Development of Synergy-Based Combination of Methanolic Extract of Andrographis paniculata and Berberis aristata Against E. coli and S. aureus.

This study evaluates the antibacterial activity and phytochemical characterizations of Andrographis paniculata extract (APE) and Berberis aristata extract (BAE). The stem of Andrographis paniculata (AP) and root of Berberis aristata (BA) were extracted with methanol. The results confirmed that APE and BAE possess high phenolic and flavonoid content. The antioxidant activity of the APE and BAE showed an elevated potential to scavenge DPPH (2,2-diphenyl-1-picrylhydrazyl) radicals with IC50 of 95.03 μg/mL and 256.26 μg/mL, respectively. A total of 35 and 32 metabolites in APE and BAE, respectively, were identified through mass spectrometry analysis, whereas 17 and 12 metabolites in APE and BAE, respectively, were detected through high-performance thin-layer chromatography (HPTLC) fingerprinting profiling. Antibacterial activity of the extracts was performed by the well diffusion and microdilution method, and the findings showed that APE and BAE had antibacterial activities against E. coli and S. aureus. The growth curve and time-kill study showed that the extracts had a bacteriostatic effect. A combination study with the standard drug was carried out using the microdilution checkerboard method in which most of the combinations showed synergistic interactions. The findings of this study have shown that APE and BAE are good sources of antibacterial compounds and can be used for treating infectious diseases caused by E. coli and S. aureus.