Phytochemical Profiling and Antibacterial Activity of Aphanamixis polystachya Seed Extracts against Soil Bacterial Isolates

The present study investigated the growth response of soil bacteria towards four selected agents: distilled water, methanol, the crude and methanolic extracts of Aphanamixis polystachya seeds. Soil samples collected from two sites yielded Gram-positive, rod-shaped bacterial isolates, exhibiting diverse colony morphologies and moderate colony forming unit (CFU) counts. Antibacterial assays revealed that while distilled water and crude seed extracts exhibited no inhibitory effects, the methanolic extract of the seeds demonstrated significant antibacterial activity, with a maximum zone of inhibition measuring 4.5 mm. Phytochemical profiling indicated the presence of eight bioactive compounds, including alkaloids, flavonoids, phenolic compounds, steroids, quinones, tannins, triterpenoids and cardiac glycosides, predominantly in the methanolic extract. These findings highlight the importance of solvent selection in bioactive compound extraction and suggest the potential of A. polystachya seeds as a source of natural antibacterial agents against soil-borne bacteria.