Soyasaponins from soybeans

Figure 12.1 Basic structures of saponins (a) triterpene saponin QS-21 from Quillaya saponaria (b) steroidal saponin from Yucca schidigera (c) hederagenin glycoside from Sapindus mukurossi (d) soyasaponin I from soybean (Glycine max).

Glycine soya is a wild-type relative to the cultivated soybean (Glycine max). We isolated four known OGs, soyasaponins 1(1), II (3), III (6) and IV (8) from the aerial parts of this plant [37]. The results of hepatoprotective actions of these OGs are shown in Fig. (7) [37]. 

Hu et al. (2002) developed HPLG methods for quantitative determination of the group B soyasaponins. Saponin concentrations in 46 soybean varieties ranged from... 

Kim et al. (2006) reported changes in soybean composition, such as protein, lipid, free sugars, isoflavones, and saponins during soybean development and maturation in two Korean soybean cultivars. As soybean seed matured, total soy saponin concentration constantly decreased. The ratio of total isoflavone to total soyasaponin in the developing soybean increased from 0.06 to 1.31. Total soy saponin content was negatively correlated with isoflavone content. 

Figure 8.4 A partial diagram of the biosynthetic pathway to saponins dashed arrows represent multiple steps. Shown here arc examples of the two main classes of saponins found in soybeans. Soyasaponin Ab is an example of the bidesmosidic A saponins. Soyasaponin ag is an example of the DDMP-conjugated saponins that lead to B and H soyasaponins upon hydrolysis of the DDMP moiety from the triterpenoid backbone.

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