Lignans biological activity

Another group of natural products, namely the biologically active lignans of the aryltetralin series - for example, isopodophyllotoxone (2-59), picropodophyllone (2-60), and podophyllotoxin (2-61) (Scheme 2.13) [19] - have also been synthesized using a domino Michael/aldol process. 

Lignans are secondary plant metabolites possessing a variety of biological activities [1,2]. They are dimers of phenylpropenes, which are by definition connected between C(8) and C(8 ) [3]. Lignans are of great structural variety due to numerous potential oxidation states at the C(7)/C(7 ) and C(9)/C(9 ) positions, and to the possibility of aryl-aryl bond formation [1-3]. 

The morama bean is an excellent source of lignans (Holse et al., 2010). The content of secoisolariciresinol in morama beans (305-406 gg/100 g) is higher than that of soybean (13-273 gg/100 g) and peanut (333 pg/100 g) (Mazur et al., 1998). Likewise, the level of lariciresinol in morama beans (614-825 [tg/100 g) is higher than that of soybeans (287 gg/lOO g), while the level of pinoresinol in morama beans (21-23 gg/lOO g) is lower than the level in soybeans (446 gg/lOO g) (Penalvo et ah, 2004). These lignans can be converted by intestinal bacteria into enterolignans, which possess biological activities such as (anti) estrogenic and antioxidant action. Therefore, they may reduce the risk of certain types of cancers as well as cardiovascular diseases (Adlercreutz, 2007). 

Sonnenbichler, J., I. Sonnenbichler, and F. Scalera. 1998. Influence of the flavono-lignan silibinin of milk thistle on hepatocytes and kidney cells. In Lawsib, L. D. and R. Bauer (eds.) Phytomedicines of Europe, Chemistry and Biological Activity. American Chemical Society. Washington, D.C. p. 263-277. 

Keywords Biological Activity Biosynthesis Lignans Synthesis Taxaceae Taxus... 

The non-flavonoid phenolic constituents in wine are divided into hydroxybenzoic acids and hydroxycinnamic acids, volatile phenols, stilbenes and miscellaneous compounds (e.g. lignans and coumarins). Although non-colored, the non-flavonoid constituents are known to enhance and stabilize the color of red wines by intra- and intermolecular reactions. They furthermore contribute to wine flavor (volatile phenolic acids) and some of them (e.g. resveratrol) exhibit potent biological activities. 

The first chemical constituent was isolated from podophyllin in 1880 and named podophyllotoxin (97). A structure was proposed in 1932 and after some fine-tuning (98) was shown to be the lignan (60). As might be expected, the crude resin contains a variety of chemical types, including the flavonols quercetin and kaempferol (99). Although these other constituents undoubtedly have biological activity, it is the lignans that have received most attention and to which we shall devote the remainder of this section. 

A measure of the interest in the biological activity of these dibenzyl-butyrolactone lignans is evinced in the recent spate of publications dealing with the total synthesis of the natural optically active products. Again, the Stobbe condensation pathway (Scheme 9) has been usefully exploited for this purpose. In a series of papers, resolution of the intermediate hemisuccinate esters (433 by chiral bases has been described (54), as has asymmetric hydrogenation (55), and the optically active lignan products synthesized in the usual way (42 - 44 45). 

Distribution, classification, structural analysis, and biological activity of phenyl-propanoids (lignanes) of medicinal plants 03KPS87. 

Cyclic adenosine monophosphate (c-AMP) is a secondary messenger within cells. The c-AMP phosphodiesterase inhibition test is a useful means for screening biologically active compounds [65], Correlations of structure with inhibitory activity for lignans and their glucosides are shown in Tables 17.2-1 through 17.2-5. For... 

It is clear that lignans have a rich diversity of biological activities, which we have only begun to understand. As further studies reveal the mechanisms of their effects, benefits to human health should follow. 

WD MacRae, GHN Towers. Biological activity of lignans. Phytochem 23 1207-1200, 1984. 

S Nishibe. Structural elucidation and biological activities of phenylpropanoids, cou-marins and lignans from medicinal plants. In AU Rahman, ed. Studies in Natural Products Chemistry, vol. 5. Structure Elucidation (Part B). Amsterdam Elsevier, 1989, pp. 505-548. 

AD Mnir, ND Westcott. Flax seed lignans, stereochemistry, quantitation and biological activity. Proceedings of Phytochemical Society of North America for Phytochemicals in Human Health Protection, Nutrition and Plant Defense. Pullman, USA, 1998, pp. 29. 

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