Modeling and spectroscopic investigation of U(VI) removal on porous amidoxime-functionalized metal organic framework derived from macromolecular carbohydrate.

The investigation of interaction mechanism of U(VI) selective removal on amidoxime-functionalized metal organic framework (i.e., UiO-66(Zr)-AO) derived from macromolecular carbohydrate is conducive to apply metal organic frameworks in actual environmental remediation. The batch experiments showed that UiO-66(Zr)-AO displayed the fast removal rate (equilibrium time of 0.5 h), high adsorption capacity (384.6 mg/g), excellent regeneration performance (<10 % decrease after three cycles) towards U(VI) removal due to the unprecedented chemical stability, large surface area and simple fabrication. U(VI) removal at different pH can be satisfactorily fitted by diffuse layer modeling with cation exchange at low pH and an inner-sphere surface complexation at high pH. The inner-sphere surface complexation was further demonstrated by X-ray absorption near edge structure (XANES) and extended X-ray absorption fine structure (EXAFS) analysis. These findings revealed that UiO-66(Zr)-AO can be an effective adsorbent to remove the radionuclides from aqueous solution, which is crucial for recycling of uranium resource and decreasing the uranium harm to the environment.

Flavonoid glycosides and alkaloids from the embryos of Nelumbo nucifera seeds and their antioxidant activity.

Chemical investigation of the embryos of Nelumbo nucifera afforded four new flavone C-glycosides, named nelumbosides A-D (1-4), together with nine known ones, comprising five flavonoids (5-9) and four alkaloids (10-13). The chemical structures of the new compounds were elucidated by 1D, 2D-NMR and HR-ESI-MS techniques, together with chemical methods. Nelumbosides A-D (1-4) are rarely present in naturally occurring flavone C-glycosides featuring a 4-hydroxystyrene unit connected to the flavonoid skeleton. Compounds 2-13 were evaluated for their antioxidant activity by ABTS and DPPH radical-scavenging assay. Among them, compounds 2, 6, 7 and 11 exhibited strong scavenging activity with SC50 values ranging from 12.07 to 25.68µM compared with the positive control l-ascorbic acid.

[Effect of exogenous calcium on seed germination and seedling physiological characteristics of Lycium ruthenium].

OBJECTIVE: In order to get the method for improving the salt resistance of Lycium ruthenium seeds and seedlings under NaCl stress, the seed germination and physiological characteristics of L. ruthenium seedlings was studied. METHOD: Several physiological indexes of L. ruthenium seeds under NaCl stress, such as the germination rate (Gr), germination vigor (Gv), germination index (Gi), vigor index (Vi), and relative salt damage rate were measured. Other indexes of the seedlings like relative water contents (RWC) , chlorophyll contents, soluble protein contents, electrolyte leakage, the contents of malondialdehyde (MDA), and peroxidase (POD) were also measured. RESULT: NaCl at lower concentration could promote the seed germination but inhibit the seed germination at higher concentration. After the treatment by CaCl2 at the different concentrations, all germination indexes were increased. With the increase of salt concentration, the relative water contents and the contents of chlorophyll were decreased, the content of MDA and electrolyte leakage were increased. The change trend of POD activity showed the first increase and then decrease with the increase of salt concentration, which was similar to that of the soluble protein. After the treatment by CaCl2, relative water contents, chlorophyll and POD activities were decreased more slowly, and also electrolyte leakage and MDA contents increased slowly. CONCLUSION: The CaCl2 could significantly alleviate the damages to the seeds and seedlings of L. ruthenium under NaCl stress, and promote the salt resistance to the seeds and seedlings of L. ruthenium.

[Five alkaloids from vine stems of Diploclisia affinis].

OBJECTIVE: To study alkaloid constituents of Diploclisia affinis. METHOD: The air-dried vine stems of D. affinis were extracted with 90% EtOH three times at room temperature. The EtOH extract was suspended in H2 O and adjusted to pH 2 with 5% HCl solution. After extracted with petroleum ether and CHCl3 successively, the aqueous fraction was adjusted to pH 9 with 10% NH3 x H2O and extracted with CHCl3 again to afford the total alkaloids fraction. The compounds were isolated through column chromatography from the total alkaloids fraction. Their structures were determined on the basis of spectral analysis (MS, 1H-NMR, 13C-NMR). RESULT: Five alkaloids was identified as reticuline (1), asimilobine (2), acutumine (3), dihydroxyprotoberberine (4), stepholidine (5), were isolated from the vine stems of D. affinis. CONCLUSION: All the compounds were obtained from D. affinis for the first time.

[Investigation on explovitage of Gentiana straminea].

Gentiopicrin contents in different organs, habitats and harvest time of Gentiana straminea cultivated at Gansu were determined by high performance liquid chromatography (HPLC). The results showed that the gentiopicrin contents in the plants growing for three years were slightly higher than those of two years, but the difference was not significant (P > 0.05). The average gentiopicrin contents in roots, stems and leaves were 13.30%, 2.95% and 2.24% respectively. Within the same growing year, gentiopicrin contents were decreased in stems and leaves but increased in roots with the harvest delay. The gentiopicrin contents also varied with lower to high altilude were 10.23%, 13.12% and 15.54% in Longxi, Kangle and Lintan county respectively. All these results indicated that the gentiopicrin contents in roots, stems and leaves of cultivated G. straminea were all conformable to the Codex criterion (2%). Considering both gentiopicrin yield and production cost, the biennial roots should be taken and harvested after October before soil frozen. However, the harvest should be predated by the end of August or the beginning of September only for stems and leaves. It is benefit for gentiopicrin accumulation in G. straminea when cultivated in high-altitude areas.