Stereochemical Diversity in Lignan Biosynthesis ofArctium lappaL.

Abstract

The stereochemistry of lignan biosynthesis in Arctium lappa L. is regulated organ-specifically. (+)-Secoisolariciresinol [81% enantiomeric excess (e.e.)] was isolated from A. lappa petioles. In sharp contrast, lignans whose predominant enantiomers have the opposite absolute configuration to that of (+)-secoisolariciresinol [i.e., (-)-matairesinol (>99% e.e.), (-)-arctigenin (>99% e.e.), and (-)-secoisolariciresinol (65% e.e.)] were isolated from seeds of the species. The stereochemical diversity of secoisolariciresinol was demonstrated with enzyme preparations from A. lappa petioles and seeds. Thus, a petiole enzyme preparation catalyzed the formation of (+)-pinoresinol (33% e.e.), (+)-lariciresinol (30% e.e.), and (+)-secoisolariciresinol (20% e.e.) from achiral coniferyl alcohol in the presence of NADPH and H202, whereas that from ripening seeds catalyzed the formation of (-)-pinoresinol (22% e.e.), (-)-lariciresinol (>99% e.e.), and (-)-secoisolariciresinol (38% e.e.) under the same conditions. In addition, the ripening seed enzyme preparation mediated the selective formation of the optically pure (>99% e.e.) (-)-enantiomer of matairesinol from racemic (+/-)-secoisolariciresinols in the presence of NADP. These results indicate that the stereochemical mechanism for lignan biosynthesis in A. lappa varies with organs, suggesting that multiple lignan-synthesizing isozymes are involved in the stereochemical control of lignan formation in A. lappa.

A lignan O-methyltransferase catalyzing the regioselective methylation of matairesinol in Carthamus tinctorius

“…β-Peltatin 6-O-methyltransferase was isolated and characterized from cell suspension cultures of Linum nodiflorum by Kranz and Petersen (Kranz and Petersen 2003). Members of the tribe Cynareae in the family Asteraceae such as Carthamus tinctorius (safflower) are enriched with 4′-O-methyldibenzylbutyrolactone lignans such as arctigenin and arctiin (Figure 2), especially in their seeds (Hänsel et al 1964;Nishibe et al 1972;Palter and Lundin 1970;Palter et al 1971;Palter et al 1972;Sakakibara et al 2007;Suzuki et al 2002b;Umezawa 2003b). Our survey of lignans in C. tinctorius indicated that matairesinol and arctigenin (or their glucosides) started to accumulate several days after flowering (DAF) ).…”

Antioxidant Activity of Butane Type Lignans, Secoisolariciresinol, Dihydroguaiaretic Acid, and 7,7′-Oxodihydroguaiaretic Acid

“…1). Since the biosyntheses of lignans as an enantiomeric mixture have been reported, 6) optically pure synthesized lignans were used in this research. The lipoprotein-antioxidant activity of isolated 2 0 -hydroxy dihydroguaiaretic acid 7) and lipoxygenase inhibition of nordihydroguaiaretic acid (NDGA) have been reported.…”

Structure–Plant Growth Inhibitory Activity Relationship of Lariciresinol

“…1,42.6,50.4,55.9,59.0,70.6,72.7,82.7,108.4,111.3,114.2,114.4,118.8,121.3,132.4,134.8,143.9,145.0,146.5,146.6;MS (EI) 7,43.2,48.8,55.87,55.89,58.6,72.3,73.1,82.1,109.0,111.2,113.9,114.3,119.2,121.3,131.6,132.0,143.9,144.6,146.1,146.4;MS (EI) 3,44.4,53.4,55.86,55.88,59.0,72.8,83.8,108.6,111.2,114.1,114.2,119.1,121.4,132.2,134.2,143.9,144.9,146.4,146.5;…”