) and clove oil (Syzygium aromaticum) at a concentration of 3%, each followed by an in-vitro antifungal activity evaluation against T. rubrum. The formula consists of Virgin Coconut Oil (oil phase), tween 80 – polyethylene glycol 400 (surfactant-cosurfactant), and water (aqueous phase) at various compositions plotted on a pseudo-ternary phase diagram as a platform for screening of the best microemulsion compositions. Only six from fifty-four selected compositions in the diagram (MA1, MB1, MC1, MD1, ME1 and MF1) produced transparent and homogenous solutions as an indication of microemulsion. They were subjected to evaluation procedures, including determination of interfacial tension, physical stability, transmittance, relative density, droplet size, pH, and viscosity. In vitro antifungal activity test of the six formulations against T. rubrum was conducted by disc diffusion method using Potato-Dextrose Agar. The inhibition zone of the antifungal test of the six formulations was in the range 7.05±0.07 to 8.85±0.21 mm, compared to itraconazole (positive control) with inhibition zone of 7.70±0.14 mm. The MD1, ME1 and MF1 formulations showed a better inhibition diameter than the positive  control.