DEVELOPMENT AND CHARACTERIZATION OF PICKERING EMULSION OF BASIL LEAF EXTRACT AND IN VITRO STUDY OF THE OXIDATIVE STRESS REDUCTION EFFECT ON RAW 264.7 CELL LINE

• Main Author: Nur Viviani, Rafiqah
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/77999
• Institution: Institut Teknologi Bandung

Background and purpose: Basil (Ocimum americanum L.) is a family medicinal plant (TOGA) that contains various phenolic compounds and has been known to have benefits as a natural antioxidant. This study aims to develop a Pickering emulsion formula stabilized by basil leaf extract at the oil/water interface to produce better antioxidant activity and oxidative stress reduction effect. Methods: Basil leaf was extracted using a combination of maceration and sonication methods with 96% ethanol and 1% citric acid at a ratio of 60:40. Optimization of the Pickering emulsion preparation method was carried out. Then, the Pickering emulsions were fabricated using components, i.e., basil leaf extract, humectant (hexylene glycol and glycerin), Tween 20, sunflower oil, and urea or arginine. The study focused on Pickering emulsion added with urea (PEMU), arginine (PEMA), and, as a comparison, their bases (BSU and BSA). Pickering emulsions were characterized, and stability was studied for 28 days. In addition, reactive oxygen species (ROS) and nitric oxide (NO) inhibition studies were performed on H2O2- or lipopolysaccharide (LPS)-stimulated RAW 264.7 cells. Results: Optimizing the emulsification method results showed that the combination of ultra-turrax, bath, and probe sonicator produced the smallest globule size. Pickering emulsion was successfully fabricated, confirmed through microstructural observations with a polarizing light microscope, confocal laser scanning microscope (CLSM), and transmission electron microscope (TEM). The globule sizes of PEMU and PEMA were 170.97 ± 6.14 nm and 196.17 ± 1.25 nm, respectively. Antioxidant activity increased in extracts formulated into PEMU and PEMA by 48.61% and 75.51%, respectively. PEMA showed better antioxidant activity, ROS inhibition, and was confirmed to have a positive charge. On the other hand, PEMU showed better cell viability, globule size, and NO inhibition. Conclusion: Basil leaf extract has the potential to stabilize Pickering emulsions through PEMU and PEMA formulations with increased antioxidant activity and reduced oxidative stress activity.