Influence of 8-Methyl-nonenoic Acid on Capsaicin Biosynthesis in In-Vivo and In-Vitro Cell Cultures of Capsicum Spp.

Abstract

Capsaicin is a bioactive molecule synthesized by enzymatic (putative capsaicin synthase) condensation of vanillylamine, a phenyl propanoid intermediate with 8-methyl-nonenoic acid, a fatty acid derivative from leucine/valine pathway. Analysis of levels of 8-methyl-nonenoic acid and phenyl propanoid intermediates in high, medium, and low pungent Capsicum genotypes revealed that the 8-methyl-nonenoic acid pool plays a crucial role in determining the efficacy of capsaicin levels. Cerulenin-mediated inhibition of 8-methyl-nonenoic acid synthesis decreased the capsaicin biosynthesis in Capsicum cell suspension cultures. Similarly amino oxy acetate inhibited vanillylamine synthesis but failed to reduce capsaicin production. The mRNA transcript analysis of keto acyl synthase (KAS), a crucial enzyme involved in 8-methyl-nonenoic acid and an amino transferase (AMT), involved in vanillylamine biosynthesis was studied. The mRNA transcript analysis revealed the progressive developmental expression of KAS gene in the placenta during the ontogeny of the fruit, whereas AMT transcripts levels did not show significant differences. Hence, the study demonstrates the influence of 8-methyl-nonenoic acid and its possible regulatory role in capsaicin biosynthesis in Capsicum spp.

Characterization of Different Capsicum Varieties by Evaluation of Their Capsaicinoids Content by High Performance Liquid Chromatography, Determination of Pungency and Effect of High Temperature

“…Despite our understanding of capsaicinoids biosynthesis, we know very little about the capsaicinoids-accumulation behavior of peppers under different environmental conditions. Phenolic intermediates can influence the biosynthesis of capsaicinoids [50]; for instance, it has been demonstrated that 8-methylnonenoic acid could have an important regulatory role in the capsaicinoids biosynthesis pathway [51]. The synthesis of flavonoids may converge with the capsaicinoids pathway during pepper maturation [52].…”

Identification of Optimal Reference Genes for Normalization of qPCR Analysis during Pepper Fruit Development

“…Fortunately, the regulatory mechanism of capsaicin biosynthesis has been clearly elucidated (Curry et al, 1999; Perucka and Materska, 2001; Narasimha Prasad et al, 2006). Moreover, CaPAL is one of the key genes which regulates capsaicin accumulation in pepper fruit (Curry et al, 1999; Perucka and Materska, 2001).…”

Capsaicin Synthesis Requires in Situ Phenylalanine and Valine Formation in in Vitro Maintained Placentas from Capsicum chinense

“…Our results show that affecting the accumulation of Val and/or that of Phe in placentas also reduces CAP accumulation. In cell suspensions, both Val [13] and Phe [30] availability have been shown to be limiting factors for CAP accumulation. However, CAP amounts in non-differentiated cultures are frequently low, perhaps due the lack of the specialized structures required for its accumulation [31].…”

“…It has been demonstrated that both amino acids have been shown to be required to increase CAP synthesis in non-differentiated cell cultures [12,13]. However, under normal conditions, both Phe (2–22 nmol·g −1 FW; [14]) and Val (2–9 nmol·g −1 FW; [14]) cell pools in C. chinense placentas are very low, suggesting that their synthesis must be triggered only when it is required to satisfy specific demands [14].…”