Abstract: Phytochemical investigation of the leaves of C. petersiana afforded two new compounds (4 α-Acetyl-3,7-dihydroxy-3,6-dimethyldihydronaphtalenone and 5-Hydroxy-7-acetonyl-2-methylenechromone), in addition to common terpenes as sitosterol, stigmasterol glucoside. The crude extract and the new compounds were tested for antisalmonellal activity. The structures of the compounds were determined from comprehensive NMR studies, including 1H, 13C, DEPT, COSY, HMQC, HMBC, MS, IR and comparison with literature data.