The present invention provides S-(-)-tulipalin B, acetylated-S-(-)-tulipalin B and an antibacterial composition comprising the same. The active compound tulipalin B and composition of the present invention exhibit superior and stable antibacterial activity over a broad range of temperature and pH, as compared to conventional natural antibacterial agents used in related industries. Therefore, the composition and active compound of the present invention can be widely used as a natural food preservative and/or an antibacterial agent in a variety of fields such as foods, pharmaceuticals, cosmetics, fibers, livingwares, and the like.