ANTIBACTERIAL POTENTIAL OF POLYALTHIA LOGIFOLIA (SONN. THWAITES) SEED AND PERICARP EXTRACTS AGAINST SALMONELLA TYPHI AND ESCHERICHIA COLI

The growing issue of antibiotic resistance has made it harder and more expensive to treat common bacterial infections, especially in developing countries. This project research investigated the antibacterial potential of ethanolic extracts from the seed and pericarp of Polyalthia longifolia against two harmful bacteria: Salmonella typhi and Escherichia coli. These bacteria are known to cause diseases like typhoid fever, gastrointestinal, and urinary tract infections, and many strains have become resistant to commonly used antibiotics. The plant materials were collected, dried, and extracted using ethanol. The antibacterial effects were tested using the agar well diffusion method, and the Minimum Inhibitory Concentration (MIC) as well as the Minimum Bactericidal Concentration (MBC) were determined. Phytochemical screening was carried out to identify the active plant compounds and Gas Chromatography-Mass Spectrometry (GC-MS) was used to detect the specific bioactive components in the extracts. All analysis were carried out using standard methods. Results obtained from this study showed that both seed and pericarp extracts had antibacterial effects that increased with concentration. The seed extract was more effective against Salmonella typhi, while the pericarp extract showed better results against Escherichia coli. The MIC and MBC results confirmed that the seed extract had stronger bactericidal action against S. typhi. Phytochemical analysis revealed the presence of flavonoids, saponins, cardiac glycosides, steroids, and tannins. The GC-MS analysis identified various bioactive compounds such as oleic acid, methyl oleate, isoborneol, caryophyllene, and humulene, which are known for their antimicrobial and anti-inflammatory properties. This study supports the traditional use of Polyalthia longifolia in the treatment of infections and adds new knowledge about the antibacterial activity of its seed and pericarp. These findings suggest that the plant could serve as a natural source for developing affordable antibacterial treatments, especially in places where drug-resistant infections are becoming a serious concern. Further research is recommended to isolate specific compounds and evaluate their safety for human use.