Chemical. CAS 334-49-6. Formula C10H18O2. MW 170.25. Synthetic. trans-2-Decenoic acid is an unsaturated short chain fatty acid that is secreted by S. mutans. It is a novel interkingdom-signaling molecule from a Gram-positive organism that inhibits hyphal formation of the dimorphic fungus C. albicans by blocking the yeast-to-hyphal morphological transition. It might play a critical role in regulating the disintegration of aerobic granules. As in other parts of the body, Streptococci and Candida coexist in the mouth and compete for the same substrate. In a mixed species environment such as the oral cavity the quantitative and qualitative nature of the bacteria modulates the biofilm formation of C. albicans. trans-2-Decenoic acid is structurally similar to undecylenic acid, the active ingredient of Desenex, a widely used antifungal agent.