Matairesinol from

Matairesinol (from Podocarpus spicatus, or New Zealand "matai", and many different woods)... 

From bark, valuable chemicals, such as betulinol, can be obtained [5]. Betulinol is used as a health-promoting agent. Recently Holmbom et al. [27, 28] discovered that hydroxymatairesinol (HMR) is concentrated in the stems and knots of Norway spruce Picea abies). It can be extracted and transformed catalytically to matairesinol (MAT), which is an antioxidant and anticarcinogenic agent [29-31]. 

For example, yatein and podophyllotoxin are biosynthesized from matairesinol (Fig. 12.4) [11, 13, 49]. This conversion involves 5-hydroxylation of one of the 3-methoxy-4-hydroxylphenyl (guaiacyl) moieties of matairesinol to give rise to 5-hydroxymatairesinol (thujaplicatin) followed by dual methylation at the 4- and 5-hydroxyls, giving rise to a 3,4,5-trialkoxyphenyl moiety (Fig. 12.4) [11, 13,49],... 

On the other hand, biosynthetic pathways that do not involve the conversion from coniferyl alcohol to matairesinol have been proposed for lignans composed of two syringyl (3,5-dimethoxy-4-hydroxyphenyl) groups (+)-syringaresinol formation in Liriodendron tulipifera [50] and (H-)-lyoniresinol biosynthesis in Lyonia ovalifolia var. elliptica [51]. Enantioselective coupling of two sinapyl alcohol units was proposed for the selective formation of (H-)-syringaresinol [50], On the other hand, a non-enantioselective dimerization of sinapyl alcohol was proposed for (+)-lyoniresinol biosynthesis and the enantioselectivity in the biosynthesis was ascribed... 

However, the enantiomeric control by DPs does not lead to the production of optically pure pinoresinol in plants, because the enantiomeric compositions of pinoresinol from various plant species vary widely and optically pure pinoresinol has not yet been isolated from plants [11,13, 53]. Downstream lignans in the lignan biosynthetic pathway, such as dibenzylbutyrolactone lignans including matairesinol, are optically pure [11, 13, 53]. These facts unequivocally indicate that not only was... 

The lignans are a large group of plant phenolics, biosynthesized from the union of two phenylpropane molecules e.g., both matairesinol (Centaurea species, family Asteraceae) and podophyllotoxin Podophyllum peltatum, family Berberidaceae) are formed from the phenylpropane coniferyl alcohol. Lignans are essentially cinnamoyl alcohol dimers, though further cyclization and other structural modifications result in various structural types, e.g. dibenzylbutyrolactone and epoxy lignan. 

Xia et al (2000) proposed a biosynthetic route starting coniferyl alcohol (3.79) and subsequent formation of (+)-pinoresinol (3.82), as shown in Figure 3-12. The enzyme pinoresinol/lariciresionol reductase converts this compound to (+)-lariciresinol (3.87), and then to (-)-secoisolariciresionol (3.88). The enzyme secoisolariciresinol dehydrogenase converts (3.88) into (-)-matairesinol (3.83). The conversion from (-)-matairesinol (3.83) to podophyllotoxin (3.86) is likely to be similar to the route shown in Figure 3-11. 

The dibenzylbutyrolactone lignan matairesinol was also found to be an anti-HIV agent [110], although the sample used in this bioassay was not isolated from a Taxus species. Another dibenzylbutyrolactone lignan, arctigenin, as well as its unsubstituted benzyl derivative exhibited anti-HIV replication activity, with EC50 values of 0.16 and 22 ig/mL and therapeutic index values of 5 and 9.1, respectively [111]. 

Figure 4.8 Biosynthetic pathway from coniferyl alcohol to (—)-matairesinol. Enzymes and proteins Involved are (1) pinoresinol synthase (laccase + dirigent protein), (2) pinoresinol/lariciresinol synthase, (3) secoisolariciresinol dehydrogenase.

SDH in crude protein preparations from Daphne species (Thymelaeaceae) showed the preferential NADP-dependent formation of (-)-matairesinol, although the (-l-)-enantiomer is accumulated in the plant (Okunishi et at, 2004). 

Figure 4.9 Biosynthetic steps from matairesinol to yatein as shown by feeding experiments with Anthriscus sylvestris according to Sakakibara et al. (2003).

The alcohols formed from some cinnamic acid derivatives, namely /7-coumaryl alcohol, coniferyl alcohol (LI), and sinapyl alcohol (L2), commonly known as monolignols, undergo dimerization reactions that yield lignans such as (-l-)-pinoresinol (L3), (-l-)-sesamin (L4), (-)-matairesinol (L5), and podophyllotoxin (L6) (Fig. 13). Several thousand lignans are found to occur in nature. Lignins, the structural components of plant cell walls, are polymers of monolignols and/or lignans. 

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