Capsaicin cinnamic acid

Yu et al. (2005) evaluated capsaicin biosynthesis in water-stressed hot pepper fruits. The concentration of capsaicin in the placenta of fruits in the water deficit treatment began to increase rapidly 10 DAF. It reached maximum at 30 DAF and was 3.84-fold higher than in the placenta of control treatment plants. In the pericarp, the concentration of capsaicin reached maximum at 50 DAF and was 4.52-fold higher than in the control treatment. PAL activity was higher in the placenta of fruits in the water deficit treatment than in the fruits of control plants at 50 DAF. At 40 or 50 DAF, cinnamic acid 4-hydroxylase (trans-cinnamate-4-monoox-ygenase) (C4H) activity was higher in plants subjected to the water deficit treatment than in control plants. Capsaicinoid synthase (CS) activity 40 DAF was 1.45- to 1.58-fold higher in fruits in the water deficit treatment than in fruits in the control treatment. 

The biological conversion of cinnamic acid via hydroxylated cinnamic acids into the C -Ci units of capsaicin (107) and norpluviine (108) has been used in a study of hydroxylation mechanisms in higher plants. ... 

When [4- H,)5- C]cinnamic acid was fed to Capsicum annuum, the derived capsaicin (107) showed a 50% tritium retention with essentially all of this label... 

The pungent principle of Capsicum, capsaicin, was isolated by Thresh et al. in 1876 [1]. Afterward, several synthetic methods for capsaicin were reported [2,3]. According to reports concerning the biosynthesis of capsaicin [4], when tritium-labeled precursors were administered to immature red pepper (C. annuum), it was demonstrated that DT-[3phenylalanine, L-[3, 5 - H2]tyrosine, [5 - H]vaniUylamine, and various cinnamic acids (labeled in the aromatic ring) were incorporated. It was also shown that the rate of uptake of phenylalanine was better than that of tyrosine. 

Bowman WR, Bruce IT, Kirby GW (1969) Biosynthetic incorporatitm of [p- C, 3,5- H2, 4- H]-cinnamic acid into capsaicin and norpluviine lack of an apparent isotope effect following an NIH shift. J Chem Soc Chem Commun 1075-1077... 

Further, phenolic phytochemicals can be targeted for antimicrobial applications. Many phenolic containing Ifuit and herbal products have shown to possess antimicrobial activity agdimsi Listeria monocytogenes (Chung etal. 1990 Hao et al. 1998 Puupponen-Pimia etal. 2001 Sa-gun et al. 2006). Recent research with purified compoimds from natural products has shown that phenolic phytochemicals such as cinnamic acid, cinnamaldehydes, coumarins, capsaicin, and tannins have anti-7/. pylori activity (Bae et al. 1999, 1998 Jones et al. 1997) when caffeic and gallic acid have Staphylococcus aureus inhibitory activity (Kwon etal. 2007). 

Alejo and Garciglia (1992) conducted studies relating PAL activity and capsaicin-precursor compounds in p-fluorophenyla-lanine-resistant and -sensitive variant cells of chilli pepper. PFP (p-fluorophenylalanine)-resistant cells exhibited the highest PAL activity and free phenylalanine and phenolic compound concentrations, even after a minimum of nine subcultures (15 days each), in the absence of PFP, indicating that the selected trait was stable. PFP-resistant cells accumulated greater amounts of capsaicin precursors (cinnamic, caffeic and ferulic acids) than either the non-selected cells or the sensitive cell line. p-Coumaric acid was not detected... 

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