<![CDATA[The increasingly alarming cases of Staphylococcus aureus resistance to amoxicillin have spurred the search for antibacterial agents that can be co-administered with antibiotics through the addition of combination agents such as butterfly pea (Clitoria ternatea L.). To obtain these bioactive compounds, Natural Deep Eutectic Solvent (NADES) can be used for optimal and environmentally friendly extraction. This study aims to determine the interaction patterns between amoxicillin and butterfly pea flowers extracted with NADES against S. aureus using the AZDAST method. The butterfly pea flowers were extracted using the Ultrasonic-Assisted Extraction (UAE) method with choline chloride-glycerol NADES. The evaluation examined the physical properties of the extract, the phytochemical profile, the total anthocyanin content, and the diameter of the inhibition zone for both agents individually and in combination (amoxicillin and NADES extract from butterfly pea flowers). The interaction analysis was conducted using various top-bottom disc arrangements (AE and EA), different extract concentrations (100%, 90%, and 80%), and different incubation times (12, 18, and 24 hours). Physical evaluation showed that the extract was a thick, oily liquid with a striking dark blue color, a density of 1.130 g/cm³, a viscosity of 6.752 cP, and a pH of 4.93. The extract was found to contain alkaloids, phenols, triterpenoids, flavonoids, and saponins. The highest total anthocyanin content was found at a 100% concentration (75.590 ± 0.193 mg/L), which is equivalent to 0.100 mg/g of flower petals. Based on AZDAST interaction testing, the combination of amoxicillin and NADES extract from butterfly pea flowers produced an antagonistic interaction according to the AZDAST criteria, which is characterized by a reduction in the inhibition-zone diameter. The viscosity of the extract (6.752 cP) is hypothesized to be one of the factors that may create a diffusion barrier, thereby inhibiting the penetration of the active compound into the agar. In addition to viscosity, the bacteriostatic properties of the extract may also interfere with the bactericidal effectiveness of amoxicillin. This study shows that the addition of NADES extract from butterfly pea flowers actually significantly reduces the diameter of the amoxicillin inhibition zone under the tested AZDAST conditions, distinguishing this physical interaction from a general biological incompatibility compared to the use of amoxicillin alone.]]>
