*Corresponding author: Tel.:#49-211-8114172; fax:#49-211-8111923.
E-mail address:passreit@uni-duesseldorf.de (C.M. Passreiter)
Biochemical Systematics and Ecology 28 (2000) 705}706
New Source Report
2-Pyrrolidineacetic Acid and Pyrrolizidine
Alkaloids from Melampodium divaricatum
Juliane Schu
K
ngel, Claus.M. Passreiter
*
Institut fu(r Pharmazeutische Biologie, Heinrich-Heine-Universita(t Du(sseldorf, Universitatsstrasse 1, Geb. 26.23, D-40225 Du(sseldorf, Germany
Received 17 June 1999; accepted 27 July 1999
Keywords: Melampodium divaricatum; Asteraceae; Heliantheae; Pyrrolidineacetic acid; Tussilagin; Isotus-silagin; Neo-tusIsotus-silagin; Neo-isotussilagin
1. Subject and source
Above ground organs ofMelampodium divaricatum(Rich. In Pers.) DC. grown from
seeds in the New York Botanical Garden, Bronx, NY, USA were collected in summer 1994. A voucher specimen (no. 147) is deposited in the herbarium of the Institut fuKr Pharmazeutische Biologie, DuKsseldorf.
2. Previous work
The atypical, non-toxic pyrrolizidine alkaloid tussilagin and its isomers have been found in only a few plants of the Asteraceae (Roeder et al., 1981,1984; Passreiter et al., 1992; Roeder et al., 1993; Sener and Etgun, 1996; Wernery et al., 1997; Passreiter, 1998). Their possible biosynthetic precursor pyrrolidine-2-acetic acid and its methyl-ester were isolated and identi"ed together with the pyrrolizidine alkaloids tussilagin, isotussilagin and their C-1 epimers neo-tussilagin and neo-isotussilagin fromArnica
species and Tussilago farfara(Passreiter, 1992). Later on both types of compounds
were also found inNeurolaena lobata(Passreiter, 1998).
3. Present study
The dried, powdered plant material (1025 g) was exhaustively extracted with dich-loromethane and then with methanol in a Soxhlet apparatus. Forty-"ve grams of the methanolic extract was puri"ed as previously described (Passreiter, 1992). The ob-tained alkaloid extract (19 mg) was analysed by GLC-MS. Pyrrolidine-2-acetic acid methyl ester as well as tussilagin, isotussilagin, neo-tussilagin and neo-isotussilagin were identi"ed by their mass spectra at their respective retention times in comparison with authentic compounds. Additionally, all compounds were identi"ed together with pyrrolidine-2-acetic acid as violet spots in TLC after detection with the reagent of Dann and Mattocks (Dann, 1960; Mattocks, 1967).
4. Chemotaxonomic signi5cance
The Asteraceae pyrrolizidine alkaloids are commonly found in the tribes Senecioneae and Eupatorieae (Mattocks, 1986). Tussilagin and isotussilagin as well as their C-1 epimers are atypical pyrrolizidine alkaloids because of the presence of a C-3 methyl group and their C-1 oxidation (Passreiter, 1992). Moreover, since we found that all methyl esters are artefacts built during the extraction process with methanol, they have to be seen asb-amino acids rather than as alkaloids. Except forTussilago,
Petasites and Iphiona, all plants containing such compounds are members of the
Heliantheae, which lack other pyrrolizidines. The genus Melampodiumis the third genus so far, from which the co-occurrence of pyrrolidine-2-acetic acid with the tussilaginic acids is known. Since 12 investigated species have been reported to contain the pyrrolizidines of the tussilagin type, it seems very likely that they are more common than previously expected.
References
Dann, A.T., 1960. Nature 186, 1051. Mattocks, A.R., 1967. Anal. Chem. 39, 443.
Mattocks, A.R., 1986. Chemistry and Toxicology of Pyrrolizidine Alkaloids. Academic Press, London. Passreiter, C.M., 1992. Phytochemistry 31, 4135.
Passreiter, C.M., 1998. Biochem. Syst. Ecol. 26, 839.
Passreiter, C.M., Willuhn, G., Roeder, E., 1992. Planta Med. 58, 556. Roeder, E., Eckert, A., Bourauel, T., 1993. Pharmazie 48, 953.
Roeder, E., Wiedenfeld, H., Hille, T., Britz-Kirstgen, R., 1984. Dtsch. Apoth. Ztg. 45, 2316. Roeder, E., Wiedenfeld, H., Jost, E.J., 1981. Planta Med. 43, 99.
Sener, B., Etgun, F., 1996. J. Fac. Pharm. Gazi Univ. 13, 171.
