^1H-NMR and Mass Spectral Study of a D-Enriched Acetylenic Norlignan, Asparenyol, form Cultured Cells of Asparagus officinalis

A suspension of cultured cells of Asparagus officinalis fed L-phenyl-D5-alanine-2, 3, 3-D3 (D8-phe) and DL-phenylalanine-3, 3-D2 (D2-phe) yielded D-enriched asparenyol, 4-[5-(4-methoxyphenoxy)-3-penten-1-ynyl]phenol(1). A 1H-NMR spectral study indicated that incorporation of deuterium atoms into the chains of the products was restricted to the C-9 position. The molecular ion regions of the MS of D-enriched metabolites, 1(D8-200), 1(D8-100) and 1(D8-50), obtained from feeding experiments using 200 mg, 100 mg and 50 mg of D8-phe, respectively, coincided with the theoretical spectra. This confirmed that a single phenylalanine molecule supplies the nine carbon atoms in the -CH=CH-CH2-O-C6H4-O- moiety of 1. The biosynthetic sequence forming 1 as a norlignan class of metabolite is considered.