The invention relates to a novel compound isosquamocin obtained from the plant Annona squamosa; also provides insecticidal compositions containing isosquamocin, squamocin-B (9), squamocin-C (6), squamocin-G (2), squamocin-H (3), squamocin-J (7), squamocin-K (8), squamocin-L (5), squamocin-M (4), squamostatin-A (10), bullatalicin (11), bullatanocin (12) and three unidentified related compounds with retention times 5.88, 14.18 and 45.25 min. in HPLC obtained from the plant Annona squamosa and a process for the preparation of the novel compound and the insecticidal composition.