Acmella radicans (Asteraceae) produces at least seven alkamides, most with either an isobutyl- or phenylethyl group as the amine moiety. These moieties suggest that the amino acids valine and phenylalanine are the biosynthetic precursors of these alkamides. On the basis of labeled feeding experiments using either L-[2H8]valine or L-[2H8]phenylalanine we present evidence for the involvement of these two amino acids in the biosynthesis of (2E,6Z,8E)-N-isobutyl-2,6,8-decatrienamide (affinin) (1), (2Z,4E)-N-(2-phenylethyl)-2,4-octadienamide (2), (2E)-N-(2-phenylethyl)-nona-2-en-6,8-diynamide (3), and 3-phenyl-N-(2-phenylethyl)-2-propenamide (4). Alkamides were isolated from young A. radicans plants and analyzed by gas chromatography-mass spectrometry (GC-MS). Additionally, in cell free in vitro experiments based on isobutyl and phenylethylamide biosynthesis, using a colorimetric assay and GC-MS, valine and phenylalanine decarboxylase activities were assayed in the soluble extract of A. radicans leaves.
Rios-ChávezP., Ramírez-ChávezE., Armenta-SalinasC., Molina-TorresJ. (2003) Acmella radicans var. radicans: in vitro culture establishment and alkamide content. In Vitro Cellular & Developmental Biology Plant, 39, 37–41.
2.
AcreeF., JacobsonM., HallerH.J. (1945) An amide possessing insecticidal properties from the roots of Erigeron affinis DC. Journal of Organic Chemistry, 10, 236–242.
3.
Molina-TorresJ., Salgado-GarcigliaR., Ramírez-ChávezE., del-RioR.M. (1996) Purely olefinic alkamides in Heliopsis longipes and Acmella (Spilanthes) oppositifolia. Biochemical Systematics and Ecology, 24, 43–47.
4.
KadirH.A., ZakariaM.B., KechilA.A., AzirunM.S. (1989) Toxicity and electrophysiological effects of Sphilanthes acmella Murr. extracts on Periplaneta americana L. Pesticide Science, 25, 329–335.
5.
Molina-TorresJ., Salazar-CabreraC.J., Armenta-SalinasC., Ramírez-ChávezE. (2004) Fungistatic and bacteriostatic activities of alkamides from Heliopis longipes roots: Affinin and reduced amides. Journal of Agricultural and Food Chemistry, 52, 4700–4704.
6.
JohnsT., GrahamK., TowersG.H.N. (1982) Molluscicidal activity of affinin and other isobutylamides from the Asteraceae. Phytochemistry, 21, 2737–2738.
7.
Gutierrez-LugoM.T., Barrientos-BenitezT., LunaB., Ramirez-GamaR.M., ByeR., LinaresE., MataR. (1996) Antimicrobial and cytotoxic activities of some crude drug extracts from Mexican medicinal plants. Phytomedicine, 2, 341–347.
8.
Molina-TorresJ., Garcia-ChávezA., Ramirez-ChávezE. (1999) Antimicrobial properties of alkamides present in flavouring plants traditionally used in Mesoamerica: affinin and capsaicin. Journal of Ethnopharmacology, 64, 241–248.
9.
Ramírez ChávezE., López-BucioJ., Herrera-EstrellaL., Molina-TorresJ. (2004) Alkamides isolated from plants promote growth and alter root development in Arabidopsis. Plant Physiology, 134, 1–11.
10.
HernándezI., MárquezL., MartínezI., DieguezR., DelporteC., PrietoS., Molina-TorresJ., GarridoG. (2009) Anti-inflammatory effects of ethanolic extract and alkamides-derived from Heliopsis longipes roots. Journal of Ethnopharmacology, 124, 649–652.
11.
Müller-JakicB., BreuW., PröbstleA., RedK., GregerH., BauerR. (1994) In vitro inhibition of cyclooxygenase and 5-lipoxygenase by alkamides from Echinacea and Achillea species. Planta Medica, 60, 37–40.
12.
StöhrJ.R., XiaoP.G., BauerR. (1999) Isobutylamides and a new methylbutylamide from Piper sarmentosum. Planta Medica, 65, 175–177.
13.
CliffordL.J., NairM.G., RanaJ., DewittD.L. (2002) Bioactivity of alkamides isolated from Echinacea purpurea (L.) Moench. Phytomedicine, 9, 249–253.
14.
ChenY., FuT., TaoT., YangJ., ChangY., WangM., KimL., QuL., CassadyJ., ScalzoR., WangX. (2005) Macrophage activating effects of new alkamides from the roots of Echinacea species. Journal of Natural Products, 68, 773–776.
15.
GregerH. (1984) Alkamides: Structural relationships, distribution and biological activity. Planta Medica, 50, 366–375.
PedrasM.S.C., Okinyo-OwitiD.P., ThomsK., AdioA.M. (2009) The biosynthetic pathway of crucifer phytoalexins and phytoanticipins: De novo incorporation of deuterated tryptophans and quasi-natural compounds. Phytochemistry, 70, 1129–1138.
NagashimaM., NakataniN. (1992) LC-MS analysis and structure determination of pungent alkamides from Spilanthes acmella L. flowers. Lobensmitel-Wissenschaft und-Technologie, 25, 417–421.
20.
MartinR., BeckerH. (1985) Amides and other constituents from Acmella ciliata. Phytochemistry, 24, 2295–2300.
21.
Ochoa-AlejoN., Salgado-GarcigliaR. (1992) Phenylalanine ammonia-lyase activity and capsaicin-precursor compounds in p-fluorophenylalanine-resistant and –sensitive variant cells of chili pepper (Capsicum annuum). Physiologia Plantarum, 85, 173–179.
22.
TangL., ZhangY.X., HutchinsonC.R. (1994) Amino acid catabolism and antibiotic synthesis: Valine is a source of precursors for macrolide biosynthesis in Streptomyces ambofaciens and Streptomyces fradiae. Journal of Bacteriology, 176, 6107–6119.
KarppinenK., HokkanenJ., TolonenA., MattilaS., HohtolaA. (2007) Biosynthesis of hyperforin and adhyperforin from amino acid precursors in shoot cultures of Hypericum perforatum. Phytochemistry, 68, 1038–1045.
25.
VarmaR.J., GaikwadB.G. (2008) Spectrophotometric method for estimation of aliphatic primary amines in biological samples. World Journal of Microbiology Biotechnology, 24, 573–576.
26.
MurashigeT., SkoogF. (1962) A revised medium for rapid growth and bioassays with tobacco tissue cultures. Physiology Plant, 15, 473–497.
27.
ChattopadhyayM.K., GuptaS., SenguptaD.N., GhoshB. (1997) Expression of arginine decarboxylase in seedling of indica rice (Oryza sativa L.) cultivars as affected by salinity stress. Plant Molecular Biology, 34, 477–483.
28.
GargR.P., MaY., HoyJ.C., ParryR.J. (2002) Molecular characterization and analysis of the biosynthetic gene cluster for the azoxy antibiotic valanimycin. Molecular Microbiology, 2, 505–517.
29.
BradfordM. (1976) A rapid and sensitive method of the quantitation of microgram quantities of protein utilizing the principle of protein-dye binding. Analytical Biochemistry, 72, 248–254.
