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Saponins, which are glycosylated, represent a diverse group of biologically functional products in plants. In the present study, we investigated the effects of soyasaponin Ag, a secondary metabolite extracted from soybean, on α‑melanocyte-stimulating hormone (α‑MSH)‑induced melanin synthesis in B16F10 mouse melanoma cells and the underlying molecular mechanisms. To elucidate the mechanisms through which soyasaponin Ag inhibits melanin synthesis, we performed cellular tyrosinase activity assays and analyzed the expression of the melanogenesis‑related genes, tyrosinase, tyrosinase‑related protein (TRP)‑1 and TRP‑2. We demonstrated that soyasaponin Ag inhibited α‑MSH‑induced melanin synthesis in melanoma cells. Of note, soyasaponin Ag had no inhibitory effect on intracellular tyrosinase activity. However, soyasaponin Ag inhibited TRP‑2 expression in a dose‑dependent manner. Therefore, the depigmenting effect of soyasaponin Ag may be due to the inhibition of tyrosinase expression or the enhancement of tyrosinase degradation. Moreover, soyasaponin Ag did not exert any toxic on B16F10 mouse melanoma cells, suggesting that soyasaponin is a safe component for use in skin care cosmetic formulations that are used for skin whitening.

Saponins are a diverse group of biologically functional products in plants. Soyasaponins are usually glycosylated, which give rise to a wide diversity of structures and functions. In this study, we investigated the effects and molecular mechanism of soyasaponins Aa and Ab in regulating adipocyte differentiation and expression of adipogenic marker genes in 3T3-L1 adipocytes. Soyasaponins Aa and Ab dose-dependently inhibited the accumulation of lipids and the expression of adiponectin, adipocyte determination and differentiation factor 1/sterol regulatory element binding protein 1c, adipocyte fatty acid-binding protein 2, fatty acid synthase, and resistin in 3T3-L1 adipocytes. In addition, soyasaponins Aa and Ab suppressed the transcriptional activity of peroxisome proliferator-activated receptor γ (PPARγ) in HEK 293T cells. Furthermore, we confirmed that the expression of PPARγ and of CCAAT-enhancer-binding protein α (C/EBPα) was suppressed at both the mRNA and protein levels in 3T3-L1 adipocytes by treatment with soyasaponins Aa and Ab. Taken together, these findings indicate that soyasaponin Aa and Ab markedly inhibit adipocyte differentiation and expression of various adipogenic marker genes through the downregulation of the adipogenesis-related transcription factors PPARγ and C/EBPα in 3T3-L1 adipocytes., (Copyright © 2014 John Wiley & Sons, Ltd.)

New saponin components, Sg-6 saponins, have been recently reported from the seeds of wild soybean (Glycine soja) which may have specific health benefits. To evaluate the possible health benefits, a large amount of Sg-6 saponins are needed, but general group A acetyl saponins and new Sg-6 saponins are eluted in overlapping peaks by ordinal preparative high-performance liquid chromatography and/or open column methods. A new method is proposed in this report. This method includes (1) deacetylation of group A acetyl saponins in alkali condition with KOH, (2) precipitation of Sg-6 saponins in acid condition with HCl, (3) recovery of Sg-6 saponins with aqueous methanol from the precipitate, and (4) elution of Sg-6 saponins by preparative reverse-phase open column. With this method, from 450 g of wild soybean whole seed powder, about 1 g of Sg-6 saponins (mixture of six components) was clearly separated from other saponins with 61% recovery. [ABSTRACT FROM AUTHOR]

Hypocotyl saponin composition of 1,198 accessions of wild soybean ( Glycine soja) collected from China, Korea, Japan and Russia Far East was analyzed by thin-layer chromatography to determine polymorphic variation and geographical distribution. Eight common distinguishable saponin phenotypes were identified: Aa, Ab, AaBc, AbBc, Aa+α, Ab+α, AaBc+α and AbBc+α. The latter four +α type were new. All eight types were identified in China. Type Ab+α was absent in Korea. Types Ab+α and AbBc+α, and Aa+α and Ab+α were not identified in Japan and Russia far east, respectively. Six new triterpene saponins were detected in +α type via LC-PDA/MS/MS analyses. They were, tentatively, designated as H-αg, H-αa, I-αg, I-αa, J-αg and J-αa. These saponins were inherited together by a single dominant allele. A gene symbol Sg- 6 was assigned. Hence, the new saponins were collectively named as Sg-6 saponins. The frequency of Sg- 6 allele was 17.6 % in Chinese, 10.0 % in Korean and 1.0 % in Japanese wild soybean. The wild soybeans having Sg-6 saponins can be utilized in soybean breeding programs as well as in saponin biosynthesis studies in soybean. [ABSTRACT FROM AUTHOR]

Seed saponin composition of 3025 wild soybean ( Glycine soja Sieb. and Zucc.) accessions collected from nine regions of Korea was analysed by thin-layer chromatography to determine its polymorphic variation and geographical distribution and find mutants in saponin components. The saponin composition of seed hypocotyls was primarily divided into seven phenotypes, designated as Aa, Ab, AaBc, AbBc, Aa+α, AaBc+α and AbBc+α. The predominant phenotypes were AaBc (55%), Aa (33%), AaBc+α (7.5%) and Aa+α (3.3%). The frequencies of Ab, AbBc and AbBc+α were very low (0.3-0.5%). Codominant alleles Sg-1 a and Sg-1 b and dominant allele Sg-4 occupied 98.6, 1.1 and 63.3%, respectively. Alleles Sg-3 and Sg-5 were found to be dominant in all the analysed accessions except the mutants. Three accessions were discovered as mutants via LC- PDA/ MS/ MS. The accession CWS0115 did not produce saponin Aa and Ax, CWS2133 did not produce saponin Aa and Ab and CWS5095 did not produce any group A saponins. These newly determined mutants might be utilized in producing a new soybean variety with good taste as well as in biosynthetic studies. [ABSTRACT FROM AUTHOR]

Asparagus bean immature pods and seeds are popular as food products for healthy and functional nutrition. Gas chromatography with mass spectrometry was used to compare metabolomic profiles of seeds and pods yielded by old Chinese landraces and the modern cultivars 'Yunanskaya' and 'Sibirskiy razmer'. About 120 compounds were identified. The content of a majority among groups of compounds was higher in pods than in seeds. The amount of free amino acids in pods was 47 times higher, polyols and phytosterols 5 times higher, phenolics 4 times higher, and organic acids and saponins 3 times higher than in seeds. Differences were found in the relative content of compounds. Among phenolic compounds, the dominant one for seeds was protocatechuic acid, and for pods 4-hydroxycinnamic acid. Only polyols were identified in seeds, but pods additionally contained ethanolamine, phytol, and phytosphingosine. The ratio for nonsaturated/saturated fatty acids was 2.2 in seeds and 1.4 in pods. Seeds contained more stigmasterol, and pods more β-sitosterol. Aglycones of saponins were identified: cycloartenol in seeds, α- and β-amyrins in pods. Oligosaccharides dominated in both seeds and pods. Landraces manifested higher protein content in pods, while modern cultivars had pods with higher contents of organic acids, polyols, monosaccharides, and fatty acids. The results obtained confirm the high nutritional value of asparagus bean seeds and pods, and the prospects of their use in various diets. [ABSTRACT FROM AUTHOR]