LC-ESI-MS based characterisation of isoflavones in soybean (Glycine max (L.) Merr.) from India.

A total of twenty-one soybean varieties were screened for their morphological characteristics followed by isoflavone content analysis by HPLC. The total isoflavone (TI) content was found within a wide range of 140.9-1048.6 µg/g of soy in different varieties. The highest isoflavone content was found in MAUS-2 followed by DS_2613 and lowest in Karunae (140.9 µg/g of soy). Various isoflavone forms were identified by LC-ESI+ MS. Significant differences in the isoflavone content were observed for all the aglycones and their glucoside conjugates as well as total daidzein, total genistein, total glycitein, and TI. A positive correlation between TI content and growth stages was found during the progression of seed development. An increase of 5.4-fold and 5.3-fold of TI concentration was observed for JS 335 and MAUS-2 respectively, from early to green mature (R5-R8) stage of bean development.

High yield production of folates from soybean callus cultures in response to elicitors.

Soybean (Indian variety, JS 335) callus growth and its folate content was sustained on Murashige and Skoog (MS) medium supplemented with optimized levels of auxins and cytokinins. Callus cultures exhibited moderate production of total folate. Callus growth was stimulated with highest biomass content of 21.3 g/L DW (24 days culture) on medium supplemented with 1.5 mg/L 2,4-dichlorophenoxy acetic acid (2,4-D) and 0.1 mg/L Kinetin (Kn). Total folate production was enhanced by an increase in indole-3-acetic acid (IAA) from 0.5 to 1.0 mg/L and decreased thereafter up to 1.5 mg/L. 2,4-D at 1.5 mg/L repressed the callus growth and also folate production. A concentration of 1.0 mg/L IAA and 0.2 mg/L Kn elicited folate production to a maximum total folate content of 323.82 µg/100 g DW. The results indicate that optimized medium for callus suspension cultures conceivably are applied for scale-up studies in bioreactors.

Isoflavone Augmentation in Soybean Cell Cultures Is Optimized Using Response Surface Methodology.

Glycine max contains potential therapeutic isoflavones, and its productivity in plants is considerably influenced worldwide by several biotic and abiotic factors. Optimization of soybean cell suspension cultures (Indian variety, JS 335) to maximize the cell growth and isoflavone production in the present study was performed using response surface methodology (RSM) with three independent variables of plant growth regulators, 2,4-dichlorophenoxyacetic acid (2,4-D), 1-naphthalene acetic acid (α-NAA), and kinetin (Kn). The maximum biomass achieved was 70.62 g/L dry weight (dw) using the optimized medium of 2.10 mg/L 2,4-D, 5.52 mg/L α-NAA, and 0.35 mg/L Kn supplemented in the Murashige and Skoog (MS) basal medium. The total isoflavone content of 38.59 mg/g of dw was obtained in the medium with optimized conditions of 1.33 mg/L 2,4-D, 1.76 mg/L α-NAA, and 0.15 mg/L Kn. In comparison to field-grown soybean seeds, the cell suspension cultures profoundly augmented isoflavone concentrations. The optimized conditions for both biomass and total isoflavone content were evaluated by superimposing the contour plots. The results suggested that the optimized medium of cell suspension cultures possibly be used for scale-up studies in bioreactors to offer a high content of bioactive isoflavones.

Isoflavone composition, phenol content, and antioxidant activity of soybean seeds from India and Bulgaria.

Isoflavone levels and isoflavone chemical composition in 11 cultivars of soybean, including 4 Indian and 7 genotypes of soybean grown in Bulgaria, were analyzed as determined by C 18 reversed phase high-performance liquid chromatography coupled with a photodiode array detector. Antioxidant activity of soybean extracts was assessed using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity, and total phenolic compounds (TPC) were determined by using Folin-Ciocalteu reagent. The range of total isoflavones (TI) was 558.2-1048.6 microg g (-1) of soy in Indian cultivars, and it was 627.9-1716.9 microg g (-1) of soy in the case of Bulgarian cultivars. The highest and lowest total isoflavone contents were observed for Maus-2 (1048.6 microg g (-1) of soy) and Hardee (558.2 microg g (-1) of soy), respectively, for the Indian cultivars, and they were observed for Boryara (1716.9 microg g (-1) of soy) and Line 5 (627.9 microg g (-1) of soy) for the Bulgarian genotypes. DPPH radical scavenging activity did not differ significantly among the cultivars and did not correlate with TI, whereas TPC correlated well with TI and weakly with DPPH. Malonylglucoside of all the aglycones, total genistein (TGin), and total daidzein (TDin) showed strong correlation with total isoflavones, whereas acetylglucoside and aglycone levels did not significantly correlate with total isoflavone. Profiling of soybean isoflavone is helpful in understanding the regulation of isoflavone biosynthesis for greater improved resistance of crops to disease and greater health benefits for humans. This comparative study of soybean cultivars grown in India and Bulgaria throws light on their composition and nutraceutical value.