Ultrasonication induced osthole loaded nanoemulsion: A medium with superior antioxidant activity, antimicrobial activity and improved cell viability against caco-2 cells

Osthole (OST) is a naturally occurring bioactive molecule mainly found in the medicinal plants; Cnidium monnieri and Angelica pubescens, which is known to has its exceptional therapeutic properties due to its unique structure and strong antioxidant potential. Herein, we prepared OST loaded oil (Corn/Lemon oil (1:1)) in water nano -emulsion (OST-NEm) using low cost and highly effective ultrasonication emulsification method. The obtained NEm was clear, spherical droplet-shaped with an average size of 65.32 nm. NEm displayed good storage stability for 60 days; Moreover NEm stability under variable salt (NaCl) concentration (100-500 mM) and different pH (2-7.4) conditions was also optimized. The toxicity of the NEm was reduced by using a biocompatible stabilizer D-alpha-Tocopherol polyethylene glycol 1000 succinate (TPGS). NEm exhibits 79.89% OST encapsulation efficiency and 64% cumulative release at pH 7.4. The cell viability studies of both pure and OST-NEm were tested on Caco-2 cells and confirmed no toxicity up to a concentration of 160 mu M. The antioxidant potential of both pure OST and OST-NEm was measured with DPPH radical and the results were compared with the control butylated hy-droxy toluene (BHT). The IC50 values for the OST, OST-NEm, pure NEm and BHT were found to be 17 +/- 0.7, 22 +/- 2.0, 27 +/- 0, 15 +/- 1.0 mu M, respectively. Efforts have also been made to study the interactions between OST and riboflavin via photoluminescence spectroscopy to understand the location of the OST in NEm.

Automated summary

In this study, OST-loaded oil in water nano-emulsion (OST-NEm) was prepared using a low-cost and highly effective ultrasonication emulsification method. The NEm showed good storage stability and stability under different salt concentrations and pH conditions. The cell viability studies confirmed the lack of toxicity of OST-NEm up to a concentration of 160 muM. OST and OST-NEm exhibited higher antioxidant potential compared to the control substance BHT.