Vol. 9, Special Issue 2, Part A (2025)

Thin Layer Chromatography (TLC) analysis of ethanolic extracts from Sargassum polycystum, S. cristaefolium, and S. wightii was performed using various solvent systems to determine retention factor (RF) values and zones of inhibition (ZOI) against Pseudomonas aeruginosa. Among the extracts, S. polycystum exhibited the highest antibacterial activity with a maximum ZOI of 22 mm at an RF value of 0.65, using a benzene: ethanol (3:7) solvent system. For S. cristaefolium, a maximum ZOI of 6 mm was observed at an RF value of 0.8 in ethanol: water (4:6). Likewise, S. wightii achieved a ZOI of 10 mm at an RF value of 0.69 with ethyl acetate: ethanol (3:7). Comparative solvent analysis showed that benzene: ethanol combinations consistently enhanced antibacterial activity for S. polycystum, with ZOIs ranging from 5 mm to 22 mm. In contrast, ethanol: water mixtures yielded modest inhibition for S. cristaefolium (6 mm) and S. wightii (5 mm). TLC revealed distinct RF values for the various solvent systems, with the benzene: hexane combination showing no inhibition for any species. These findings highlight S. polycystum as a promising candidate for bioactive compound isolation and underscore the influence of solvent systems on extract potency.