Comparison of Accumulation of Capsaicinoid Contents with Capsaicinoid Synthetase Activity at Different Developmental Stages of Capsicum annuum L.

The contents of various capsaicinoids viz. nordihydrocapsaicin (NDC), capsaicin (CAP), and dihydrocapsaicin (DHC) were determined in different parts of fruits (placenta, pericarps, seeds, and whole fruits) at different developmental stages after flowering and compared with the capsaicinoid synthetase (CS) activity. The capsaicinoid contents were very low up to 24 days after flowering (DAF), and there was a significant increase at 36 DAF in all parts of fruits. The enzyme activity of placenta increased to maximum at 24 DAF, and thereafter it gradually decreased. There were no significant amounts of enzyme activities in other parts of the fruits. In Subicho (inbred line) the content of DHC was slightly higher than CAP in all parts. of the fruits throughout the development stages of fruits, whereas in Chung Yang the CAP content was higher compared to the DHC content. The contents of total capsaicinoids in Chung Yang were also higher than Subicho. However, the crude enzyme extract obtained from Chung Yang led to the synthesis of DHC almost exclusively when the substrate, 8-methyl nonanoic acid, was added to the reaction mixture. Our results suggest that the composition of individual analogue of capsaicinoids depends upon the substrate available in the fruits.