Microencapsulation of <i>Ruellia tuberosa</i> L. Extracts Using Alginate: Preparation, Biological Activities, and Release

Abstract

The bioactive compounds naturally present in plants have great importance due to their biological characteristics. These substances could lose their active characteristics since they are highly unstable. Microencapsulation is one of the techniques to improve stability and protect these compounds. In this work, Ruellia tuberosa L. ethanolic extracts microcapsules were prepared using a freeze-drying method by varying pH, alginate concentration, and stirring time. The encapsulation efficiency (EE), characteristics, alpha-amylase inhibition activity, and release behavior of the microcapsules were investigated. The results highlighted that the highest encapsulation efficiency for the microcapsules was obtained at pH 6, alginate concentration of 1% (w/v), and 30 min of stirring time (51.63% EE). The microcapsules mostly had spherical shapes with a mean diameter of 197.53 μm. The alpha-amylase inhibition assay from microcapsules resulted in the IC50 value of 46.66 ± 0.13 μg/mL, demonstrating high biological activity. The bioactive substances from microcapsules were released during intervals of 30–120 min at pH values of 1.2 and 7.4. Only 3.51% of the bioactive substances were released at pH 1.2 after 120 min, compared to 55.78% at pH 7.4. Overall, this work confirms the possibility of developing plant extracts with preserved biological activity using the produced microcapsules.

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

“…Tis can help in increasing the efectiveness of treatment, reducing unwanted side efects, and allowing the use of therapies tailored to the needs of patients [22]. In microcapsules preparations, there are several factors that afect microencapsulation, including the pH of the medium, temperature, type and concentration of coating material, concentration of crosslinking compounds, and stirring time and speed [19].…”

“…Stirring is carried out at a speed of 100 rpm to function so that the drug released through the membrane is faster during the dissolution process. During the testing process, the temperature is maintained at 37 ± 5 °C because it describes the temperature of the human body [19][20][21]. Phosphate bufer saline (PBS) is commonly used in release tests because it mimics the physiological condition of the human body [35].…”

“…Tis can be infuenced by the type of polymer used in the microencapsulation process. Terefore, further research needs to be carried out regarding the combination of gum Arabic with other types of polymers; therefore, the microcapsule results obtained are more optimal [19][20][21].…”

“…Gum Arabic as a natural polymer was chosen for its low viscosity, emulsion forming ability, environmental friendliness, and nontoxicity [18]. Te microencapsulation process is infuenced by various factors, such as temperature, pH, crosslinking compound concentration, stirring time, stirring speed, and polymer concentration [19]. Optimization of microcapsules can be done by fnding the best formulation of related parameters.…”