• Natural Product Sciences
• /
• v.14 no.1
• /
• pp.37-46
• /
• 2008

From the 70% EtOH extract of the roots of Astragalus membranaceus (Leguminosae), fifteen saponins were isolated and identified as astragaloside I (1), isoastragaloside II (2), astragaloside II (3), agroastragaloside I (4), cyclogaleginoside B (5), cycloaraloside A (6), brachyoside B (7), agroastragaloside II (8), astragaloside III (9), astragaloside IV (10), astramembranoside A (11), astramembranoside B (12), cylocanthoside E (13), cyclounifolioside B (14) and azukisaponin V methyl ester (15) by spectroscopic methods. Ten compounds 1 - 3, 5 - 7, 9 - 11 and 14 have cycloastragenol as an aglycon, and four compounds 4, 8 , 12, and 13 have cyclocanthogenin as an aglycon. The hairy roots of A. membranaceus were shown to produce previously unreported cycloartane-type saponins such as agroastragalosides I (4) and II (8) and cycloastragenol $3-O-{\beta}-D-xyloside$ (5), together with the known saponins. This is the first report of these saponins (4, 5, and 8) from the intact plant. Although the occurrence of the oleanane-type triterpene saponin, azukisaponin V methyl ester (15), in Astragalus plants has been demonstrated by others, this is the first report of the azukisaponin V methyl ester (15) from the Astragalus plants.

• Journal of Microbiology and Biotechnology
• /
• v.29 no.12
• /
• pp.1882-1893
• /
• 2019

β-Glucosidases and β-xylosidases are two categories of enzymes that could cleave out non-reducing, terminal β-D-glucosyl and β-D-xylosyl residues with release of D-glucose and D-xylose, respectively. In this paper, two functional β-glucosidase Dth3 and β-xylosidase Xln-DT from Dictyoglomus thermophilum were heterologously expressed in E.coli BL21 (DE3). Dth3 and Xln-DT were relatively stable at 75℃ and were tolerant or even stimulated by glucose and xylose. Dth3 was highly tolerant to glucose with a K_i value of approximately 3 M. Meanwhile, it was not affected by xylose in high concentration. The activity of Xln-DT was stimulated 2.13-fold by 1 M glucose and 1.29-fold by 0.3 M xylose, respectively. Furthermore, the βglucosidase Dth3 and β-xylosidase Xln-DT showed excellent selectivity to cleave the outer C-6 and C-3 sugar moieties of ASI, which established an effective and green method to produce the more pharmacologically active CAG, an exclusive telomerase activator. We measured temperature, pH and dosage of enzyme using a single-factor experiment in ASI biotransformation. After optimization, the optimal reaction conditions were as follows: 75℃, pH 5.5, 1 U of Dth3 and 0.2 U of Xln-DT, respectively. Under the optimized conditions, 1 g/l ASI was transformed into 0.63 g/l CAG with a corresponding molar conversion of 94.5% within 3 h. This is the first report to use the purified thermostable and sugar-tolerant enzymes from Dictyoglomus thermophilum to hydrolyze ASI synergistically, which provides a specific, environment-friendly and cost-effective way to produce CAG.

• Herbal Formula Science
• /
• v.26 no.4
• /
• pp.319-327
• /
• 2018

Objectives : Astragali Radix is known as a perennial plant, and it is estimated that there may be differences in the contents and their components depending on the ages. The components of astragali radix may activate differently. Methods : The astragali radix components cultivated in Jecheon( one year ), Korea, Shanxi province( 7 years ), China, Inner Mongolia( 5 years) and Inner Mongolia ( 8 years ) were extracted with pure ethyl alcohol and identified the component molecules. The extracted components of astragali radix were measured the activity of Telomerase for confirmation of their Telomere lengths. Results : The cell activity has been shown the greatest contribution in astragali radix of Inner Mongolia(8 years). Although there is the difference in cell activity between the two products of the 5 and 7 years, the difference between the values was small and the 7 years product was slightly higher than 5 years product. Conclusions : Total Astragaloside contents were highest in the product of Inner Mongolia(8 years), followed by the 7 year product of Shanxi province. Especially, astragaloside and cycloastragenol (TA-65) among the astragali radix components have shown to be increased Telomerase activity in the DNA metabolism of the cells, and the efficacy depends on the ages of growth.