Biological Activities of Soyasaponins and Their Genetic and Environmental Variations in Soybean

There is much evidence suggesting that compounds present in soybean can prevent cancer in many different organ systems. Especially, soybean is one of the most important source of dietary saponins, which have been considered as possible anticarcinogens to inhibit tumor development and major active components contributing to the cholesterol-towering effect. Also they were reported to inhibit of the infectivity of the AIDS virus (HIV) and the Epstein-Barr virus. The biological activity of saponins depend on their specific chemical structures. Various types of triterpenoid saponins are present in soy-bean seeds. Among them, group B soyasaponis were found as the primary soyasaponins present in soybean, and th e 2, 3-dihydro-2, 5-dihydroxy-6- methyl-4H-pyran-4-one(DDMP)-conjugated soyasaponin $\alpha\textrm{g}$, $\beta\textrm{g}$, and $\beta$ a were the genuine group B saponins, which have health benefits. On the other hand, group A saponins are responsible for the undesirable bitter and astringent taste in soybean. The variation of saponin composition in soybean seeds is explained by different combinations of 9 alleles of 4 gene loci that control the utilization of soyasapogenol glycosides as substrates. The mode of inheritance of saponin types is explained by a combination of co-dominant, dominant and recessive acting genes. The funtion of theses genes is variety-specific and organ specific. Therefore distribution of various saponins types was different according to seed tissues. Soyasaponin $\beta\textrm{g}$ was detected in both parts whereas $\alpha\textrm{g}$ and $\beta$ a was detected only in hypocotyls and cotyledons, respectively. Soyasaponins ${\gamma}$g and $\gamma\textrm{g}$ were minor saponin constituents in soybean. In case group A saponins were mostly detected in hypocotyls. Also, the total soyasaponin contents varied among different soy-bean varieties and concentrations in the cultivated soy-beans were 2-fold lower than in the wild soybeans. But the contents of soyasaponin were not so influenced by environmental effects. The composition and concentration of soyasaponins were different among the soy products (soybean flour, soycurd, tempeh, soymilk, etc.) depending on the processing conditions.

콩 Saponin의 생리활성 기능과 함량변이