A new stable and bioactive formulation of Geniotrigona thoracia propolis microemulsion for oral delivery

Abstract

Propolis, particularly those produced by stingless bees, is known to have a broad range of medicinal benefits due to its antioxidant properties. However, its strong and unpleasant flavour and sticky texture make it less palatable. This study aimed to improve the oral administration of stingless bee propolis extract for nutraceutical use by formulating it into a microemulsion. The microemulsion was created using a water titration method and a pseudo-ternary phase diagram to determine the optimal surfactant: co-surfactant ratio. The formulation was then characterized for its globule size, pH, viscosity, and phenolic content, and subjected to stability tests under ambient and accelerated conditions. Anti-microbial and antioxidant activity were evaluated through the disk diffusion method and the ABTS assay. The microemulsion had an average droplet size of 229.2 nm, a pH of 4.78 ± 0.18, and a viscosity of 0.149 Pa, which falls within the typical range for oral formulations. The microemulsion successfully preserved the antioxidant and antibacterial properties of the propolis extract. Long-term and accelerated stability studies indicated that the microemulsion's pH, appearance, and viscosity remained stable for up to 12 months, although there was a 24 % loss in phenolic activity over the same period. Overall, a stable and potent propolis microemulsion was successfully developed using pharmaceutical and food-grade ingredients, providing a safe and effective way to orally deliver propolis.

Keywords

• Propolis
• Microemulsion
• Antioxidant
• Antibacterial
• Functional food