Papers by Keyword: Saponins

Abstract: Microbial transformation of plant tubers for diosgenin production is an attractive clean method in industry. The purpose of this study was to evaluate the quality of the product obtained this way. Changes of saponins during the hydrolysis of Dioscorea zingiberensis tubers by Trichoderma reesei were investigated. Four main saponins were isolated from the plant herbs. Sugar chains, which connected to the C-3 hydroxyl group in saponins, were cleaved stepwisely by Trichoderma reesei from the terminal sugar until the aglycone was released. Diosgenin-3-O-β-D-glucose was a byproduct in this process. While, in the petrol extract of the microbial hydrolyzate, only diosgenin was detected. Melting point, IR spectra and ¹³C NMR spectroscopy were used to estimate the quality of the product. Diosgenin obtained from bioconversion showed similar characteristic to that from acid hydrolyzation, confirming microbial transformation was an effective method for diosgenin production.

Abstract: 50% (V/V) ethanol extract from laoying tea (Litsea coreana Level.) was fractionated by liquid-liquid partition using ethyl acetate, n-butanol and water, respectively. The activities of nitrite scavenging (NS) and nitrosamine formation inhibiting (NFI) of three different fractions have been investigated in vitro systems. In the above assays, all the fractions showed NS and NFI potentials to varying degrees. With regard to NS activity, fractions were effective in the order: ethyl acetate > n-butanol > water fraction. EC₅₀ values for inhibiting ability on nitrosamine formation for ethyl acetate, n-butanol and water fraction were 0.170, 0.554 and 0.725 mg/mL, respectively. Total flavonoids could be the major NS and NFI components and were in the order: ethyl acetate > n-butanol > water fraction. Based on EC₅₀ values, laoying tea especially ethyl acetate-soluble fraction may have a preventive effect against carcinogenesis induced by nitrosamines.