Objective: Recent advancements in scientific understanding of free radicals have stimulated progress in medicine. Antioxidants are known to neutralize free radicals by giving up electrons. The current research was carried out to explore the antioxidant capabilities and phytochemical composition of a synergy-based combined extracts of Spondias mombin, Spilanthes filicaulis, and Piper guineense, with the goal to determine the optimal ratio for the most effective antioxidant activity, suitable for herbal product development.Material and methods: Combined extracts H1 and H2 were obtained through aqueous maceration of S. mombin leaves, S. filicaulis plants, and P. guineense fruits. Antioxidant activity of combined extract was evaluated in 2, 2 - diphenyl-1-picrylhydrazyl (DPPH) and ferric ion reducing power (FRAP) assay. Evaluations included total phenolic and flavonoid content determination. Furthermore, the phytochemical constituents were determined using Gas Chromatography-Mass Spectrometry (GC-MS).Results: The combined-extract H1 exhibited better free radical scavenging ability in DPPH (IC50 = 72.87 ± 0.63 µg/mL) than H2 (IC50 = 150.2 ± 1.08 µg/mL). The FRAP assay results revealed its highest reducing power (12.385± 0.002 AAE/mg/g) compared to H2 (11.657±0.002 AAE/mg/g). Additionally, H1 had higher of both total phenolic and flavonoid content. GC-MS profiling revealed 28 compounds within H1 and 17 compounds within H2.Conclusion: This study demonstrated that the combined extract H1 has significant antioxidant potential, with consistently positive results across all conducted assays. It contains a variety of phytochemical constituents, mainly phenolic and flavonoids that could be explored in pharmaceutical industries to develop antioxidant agents.