Stability of capsinoid in various solvents

To investigate the stability of capsinoid in solvents, the quantitative cha nge of vanillyl nonanoate, a synthetic model capsinoid, in various solvents was measured by HPLC. Vanillyl nonanoate was stable in nonpolar solvents, whereas it was labile in polar solvents. In particular, vanillyl nonanoate tended to decompose in protic solvents such as alcohol and water. Structure s of the decomposition products from vanillyl nonanoate in methanol and eth anol were determined to be methyl and ethyl vanillyl ethers, respectively. To clarify the decomposition mechanism of capsinoid, six analogues of vanil lyl nonanoate were tested. The stability of the analogues in organic solven ts suggested that the hydroxyl group in the para-position of the benzene ri ng largely contributes to the decomposition of capsinoid.