Capsaicin, the chemical that imparts the spicy-hot quality of chili peppers, is produced by the fruits of plants belonging to the Capsicum family. 8-methyl Nonanoic acid is an immediate precursor of capsaicin as well as a by-product of capsaicin degradation.[1] Addition of 5 mM of 8-methyl nonanoic acid significantly increases the yield of capsaicin in both immobilized and freely suspended cells of C. frutescens. [2] Capsaicin has reported antimicrobial properties, however isocapric acid can act as a growth substrate in certain bacterial strains.[3]

Reference:
[1]. Kaga, H., Miura, M., and Orito, K. A facile procedure for synthesis of capsaicin. The Journal of Organic Chemistry 54, 3477-3478 (1989).
[2]. Lindsey, K., and Yeoman, M.M. The synthetic potential of immobilised cells of Capsicum frutescens mill cv. annuum. Planta 162, 495-501 (1984).
[3]. Flagan, S.F., and Leadbetter, J.R. Utilization of capsaicin and vanillylamine as growth substrates by Capsicum (hot pepper)-associated bacteria. Environmental Microbiology 8(3), 560-565 (2006).