Effectiveness of Using Gum Arabic for Co-Microencapsulation of Ruellia tuberosa L. and Tithonia diversifolia Extracts as Encapsulating Agent and Release Studies.

This study used a combination of leaves extracts from Ruellia tuberosa L. and Tithonia diversifolia plants encapsulated using gum Arabic. The selection of leaves in medicinal plants because they are rich in bioactive compounds that provide health benefits. The encapsulation technique was microencapsulation through freeze-drying, since the nanoencapsulation for the plant extracts is unlikely to be conducted due to their large particle sizes. The resulting microcapsules were then tested their biological activities in vitro. Several conditions affect microcapsules' production, including pH, gum Arabic concentration, and stirring time were assessed. The optimum conditions were chosen based on the highest encapsulation efficiency. The results showed that the optimum microcapsules preparation was achived at pH 5, gum Arabic concentration of 4% (w/v), and stirring time of 60 min with an encapsulation efficiency of 84.29%. The in vitro assays include inhibition of alpha-amylase and antioxidant activities, resulted in the respective IC₅₀ values of 54.74 μg/mL and 152.74 μg/mL. Releases of bioactive compounds from the microcapsules were investigated under pH 2.2 and pH 7.4 from 30 to 120 min. Results indicated a release of 43.10% at pH 2.2 and 42.26% at pH 7.4 during 120 min, demonstrating the controlled release behavior of the encapsulated bioactive compounds; nonetheless, their release behavior was not pH-dependent. This study confirms that microencapsulation has an important role in the development of plant extracts with maintained biological functions as well as maintaining their stability.